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Mazzotti, F.J., Cherkiss, M.S., Hart, K.M., Snow, R.W., Rochford, M.R., Dorcas, M.E. and Reed, R.N. (2011) Cold-induced mortality of invasive Burmese pythons in south Florida. Biological Invasions 13(1), 143-51.

  ABSTRACT
A recent record cold spell in southern Florida (2-11 January 2010) provided an opportunity to evaluate responses of an established population of Burmese pythons (Python molurus bivittatus) to a prolonged period of unusually cold weather. We observed behavior, characterized thermal biology, determined fate of radio-telemetered (n = 10) and non-telemetered (n = 104) Burmese pythons, and analyzed habitat and environmental conditions experienced by pythons during and after a historic cold spell. Telemetered pythons had been implanted with radio-transmitters and temperature-recording data loggers prior to the cold snap. Only one of 10 telemetered pythons survived the cold snap, whereas 59 of 99 (60%) non-telemetered pythons for which we determined fate survived. Body temperatures of eight dead telemetered pythons fluctuated regularly prior to 9 January 2010, then declined substantially during the cold period (9-11 January) and exhibited no further evidence of active thermoregulation indicating they were likely dead. Unusually cold temperatures in January 2010 were clearly associated with mortality of Burmese pythons in the Everglades. Some radio-telemetered pythons appeared to exhibit maladaptive behavior during the cold spell, including attempting to bask instead of retreating to sheltered refugia. We discuss implications of our findings for persistence and spread of introduced Burmese pythons in the United States and for maximizing their rate of removal.
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McCormick, P.V. (2011) Soil and periphyton indicators of anthropogenic water-quality changes in a rainfall-driven wetland. Wetlands Ecology and Management 19(1), 19-34.

  ABSTRACT
Surface soils and periphyton communities were sampled across an oligotrophic, soft-water wetland to document changes associated with pulsed inputs of nutrient- and mineral-rich canal drainage waters. A gradient of canal-water influence was indicated by the surface-water specific conductance, which ranged between 743 and 963 mu S cm(-1) in the canals to as low as 60 mu S cm(-1) in the rainfall-driven wetland interior. Changes in soil chemistry and periphyton taxonomic composition across this gradient were described using piecewise regressions models. The greatest increase in soil phosphorus (P) concentration occurred at sites closest to the canal while soil mineral (sulfur, calcium) concentrations increased most rapidly at the lower end of the gradient. Multiple periphyton shifts occurred at the lower end of the gradient and included; (1) a decline in desmids and non-desmid filamentous chlorophytes, and their replacement by a diatom-dominated community; (2) the loss of soft-water diatom indicator species and their replacement by hard-water species. Increased dominance by cyanobacteria and eutrophic diatom indicators occurred closer to the canals. Soil and periphyton changes indicated four zones of increasing canal influence across the wetland: (1) a zone of increasing mineral concentrations where soft-water taxa remained dominant; (2) a transition towards hard-water, oligotrophic diatoms as mineral concentrations increased further; (3) a zone of dominance by these hard-water species; (4) a zone of rapidly increasing P concentrations and dominance by eutrophic taxa. In contrast to conclusions drawn from routine water-chemistry monitoring, measures of chemical and biological change presented here indicate that most of this rainfall-driven peatland receives some influence from canal discharges. These changes are multifaceted and induced by shifts in multiple chemical constituents.
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McCormick, P.V., Harvey, J.W. and Crawford, E.S. (2011) Influence of Changing Water Sources and Mineral Chemistry on the Everglades Ecosystem. Critical Reviews in Critical Reviews in Environmental Science and Technology 41, 28-63.

  ABSTRACT
Human influences during the previous century increased mineral inputs to the Florida Everglades by changing the sources and chemistry of surface inflows. Biogeochemical responses to this enrichment include changes in the availability of key limiting nutrients such as P, the potential for increased turnover of nutrient pools due to accelerated plant decomposition, and increased rates of mercury methylation associated with sulfate enrichment. Mineral enrichment has also been linked to the loss of sensitive macrophyte species, although dominant Everglades species appear tolerant of a broad range of mineral chemistry. Shifts in periphyton community composition and function provide an especially sensitive indicator of mineral enrichment. Understanding the influence of mineral chemistry on Everglades processes and biota may improve predictions of ecosystem responses to ongoing hydrologic restoration efforts and provide guidelines for protecting remaining mineral-poor areas of this peatland.
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McElroy, T.C., Kandl, K.L. and Trexler, J.C. (2011) Temporal Population Genetic Structure of Eastern Mosquitofish in a Dynamic Aquatic Landscape. Journal of Heredity 102(6), 678-87.

  ABSTRACT
We analyzed the effect of periodic drying in the Florida Everglades on spatiotemporal population genetic structure of eastern mosquitofish (Gambusia holbrooki). Severe periodic drying events force individuals from disparate sources to mix in dry season relatively deep-water refuges. In 1996 (a wet year) and 1999 (a dry year), we sampled mosquitofish at 20 dry-season refuges distributed in 3 water management regions and characterized genetic variation for 10 allozyme and 3 microsatellite loci. In 1996, most of the ecosystem did not dry, whereas in 1999, many of our sampling locations were isolated by expanses of dried marsh surface. In 1996, most spatial genetic variation was attributed to heterogeneity within regions. In 1999, spatial genetic variation within regions was not significant. In both years, a small but significant amount of variation (less than 1% of the total variation) was partitioned among regions. Variance was consistently greater than zero among long-hydroperiod sites within a region, but not among short-hydroperiod sites within a region, where hydroperiod was measured as time since last marsh surface dry-down forcing fishes into local refuges. In 1996, all sites were in Hardy-Weinberg equilibrium. In 1999, we observed fewer heterozygotes than expected for most loci and sites suggesting a Wahlund effect arising from fish leaving areas that dried and mixing in deep-water refuges.
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McFadden, J.E., Hiller, T.L. and Tyre, A.J. (2011) Evaluating the efficacy of adaptive management approaches: Is there a formula for success? Journal of Environmental Management 92(5), 1354-59.

  ABSTRACT
Within the field of natural-resources management, the application of adaptive management is appropriate for complex problems high in uncertainty. Adaptive management is becoming an increasingly popular management-decision tool within the scientific community and has developed into two primary schools of thought: the Resilience-Experimentalist School (with high emphasis on stakeholder involvement, resilience, and highly complex models) and the Decision-Theoretic School (which results in relatively simple models through emphasizing stakeholder involvement for identifying management objectives). Because of these differences, adaptive management plans implemented under each of these schools may yield varying levels of success. We evaluated peer-reviewed literature focused on incorporation of adaptive management to identify components of successful adaptive management plans. Our evaluation included adaptive management elements such as stakeholder involvement, definitions of management objectives and actions, use and complexity of predictive models, and the sequence in which these elements were applied. We also defined a scale of degrees of success to make comparisons between the two adaptive management schools of thought. Our results include the relationship between the adaptive management process documented in the reviewed literature and our defined continuum of successful outcomes. Our data suggest an increase in the number of published articles with substantive discussion of adaptive management from 2000 to 2009 at a mean rate of annual change of 0.92 (r(2) = 0.56). Additionally, our examination of data for temporal patterns related to each school resulted in an increase in acknowledgement of the Decision-Theoretic School of thought at a mean annual rate of change of 0.02 (r(2) = 0.6679) and a stable acknowledgement for the Resilience-Experimentalist School of thought (r(2) = 0.0042; slope = 0.0013). Identifying the elements of successful adaptive management will be advantageous to natural-resources managers considering adaptive management as a decision tool.
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Michot, B., Meselhe, E.A., Riyera-Monroy, V.H., Coronado-Molina, C. and Twilley, R.R. (2011) A tidal creek water budget: Estimation of groundwater discharge and overland flow using hydrologic modeling in the Southern Everglades. Estuarine Coastal and Shelf Science 93(4), 438-48.

  ABSTRACT
Taylor Slough is one of the natural freshwater contributors to Florida Bay through a network of microtidal creeks crossing the Everglades Mangrove Ecotone Region (EMER). The EMER ecological function is critical since it mediates freshwater and nutrient inputs and controls the water quality in Eastern Florida Bay. Furthermore, this region is vulnerable to changing hydrodynamics and nutrient loadings as a result of upstream freshwater management practices proposed by the Comprehensive Everglades Restoration Program (CERP), currently the largest wetland restoration project in the USA. Despite the hydrological importance of Taylor Slough in the water budget of Florida Bay, there are no fine scale (similar to 1 km(2)) hydrodynamic models of this system that can be utilized as a tool to evaluate potential changes in water flow, salinity, and water quality. Taylor River is one of the major creeks draining Taylor Slough freshwater into Florida Bay. We performed a water budget analysis for the Taylor River area, based on long-term hydrologic data (1999-2007) and supplemented by hydrodynamic modeling using a MIKE FLOOD (DHI, http://dhigroup.com/) model to evaluate groundwater and overland water discharges. The seasonal hydrologic characteristics are very distinctive (average Taylor River wet vs. dry season outflow was 6 to 1 during 1999-2006) with a pronounced interannual variability of flow. The water budget shows a net dominance of through flow in the tidal mixing zone, while local precipitation and evapotranspiration play only a secondary role, at least in the wet season. During the dry season, the tidal flood reaches the upstream boundary of the study area during approximately 80 days per year on average. The groundwater field measurements indicate a mostly upwards-oriented leakage, which possibly equals the evapotranspiration term. The model results suggest a high importance of groundwater contribution to the water salinity in the EMER. The model performance is satisfactory during the dry season where surface flow in the area is confined to the Taylor River channel. The model also provided guidance on the importance of capturing the overland flow component, which enters the area as sheet flow during the rainy season. Overall, the modeling approach is suitable to reach better understanding of the water budget in the mangrove region. However, more detailed field data is needed to ascertain model predictions by further calibrating overland flow parameters.
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Miletto, M., Williams, K.H., N'Guessan, A.L. and Lovley, D.R. (2011) Molecular Analysis of the Metabolic Rates of Discrete Subsurface Populations of Sulfate Reducers. Applied and Environmental Microbiology 77(18), 6502-09.

  ABSTRACT
Elucidating the in situ metabolic activity of phylogenetically diverse populations of sulfate-reducing microorganisms that populate anoxic sedimentary environments is key to understanding subsurface ecology. Previous pure culture studies have demonstrated that the transcript abundance of dissimilatory (bi)sulfite reductase genes is correlated with the sulfate-reducing activity of individual cells. To evaluate whether expression of these genes was diagnostic for subsurface communities, dissimilatory (bi) sulfite reductase gene transcript abundance in phylogenetically distinct sulfate-reducing populations was quantified during a field experiment in which acetate was added to uranium-contaminated groundwater. Analysis of dsrAB sequences prior to the addition of acetate indicated that Desulfobacteraceae, Desulfobulbaceae, and Syntrophaceae-related sulfate reducers were the most abundant. Quantifying dsrB transcripts of the individual populations suggested that Desulfobacteraceae initially had higher dsrB transcripts per cell than Desulfobulbaceae or Syntrophaceae populations and that the activity of Desulfobacteraceae increased further when the metabolism of dissimilatory metal reducers competing for the added acetate declined. In contrast, dsrB transcript abundance in Desulfobulbaceae and Syntrophaceae remained relatively constant, suggesting a lack of stimulation by added acetate. The indication of higher sulfate-reducing activity in the Desulfobacteraceae was consistent with the finding that Desulfobacteraceae became the predominant component of the sulfate-reducing community. Discontinuing acetate additions resulted in a decline in dsrB transcript abundance in the Desulfobacteraceae. These results suggest that monitoring transcripts of dissimilatory (bi) sulfite reductase genes in distinct populations of sulfate reducers can provide insight into the relative rates of metabolism of different components of the sulfate-reducing community and their ability to respond to environmental perturbations.
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Miller, M.W., Pearlstine, E.V., Dorazio, R.M. and Mazzotti, F.J. (2011) Occupancy and Abundance of Wintering Birds in a Dynamic Agricultural Landscape. Journal of Wildlife Management 75(4), 836-47.

  ABSTRACT
Assessing wildlife management action requires monitoring populations, and abundance often is the parameter monitored. Recent methodological advances have enabled estimation of mean abundance within a habitat using presence-absence or count data obtained via repeated visits to a sample of sites. These methods assume populations are closed and intuitively assume habitats within sites change little during a field season. However, many habitats are highly variable over short periods. We developed a variation of existing occupancy and abundance models that allows for extreme spatio-temporal differences in habitat, and resulting changes in wildlife abundance, among sites and among visits to a site within a field season. We conducted our study in sugarcane habitat within the Everglades Agricultural Area southeast of Lake Okeechobee in south Florida. We counted wintering birds, primarily passerines, within 245 sites usually 5 times at each site during December 2006-March 2007. We estimated occupancy and mean abundance of birds in 6 vegetation states during the sugarcane harvest and allowed these parameters to vary temporally or spatially within a vegetation state. Occupancy and mean abundance of the common yellowthroat (Geothlypis trichas) was affected by structure of sugarcane and uncultivated edge vegetation (occupancy = 1.00 [95% CI = 0.96-1.00] and mean abundance = 7.9 [95% CI = 3.2-19.5] in tall sugarcane with tall edge vegetation versus 0.20 [95% CI = 0.04-0.71] and 0.22 [95% CI = 0.04-1.2], respectively, in short sugarcane with short edge vegetation in one half of the study area). Occupancy and mean abundance of palm warblers (Dendroica palmarum) were constant (occupancy = 1.00, 95% CI = 0.69-1.00; mean abundance = 18, 95% CI = 1-270). Our model may enable wildlife managers to assess rigorously effects of future edge habitat management on avian distribution and abundance within agricultural landscapes during winter or the breeding season. The model may also help wildlife managers make similar management decisions involving other dynamic habitats such as wetlands, prairies, and even forested areas if forest management or fires occur during the field season.
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Min, J.H., Paudel, R. and Jawitz, J.W. (2011) Mechanistic Biogeochemical Model Applications for Everglades Restoration: A Review of Case Studies and Suggestions for Future Modeling Needs. Critical Reviews in Environmental Science and Technology 41, 489-516.

