Hydrology, landscape ecology, and wetland structure & function
The west-central Florida landscape presents an archipelago of freshwater wetlands set in matrices of upland native scrub, urban, and agricultural habitats, as seen in the images below. These wetlands form in topographic depressions, or sinkholes, and by some estimates cover nearly 30% of Florida. This population of wetlands exhibits highly variable ecology, hydrology, and biogeochemistry. The main goal of this research is to identify sources of this variability in order to test basic hypotheses in ecohydrology and to inform wetland ecosystem management.
Hydroperiod provides one striking difference among wetlands, even among wetlands in close proximity. Some wetlands are inundated for nearly half of each year, others for merely one month each year, and yet other wetlands have seen surface water on perhaps three brief occasions during the past two decades. This variability in hydroperiod probably derives from spatial heterogeneity in geological formations and anthropogenic influences (groundwater pumping, redirection of storm runoff). Moreover, the annual hydroperiod exhibited by many wetlands has changed across the years owing to changes in climate and human activities. We are using this spatial and temporal variability in hydroperiod to understand the importance of hydroperiod for soil organic matter oxidation and element cycles in both soil and water, for the diversity and composition of ecological assemblages such as those of plants, and for the relationships between biogeochemical cycles and ecological communities.
Another striking aspect of these wetlands is the variety of upland matrix in which they are set. Wetlands have a multivariate landscape context characterized by their immediate surroundings, by their proximity to potential sources of disturbance (e.g., groundwater extraction), and by their position in regional geological and hydrological templates. So in addition to studying relationships among variables within wetlands, as described above, we also seek to develop a landscape template model as an organizing framework for the 100s to 1000s of individual wetlands in the regional wetland population.
These wetlands may be sensitive to a variety of anthropogenic drivers such as land use, groundwater extraction, and nutrient loading. They also provide a sense of place for many people and they inform regional water policy. Thus, our studies of wetland ecology are part of an interdisciplinary socioecological research program that examines the social and ecological drivers and outcomes of water distribution.