Eco Hydrology


Eco Hydrology

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Rivera-Monroy V.H.,Louisiana State University | Lenaker P.,Louisiana State University | Twilley R.R.,Louisiana State University | Delaune R.D.,Louisiana State University | And 5 more authors.
Journal of Sea Research | Year: 2010

By transforming fixed nitrogen (N) into nitrogen gas, the biochemical processes that support denitrification provide a function critical to maintaining the integrity of ecosystems subjected to increased loading of N from anthropogenic sources. The Louisiana coastal region receives high nitrate (NO3 -) concentrations (> 100 μM) from the Mississippi-Ohio-Missouri River Basin and is also an area undergoing high rates of wetland loss. Ongoing and anticipated changes in the Louisiana coastal region promise to alter biogeochemical cycles including the net rate of denitrification by ecosystems. Projecting what these changes could mean for coastal water quality and natural resources requires an understanding of the magnitude and patterns of variation in denitrification rates and their connection to estuarine water quality at large temporal and spatial scales under current conditions. We compile and review denitrification rates reported in 32 studies conducted in a variety of habitats across coastal Louisiana during the period 1981- 2008. The acetylene inhibition and 15N flux were the preferred techniques (95%); most of the studies used sediment slurries rather than intact sediment cores. There are no estimates of denitrification rates using the N2/Ar ratio and isotope pairing techniques, which address some of the problems and limitations of the acetylene inhibition and 15N flux techniques. These studies have shown that sediments from estuaries, lakes, marshes, forested wetlands, and the coastal shelf region are capable of high potential denitrification rates when exposed to high NO3 - concentrations (> 100 μM). Maximum potential denitrification rates in experimental and natural settings can reach values > 2500 μmol m2 h- 1. The lack of contemporary studies to understand the interactions among critical nitrogen transformations (e.g., organic matter mineralization, immobilization, aquatic plant assimilation, nitrification, nitrogen fixation, dissimilatory nitrate reduction to ammonium (DNRA) and anaerobic ammonium oxidation (annamox) limits our understanding of nitrogen cycling in coastal Louisiana, particularly the role of respiratory and chemolithoautotrophic denitrification in areas undergoing wetland restoration. © 2009 Elsevier B.V.

Rivera-Monroy V.H.,Louisiana State University | Twilley R.R.,Louisiana State University | Davis S.E.,Texas A&M University | Childers D.L.,Arizona State University | And 17 more authors.
Critical Reviews in Environmental Science and Technology | Year: 2011

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 μg 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. Copyright © 2011 Taylor & Francis Group, LLC.

Ugarte C.A.,University of Florida | Bass O.L.,South Florida Natural Resource Center | Nuttle W.,Eco hydrology | Mazzotti F.J.,University of Florida | And 3 more authors.
Journal of Wildlife Management | Year: 2013

Hydrologic conditions are critical to the nesting behavior and reproductive success of crocodilians. In South Florida, USA, growing human settlement has led to extensive surface water management and modification of historical water flows in the wetlands, which have affected regional nesting of the American alligator (Alligator mississippiensis). Although both natural and anthropogenic factors are considered to determine hydrologic conditions, the aspects of hydrological patterns that affect alligator nest effort, flooding (partial and complete), and failure (no hatchling) are unclear. We deconstructed annual hydrological patterns using harmonic models that estimated hydrological matrices including mean, amplitude, timing of peak, and periodicity of surface water depth and discharge and examined their effects on alligator nesting using survey data from Shark Slough, Everglades National Park, from 1985 to 2005. Nest effort increased in years with higher mean and lesser periodicity of water depth. A greater proportion of nests were flooded and failed when peak discharge occurred earlier in the year. Also, nest flooding rates were greater in years with greater periodicity of water depth, and nest failure rate was greater when mean discharge was higher. This study guides future water management decisions to mitigate negative impacts on reproduction of alligators and provides wildlife managers with a tool for assessing and modifying annual water management plans to conserve crocodilians and other wetland species. Copyright © 2012 The Wildlife Society.

Johns G.,Hazen and Sawyer | Lee D.J.,DJL Economic Consulting | Leeworthy V.B.,West Marine | Boyer J.,Plymouth State University | Nuttle W.,Eco Hydrology
Ecological Indicators | Year: 2014