  ABSTRACT
Mechanistic biogeochemical model applications for freshwater wetland ecosystems are reviewed with an emphasis on applications in the Florida Everglades. Two significant human impacts on the Everglades have been hydrologic alteration and phosphorus (P) enrichment. Thus, it is important for research conducted in support of Everglades restoration to integrate understanding of the coupled effects of hydrologic and biogeochemical processes. Models are tools that can facilitate such integration, but an important challenge in model development is determining the appropriate level of model complexity. Previous wetland biogeochemical and flow modeling efforts are categorized across the spectrum of complexity from empirical and spatially aggregated to mechanistic and spatially distributed. The focus of this review is on mercury and P, as these two elements represent major environmental concerns in this ecosystem. Two case studies of coupled hydrologic and biogeochemical modeling for P transport are described in further detail to illustrate the implications of different levels of model complexity. The case study simulation results on time series TP data revealed that the mechanistic biogeochemical model with more complexity did not guarantee significantly better simulation accuracy compared to the simpler one. It is concluded that the level of model complexity should be represented appropriately based on the modeling objectives, hypotheses to be tested, and data availability. Finally, better integration between data collection and model development is encouraged as cross-fertilization between these processes may stimulate improved system understanding.
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Mishra, B., O'Loughlin, E.J., Boyanov, M.I. and Kemner, K.M. (2011) Binding of Hg(II) to High-Affinity Sites on Bacteria Inhibits Reduction to Hg(0) by Mixed Fe(II/III) Phases. Environmental Science & Technology 45(22), 9597-603.

  ABSTRACT
Magnetite and green rust have been shown to reduce aqueous Hg(II) to Hg(0). In this study, we tested the ability of magnetite and green rust to reduce Hg(II) sorbed to 2 g . L(-1) of biomass (Bacillus subtilis), at high (50 mu M) and low (5 mu M) Hg loadings and at pH 6.5 and 5.0. At high Hg:biomass loading, where Hg(II) binding to biomass is predominantly through carboxyl functional groups, Hg L(III)-edge X-ray absorption spectroscopy showed reduction of Hg(II) to Hg(0) by magnetite. Reduction occurred within 2 h and 2 d at pH 6.5 and 5.0, respectively. At low Hg:biomass loading, where Hg(II) binds to biomass via sulfhydryl functional groups, Hg(II) was not reduced by magnetite at pH 6.5 or 5.0 after 2 months of reaction. Green rust, which is generally a stronger reductant than magnetite, reduced about 20% of the total Hg(II) bound to biomass via sulfhydryl groups to Hg(0) in 2 d. These results suggest that He binding to carboxyl groups does not significantly inhibit the reduction of He by magnetite. However, the binding of Hg(II) to biomass via sulfhydryl groups severely inhibits the ability of mixed Fe(II/III) in phases like magnetite and green rust to reduce Hg(II) to Hg(0). The mobility of heavy metal contaminants in aquatic and terrestrial environments is greatly influenced by their speciation, especially their oxidation state. In the case of Hg, reduction of Hg(II) to Hg(0) can increase Hg mobility because of the volatility of Hg(0). Since Hg is typically present in aquatic and terrestrial systems at low concentrations, binding of Hg to high-affinity sites on bacteria could have important implications for the potential reduction of Hg(II) to Hg(0) and the overall mobility of Hg in biostimulated subsurface environments.
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Morrison, W.E. and Hay, M.E. (2011) Feeding and growth of native, invasive and non-invasive alien apple snails (Ampullariidae) in the United States: Invasives eat more and grow more. Biological Invasions 13(4), 945-55.

  ABSTRACT
The United States hosts one native and five non-native species of aquatic apple snails (Ampullariidae). All are currently found in or around the Everglades in Florida. Two of these introduced species have devastated wetlands in Southeast Asia, but little is known about how they may impact the Everglades. To evaluate potential impacts of introduced apple snails relative to the native species, we investigated plant species preference, consumption rates, growth rates, and growth efficiencies in five introduced and the single native species across eight native macrophytes common in the Everglades. Three of the non-native snails are invasive, one has shown no tendency to expand, and one appears to have minimal direct impact on macrophytes due to its diet. All snails exhibited similar feeding preferences, with Utricularia sp. being the most preferred, Bacopa caroliniana, Sagittaria latifolia, and Nymphaea odorata being of intermediate preference, and Eleocharis cellulosa, Pontederia cordata, Panicum hemitomon and Typha sp. being least preferred (avoided as foods). Consumption and growth was minimal for P. diffusa on all macrophytes. On Utricularia sp. and Bacopa caroliniana, the invasive species Pomacea insularum and P. canaliculata tended to eat more, grow more, and have higher conversion efficiencies than the native P. paludosa or the non-invasive P. haustrum. These contrasts were more often significant for P. insularum than for P. canaliculata. The greater rates of expansion by the invasive species may derive from their enhanced feeding and growth rates.
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Muneepeerakul, C.P., Muneepeerakul, R., Miralles-Wilhelm, F., Rinaldo, A. and Rodriguez-Iturbe, I. (2011) Dynamics of wetland vegetation under multiple stresses: a case study of changes in sawgrass trait, structure, and productivity under coupled plant-soil- microbe dynamics. Ecohydrology 4(6), 757-90.

  ABSTRACT
This paper quantifies wetland vegetation dynamics under drought, waterlogging, shading, and nutrient stresses within the coupled plant-soil-microbe system. A plant is characterized by three independent traits, namely leaf nitrogen (N) content, specific leaf area (SLA), and allometric carbon (C) allocation to rhizome storage, while plant growth is modelled through a dynamic plant allocation scheme. The modelling of N focuses on the internal cycle in which the aerobic and anaerobic processes are determined by the dynamics of oxygen controlled by plants, microbial aerobic processes, and hydrologic dynamics. The dynamics of water levels and soil moisture are described by a simple hydrologic model with stochastic rainfall and are decoupled from the plant-soil-microbe dynamics. Using the model to investigate the dynamics of sawgrass, the results, which are consistent with field observations in the southern Everglades, indicate that SLA decreases with increasing anaerobic condition. The lower SLA maintains high stomatal opening, while at the same time prevents cavitational collapse when sawgrass lowers its root:shoot ratio to reduce C cost in root anaerobic respiration. Given a naturally low but not too scarce level of phosphorus, net N mineralization is higher in the wetter hydrologic regimes because the increase in anaerobic decomposition and N mineralization compensate for the decline in those of aerobes; and the slower growing, more nitrogen efficient anaerobes compete less with plants for N. The optimal traits are the results of several counteracting trends of trade-offs in C and N economy differently influenced by trait combinations in different wetland environments.
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Mustafa, A. and Scholz, M. (2011) Nutrient Accumulation in Typha latifolia L. and Sediment of a Representative Integrated Constructed Wetland. Water Air and Soil Pollution 219(1-4), 329-41.

  ABSTRACT
This paper investigates the role of plants and sediment in removing nutrients from wastewater being treated in a representative integrated constructed wetland (ICW). It discusses the role of plants and sediment in removing nutrients from an ICW treating agricultural wastewater for more than 7 years. More nitrogen and phosphorus were stored in wetland soils and sediments than in plants. The first cell had the highest depth of sediment accumulation (45 cm). Over the 7-year operation period, the accretion rate was approximately 6.4 cm/year. With respect to maintenance, desludging of the first wetland cell of the ICW system appears to be necessary in 2011. An average of 10,000 m(3) per year of wastewater entered the ICW. Approximately 74% (780 kg) of the phosphorus and 52% (5,175 kg) of the nitrogen that entered the wetland system was stored in the wetland soils and sediments. Plants stored a small fraction of nutrients compared to soils (< 1% for both nitrogen and phosphorus). This study demonstrates that soils within a mature wetland system are an important and sustainable nutrient storage component.
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Muthuraj, B. and Jesudasan, R.W.A. (2011) Impact of climatic factors on leaf roll-inducing mite, Floracarus perrepae (Acari: Eriophyidae) feeding on the Old World climbing fern, Lygodium microphyllum (Pteridophyta: Lygodiaceae). International Journal of Acarology 37(4), 325-30.

  ABSTRACT
The Old World climbing fern Lygodium microphyllum is native to Asia but has become a category I weed in the Everglades ecosystem of Florida, USA. The eriophyid mite Floracarus perrepae induces leaf rolls on the subpinnae of L. microphyllum through its feeding and has been found throughout the year in the host plant, with varying prevalence. The impact of weather parameters such as temperature, rainfall, and relative humidity on the phenology of leaf rolls and mite density has been studied under natural conditions at two locations: Thomaiyarpuram (Nagercoil, Tamil Nadu, India) and Ithikkara (Quilon, Kerala, India). The trend of % leaf roll at both the sites was high during the months of August, September, October, and December in both study years. The density of mites per leaf roll varied considerably during the study, peaking in August 2003 (44.2 and 33.1 mites per roll at Nagercoil and Quilon, respectively). Statistical analysis revealed that there was no significant interaction or impact between weather variables and the % leaf roll (Nagercoil, r=0.077 and Quilon, r=0.025) but in Quilon the rainfall played a role in reducing the mite population. However, a significant positive correlation was found between mite density and abiotic factors (Nagercoil r=0.6457; Quilon r=0.9514), i.e. all the abiotic factors such as temperature, rainfall and relative humidity can influence mite density.
top   full text Nagy, K.L., Manceau, A., Gasper, J.D., Ryan, J.N. and Aiken, G.R. (2011) Metallothionein-Like Multinuclear Clusters of Mercury(II) and Sulfur in Peat. Environmental Science & Technology 45(17), 7298-306.
  ABSTRACT
Strong mercury(II)-sulfur (Hg-SR) bonds in natural organic matter, which influence mercury bioavailability, are difficult to characterize. We report evidence for two new Hg-SR structures using X-ray absorption spectroscopy in peats from the Florida Everglades with added Hg. The first, observed at a mole ratio of organic reduced S to Hg (S(red)/Hg) between 220 and 1140, is a Hg(4)S(x), type of cluster with each Hg atom bonded to two S atoms at 2.34 angstrom and one Sat 2.53 angstrom, and all Hg atoms 4.12 angstrom apart. This model structure matches those of metal-thiolate clusters in metallothioneins, but not those of HgS minerals. The second, with one S atom at 2.34 angstrom and about six C atoms at 2.97 to 3.28 angstrom, occurred at S(red)/Hg between 0.80 and 4.3 and suggests Hg binding to a thiolated aromatic unit. The multinuclear Hg cluster indicates a strong binding environment to cysteinyl sulfur that might impede methylation. Along with a linear Hg(SR)(2) unit with Hg-S bond lengths of 2.34 angstrom at S(red)/Hg of about 10 to 20, the new structures support a continuum in Hg-SR binding strength in natural organic matter.
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Naja, G.M., Rivero, R., Davis, S.E. and Van Lent, T. (2011) Hydrochemical Impacts of Limestone Rock Mining. Water Air and Soil Pollution 217(1-4), 95-104.

  ABSTRACT
Hydrochemical impacts of shallow rock industrial-scale mining activities close to sensitive constructed and natural wetlands were investigated. The shallow surficial groundwater and surface water in the Everglades Agricultural Area (EAA) were characterized. The chemical composition of sulfate and chloride in groundwater increased with depth. The average concentration of chloride averaged 182 mg L(-1) at 6 m deep and increased gradually to 1,010 mg L(-1) at 15 m deep, 1,550 mg L(-1) at 30 m deep to reach 7,800 mg L(-1) at 60 m deep. Comparatively, the surface water chemical composition in the surrounding areas showed much lower cationic and anionic charge. The specific conductivity and total dissolved solids of surface water in canals (close to the mining operations) are < 900 mu S cm(-1) and < 600 mg L(-1), respectively, which should be compared to groundwater quality in wells from the EAA area (> 2,000 mu S cm(-1) and > 1,000 mg L(-1), respectively). A steady-state groundwater fluid flow and transient solute transport modeling exercise was conducted to estimate surface/groundwater interactions. The modeled solute in surface water was transported downgradient through groundwaters, migrated approximately 30 m from the source area (after 5 years of operation), and needed more than 116 years to dissipate. An upward transport was also identified whereby chloride and sulfate, naturally present in deeper groundwaters, migrated approximately 200 m (after 1 year of mining) into the pristine shallower aquifer and reached the surface water with a concentration equaling 80% of that in the rock mining pit.
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Newman, S. and Hagerthey, S.E. (2011) Water Conservation Area 1: A Case Study of Hydrology, Nutrient, and Mineral Influences on Biogeochemical Processes. Critical Reviews in Environmental Science and Technology 41, 702-22.

  ABSTRACT
At the northern tip of the remnant Everglades, Water Conservation Area 1 is the only remaining softwater peatland in the ecosystem. The spatial pattern of altered hydrology, anthropogenic nutrient, and mineral enrichment is distinct, with biogeochemical processes driven by a north-south hydrologic gradient combined with west-east nutrient and mineral gradients. Hydrology effects on carbon cycling are evident by the 10-20% lower average soil carbon concentrations in the drier oxidizing regions of the north, compared with the ponded environment in the south. Elevated nutrient and mineral inputs also increase carbon loss by causing changes in species composition, substrate quality, and microbial activity. Water management may be optimized to limit mineral intrusion and peat oxidation, while also meeting water depth requirements for habitat and wildlife, such that ecological tradeoffs are minimized.
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Obaza, A., DeAngelis, D.L. and Trexler, J.C. (2011) Using data from an encounter sampler to model fish dispersal. Journal of Fish Biology 78(2), 495-513.

  ABSTRACT
A method to estimate speed of free-ranging fishes using a passive sampling device is described and illustrated with data from the Everglades, U.S.A. Catch per unit effort (CPUE) from minnow traps embedded in drift fences was treated as an encounter rate and used to estimate speed, when combined with an independent estimate of density obtained by use of throw traps that enclose 1 m2 of marsh habitat. Underwater video was used to evaluate capture efficiency and species-specific bias of minnow traps and two sampling studies were used to estimate trap saturation and diel-movement patterns; these results were used to optimize sampling and derive correction factors to adjust species-specific encounter rates for bias and capture efficiency. Sailfin mollies Poecilia latipinna displayed a high frequency of escape from traps, whereas eastern mosquitofish Gambusia holbrooki were most likely to avoid a trap once they encountered it; dollar sunfish Lepomis marginatus were least likely to avoid the trap once they encountered it or to escape once they were captured. Length of sampling and time of day affected CPUE; fishes generally had a very low retention rate over a 24 h sample time and only the Everglades pygmy sunfish Elassoma evergladei were commonly captured at night. Dispersal speed of fishes in the Florida Everglades, U.S.A., was shown to vary seasonally and among species, ranging from 0 center dot 05 to 0 center dot 15 m s-1 for small poeciliids and fundulids to 0 center dot 1 to 1 center dot 8 m s-1 for L. marginatus. Speed was generally highest late in the wet season and lowest in the dry season, possibly tied to dispersal behaviours linked to finding and remaining in dry-season refuges. These speed estimates can be used to estimate the diffusive movement rate, which is commonly employed in spatial ecological models.
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Obeysekera, J., Kuebler, L., Ahmed, S., Chang, M.L., Engel, V., Langevin, C., Swain, E. and Wan, Y.S. (2011) Use of Hydrologic and Hydrodynamic Modeling for Ecosystem Restoration. Critical Reviews in Environmental Science and Technology 41, 447-88.

