Recent studies suggest that coastal ecosystems can bury significantly more C than tropical forests, indicating that continued coastal development and exposure to sea level rise and storms will have global biogeochemical consequences. The Florida Coastal Everglades Long Term Ecological Research (FCE LTER) site provides an excellent subtropical system for examining carbon (C) balance because of its exposure to historical changes in freshwater distribution and sea level rise and its history of significant long-term carbon-cycling studies. FCE LTER scientists used net ecosystem C balance and net ecosystem exchange data to estimate C budgets for riverine mangrove, freshwater marsh, and seagrass meadows, providing insights into the magnitude of C accumulation and lateral aquatic C transport. Rates of net C production in the riverine mangrove forest exceeded those reported for many tropical systems, including terrestrial forests, but there are considerable uncertainties around those estimates due to the high potential for gain and loss of C through aquatic fluxes. C production was approximately balanced between gain and loss in Everglades marshes; however, the contribution of periphyton increases uncertainty in these estimates. Moreover, while the approaches used for these initial estimates were informative, a resolved approach for addressing areas of uncertainty is critically needed for coastal wetland ecosystems. Once resolved, these C balance estimates, in conjunction with an understanding of drivers and key ecosystem feedbacks, can inform cross-system studies of ecosystem response to long-term changes in climate, hydrologic management, and other land use along coastlines

The modular ecosystem modeling approach was used to create a flexible landscape model structure that is easy to modify and extend for particular case studies and applications. The Library of Hydro Ecological Modules (LHEM; http://iee.umces.edu/LHEM) includes modules that describe hydrologic processes, nutrient cycling, vegetation growth, decomposition, etc., both locally and spatially. LHEM is implemented within the framework of the Spatial Modeling Environment (SME; http://iee.umces.edu/SME3) that integrates modules and places local simulation models into a spatial context. The LHEM was used to build the Patuxent Landscape Model (PLM) as well as models of several subwatersheds of the Patuxent. Local ecosystem dynamics are replicated across a grid of cells that compose the rasterized landscape. Different habitats and land use types translate into different parameter sets that drive the modules chosen. Spatial hydrologic modules define horizontal fluxes of material and information and link the cells together. Results show good agreement with data for several components of the model at several scales. The modular structure was essential to refocus the model on several problems associated with different management decisions that were to be made.

Abstract:The modular ecosystem modeling approach was used to create a flexible landscape model structure that is easy to modify and extend for particular case studies and applications. The Library of Hydro Ecological Modules (LHEM; http://iee.umces.edu/LHEM) includes modules that describe hydrologic processes, nutrient cycling, vegetation growth, decomposition, etc., both locally and spatially. LHEM is implemented within the framework of the Spatial Modeling Environment (SME; http://iee.umces.edu/SME3) that integrates modules and places local simulation models into a spatial context. The LHEM was used to build the Patuxent Landscape Model (PLM) as well as models of several subwatersheds of the Patuxent. Local ecosystem dynamics are replicated across a grid of cells that compose the rasterized landscape. Different habitats and land use types translate into different parameter sets that drive the modules chosen. Spatial hydrologic modules define horizontal fluxes of material and information and link the cells together.Results show good agreement with data for several components of the model at several scales. The modular structure was essential to refocus the model on several problems associated with different management decisions that were to be made.

Modelización del efecto de los cambios de uso sobre los flujos de nutrientes en cuencas agrícolas costeras: el caso del Mar Menor (Sudeste de España). Se ha elaborado un enfoque integrado de modelización de la dinámica hidrológica de una cuenca agrícola, la cuenca de la laguna costera del Mar Menor (Sudeste de España), para analizar los efectos de los cambios de uso a medio y largo plazo sobre los flujos de nutrientes que alcanzan la laguna y sus humedales periféricos. Se ha elaborado un modelo socioambiental sin dimensión espacial explícita que presta especial atención a los factores socio-económicos y los cambios de uso. Se presentan también los resultados preliminares de la aplicación al Mar Menor del modelo ELM (Ecological Landscape Modeling), un modelo hidroecológico con dimensión espacial explícita, como mejora de la modelización hidrológica de la cuenca. Los resultados del modelo integrado muestran el significativo incremento de la entrada de nutrientes en la laguna del Mar Menor, la existencia de grandes fluctuaciones interanuales y el papel de los humedales en la retención de una parte de tales nutrientes. Se ha aplicado el modelo para analizar los efectos previsibles de distintas medidas de gestión orientadas a reducir la exportación de nutrientes a la laguna del Mar Menor, en particular la reutilización de drenajes agrícolas y la recuperación de humedales. Los resultados de la simulación de tales medidas señalan que la recuperación de humedales es más eficaz que la reutilización de drenajes, consiguiendo una reducción más significativa de los nutrientes que finalmente alcanzan el Mar Menor.Palabras clave: modelo socio-ambiental; regadío; simulación dinámica, ciclos de nutrientes An integrated modelling approach on the nutrient dynamics has been developed for its application in the agricultural watershed of the Mar Menor coastal lagoon (South-eastern Spain), in order to analyse the long-term effects of land-use change on the nutrients inputs into the lagoon and associated wetlands. A lumped dynamic model has been developed which focuses on the socio-economic factors and land-use changes and their effects on the watershed-scale nutrient flows. In addition, a preliminary application of the ELM (Ecological Landscape Model), an eco-hydrological spatial dynamic model, has been carried out as an ongoing improvement of the hydrological modelling module. Simulation results for the 1970-2012 period showed a noticeable increase in nutrient inflows into the Mar Menor lagoon, highlighting the high inter-annual variability and the role of associated wetlands to remove part of the nutrients. The modeling approach was applied to explore the potential effects of several management measures aiming at reducing the export of nutrients from the agricultural fields into the Mar Menor lagoon, particularly studying measures to reuse agricultural leakages and plans for wetlands restoration. Results showed that wetlands restoration achieves a higher reduction in the inflow of nutrients into the lagoon, doubling those achieved...

No abstract

In this paper, we provide screening-level analysis of plausible Everglades ecosystem response by 2060 to sea level rise (0.50 m) interacting with macroclimate change (1.5 °C warming, 7% increase in evapotranspiration, and rainfall that either increases or decreases by 10%). We used these climate scenarios as input to the Ecological Landscape Model to simulate changes to seven interactive hydro-ecological metrics. Mangrove forest and other marine influences migrated up to 15 km inland in both scenarios, delineated by the saltwater front. Freshwater habitat area decreased by 25-30% under our two climate change scenarios and was largely replaced by mangroves and, in the increased rainfall scenario, open water as well. Significant mangroves drowned along northern Florida Bay in both climate change scenarios due to sea level rise. Increased rainfall of 10% provided significant benefits to the spatial and temporal salinity regime within the marine-influenced zone, providing a more gradual and natural adjustment for at-risk flora and fauna. However, increased rainfall also increased the risk of open water, due to water depths that inhibited mangrove establishment and reduced peat accumulation rates. We infer that ecological effects related to sea level rise may occur in the extreme front-edge of saltwater intrusion, that topography will control the incursion of this zone as sea level rises, and that differences in freshwater availability will have ecologically significant effects on ecosystem resilience through the temporal and spatial pattern of salinity changes.

No abstract

No abstract