Resource managers in South Florida are aware that coastal and marine ecosystems provide food, recreation, and a quality of life that are highly-valued by humans. Estimates of economic values in Florida, such as willingness-to-pay for a day of coral reef snorkeling or the change in this value from a change in coral cover, are not updated in a timely manner or are not available at all. Usually these studies are "baseline studies" that provide a snapshot of economic values under existing economic and environmental conditions. Therefore, to be useful to ecosystems management, human dimension (HD) economic indicators that are relatively easy to measure each year must be identified. In addition, they must be combined with a conceptual model that links these indicators to the ecosystem services; their relevant economic values; the HD non-economic metrics of well-being; and the quality and/or quantity of the environmental and ecologic attributes associated with the ecosystem service. Carefully selected HD economic indicators together with ecological, environmental, and non-economic human dimensions indicators can provide a rich source of information for managing the long term conservation and use of coastal and marine ecosystems. In this paper, we specify criteria for selecting HD economic indicators that measure the change in demand for ecosystem services resulting from changes in the quality or quantity of the environmental attributes that comprise the service. We assessed a suite of candidate metrics and arrived at a final set of HD economic indicators for further evaluation. These HD economic indicators are the percentage change from year to year in: (1) coastal park visitation; (2) number of registered recreational boats; (3) pounds of commercial seafood landed; (4) number of live marine organisms landed; and (5) dollar value of insured flood damage claims paid. We illustrated the use of these HD economic indicators with an empirical example for the Florida Keys and Dry Tortugas where the indicators are measured over a one year period. The changes were then scored and the scores were assigned a stop light rating of: green for good (or increasing), yellow for fair (or stable), and red for poor (or decreasing). Our empirical illustration of HD economic indicators offers a first step in developing metrics to rate the status of Florida's coastal and marine ecosystem services. The next steps are to propose a full suite of candidate HD economic indicators and metrics; final selection of HD economic indicators and their integration into the conceptual model; annual calculation of these indicators and their evaluation; and environmental/ecosystem assessment. © 2014 Elsevier Ltd.

Kelble C.R.,National Oceanic and Atmospheric Administration | Loomis D.K.,East Carolina University | Lovelace S.,National Oceanic and Atmospheric Administration | Nuttle W.K.,Eco Hydrology | And 6 more authors.
PLoS ONE | Year: 2013

There is a pressing need to integrate biophysical and human dimensions science to better inform holistic ecosystem management supporting the transition from single species or single-sector management to multi-sector ecosystem-based management. Ecosystem-based management should focus upon ecosystem services, since they reflect societal goals, values, desires, and benefits. The inclusion of ecosystem services into holistic management strategies improves management by better capturing the diversity of positive and negative human-natural interactions and making explicit the benefits to society. To facilitate this inclusion, we propose a conceptual model that merges the broadly applied Driver, Pressure, State, Impact, and Response (DPSIR) conceptual model with ecosystem services yielding a Driver, Pressure, State, Ecosystem service, and Response (EBM-DPSER) conceptual model. The impact module in traditional DPSIR models focuses attention upon negative anthropomorphic impacts on the ecosystem; by replacing impacts with ecosystem services the EBM-DPSER model incorporates not only negative, but also positive changes in the ecosystem. Responses occur as a result of changes in ecosystem services and include inter alia management actions directed at proactively altering human population or individual behavior and infrastructure to meet societal goals. The EBM-DPSER conceptual model was applied to the Florida Keys and Dry Tortugas marine ecosystem as a case study to illustrate how it can inform management decisions. This case study captures our system-level understanding and results in a more holistic representation of ecosystem and human society interactions, thus improving our ability to identify trade-offs. The EBM-DPSER model should be a useful operational tool for implementing EBM, in that it fully integrates our knowledge of all ecosystem components while focusing management attention upon those aspects of the ecosystem most important to human society and does so within a framework already familiar to resource managers.

Fletcher P.J.,University of Florida | Fletcher P.J.,National Oceanic and Atmospheric Administration | Kelble C.R.,National Oceanic and Atmospheric Administration | Nuttle W.K.,Eco Hydrology | And 2 more authors.
Ecological Indicators | Year: 2014

Ecosystem-based management is widely regarded as a method to improve the way we manage our coastal marine resources and ecosystems. Effective ecosystem-based management relies upon synthesizing our scientific knowledge and transferring this knowledge into management actions. Integrated ecosystem assessment is a framework to conduct this scientific synthesis and transfer information to resource managers. Portions of the framework were applied to build consensus on the focal ecosystem components and processes that are characteristic of a sustainable South Florida coastal ecosystem that is producing ecosystem services at the level society desires. Consensus was developed through facilitated meetings that aimed to conceptualize the ecosystem, develop ecosystem indicators, and conduct risk analysis. Resource managers, researchers, academics, and non-governmental organizations participated in these meetings and contributed to the synthesis of science and a myriad of science communications to transfer information to decision makers and the public. A proof of concept Bayesian Belief Network was developed to explore integrating the results of this assessment into an interactive management scenario evaluation tool. The four year effort resulted in the development of a research and management coordination network in South Florida that should provide the foundation for implementing ecosystem-based resource management across multiple agencies. © 2014 Elsevier Ltd.

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