  ABSTRACT
Planning and implementation of unprecedented projects for restoring the greater Everglades ecosystem are underway and the hydrologic and hydrodynamic modeling of restoration alternatives has become essential for success of restoration efforts. In view of the complex nature of the South Florida water resources system, regional-scale (system-wide) hydrologic models have been developed and used extensively for the development of the Comprehensive Everglades Restoration Plan. In addition, numerous subregional-scale hydrologic and hydrodynamic models have been developed and are being used for evaluating project-scale water management plans associated with urban, agricultural, and inland costal ecosystems. The authors provide a comprehensive summary of models of all scales, as well as the next generation models under development to meet the future needs of ecosystem restoration efforts in South Florida. The multiagency efforts to develop and apply models have allowed the agencies to understand the complex hydrologic interactions, quantify appropriate performance measures, and use new technologies in simulation algorithms, software development, and GIS/database techniques to meet the future modeling needs of the ecosystem restoration programs.
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Ogram, A., Chauhan, A., Inglett, K.S., Jayachandran, K. and Newman, S. (2011) Microbial Ecology and Everglades Restoration. Critical Reviews in Environmental Science and Technology 41, 289-308.

  ABSTRACT
Much of the activity proposed for Everglades restoration is associated with processes either controlled by or impacting microbial activities. The authors summarize some recent studies related to restoration objectives conducted in a range of Everglades environments, including marsh and tree island soils, and periphyton assemblages. These studies include research related to the development of restoration performance measures based on nutrient status, analysis of controls on organic matter decomposition that may have lead to the development of soil microtopography responsible for water flow paths, microbial drivers of methane production, and analysis of the architecture of periphyton mats and their potential use in nutrient removal treatment strategies. The authors highlight the complexity inherent in microbial control of biogeochemistry, as well as the multitude of approaches that are needed to explain these interactions. Compared to larger ecosystem attributes such as vegetation community structure, the structure and function of microbial communities have remained elusive, and significantly more research into this area is essential to ensure that restoration goals are accomplished.
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Orem, W., Gilmour, C., Axelrad, D., Krabbenhoft, D., Scheidt, D., Kalla, P., McCormick, P., Gabriel, M. and Aiken, G. (2011) Sulfur in the South Florida Ecosystem: Distribution, Sources, Biogeochemistry, Impacts, and Management for Restoration. Critical Reviews in Environmental Science and Technology 41, 249-88.

  ABSTRACT
Sulfur is broadly recognized as a water quality issue of significance for the freshwater Florida Everglades. Roughly 60% of the remnant Everglades has surface water sulfate concentrations above 1 mg l-1, a restoration performance measure based on present sulfate levels in unenriched areas. Highly enriched marshes in the northern Everglades have average sulfate levels of 60 mg l-1. Sulfate loading to the Everglades is principally a result of land and water management in South Florida. The highest concentrations of sulfate (average 60-70 mg l-1) in the ecosystem are in canal water in the Everglades Agricultural Area (EAA). Potential sulfur sourcesin the watershed are many, but geochemical data and a preliminary sulfur mass balance for the EAA are consistent with sulfur presently used in agricultural, and sulfur released by oxidation of organic EAA soils (including legacy agricultural applications and natural sulfur) as the primary sources of sulfate enrichment in the EAA canals. Sulfate loading to the Everglades increases microbial sulfate reduction in soils, leading to more reducing conditions, greater cycling of nutrients in soils, production of toxic sulfide, and enhanced methylmercury (MeHg) production and bioaccumulation. Wetlands are zones of naturally high MeHg production, but the combination of high atmospheric mercury deposition rates in South Florida and elevated sulfate loading leads to increased MeHg production and MeHg risk to Everglades wildlife and human consumers. Sulfate from the EAA drainage canals penetrates deep into the Everglades Water Conservation Areas, and may extend into Everglades National Park. Present plans to restore sheet flow and to deliver more water to the Everglades may increase overall sulfur loads to the ecosystem, and move sulfate-enriched water further south. However, water management practices that minimize soil drying and rewetting cycles can mitigate sulfate release during soil oxidation. A comprehensive Everglades restoration strategy should include reduction of sulfur loads as a goal because of the many detrimental impacts of sulfate on the ecosystem. Monitoring data show that the ecosystem response to changes in sulfate levels is rapid, and strategies for reducing sulfate loading may be effective in the near term. A multifaceted approach employing best management practices for sulfur in agriculture, agricultural practices that minimize soil oxidation, and changes to stormwater treatment areas that increase sulfate retention could help achieve reduced sulfate loads to the Everglades, with resulting benefits.
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Osborne, T.Z., Bruland, G.L., Newman, S., Reddy, K.R. and Grunwald, S. (2011a) Spatial distributions and eco-partitioning of soil biogeochemical properties in the Everglades National Park. Environmental Monitoring and Assessment 183(1-4), 395-408.

  ABSTRACT
Large-scale ecosystem restoration efforts, such as those in the Florida Everglades, can be long-term and resource intensive. To gauge success, restoration efforts must have a means to evaluate positive or negative results of instituted activities. Edaphic properties across the Everglades landscape have been determined to be a valuable metric for such evaluation, and as such, a baseline condition from which to make future comparisons and track ecosystem response is necessary. The objectives of this work were to document this baseline condition in the southern most hydrologic unit of the Everglades, Everglades National Park (ENP), and to determine if significant eco-partitioning of soil attributes exists that would suggest the need to focus monitoring efforts in particular eco-types within the ENP landscape. A total of 342 sites were sampled via soil coring and parameters such as total phosphorus (TP), total nitrogen (TN), total carbon (TC), total calcium, total magnesium, and bulk density were measured at three depth increments in the soil profile (floc, 0-10 cm, and 10-20 cm). Geostatistical analysis and GIS applications were employed to interpolate site-specific biogeochemical properties of soils across the entire extent of the ENP. Spatial patterns and eco-type comparisons suggest TC and TN to be highest in Shark River Slough (SRS) and the mangrove interface (MI), following trends of greatest organic soil accumulation. However, TP patterns suggest greatest storages in MI, SRS, and western marl and wet prairies. Eco-partitioning of soil constituents suggest local drivers of geology and hydrology are significant in determining potential areas to focus monitoring for future change detection.
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Osborne, T.Z., Newman, S., Scheidt, D.J., Kalla, P.I., Bruland, G.L., Cohen, M.J., Scinto, L.J. and Ellis, L.R. (2011b) Landscape Patterns of Significant Soil Nutrients and Contaminants in the Greater Everglades Ecosystem: Past, Present, and Future. Critical Reviews in Environmental Science and Technology 41, 121-48.

  ABSTRACT
The primary goal of this review and synthesis effort is to summarize present landscape patterns of key soil constituents such as carbon (C), phosphorus (P), sulfur (S), and mercury (Hg), all of which are of historical and present interest with respect to Everglades restoration. A secondary goal is to highlight the importance of landscape scale monitoring and assessment of soils in the Everglades Protection Area (EPA) with respect to present and future restoration efforts. Review of present information derived from the two independent landscape scale studies revealed significant patterns of soil thickness, organic matter, and P in the EPA. Two soil constituents of concern, Hg (biological toxicity) and S (linked to increased P cycling), also exhibit spatial patterns at the landscape scale, suggesting a need for focused efforts of restoration. Significant patterns of soil enrichment and change suggest a dynamic interaction between environmental stressors and soil biogeochemical properties across the landscape. Trends and patterns at the landscape scale in the EPA suggest that landscape scale monitoring and assessment is necessary and critical to determining the success of restoration efforts. However, several key questions, surrounding appropriate temporal and spatial sampling scales, the standardization of sampling methods, and the significance of short range variability must be addressed to facilitate future landscape scale assessment efforts.
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Osland, M.J., Gonzalez, E. and Richardson, C.J. (2011) Restoring diversity after cattail expansion: disturbance, resilience, and seasonality in a tropical dry wetland. Ecological Applications 21(3), 715-28.

  ABSTRACT
As the human footprint expands, ecologists and resource managers are increasingly challenged to explain and manage abrupt ecosystem transformations (i.e., regime shifts). In this study, we investigated the role of a mechanical disturbance that has been used to restore and maintain local wetland diversity after a monotypic regime shift in northwestern Costa Rica [specifically, an abrupt landscape-scale cattail (Typha) expansion]. The study was conducted in Palo Verde Marsh (Palo Verde National Park; a RAMSAR Wetland of International Importance), a seasonally flooded freshwater wetland that has historically provided habitat for large populations of wading birds and waterfowl. A cattail (T. domingensis) expansion in the 1980s greatly altered the plant community and reduced avian habitat. Since then, Typha has been managed using a form of mechanical disturbance called fangueo (a Spanish word, pronounced "fahn-gay-yo" in English). We applied a Typha removal treatment at three levels (control, fangueo, and fangueo with fencing to exclude cattle grazing). Fangueo resulted in a large reduction in Typha dominance (i.e., decreased aboveground biomass, ramet density, and ramet height) and an increase in habitat heterogeneity. As in many ecosystems that have been defined by multiple and frequent disturbances, a large portion of the plant community regenerated after disturbance (via propagule banking) and fangueo resulted in a more diverse plant community that was strongly dictated by seasonal processes (i.e., distinct wet-and dry-season assemblages). Importantly, the mechanical disturbance had no apparent short-term impact on any of the soil properties we measured (including bulk density). Interestingly, low soil and foliar N:P values indicate that Palo Verde Marsh and other wetlands in the region may be nitrogen limited. Our results quantify how, in a cultural landscape where the historical disturbance regime has been altered and diversity has declined, a mechanical disturbance in combination with seasonal drought and flooding has been used to locally restrict a clonal monodominant plant expansion, create habitat heterogeneity, and maintain plant diversity.
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Pahl-Wostl, C., Jeffrey, P., Isendahl, N. and Brugnach, M. (2011) Maturing the New Water Management Paradigm: Progressing from Aspiration to Practice.
Water Resources Management 25(3), 837-56.

  ABSTRACT
Over the past decade a series of major revisions to the generation and use of knowledge in the context of natural resources management has started to undermine basic assumptions on which traditional approaches to water management were based. Limits to our ability to predict and control water systems have become evident and both complexity and human dimensions are receiving more prominent consideration. Many voices in science and policy have advocated a paradigm shift in water management-both from a normative (it should happen) and a descriptive (it happens, and how) perspective. This paper summarizes the major arguments that have been put forward to support the need for a paradigm shift and the direction it might take. Evidence from the fields of science, policy, and management is used to demonstrate a lacuna in the translation of political rhetoric into change at the operational level. We subsequently argue that learning processes and critical reflection on innovative management approaches is a central feature of paradigm change and that contributions from psychology which emphasise the roles of frames and mental models can be usefully applied to paradigm change processes. The paper concludes with recommendations to facilitate debate and test alternative approaches to scientific inquiry and water management practice leading to critical reflection and analysis.
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Parkos, J.J., Ruetz, C.R. and Trexler, J.C. (2011) Disturbance regime and limits on benefits of refuge use for fishes in a fluctuating hydroscape. Oikos 120(10), 1519-30.

  ABSTRACT
Refuge habitats increase survival rate and recovery time of populations experiencing environmental disturbance, but limits on the ability of refuges to buff er communities are poorly understood. We hypothesized that importance of refuges in preventing population declines and alteration in community structure has a non-linear relationship with severity of disturbance. In the Florida Everglades, alligator ponds are used as refuge habitat by fishes during seasonal drying of marsh habitats. Using an 11-year record of hydrological conditions and fish abundance in 10 marshes and 34 alligator ponds from two regions of the Everglades, we sought to characterize patterns of refuge use and temporal dynamics of fish abundance and community structure across changing intensity, duration, and frequency of drought disturbance. Abundance in alligator ponds was positively related to refuge size, distance from alternative refugia (e. g. canals), and abundance in surrounding marsh prior to hydrologic disturbance. Variables negatively related to abundance in alligator ponds included water level in surrounding marsh and abundance of disturbance-tolerant species. Refuge community structure did not differ between regions because the same subset of species in both regions used alligator ponds during droughts. When time between disturbances was short, fish abundance declined in marshes, and in the region with the most spatially extensive pattern of disturbance, community structure was altered in both marshes and alligator ponds because of an increased proportion of species more resistant to disturbance. These changes in community structure were associated with increases in both duration and frequency of hydrologic disturbance. Use of refuge habitat had a modal relationship with severity of disturbance regime. Spatial patterns of response suggest that decline in refuge use was because of decreased effectiveness of refuge habitat in reducing mortality and providing sufficient time for recovery for fish communities experiencing reduced time between disturbance events.
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Pascarella, J.B. and Waddington, K. (2011) A description of the male of Hylaeus graenicheri Mitchell (Hymenoptera: Colletidae). Journal of Apicultural Research 50(4), 316-20.

  ABSTRACT
The male of the Florida endemic bee species Hylaeus graenicheri is described from specimens collected in Everglades National Park, Florida. The male has genitalia typical of the subgenus Hylaeana. The species is noted for its small size, yellow and brown colour, and lack of a supraclypeal maculation and an incomplete clypeal maculation. Figures and photos are provided to help with identification.
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Pisani, O., Yamashita, Y. and Jaffe, R. (2011) Photo-dissolution of flocculent, detrital material in aquatic environments: Contributions to the dissolved organic matter pool. Water Research 45(13), 3836-44.

  ABSTRACT
This study shows that light exposure of flocculent material (floc) from the Florida Coastal Everglades (FCE) results in significant dissolved organic matter (DOM) generation through photo-dissolution processes. Floc was collected at two sites along the Shark River Slough (SRS) and irradiated with artificial sunlight. The DOM generated was characterized using elemental analysis and excitation emission matrix fluorescence coupled with parallel factor analysis. To investigate the seasonal variations of DOM photo-generation from floc, this experiment was performed in typical dry (April) and wet (October) seasons for the FCE. Our results show that the dissolved organic carbon (DOC) for samples incubated under dark conditions displayed a relatively small increase, suggesting that microbial processes and/or leaching might be minor processes in comparison to photo-dissolution for the generation of DOM from floc. On the other hand, DOC increased substantially (as much as 259 mgC gC(-1)) for samples exposed to artificial sunlight, indicating the release of DOM through photo-induced alterations of floc. The fluorescence intensity of both humic-like and protein-like components also increased with light exposure. Terrestrial humic-like components were found to be the main contributors (up to 70%) to the chromophoric DOM (CDOM) pool, while protein-like components comprised a relatively small percentage (up to 16%) of the total CDOM. Simultaneously to the generation of DOC, both total dissolved nitrogen and soluble reactive phosphorus also increased substantially during the photo-incubation period. Thus, the photo-dissolution of floc can be an important source of DOM to the FCE environment, with the potential to influence nutrient dynamics in this system.
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Poulakis, G.R., Stevens, P.W., Timmers, A.A., Wiley, T.R. and Simpfendorfer, C.A. (2011) Abiotic affinities and spatiotemporal distribution of the endangered smalltooth sawfish, Pristis pectinata, in a south-western Florida nursery. Marine and Freshwater Research 62(10), 1165-77.

  ABSTRACT
Understanding how endangered marine species rely on coastal habitats is vital for population recovery planning. The smalltooth sawfish (Pristis pectinata) is one of several critically endangered sawfishes worldwide known to use estuaries and rivers during their early life history. In a Florida estuary designated as critical habitat by the USA government, juveniles were monitored to characterise seasonality, recruitment, and habitat use. Stretched total length ranged from 671 to 2172mm (n = 137, mean = 1248 mm). Sawfish were captured year round. Captures of neonates with embryonic rostral sheaths allowed refinement of the size at birth (671-812 mm) and confirmed a protracted timing of parturition (November-July), which peaked between April and May. Although sampling occurred throughout the estuary, five locations had the greatest catch rates. Most juvenile sawfish had an affinity for water <1 m deep, water >30 degrees C, dissolved oxygen >6 mg L(-1), and salinity between 18 and 30. Greater catch rates for sawfish >1 year old were associated with shoreline habitats with overhanging vegetation such as mangroves. These results detail habitat use within a recognised nursery that can be used for conservation of the first endangered marine fish species in the USA.
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Puri, S., Stephen, H. and Ahmad, S. (2011) Relating TRMM Precipitation Radar backscatter to water stage in wetlands. Journal of Hydrology 401(3-4), 240-49.

  ABSTRACT
Information on water stage over an extended area is important for hydrological and ecological studies. Microwave remote sensing provides an opportunity to measure changes in water stage from space because of its sensitivity to land surface characteristics; it reduces the need to monitor water stage at multiple locations. In this research, a linear model is developed which relates variation in water stage measurements (w(s)) to Tropical Rainfall Measuring Mission Precipitation Radar backscatter (sigma(o)). The estimated water stage from the model is compared with the observed water stage in the wetlands of South Florida. The model performance is assessed by comparing the correlation coefficient (R), the root mean square error (RMSE), and the non-exceedance probability of mean absolute error between observed and modeled water stage measurements for various landcovers. The model works reasonably well in the regions with tree heights greater than 5 m. For example, over woodlands R ranges between 0.59-0.93 and the average RMSE = 19.8 cm. Similarly, for wooded grassland, R ranges between 0.54-0.93 and the average RMSE = 19.8 cm. For other relatively shorter height vegetation landcovers such as grassland (R = 0.57-0.85, RMSE = 20.1 cm) and cropland (R = 0.69-0.79, RMSE = 18.2 cm), the model also performs reasonably well. The research presents a novel use of TRMMPR data and gives an insight into the effect of water level in partially inundated vegetation on radar backscatter.
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Qin, Y., Yang, Z.F. and Yang, W. (2011) Ecological risk assessment for water scarcity in China's Yellow River Delta Wetland.
Stochastic Environmental Research and Risk Assessment 25(5), 697-711.

  ABSTRACT
Wetlands are ecologically important due to their hydrologic attributes and their role as ecotones between terrestrial and aquatic ecosystems. Based on a 2-year study in the Yellow River Delta Wetland and a Markov-chain Monte Carlo (MCMC) simulation, we discovered temporal and spatial relationships between soil water content and three representative plant species (Phragmites australis (Cav.) Trin. ex Steud., Suaeda salsa (Linn.) Pall, and Tamarix chinensis Lour.). We selected eight indices (biodiversity, biomass, and the uptake of TN, TP, K, Ca, Mg, and Na) at three scales (community, single plant, and micro-scale) to assess ecological risk. We used the ecological value at risk (EVR) model, based on the three scales and eight indices, to calculate EVR and generate a three-level classification of ecological risk using MCMC simulation. The high-risk areas at a community scale were near the Bohai Sea. The high-risk areas at a single-plant scale were near the Bohai Sea and along the northern bank of the Yellow River. At a micro-scale, we found no concentration of high-risk areas. The results will provide a foundation on which the watershed's planners can allocate environmental flows and guide wetland restoration.
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Raja, H.A., Tanaka, K., Hirayama, K., Miller, A.N. and Shearer, C.A. (2011) Freshwater ascomycetes: two new species of Lindgomyces (Lindgomycetaceae, Pleosporales, Dothideomycetes) from Japan and USA. Mycologia 103(6), 1421-32.

  ABSTRACT
During independent surveys of freshwater ascomycetes in Japan and USA two new species of Lindgomyces were collected from submerged wood in freshwater. These species are described and illustrated based on morphological data and phylogenetic relationships based on analyses of nuclear ribosomal sequence data (partial SSU and LSU, and ITS). Lindgomyces apiculatus, collected in japan, is characterized by immersed to erumpent, globose to subglobose ascomata; fissitunicate, cylindrical to clavate asci; and fusiform, one-septate ascospores with acute ends and short terminal appendages. Lindgomyces lemonweirensis, collected in Wisconsin, USA, differs from L. apiculatus in having clavate to cymbiform asci and oblong to fusiform ascospores that are distinctively multiguttulate and surrounded by an oval, ephemeral gelatinous sheath. The new species formed a strongly supported clade within the family Lindgomycetaceae (Pleosporales, Dothideomycetes) based on analyses of combined SSU and LSU sequence data. In addition phylogenetic analyses with ITS sequence data support the establishment of the new taxa as separate species within Lindgomyces because they were separated from each other and other Lindgomyces species based on maximum likelihood bootstrap and Bayesian analyses.
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Reddy, K.R., Best, G.R. and Sklar, F. (2011a) Biogeochemistry and Water Quality of the Everglades: Symposium Overview. Critical Reviews in Environmental Science and Technology 41, 1-3.

  (No ABSTRACT)
Reprint Address: Reddy, KR (reprint author), Univ Florida, Gainesville, FL 32610 USA
Addresses: 1. Univ Florida, Gainesville, FL 32610 USA 2. US Geol Survey, Ft Lauderdale, FL USA 3. S Florida Water Management Dist, W Palm Beach, FL USA
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Reddy, K.R., Newman, S., Osborne, T.Z., White, J.R. and Fitz, H.C. (2011b) Phosphorous Cycling in the Greater Everglades Ecosystem: Legacy Phosphorous Implications for Management and Restoration. Critical Reviews in Environmental Science and Technology 41, 149-86.

  ABSTRACT
Phosphorus (P) retention in wetlands is an important function of watershed nutrient cycling, particularly in drainage basins with significant nonpoint nutrient contributions from agriculture and urban sources. Phosphorus storage involves complex interrelated physical, chemical, and biological processes that ultimately retain P in organic and inorganic forms. Both short-term storage of P mediated by assimilation into vegetation, translocation within above- and below-ground plant tissues, microorganisms, periphyton, and detritus, and long-term storage (retention by inorganic and organic soil particles and net accretion of organic matter) need to be considered. Here, we review and synthesize recent studies on P cycling and storage in soils and sediments throughout the Greater Everglades Ecosystem and the influence of biotic and abiotic regulation of P reactivity and mobility as related to restoration activities in south Florida. Total P storage in the floc/detrital layer and surface soils (0-10 cm) is estimated to be 400,000 metric tons (mt) within the entire Greater Everglades Ecosystem, of which 40% is present in the Lake Okeechobee Basin (LOB), 11% in sediments of Upper Chain of Lakes, Lake Istokpoga, and Lake Okeechobee, 30% in the Everglades Agricultural Area (EAA), and 19% in the Stormwater Treatment Areas (STAs) and the Everglades. Approximately, 35% of the P stored is in chemically nonreactive (not extractable after sequential extraction with acid or alkali) pool and is assumed to be stable. Phosphorus leakage rates from LOB and EAA are approximately 500 and 170 mt P per year, respectively, based on long-term P discharges into adjacent ecosystems. The estimated reactive P in the LOB soils is 65% of the total P, of which only 10 -25% is assumed to leak out of the system. Under this scenario, legacy P in LOB would maintain P loads of 500 mt per year to the lake for the next 20- 50 years. Similarly, surface soils of the EAA are estimated to release approximately 170 mt P per year for the next 50-120 years. The role of the STAs in reducing loads to downstream regions is critical and requires effective management of P forms to ensure the P is stabilized in these systems by the addition of chemical amendments or by dredging of accumulated soils. Also, additional efforts to minimize leakage of the legacy P from the northern regions should also be evaluated to reduce external P loading loads to the STAs.
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Reed, R.N., Hart, K.M., Rodda, G.H., Mazzotti, F.J., Snow, R.W., Cherkiss, M., Rozar, R. and Goetz, S. (2011) A field test of attractant traps for invasive Burmese pythons (Python molurus bivittatus) in southern Florida. Wildlife Research 38(2), 114-21.

  ABSTRACT
Context. Invasive Burmese pythons (Python molurus bivittatus) are established over thousands of square kilometres of southern Florida, USA, and consume a wide range of native vertebrates. Few tools are available to control the python population, and none of the available tools have been validated in the field to assess capture success as a proportion of pythons available to be captured. Aims. Our primary aim was to conduct a trap trial for capturing invasive pythons in an area east of Everglades National Park, where many pythons had been captured in previous years, to assess the efficacy of traps for population control. We also aimed to compare results of visual surveys with trap capture rates, to determine capture rates of non-target species, and to assess capture rates as a proportion of resident pythons in the study area. Methods. We conducted a medium-scale (6053 trap nights) experiment using two types of attractant traps baited with live rats in the Frog Pond area east of Everglades National Park. We also conducted standardised and opportunistic visual surveys in the trapping area. Following the trap trial, the area was disc harrowed to expose pythons and allow calculation of an index of the number of resident pythons. Key results. We captured three pythons and 69 individuals of various rodent, amphibian, and reptile species in traps. Eleven pythons were discovered during disc harrowing operations, as were large numbers of rodents. Conclusions. The trap trial captured a relatively small proportion of the pythons that appeared to be present in the study area, although previous research suggests that trap capture rates improve with additional testing of alternative trap designs. Potential negative impacts to non-target species were minimal. Low python capture rates may have been associated with extremely high local prey abundances during the trap experiment. Implications. Results of this trial illustrate many of the challenges in implementing and interpreting results from tests of control tools for large cryptic predators such as Burmese pythons.
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Rice, K.G., Waddle, J.H., Miller, M.W., Crockett, M.E., Mazzotti, F.J. and Percival, H.F. (2011) Recovery of native treefrogs after removal of nonindigenous Cuban treefrogs, Osteopilus septentrionalis. Herpetologica 67(2), 105-17.

  ABSTRACT
Florida is home to several introduced animal species, especially in the southern portion of the state. Most introduced species are restricted to the urban and suburban areas along the coasts, but some species, like the Cuban Treefrog (Osteopilus septentrionalis), are locally abundant in natural protected areas. Although Cuban Treefrogs are known predators of native treefrog species as both adults and larvae, no study has demonstrated a negative effect of Cuban Treefrogs on native treefrog survival, abundance, or occupancy rate. We monitored survival, capture probability, abundance, and proportion of sites occupied by Cuban Treefrogs and two native species, Green Treefrogs (Hyla cinerea) and Squirrel Treefrogs (Hyla squirella), at four sites in Everglades National Park in southern Florida with the use of capture mark recapture techniques. After at least 5 mo of monitoring all species at each site we began removing every Cuban Treefrog captured. We continued to estimate survival, abundance, and occupancy rates of native treefrogs for 1 yr after the commencement of Cuban Treefrog removal. Mark recapture models that included the effect of Cuban Treefrog removal on native treefrog survival did not have considerable Akaike's Information Criterion (AIC) weight, although capture rates of native species were generally very low prior to Cuban Treefrog removal. Estimated abundance of native treefrogs did increase after commencement of Cuban Treefrog removal, but also varied with the season of the year. The best models of native treefrog occupancy included a Cuban Treefrog removal effect at sites with high initial densities of Cuban Treefrogs. This study demonstrates that an introduced predator can have population-level effects on similar native species.
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Richards, J.H., Troxler, T.G., Lee, D.W. and Zimmerman, M.S. (2011) Experimental determination of effects of water depth on Nymphaea odorata growth, morphology and biomass allocation. Aquatic Botany 95(1), 9-16.

  ABSTRACT
Growth, morphology and biomass allocation in response to water depth was studied in white water lily, Nymphaea odorata Aiton. Plants were grown for 13 months in 30, 60 and 90 cm water in outdoor mesocosms in southern Florida. Water lily plant growth was distinctly seasonal with plants at all water levels producing more and larger leaves and more flowers in the warmer months. Plants in 30 cm water produced more but smaller and shorter-lived leaves than plants at 60 cm and 90 cm water levels. Although plants did not differ significantly in total biomass at harvest, plants in deeper water had significantly greater biomass allocated to leaves and roots, while plants in 30 cm water had significantly greater biomass allocated to rhizomes. Although lamina area and petiole length increased significantly with water level, lamina specific weight did not differ among water levels. Petiole specific weight increased significantly with increasing water level, implying a greater cost to tethering the larger laminae in deeper water. Lamina length and width scaled similarly at different water levels and modeled lamina area (LA) accurately (LA(modeled) = 0.98LA(measured) + 3.96, R(2) = 0.99). Lamina area was highly correlated with lamina weight (LW = 8.43LA -66.78, R(2) = 0.93), so simple linear measurements can predict water lily lamina area and lamina weight. These relationships were used to calculate monthly lamina surface area in the mesocosms. Plants in 30 cm water had lower total photosynthetic surface area than plants in 60 cm and 90 cm water levels throughout, and in the summer plants in 90 cm water showed a great increase in photosynthetic surface area as compared to plants in shallower water. These results support setting Everglades restoration water depth targets for sloughs at depths >= 45 cm and suggest that in the summer optimal growth for white water lilies occurs at depths >= 75 cm.
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Rivera-Monroy, V.H., Twilley, R.R., Davis, S.E., Childers, D.L., Simard, M., Chambers, R., Jaffe, R., Boyer, J.N., Rudnick, D.T., Zhang, K., Castaneda-Moya, E., Ewe, S.M.L., Price, R.M., Coronado-Molina, C., Ross, M., Smith, T.J., Michot, B., Meselhe, E., Nuttle, W., Troxler, T.G. and Noe, G.B. (2011) The Role of the Everglades Mangrove Ecotone Region (EMER) in Regulating Nutrient Cycling and Wetland Productivity in South Florida.
Critical Reviews in Environmental Science and Technology 41, 633-69.

  ABSTRACT
The authors summarize the main findings of the Florida Coastal Everglades Long-Term Ecological Research (FCE-LTER) program in the EMER, within the context of the Comprehensive Everglades Restoration Plan (CERP), to understand how regional processes, mediated by water flow, control population and ecosystem dynamics across the EMER landscape. Tree canopies with maximum height 3 m cover 49% of the EMER, particularly in the SE region. These scrub/dwarf mangroves are the result of a combination of low soil phosphorus (P 59 g P g dw-1) in the calcareous marl substrate and long hydroperiod. Phosphorus limits the EMER and its freshwater watersheds due to the lack of terrigenous sediment input and the phosphorus-limited nature of the freshwater Everglades. Reduced freshwater delivery over the past 50years, combined with Everglades compartmentalization and a 10 cm rise in coastal sea level, has led to the landward transgression (1.5 km in 54 years) of the mangrove ecotone. Seasonal variation in freshwater input strongly controls the temporal variation of nitrogen and P exports (99%) from the Everglades to Florida Bay. Rapid changes in nutrient availability and vegetation distribution during the last 50years show that future ecosystem restoration actions and land use decisions can exert a major influence, similar to sea level rise over the short term, on nutrient cycling and wetland productivity in the EMER.
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Rober, A.R., Wyatt, K.H. and Stevenson, R.J. (2011) Regulation of algal structure and function by nutrients and grazing in a boreal wetland.
Journal of the North American Benthological Society 30(3), 787-96.

  ABSTRACT
We evaluated the potential for grazers to regulate benthic algal biomass and taxonomic composition in an Alaskan marsh after enrichment with nutrients that are expected to increase in the region with ongoing climate change. We nested caged and uncaged substrates together inside mesocosm enclosures with natural abundances of snails or no snails and with or without nutrient enrichment (NO(3) + PO(4) + Si). Algal biomass was greater in all nutrient-enriched enclosures than in controls. Algal biomass was greater in enclosures where grazers were present but excluded by a cage than in enclosures where grazers were allowed to graze or where grazers were absent. In the presence of nutrients, grazed communities were dominated by small coccoid green algae and cyanobacteria, which were overgrown by filamentous green algae when grazers were excluded. In the absence of nutrients, grazers had little effect on algal biomass or taxonomic composition. However, grazers recycled a small but potentially important amount of nutrients in their waste, suggesting that consumer-driven nutrient recycling may have played a role in maintaining algal biomass when grazers were present. Our data show that grazers regulate algal responses to nutrients by suppressing algal accumulation but increasing productivity through nutrient recycling in a northern boreal wetland.
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Rolfhus, K.R., Hall, B.D., Monson, B.A., Paterson, M.J. and Jeremiason, J.D. (2011) Assessment of mercury bioaccumulation within the pelagic food web of lakes in the western Great Lakes region. Ecotoxicology 20(7), 1520-29.

  ABSTRACT
While mercury is a health hazard to humans and wildlife, the biogeochemical processes responsible for its bioaccumulation in pelagic food webs are still being examined. Previous studies have indicated both "bottomup" control of piscivorous fish Hg content through methylmercury center dot(MeHg) supply, as well as site-specific trophic factors. We evaluated ten studies from the western Great Lakes region to examine the similarity of MeHg trophic transfer efficiency within the pelagic food web, and assessed regional-scale spatial variability. Analyses of bioaccumulation and biomagnification factors between water, seston, zooplankton, and preyfish indicated that the largest increases in MeHg occurred at the base of the food web, and that the relative extent of trophic transfer was similar between sites. Positive correlations were observed between aqueous unfiltered MeHg, total Hg, and dissolved organic carbon, and measures of the efficiency of MeHg trophic transfer were consistent across widely disparate systems (both natural and experimentally manipulated) throughout North America. Such similarity suggests that the aqueous supply of MeHg is largely controlling bioaccumulation in pelagic food webs, while local, lake-specific variability can result from an array of trophic (biological) factors.
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Rosenblatt, A.E. and Heithaus, M.R. (2011) Does variation in movement tactics and trophic interactions among American alligators create habitat linkages?
Journal of Animal Ecology
80(4), 786-98.

  ABSTRACT
Highly mobile top predators are hypothesized to spatially and/or temporally link disparate habitats through the combination of their movement and feeding patterns, but recent studies suggest that individual specialization in habitat use and feeding could keep habitats compartmentalized. 2. We used passive acoustic telemetry and stable isotope analysis to investigate whether specialization in movement and feeding patterns of American alligators (Alligator mississippiensis) in an oligotrophic subtropical estuary created habitat linkages between marine and estuarine/freshwater food webs. 3. Individual alligators adopted one of the three relatively distinct movement tactics that were linked to variation in diets. Fifty-six per cent of alligators regularly travelled from the upstream (freshwater/mid-estuary) areas into the downstream (marine-influenced) areas where salinities exceed those typically tolerated by alligators. Thirty-one per cent of the alligators made regular trips from the mid-estuarine habitat into the upstream habitat; 13% remained in the mid-estuary zone year-round. 4. Stable isotopic analysis indicated that, unlike individuals remaining in the mid-estuary and upstream zones, alligators that used the downstream zone fed at least partially from marine food webs and likely moved to access higher prey abundance at the expense of salt stress. Therefore, 'commuting' alligators may link marine food webs with those of the estuary and marshes in the coastal Everglades and create an upstream vector for allochthonous nutrient inputs into the estuary. 5. This study lends further support to the hypothesis that large-bodied highly mobile predators faced with trade-offs are likely to exhibit individual specialization leading to habitat linkages, rather than compartmentalization. However, the conditions under which this scenario occurs require further investigation.
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Ross, M.S. and Sah, J.P. (2011) Forest Resource Islands in a Sub-tropical Marsh: Soil-Site Relationships in Everglades Hardwood Hammocks.
Ecosystems
14(4), 632-45.

  ABSTRACT
Spatial heterogeneity in soils is often characterized by the presence of resource-enriched patches ranging in size from a single shrub to wooded thickets. If the patches persist long enough, the primary constraint on production may transition from one limiting environmental factor to another. Tree islands that are scattered throughout the Florida Everglades basin comprise nutrient-enriched patches, or resource islands, in P-limited oligotrophic marshes. We used principal component analysis and multiple regressions to characterize the belowground environment (soil, hydrology) of one type of tree island, hardwood hammocks, and examined its relationship with the three structural variables (basal area, biomass, and canopy height) indicative of site productivity. Hardwood hammocks in the southern Everglades grow on two distinct soil types. The first, consisting of shallow, organic, relatively low-P soils, is common in the seasonally flooded Marl Prairie landscape. In contrast, hammocks on islands embedded in long hydroperiod marsh have deeper, alkaline, mineral soils with extremely high P concentrations. However, this edaphic variation does not translate simply into differences in forest structure and production. Relative water depth was unrelated to all measures of forest structure and so was soil P, but the non-carbonate component of the mineral soil fraction exhibited a strong positive relationship with canopy height. The development of P-enriched forest resource islands in the Everglades marsh is accompanied by the buildup of a mineral soil; however, limitations on growth in mature islands appear to differ substantively from those that dominate incipient stages in the transformation from marsh to forest.
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Ruehl, C.B. and Trexler, J.C. (2011) Comparison of snail density, standing stock, and body size between Caribbean karst wetlands and other freshwater ecosystems. Hydrobiologia 665(1), 1-13.

  ABSTRACT
Synthesizing data from multiple studies generates hypotheses about factors that affect the distribution and abundance of species among ecosystems. Snails are dominant herbivores in many freshwater ecosystems, but there is no comprehensive review of snail density, standing stock, or body size among freshwater ecosystems. We compile data on snail density and standing stock, estimate body size with their quotient, and discuss the major pattern that emerges. We report data from 215 freshwater ecosystems taken from 88 studies that we placed into nine categories. Sixty-five studies reported density, seven reported standing stock, and 16 reported both. Despite the breadth of studies, spatial and temporal sampling scales were limited. Researchers used 25 different sampling devices ranging in area from 0.0015 to 2.5 m(2). Most ecosystem categories had similar snail densities, standing stocks, and body sizes suggesting snails shared a similar function among ecosystems. Caribbean karst wetlands were a striking exception with much lower density and standing stock, but large body size. Disparity in body size results from the presence of ampullariids in Caribbean karst wetlands suggesting that biogeography affects the distribution of taxa, and in this case size, among aquatic ecosystems. We propose that resource quality explains the disparity in density and standing stock between Caribbean karst wetlands and other categories. Periphyton in Caribbean karst wetlands has high carbon-to-phosphorous ratios and defensive characteristics that inhibit grazers. Unlike many freshwater ecosystems where snails are key grazers, we hypothesize that a microbial loop captures much of the primary production in Caribbean karst wetlands.
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Rumbold, D.G., Evans, D.W., Niemczyk, S., Fink, L.E., Laine, K.A., Howard, N., Krabbenhoft, D.P. and Zucker, M. (2011) Source Identification of Florida Bay's Methylmercury Problem: Mainland Runoff Versus Atmospheric Deposition and In situ Production. Estuaries and Coasts 34(3), 494-513.

  ABSTRACT
The first advisory to limit consumption of Florida Bay fish due to mercury was issued in 1995. Studies done by others in the late 1990s found elevated water column concentrations of both total Hg (THg) and methylmercury (MeHg) in creeks discharging from the Everglades, which had its own recognized mercury problem. To investigate the significance of allochthonous MeHg discharging from the upstream freshwater Everglades, we collected surface water and sediment along two transects from 2000 to 2002. Concentrations of THg and MeHg, ranging from 0.36 ng THg/L to 5.98 ng THg/L and from < 0.02 ng MeHg/L to 1.79 ng MeHg/L, were elevated in the mangrove transition zone when compared both to upstream canals and the open waters of Florida Bay. Sediment concentrations ranged from 5.8 ng THg/g to 145.6 ng THg/g and from 0.05 ng MeHg/g to 5.4 ng MeHg/g, with MeHg as a percentage of THg occasionally elevated in the open bay. Methylation assays indicated that sediments from Florida Bay have the potential to methylate Hg. Assessment of mass loading suggests that canals delivering stormwater from the northern Everglades are not as large a source as direct atmospheric deposition and in situ methylation, especially within the mangrove transition zone.
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Sader, J.A., Hattori, K., Hamilton, S. and Brauneder, K. (2011) Metal binding to dissolved organic matter and adsorption to ferrihydrite in shallow peat groundwaters: Application to diamond exploration in the James Bay Lowlands, Canada. Applied Geochemistry 26(9-10), 1649-64.

  ABSTRACT
The speciation and solubility of kimberlite pathfinder metals (Ni, Nd, Ba and K) in shallow peat groundwaters is investigated over the Yankee, Zulu and Golf kimberlites in the Attawapiskat region, James Bay Lowlands, Canada. The purpose of this study is to examine the relationship between dissolved organic matter (DOM) complexation with kimberlite pathfinder metals and determine the spatial distribution of those metals in shallow peat groundwaters along sampling transects over subcropping kimberlites. Nickel, Nd, Ba and K complexation with DOM and the adsorption of these metals onto ferrihydrite were calculated using Visual MINTEQ 3.0 and the NICA-Donnan database. Calculations predict almost 100% of soluble Nd, Ni and Ba form complexes with DOM at sampling sites with little to no contribution from upwelling groundwater (i.e., dissolved organic C (DOC) concentrations = 40-132 mg/L, pH = 3.9-5.5, and log ionic strength <=-3). In only the most ombrotrophic peat groundwater conditions does a majority fraction of K bind to DOM. By contrast, under conditions with large contributions from upwelling groundwaters (i.e., DOC concentrations <= 40 mg/L, pH = 5.5-6.5, and log ionic strength = -3 to -2), as little as 10% of Nd and Ni, and 0% K and Ba are predicted to complex with DOM. The modeling calculations suggest the dominant control on metal-DOM complexation, particularly with respect to Ni and Nd, is competitive effects for DOM binding sites due to elevated ionic strength where there is evidence of strong groundwater upwelling. Visual MINTEQ modeling of metal adsorption on ferrihydrite surfaces predicts that under strong upwelling conditions, Ni and Nd are scavenged from solution due to increased ferrihydrite precipitation and decreased fractions of metals complexed with DOM. Analytical geochemical data are consistent with model predictions of metal adsorption on ferrihydrite. Total dissolved Ni and Nd concentrations at sites of strong upwelling are up to five times lower than waters with little to no upwelling and log ferrihydrite saturation indices (logSl(ferr)) indicate precipitation (values up to 5) at sites of strong groundwater upwelling. Where the majority of Ni and Nd complex with DOM and ferrihydrite is highly under saturated (logSl(ferr) = -18 to -5), the concentrations of total Ni and Nd are elevated compared to other sites along sampling transects. Metal complexation with DOM effectively inhibits metal scavenging from solution via adsorption and/or from forming secondary mineral precipitates. Also, because alkaline earth metals do not compete strongly with Ni and Nd for adsorption sites on ferrihydrite surfaces, but do compete strongly for insoluble organic sites, Ni and Nd are more likely to adsorb onto ferrihydrite.
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Saha, A.K., Saha, S., Sadle, J., Jiang, J., Ross, M.S., Price, R.M., Sternberg, L. and Wendelberger, K.S. (2011) Sea level rise and South Florida coastal forests. Climatic Change 107(1-2), 81-108.

  ABSTRACT
Coastal ecosystems lie at the forefront of sea level rise. We posit that before the onset of actual inundation, sea level rise will influence the species composition of coastal hardwood hammocks and buttonwood (Conocarpus erectus L.) forests of the Everglades National Park based on tolerance to drought and salinity. Precipitation is the major water source in coastal hammocks and is stored in the soil vadose zone, but vadose water will diminish with the rising water table as a consequence of sea level rise, thereby subjecting plants to salt water stress. A model is used to demonstrate that the constraining effect of salinity on transpiration limits the distribution of freshwater-dependent communities. Field data collected in hardwood hammocks and coastal buttonwood forests over 11 years show that halophytes have replaced glycophytes. We establish that sea level rise threatens 21 rare coastal species in Everglades National Park and estimate the relative risk to each species using basic life history and population traits. We review salinity conditions in the estuarine region over 1999-2009 and associate wide variability in the extent of the annual seawater intrusion to variation in freshwater inflows and precipitation. We also examine species composition in coastal and inland hammocks in connection with distance from the coast, depth to water table, and groundwater salinity. Though this study focuses on coastal forests and rare species of South Florida, it has implications for coastal forests threatened by saltwater intrusion across the globe.
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Santos, R.O., Lirman, D. and Serafy, J.E. (2011) Quantifying freshwater-induced fragmentation of submerged aquatic vegetation communities using a multi-scale landscape ecology approach. Marine Ecology-Progress Series 427, 233-46.

  ABSTRACT
Species composition and abundance of nearshore submerged aquatic vegetation (SAV) of Biscayne Bay, Florida, USA, are influenced by pulsed delivery of fresh water from canals that drain the Everglades and adjacent urban and agricultural areas. In the present study, we evaluated whether freshwater inflows were correlated with the spatial structure (e. g. patchiness, fragmentation, spatial heterogeneity) of SAV. SAV patches were delineated using aerial photographs and object-based classification, and the SAV seascape structure was characterized at different spatial scales (200 m to 1 km from shore) using landscape metrics. The area closest to shore (200 m buffer) was identified as the area with the highest heterogeneity in SAV seascape structure; areas beyond this buffer did not differ significantly in landscape metrics. Within the 200 m buffer, SAV seascapes clustered into continuous SAV structures (CSS) and fragmented SAV structures (FSS). CSS had a higher proportion of the benthos covered by larger SAV patches with simpler boundaries. FSS had a higher density of smaller SAV patches with complex shapes and a lower proportion of the substrate covered by SAV patches. Neither structure type was distributed randomly along the shoreline. CSS were prevalent in areas with high and stable salinity. FSS were prevalent in areas influenced by freshwater discharges where salinity is low and variable, highlighting how the pulsed release of fresh water may adversely influence the structure of SAV seascapes, potentially resulting in fragmentation of the benthic community. Thus, this seascape approach provides a tool to assess the influences and effectiveness of the Everglades Restoration Project in Biscayne Bay.
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Sargeant, B.L., Gaiser, E.E. and Trexler, J.C. (2011) Indirect and direct controls of macroinvertebrates and small fish by abiotic factors and trophic interactions in the Florida Everglades. Freshwater Biology 56(11), 2334-46.

  ABSTRACT
1. The roles of nutrients, disturbance and predation in regulating consumer densities have long been of interest, but their indirect effects have rarely been quantified in wetland ecosystems. The Florida Everglades contains gradients of hydrological disturbance (marsh drying) and nutrient enrichment (phosphorus), often correlated with densities of macroinvertebrate infauna (macroinvertebrates inhabiting periphyton), small fish and larger invertebrates, such as snails, grass shrimp, insects and crayfish. However, most causal relationships have yet to be quantified. 2. We sampled periphyton (content and community structure) and consumer (small omnivores, carnivores and herbivores, and infaunal macroinvertebrates inhabiting periphyton) density at 28 sites spanning a range of hydrological and nutrient conditions and compared our data to seven a priori structural equation models. 3. The best model included bottom-up and top-down effects among trophic groups and supported top-down control of infauna by omnivores and predators that cascaded to periphyton biomass. The next best model included bottom-up paths only and allowed direct effects of periphyton on omnivore density. Both models suggested a positive relationship between small herbivores and small omnivores, indicating that predation was unable to limit herbivore numbers. Total effects of time following flooding were negative for all three consumer groups even when both preferred models suggested positive direct effects for some groups. Total effects of nutrient levels (phosphorus) were positive for consumers and generally larger than those of hydrological disturbance and were mediated by changes in periphyton content. 4. Our findings provide quantitative support for indirect effects of nutrient enrichment on consumers, and the importance of both algal community structure and periphyton biomass to Everglades food webs. Evidence for top-down control of infauna by omnivores was noted, though without substantially greater support than a competing bottom-up-only model.
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Scully, B.T., Nagata, R.T., Sistrunk, D.M., Cherry, R.H., Nuessly, G.S., Kenworthy, K.E. and DeFrank, J. (2011) Registration of 'Aloha' Seashore Paspalum. Journal of Plant Registrations 5(1), 22-26.

  ABSTRACT
'Aloha' (Reg. No. CV-3, PI 652948) seashore paspalum (Paspalum vaginatum O. Swartz) was developed at the Everglades Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida and jointly released by the Florida and Hawaii agricultural experiment stations. It was initially approved for release in early 2005 and a pending plant patent was submitted in late 2005. This variety of seashore paspalum was selected as an open-pollinated progeny derived from naturalized local landraces growing on the island of Hawaii and was tested in southern Florida under the coded breeding line number H99-47. Aloha was selected for improved agronomic, horticultural, and host-plant resistance traits including a faster rate of crop establishment and ground coverage, darker and deeper green leaf color, and superior resistance to the greenbug aphid (Schizaphis graminum Rondani; Homoptera:Aphididae). In comparison to a set of standard varieties, Aloha attained 50% plot coverage in less than 4 mo whereas the standards took, on average, more than 5 mo. The leaf color of Aloha was a darker green and had a deeper hue than the standard varieties, and the greenbug aphids took longer to reach reproductive maturity, had a shorter lifespan, and produced fewer offspring when cultured on Aloha. Aloha also exhibited a morphology distinct from the standards for a set of measured inflorescence and vegetative traits.
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Serrano, X., Serafy, J. and Grosell, M. (2011) Osmoregulatory capabilities of the gray snapper, Lutjanus griseus: salinity challenges and field observations. Marine and Freshwater Behaviour and Physiology 44(3), 185-96.

  ABSTRACT
We investigated the osmoregulatory responses (plasma osmolality and blood hematocrit) displayed by the gray snapper 6-192 h after abrupt changes in ambient salinity. Fish were challenged with six different salinity treatments including a control (0, 5, 30, 50, 60, and 70 ppt) and blood samples were collected at various time points post-transfer. Gray snapper across all size classes tested (13.5-24.5 cm total length) acclimated successfully to hypo- and hyper-saline environments (0-60 ppt) after an adjustment period of similar to 96 h. However, abrupt transfers to 70 ppt resulted in 100% mortality within 48 h. Laboratory results were then compared with field measurements obtained after fish were captured in low salinity (0-4 ppt) or marine (similar to 30 ppt) habitats, suggesting that osmoregulatory processes occurred similarly in both settings. Overall, findings suggest that gray snapper possess similar or higher osmoregulatory capabilities compared to many euryhaline species examined to date, and thus should be considered a euryhaline species.
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Shetty, K.G., Minnis, A.M., Rossman, A.Y. and Jayachandran, K. (2011) The Brazilian peppertree seed-borne pathogen, Neofusicoccum batangarum, a potential biocontrol agent. Biological Control 56(1), 91-97.

  ABSTRACT
The invasive exotic Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae) has become a serious threat to the delicate ecosystem of Everglades National Park in Florida, USA. More than 4000 ha in the Hole-in-the-Donut (HID) area within the park have been infested with Brazilian peppertree. Brazilian peppertree is a prolific seed producer, which enhances its invasive potential. Native phytopathogens can be a viable tool in the management of exotic species; no prior studies have reported on the occurrence of native seed-borne pathogens of Brazilian peppertree in Florida. This study showed that drupes of Brazilian peppertree are affected by seed-borne fungal pathogens. These fungal pathogens either cause germination failure or attack seedlings after germination, which results in reduced vigor or seedling death. The seed-borne fungal isolate BPSPF-1 was found to be virulent, and when inoculated it was able to kill Brazilian peppertree seedlings in seedling assays, and 1 year old saplings in greenhouse trials. Field inoculation of Brazilian peppertree branches with BPSPF-1 resulted in dieback symptoms. Host range studies on one related native species (winged sumac, Rhus copallinum) and one non-native species (mango, Mangifera indica) showed that neither was affected by girdle inoculation of stems. The BPSPF-1 isolate produced dark melanized mycelium on agar media and did not produce conidia or other fruiting structures. Based on ITS DNA sequence analyses, the isolate was identified as Neofusicoccum batangarum.
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Slone, D.H. (2011) Increasing accuracy of dispersal kernels in grid-based population models. Ecological Modelling 222(3), 573-79.

  ABSTRACT
Dispersal kernels in grid-based population models specify the proportion, distance and direction of movements within the model landscape. Spatial errors in dispersal kernels can have large compounding effects on model accuracy. Circular Gaussian and Laplacian dispersal kernels at a range of spatial resolutions were investigated, and methods for minimizing errors caused by the discretizing process were explored. Kernels of progressively smaller sizes relative to the landscape grid size were calculated using cell-integration and cell-center methods. These kernels were convolved repeatedly, and the final distribution was compared with a reference analytical solution. For large Gaussian kernels (sigma>10 cells), the total kernel error was <10(-11) compared to analytical results. Using an invasion model that tracked the time a population took to reach a defined goal, the discrete model results were comparable to the analytical reference. With Gaussian kernels that had sigma <= 0.12 using the cell integration method, or sigma <= 0.22 using the cell center method, the kernel error was greater than 10%, which resulted in invasion times that were orders of magnitude different than theoretical results. A goal-seeking routine was developed to adjust the kernels to minimize overall error. With this, corrections for small kernels were found that decreased overall kernel error to <10(-11) and invasion time error to <5%.
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Smith, C.S., Serra, L., Li, Y.C., Inglett, P. and Inglett, K. (2011) Restoration of Disturbed Lands: The Hole-in-the-Donut Restoration in the Everglades. Critical Reviews in Environmental Science and Technology 41, 723-39.

  ABSTRACT
The Hole-in-the-Donut (HID) wetland restoration project was established on former agricultural land inside Everglades National Park, where rock plowing and fertilization had altered the hydrology, structure, depth, aeration, and nutrient content of soils. Following the cessation of farming, highly disturbed HID soils were invaded by dense, nearly monospecific stands of Brazilian pepper (Schinus terebinthifolius Raddi). Initial efforts to restore Brazilian pepper-dominated areas failed, and only complete removal of the substrate down to the surface of bedrock was successful. Complete soil removal resulted in the restoration of a plant community dominated by native wetland plants. Following restoration, initially very shallow soils gradually deepened as marl accreted as due to the activities of periphyton. By 15 years postrestoration, an average of 3.7cm of soil had developed. Initially low nitrogen concentrations increased following restoration, whereas phosphorus was converted to organic forms and diluted by the accumulation of marl. The result of these changes was a gradual switch from nitrogen limitation to phosphorus limitation, eventually mirroring the situation in adjacent undisturbed wetland sites. Complete substrate removal, as used in the HID, could be used to restore other areas of the Everglades degraded by nutrient enrichment.
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Stamates, S.J. and Lee (2011) Using Acoustic Modeling to Develop a Hybrid H-ADCP Configuration.

  ABSTRACT
The Port Everglades Shipping Channel (PESC) in Ft. Lauderdale, Florida is thought to be a pathway by which anthropogenic nutrients and pathogens reach the coastal ocean from inland waters. To quantify this, a flow measurement system was installed in the PESC. In planning this measurement system, conventional vertical and horizontal ADCP configurations were considered but found to be unsuitable for differing reasons. This motivated the development of a hybrid deployment configuration. A Teledyne-RDI 300 kHz H-ADCP was deployed near the surface with an 8.5 degree downward tilt so that measurement cells nearest to the instrument would record data from the upper water column while cells further from the instrument would record data from deeper depths. The PESC is often times vertically stratified and it was realized that this stratification could affect the data received from a system deployed in this manner. To estimate these effects, sound speed profiles taken in the PESC were used as input to an acoustic propagation model. This model simulated the acoustic paths from the instrument deployed at different angles. Analysis of these simulations enabled the selection of the optimal angle for deployment that allowed for the maximum profiling range while minimizing the effects of stratification on the acoustic path.
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Stephenson, K.E. (2011) Distribution of Grasslands in 19th Century Florida. American Midland Naturalist 165(1), 50-59.

  ABSTRACT
Presettlement Florida had a variety of open habitats, including grasslands and savannas. This study examined the historic distribution of the Florida grasslands using U.S. General Land Office land surveys made during the 19th century. All survey maps with areas labeled "prairie" or "savanna" were compiled into a composite map. A total of 791,140 ha of prairies and 15,820 ha of savanna were shown on the maps. The most extensive prairies were located in central Florida stretching from the west coast of Lake Okeechobee into Hillsboro and Manatee counties. Patches of prairie and savanna extended north into Clay County. South of Lake Okeechobee, prairies were found in the Big Cypress Swamp, along the western edge of the Everglades and along the eastern coast. Surveyor's notes and historical documents were then used to find additional references to grasslands. These references indicate that there were extensive prairies and savannas in the northern part of the peninsula and in the panhandle. Areas with prairie and savanna were compared to soil descriptions found in county soil surveys by the U.S. Department of Agriculture. Soils typical of forested areas (spodosols and alfisols) were more common in Florida prairies and savannas than mollisol soils that are characteristic of grasslands. The soil data, in addition with the proximity of prairies to pine forests, supports the hypothesis that these ecosystems are determined more by topography, fire frequency and flooding patterns than by soil type.
top   full text Stith, B.M., Reid, J.P., Langtimm, C.A., Swain, E.D., Doyle, T.J., Slone, D.H., Decker, J.D. and Soderqvist, L.E. (2011) Temperature Inverted Haloclines Provide Winter Warm-Water Refugia for Manatees in Southwest Florida. Estuaries and Coasts 34(1), 106-19.
  ABSTRACT
Florida manatees (Trichechus manatus latirostris) overwintering in the Ten Thousand Islands and western Everglades have no access to power plants or major artesian springs that provide warm-water refugia in other parts of Florida. Instead, hundreds of manatees aggregate at artificial canals, basins, and natural deep water sites that act as passive thermal refugia (PTR). Monitoring at two canal sites revealed temperature inverted haloclines, which provided warm salty bottom layers that generally remained above temperatures considered adverse for manatees. At the largest PTR, the warmer bottom layer disappeared unless significant salt stratification was maintained by upstream freshwater inflow over a persistent tidal wedge. A detailed three-dimensional hydrology model showed that salinity stratification inhibited vertical convection induced by atmospheric cooling. Management or creation of temperature inverted haloclines may be a feasible and desirable option for resource managers to provide passive thermal refugia for manatees and other temperature sensitive aquatic species.
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Sullivan, P.L., Price, R.M., Ross, M.S., Scinto, L.J., Stoffella, S.L., Cline, E., Dreschel, T.W. and Sklar, F.H. (2011) Hydrologic processes on tree islands in the Everglades (Florida, USA): tracking the effects of tree establishment and growth. Hydrogeology Journal 19(2), 367-78.

  ABSTRACT
The hydrodynamics of tree islands during the growth of newly planted trees has been found to be influenced by both vegetation biomass and geologic conditions. From July 2007 through June 2009, groundwater and surface-water levels were monitored on eight recently planted tree islands at the Loxahatchee Impoundment Landscape Assessment (LILA) facility in Boynton Beach, Florida, USA. Over the 2-year study, stand development coincided with the development of a water-table depression in the center of each of the islands that was bounded by a hydraulic divide along the edges. The water-table depression was greater in islands composed of limestone as compared to those composed of peat. The findings of this study suggest that groundwater evapotranspiration by trees on tree islands creates complex hydrologic interactions between the shallow groundwater in tree islands and the surrounding surface water and groundwater bodies.
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Torres, I.C., Inglett, K.S. and Reddy, K.R. (2011) Heterotrophic microbial activity in lake sediments: effects of organic electron donors. Biogeochemistry 104(1-3), 165-81.

  ABSTRACT
Allochthonous and autochthonous organic matter deposited in benthic sediments are mineralized by microbial communities, resulting in release of nutrients to the water column. Lakes with different trophic states may have sediments with different carbon and nutrient concentration with consequently different microbial communities. Microbial diversity of surface sediments of three subtropical lakes of different trophic state was investigated by measuring catabolic response to a wide variety of carbon-substrates. Basal carbon dioxide and methane production rates were highest in Lake Apopka (hypereutrophic), followed by Lake Annie (oligo-mesotrophic) and Lake Okeechobee (eutrophic) sediments. The oligo-mesotrophic Lake Annie showed the highest metabolic quotient (qCO(2); proportion of basal respiration per unit of microbial biomass, 0.008 +/- A 0.001) indicating inefficient use of energy. The low qCO(2) found in Lake Apopka sediment indicated higher efficiency in using energy. Lake Okeechobee sediments had intermediary values of qCO(2) (M9 0.005 +/- A 0.001; M17 0.006 +/- A 0.0003; KR 0.004 +/- A 0.001) as compared with other lakes (lake Apopka 0.004 +/- A 0.14). Lake Apopka's sediment catabolic diversity was higher than that observed in other sediments. Addition of organic electron donors to sediment samples from all lakes stimulated heterotrophic activity; however, the extent of the response varied greatly and was related to microbial biomass. The hypereutrophic Lake Apopka sediments had the highest respiration per unit of microbial biomass with the addition of electron donors indicating that these sediments respired most of the C added. These results showed that sediments with different biogeochemical properties had microbial communities with distinct catabolic responses to addition of the C sources.
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Vieira, L.M., Nunes, V.D., Amaral, M.C.D., Oliveira, A.C., Hauser-Davis, R.A. and Campos, R.C. (2011) Mercury and methyl mercury ratios in caimans (Caiman crocodilus yacare) from the Pantanal area, Brazil. Journal of Environmental Monitoring 13(2), 280-87.

  ABSTRACT
The Pantanal region is the largest floodplain area in the world and of great biological importance due to its unique flora and fauna. This area is continuously undergoing increasing anthropogenic threats, and has also experienced mercury contamination associated with gold mining and other anthropogenic activities. Pantanal caimans are top-level predators, and, as such, show great potential to accumulate mercury (Hg) by biomagnification. In this study 79 specimens from four locations in the Pantanal were analyzed for total Hg and methyl mercury (MeHg) by cold vapor atomic absorption spectrometry. Total Hg contents ranged from 0.02 to 0.36 mu g g(-1) (ww), and most specimens presented MeHg ratios above 70%. One of the sites, impacted by anthropogenic activities, presented significantly higher total Hg in comparison to three less impacted sites, supporting the hypothesis that caimans can, in fact, be considered effective bioindicators of ecosystem health.
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Vourlitis, G.L., Lobo, F.D., Biudes, M.S., Ortiz, C.E.R. and Nogueira, J.D. (2011) Spatial Variations in Soil Chemistry and Organic Matter Content across a Vochysia divergens Invasion Front in the Brazilian Pantanal. Soil Science Society of America Journal 75(4), 1554-61.

  ABSTRACT
The Pantanal is a large and diverse wetland that spans three South American countries including parts of Brazil, Paraguay, and Bolivia. An invasive tree, Vochysia divergens Pohl (commonly known as Cambara), has been expanding throughout the Pantanal for more than four decades forming monospecific stands. Given the rapid and extensive spread of Cambara, and the potential for woody plant invasion to alter soil organic matter and nutrient stocks, we hypothesized that Cambara invasion would significantly increase soil organic matter and nutrient content. To test this hypothesis we sampled the soil, litter, and vegetation of a monospecific Cambara stand, a grassland (campo) stand in the process of Cambara invasion (transitional), and a campo stand free of Cambara during the dry season in July and August of 2009 and 2010 when stands were free from seasonal flooding. Surface (0-10 cm) soil in sites dominated by Cambara had significantly higher soil organic matter (SOM), P, and cation content, and higher cation exchange capacity (CEC), but soil pH and K(+) concentration were less coincident with Cambara presence. The variation of soil characteristics was also significantly higher in the transitional site, indicating that the transition from a grassland-to a Cambara-dominated system significantly increased the spatial variability of soil chemistry. These results indicate that Cambara invasion fundamentally alters the C and nutrient storage of Panatanal soils. Future research will investigate if these results are general for Cambara invasion and address mechanisms of how Cambara invasion affects the nutrient cycling and storage of Pantanal soils.
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Walker, W.W. (2011) Modeling Phosphorous Dynamics in Everglades Wetlands and Stormwater Treatment Areas (vol 41, pg 430, 2011). Critical Reviews in Environmental Science and Technology 41(8), 805-05.

  (No ABSTRACT)
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Walker, W.W. and Kadlec, R.H. (2011) Modeling Phosphorus Dynamics in Everglades Wetlands and Stormwater Treatment Areas. Critical Reviews in Environmental Science and Technology 41, 430-46.

  ABSTRACT
Longitudinal gradients in phosphorus (P) stored in the water column, vegetation, and soils develop in the wetlands where inflow P concentrations exceed background levels. Before the mid 1990's, the Everglades regional P gradient ranged from 100-200 mg L-1 in marsh inflows to background levels of 4-8 mg L-1. Subsequent implementation of P controls, including agricultural Best Management Practices and Stormwater Treatment Areas (STAs), has reduced the average inflow concentration along the northern edge of the Water Conservations Areas to approximately 30-50 mg L-1. Additional P controls are being implemented and further measures beyond those currently planned will be required to restore the entire marsh. The authors describe the evolution and application of relatively simple mass-balance models to simulate P storage and cycling processes along P gradients in the STAs and marsh. The models are practical tools with historical and future applications to designing P control measures involving source controls, water management, reservoirs, and STAs, as well as forecasting marsh responses to implementation of those control measures.
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Wallis, E. and Raulings, E. (2011) Relationship between water regime and hummock-building by Melaleuca ericifolia and Phragmites australis in a brackish wetland. Aquatic Botany 95(3), 182-88.

  ABSTRACT
We investigated the relationship between hummock height and depth of inundation in a permanently inundated wetland in south-eastern Australia. Our survey of 318 hummocks, in water ranging from 0 to 70cm depth, revealed a significant positive linear relationship and strong correlation between hummock height and water depth (r(2) = 0.53 and 0.79 for Melaleuca ericifolia and Phragmites australis hummocks respectively). We also investigated whether water regime affects the decomposition rate of litter on hummocks; specifically, whether constant inundation slows decomposition to an extent that would promote accumulation of litter and hummock-building. On the contrary, we found that constantly submerged M. ericifolia litter decomposed faster than dry litter, but at a similar rate to litter that experienced intermittent inundation (decay rates (k) 0.0015 d(-1), 0.0010d(-1) and 0.0008d(-1) for submerged, intermittent and dry treatments respectively). Submerged P. australis litter also decomposed faster (k = 0.0024 d(-1)) than dry litter (k = 0.0011 d(-1)). We discuss the interaction of water regime and decomposition of organic material and implications for the maintenance of hummock and hollow topography.
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Wang, Q.R., Li, Y.C. and Ouyang, Y. (2011a) Phosphorus fractionation and distribution in sediments from wetlands and canals of a water conservation area in the Florida Everglades. Water Resources Research 47.

  ABSTRACT
Phosphorus (P) fractionation and distribution in sediments are of great concern in the Florida Everglades ecosystem because potential eutrophication of surface waters usually results from P external loading and stability. Intact core sediment samples were collected to a depth of 35 cm from wetlands and canals across Water Conservation Area 3 (WCA-3) of the Florida Everglades. These sediment cores were sliced into 5 cm increments and analyzed for P contents in different fractions by sequential extraction. These fractions mainly included total P (TP), readily available P (Pi-KCl), Fe/Al-bound P (Pi-NaOH), Ca/Mg-bound P (Pi-HCl), organic P (Po-NaOH), and residual P (Po(Residue)). Results showed that the canal sediments had the highest concentrations of TP, with about 87% in the form of Ca/Mg-bound fraction, and the concentrations of TP in these sediments increased with depth. In contrast, the wetland sediments contained the lowest concentrations of TP (predominantly in the organic fraction), with 43% residual P and 27% Po-NaOH, and the concentrations of TP in these sediments decreased with depth. In addition, a large amount of the readily available P (up to 1500 mg kg(-1)) in the canal sediments was accumulated at the top layer of 0-5 cm. This study suggests that any disturbance and/or environmental alterations, such as high canal flow and dredging in canal sediments, could pose a potential risk of a P increase in the water column and, consequently, in the wetlands because of the release of readily available P despite the relatively stable nature of such P fractions in these sediments.
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Wang, S.W., Kuo, Y.M., Kao, Y.H., Jang, C.S., Maji, S.K., Chang, F.J. and Liu, C.W. (2011b) Influence of hydrological and hydrogeochemical parameters on arsenic variation in shallow groundwater of southwestern Taiwan. Journal of Hydrology 408(3-4), 286-95.

  ABSTRACT
Shallow groundwater in the Choushui river alluvial fan of southwestern Taiwan contains high As contents. Arsenic concentrations in most of wells varied spatial-temporally. The purpose of this study is to quantitatively evaluate the hydrological and hydrogeochemical factors that influence As concentration in the shallow groundwater of southwestern Taiwan. Dynamic factor analysis (DFA), a dimension reduction technique that considers the time component for studying multivariate time series, is adopted to obtain underlying common trends of response time series and influences of explanatory variables. The major As-associated hydrological and hydrogeochemical parameters were identified and applied to predict the variation of As concentrations in groundwater. The results showed that As fluctuation in groundwater were governed by the rainfall and river water recharges in both dry and wet seasons. Rapid infiltration of surface water caused a rise in groundwater elevation in the rainy season and created a reductive environment, inducing reductive dissolution of As-bearing Fe (hydr)oxides. Dissolved As concentration was subsequently transported by fast groundwater flow to downstream areas. Moreover, extensive pumping for agricultural and aquacultural demands masked the influences of groundwater elevation on variations of As concentrations and led to critical seawater intrusion. In non-saline wells. Fe reduction and subsequent secondary mineralization between dry and wet seasons was responsible for As mobility. Sulfate reduction in saline wells promoted sulfide precipitation and restrained As mobility in wet season. Collectively, hydrological and hydrogeochemical variables controlled the temporal variation and spatial distribution of As concentration, respectively, in the shallow groundwater of southwestern Taiwan.
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Wang, X., Fuller, D.O., Sternberg, L. and Miralles-Wilhelm, F. (2011c) Foliar nutrient and water content in subtropical tree islands: A new chemohydrodynamic link between satellite vegetation indices and foliar delta(15)N values. Remote Sensing of Environment 115(3), 923-30.

  ABSTRACT
We examined the relationships between two satellite-derived vegetation indices and foliar delta(15)N values obtained from dominant canopy species in a set of tree islands located in the Everglades National Park in South Florida, USA. These tree islands constitute important nutrient hotspots in an otherwise P-limited wetland environment. Foliar delta(15)N values obtained from a previous study of 17 tree islands in both slough (perennially wet) and prairie (seasonally wet) locations served as a proxy of P availability at the stand level. We utilized five cloud-free SPOT 4 multispectral images (20 m spatial resolution) from different times of the seasonal cycle to derive two atmospherically corrected vegetation indices: the normalized difference vegetation index (NDVI) and the normalized difference water index (NDWI), averaged for each tree island. NDWI, which incorporates a shortwave infrared (SWIR) band that provides information on leaf water content, showed consistently higher linear fits with island foliar delta(15)N values than did NDVI. In addition, NDWI showed greater variation throughout the seasonal cycle than did NDVI, and was significantly correlated with average water stage, which suggests that the SWIR band captures important information on seasonally variable water status. Tree islands in slough locations showed higher NDWI than prairie islands during the dry season, which is consistent with higher levels of transpiration and nutrient harvesting and accumulation for perennially wet locations. Overall, the results suggest that water availability is closely related to P availability in subtropical tree islands, and that NDWI may provide a robust indicator of community-level water and nutrient status.
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Wang, X., Sternberg, L.O., Ross, M.S. and Engel, V.C. (2011d) Linking water use and nutrient accumulation in tree island upland hammock plant communities in the Everglades National Park, USA. Biogeochemistry 104(1-3), 133-46.

  ABSTRACT
The tree island hammock communities in the Florida Everglades provide one of many examples of self-organized wetland landscape. However, little is understood about why these elevated tree island communities have higher nutrient concentration than the surrounding freshwater marshes. Here we used stable isotopes and elemental analysis to compare dry season water limitation and soil and foliar nutrient status in upland hammock communities of 18 different tree islands located in the Shark River Slough and adjacent prairie landscapes. We observed that prairie tree islands, having a shorter hydroperiod, suffer greater water deficits during the dry season than slough tree islands by examining shifts in foliar delta(13)C values. We also found that prairie tree islands have lower soil total phosphorus concentration and higher foliar N/P ratio than slough tree islands. Foliar delta(15)N values, which often increase with greater P availability, was also found to be lower in prairie tree islands than in slough tree islands. Both the elemental N and P and foliar delta(15)N results indicate that the upland hammock plant communities in slough tree islands have higher amount of P available than those in prairie tree islands. Our findings are consistent with the transpiration driven nutrient harvesting chemohydrodynamic model. The water limited prairie tree islands hypothetically transpire less and harvest less P from the surrounding marshes than slough tree islands during the dry season. These findings suggest that hydroperiod is important to nutrient accumulation of tree island habitats.
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Wetzel, P.R., Sklar, F.H., Coronado, C.A., Troxler, T.G., Krupa, S.L., Sullivan, P.L., Ewe, S., Price, R.M., Newman, S. and Orem, W.H. (2011) Biogeochemical Processes on Tree Islands in the Greater Everglades: Initiating a New Paradigm. Critical Reviews in Environmental Science and Technology 41, 670-701.

  ABSTRACT
Scientists' understanding of the role of tree islands in the Everglades has evolved from a plant community of minor biogeochemical importance to a plant community recognized as the driving force for localized phosphorus accumulation within the landscape. Results from this review suggest that tree transpiration, nutrient infiltration from the soil surface, and groundwater flow create a soil zone of confluence where nutrients and salts accumulate under the head of a tree island during dry periods. Results also suggest accumulated salts and nutrients are flushed downstream by regional water flows during wet periods. That trees modulate their environment to create biogeochemical hot spots and strong nutrient gradients is a significant ecological paradigm shift in the understanding of the biogeochemical processes in the Everglades. In terms of island sustainability, this new paradigm suggests the need for distinct dry-wet cycles as well as a hydrologic regime that supports tree survival. Restoration of historic tree islands needs further investigation but the creation of functional tree islands is promising.
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Willard, D.A. and Bernhardt, C.E. (2011) Impacts of past climate and sea level change on Everglades wetlands: placing a century of anthropogenic change into a late-Holocene context. Climatic Change 107(1-2), 59-80.

  ABSTRACT
We synthesize existing evidence on the ecological history of the Florida Everglades since its inception similar to 7 ka (calibrated kiloannum) and evaluate the relative impacts of sea level rise, climate variability, and human alteration of Everglades hydrology on wetland plant communities. Initial freshwater peat accumulation began between 6 and 7 ka on the platform underlying modern Florida Bay when sea level was similar to 6.2 m below its current position. By 5 ka, sawgrass and waterlily peats covered the area bounded by Lake Okeechobee to the north and the Florida Keys to the south. Slower rates of relative sea level rise similar to 3 ka stabilized the south Florida coastline and initiated transitions from freshwater to mangrove peats near the coast. Hydrologic changes in freshwater marshes also are indicated similar to 3 ka. During the last similar to 2 ka, the Everglades wetland was affected by a series of hydrologic fluctuations related to regional to global-scale fluctuations in climate and sea level. Pollen evidence indicates that regional-scale droughts lasting two to four centuries occurred similar to 1 ka and similar to 0.4 ka, altering wetland community composition and triggering development of characteristic Everglades habitats such as sawgrass ridges and tree islands. Intercalation of mangrove peats with estuarine muds similar to 1 ka indicates a temporary slowing or stillstand of sea level. Although sustained droughts and Holocene sea level rise played large roles in structuring the greater Everglades ecosystem, twentieth century reductions in freshwater flow, compartmentalization of the wetland, and accelerated rates of sea level rise had unprecedented impacts on oxidation and subsidence of organic soils, changes/loss of key Everglades habitats, and altered distribution of coastal vegetation.
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Williams, K.A., Frederick, P.C. and Nichols, J.D. (2011) Use of the superpopulation approach to estimate breeding population size: an example in asynchronously breeding birds. Ecology 92(4), 821-28.

  ABSTRACT
Many populations of animals are fluid in both space and time, making estimation of numbers difficult. Much attention has been devoted to estimation of bias in detection of animals that are present at the time of survey. However, an equally important problem is estimation of population size when all animals are not present on all survey occasions. Here, we showcase use of the superpopulation approach to capture-recapture modeling for estimating populations where group membership is asynchronous, and where considerable overlap in group membership among sampling occasions may occur. We estimate total population size of long-legged wading bird (Great Egret and White Ibis) breeding colonies from aerial observations of individually identifiable nests at various times in the nesting season. Initiation and termination of nests were analogous to entry and departure from a population. Estimates using the superpopulation approach were 47-382% larger than peak aerial counts of the same colonies. Our results indicate that the use of the superpopulation approach to model nesting asynchrony provides a considerably less biased and more efficient estimate of nesting activity than traditional methods. We suggest that this approach may also be used to derive population estimates in a variety of situations where group membership is fluid.
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Willson, J.D., Dorcas, M.E. and Snow, R.W. (2011) Identifying plausible scenarios for the establishment of invasive Burmese pythons (Python molurus) in Southern Florida. Biological Invasions 13(7), 1493-504.

  ABSTRACT
Successful invasions of secretive alien species often go unrecognized until spread has exceeded the point where control or eradication is feasible. In such situations, understanding factors that contributed to establishment can be critical to preventing subsequent introductions of previously-successful invaders or ecologically similar species. The Burmese python (Python molurus bivittatus), a native to Southeast Asia, is abundant in the pet trade and is now well-established in southern Florida. Although there can be little argument that the ultimate source of Florida pythons was the pet industry, there has been limited consideration of biological support for scenarios that may have lead to their establishment. In this study we use information on python capture rates and biologically-derived population growth models to evaluate the plausibility of various scenarios for python establishment. Our results indicate that scenarios involving relatively recent establishment (post-1990) require large numbers (100-1,000) of founders or unrealistically high juvenile survivorship. Intentional simultaneous release of large numbers of pythons is unlikely and accidental release of large numbers of founders is inconsistent with the spatial and temporal pattern of pythons captures in the region. We conclude that the most parsimonious scenario for establishment of pythons in Florida involves the release of a relatively small number of founders prior to 1985. Our results demonstrate that for pythons and other species with low inherent detection probabilities, early action during incipient phases of an invasion is critical and understanding likely introduction scenarios is important for preventing similar situations from occurring elsewhere or with other species.
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Xiao, H.Y. and Liu, C.Q. (2011) The elemental and isotopic composition of sulfur and nitrogen in Chinese coals. Organic Geochemistry 42(1), 84-93.

  ABSTRACT
Coal combustion is an important atmospheric pollution source in most Chinese cities, so systematic studies on sulfur and nitrogen in Chinese coals are needed. The sulfur contents in Chinese coals average 0.9 +/- 1.0%, indicating that most Chinese coals are low in sulfur. A nearly constant mean delta(34)S value is observed in low sulfur (TS < 1) Chinese coals of different ages (D, P(1), T(3) and J(3)). High sulfur Chinese coals (OS > 0.8%), often found at late Carboniferous (C(3)) and late Permian (P(2)) in southern China, had two main sulfur sources (original plant sulfur and secondary sulfur). The wide variety of delta(34)S values of Chinese coals (-15 parts per thousand to +50 parts per thousand) is a result of a complex sulfur origin. The delta(15)N values of Chinese coals ranged from -6 parts per thousand to +4 parts per thousand, showing a lack of correlation with coal ages, whereas nitrogen contents are higher in Paleozoic coals than in Mesozoic coals. This may be related to their original precursor plant species: high nitrogen pteridophytes for the Paleozoic coals and low nitrogen gymnosperms for the Mesozoic coals. Different to, delta(34)S values, Chinese coals showed higher delta(15)N values in marine environments than in freshwater environments.
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Xie, Z.X., Liu, Z.W., Jones, J.W., Higer, A.L. and Telis, P.A. (2011) Landscape unit based digital elevation model development for the freshwater wetlands within the Arthur C. Marshall Loxahatchee National Wildlife Refuge, Southeastern Florida. Applied Geography 31(2), 401-12.

  ABSTRACT
The hydrologic regime is a critical limiting factor in the delicate ecosystem of the greater Everglades freshwater wetlands in south Florida that has been severely altered by management activities in the past several decades. "Getting the water right" is regarded as the key to successful restoration of this unique wetland ecosystem. An essential component to represent and model its hydrologic regime, specifically water depth, is an accurate ground Digital Elevation Model (DEM). The Everglades Depth Estimation Network (EDEN) supplies important hydrologic data, and its products (including a ground DEM) have been well received by scientists and resource managers involved in Everglades restoration. This study improves the EDEN DEMs of the Loxahatchee National Wildlife Refuge, also known as Water Conservation Area 1 (WCA1), by adopting a landscape unit (LU) based interpolation approach. The study first filtered the input elevation data based on newly available vegetation data, and then created a separate geostatistical model (universal kriging) for each LU. The resultant DEMs have encouraging cross-validation and validation results, especially since the validation is based on an independent elevation dataset (derived by subtracting water depth measurements from EDEN water surface elevations). The DEM product of this study will directly benefit hydrologic and ecological studies as well as restoration efforts. The study will also be valuable for a broad range of wetland studies.
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Ye, R.Z., McCray, J.M. and Wright, A.L. (2011) Microbial Response of a Calcareous Histosol to Sulfur Amendment. Soil Science 176(9), 479-86.

  ABSTRACT
The objective of this study was to assess the functional response of microbial communities to sulfur amendment in calcareous organic soils of the Everglades Agricultural Area in south Florida. Soils under sugarcane cultivation were amended with elemental S at four rates up to 448 kg S ha(-1) to decrease pH and enhance nutrient availability. Soil samples were collected 2, 6, 9, and 13 months after S application and subjected to microbial, enzyme, and nutrient analysis. Application of S at rates up to 448 kg S ha(-1) enhanced labile P availability by 103% compared with unamended soils. Nonetheless, stimulatory effects were limited and temporary because of the high buffering capacity of this calcareous organic soil against acidification. Activities of leucine aminopeptidase and sulfatase were independent of S application. Phosphatase activities were 115% higher and glucosidase activities 573% higher for soils receiving the highest S rates than unamended soils at 2 months. Microbial biomass C and N were not affected by S amendment, but biomass P was 314% higher for soils amended with the highest S rates at 2 months than soils receiving the lowest rates, primarily as a result of increased P availability. The C, N, and P mineralization rates were not affected by S, although all rates varied seasonally, suggesting that S application did not stimulate soil oxidation. Overall, application of S generally did not result in pulse or flux of nutrients from soil, suggesting that S application had minimal benefits for increasing nutrient availability to sugarcane.
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Zhang, J.Z. and Huang, X.L. (2011) Effect of Temperature and Salinity on Phosphate Sorption on Marine Sediments.
Environmental Science & Technology 45(16), 6831-37.

  ABSTRACT
Our previous studies on the phosphate sorption on sediments in Florida Bay at 25 degrees C in salinity 36 seawater revealed that the sorption capacity varies considerably within the bay but can be attributed to the content of sedimentary P and Fe. It is known that both temperature and salinity influence the sorption process and their natural variations are the greatest in estuaries. To provide useful sorption parameters for modeling phosphate cycle in Florida Bay, a systematic study was carried out to quantify the effects of salinity and temperature on phosphate sorption on sediments. For a given sample, the zero equilibrium phosphate concentration and the distribution coefficient were measured over a range of salinity (2-72) and temperature (15-35 degrees C) conditions. Such a suite of experiments with combinations of different temperature and salinity were performed for 14 selected stations that cover a range of sediment characteristics and geographic locations of the bay. Phosphate sorption was found to increase with increasing temperature or decreasing salinity and their effects depended upon sediment's exchangeable P content. This study provided the first estimate of the phosphate sorption parameters as a function of salinity and temperature in marine sediments. Incorporation of these parameters in water quality models will enable them to predict the effect of increasing freshwater input, as proposed by the Comprehensive Everglades Restoration Plan, on the seasonal cycle of phosphate in Florida Bay.
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Zhang, K.Q. (2011) Analysis of non-linear inundation from sea-level rise using LIDAR data: a case study for South Florida. Climatic Change 106(4), 537-65.

  ABSTRACT
By analyzing a digital elevation model (DEM) derived from airborne light detection and ranging (LIDAR) data and airborne height finder measurements, this study demonstrates that a 1.5 m sea-level rise by 2100 would cause inundation of large areas of Miami-Dade County, southern Broward County, and Everglades National Park. Inundation processes are non-linear: inundation is gradual before reaching a threshold, and speeds up rapidly afterwards due to the regional topography. Accelerated sea-level rise will cause the threshold to be reached sooner by amplifying the non-linear inundation, and must be considered in policy-making. Comparison of inundated areas extracted from 30 m LIDAR and USGS DEMs indicates that the vertical accuracy of a DEM has a great effect on delineation of inundation areas. For a 1.5 m sea-level rise, the inundated area delineated by USGS DEM for Broward County is 1.65 times greater than that indicated by the LIDAR DEM.
   
  2011 second part (M-Z)                  END  of new 2011 references
   

   

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