Treesearch

Management of aquatic and riparian ecosystems is constrained because of the reliance on “off-the-shelf” and one-size-fits-all concepts and designs, rather than considering specific features and capabilities of the location of interest. As a result, use of fixed- width buffers that generally depend on stream size is the most common approach.

Dynamic landscapes are shaped by a variety of natural processes and disturbances operating across multiple temporal and spatial scales. Persistence of species in these dynamic environments is also a matter of scale: how do species dispersal and reproductive rates merge with the scales of disturbance?

The Chesapeake Bay, the nation’s largest estuary, remains in relatively poor condition despite intensive public and scientific attention. In order to better understand the stressors and impacts occurring in the Bay as a result of land management decisions we conducted an assessment of both habitat condition and organismal response in three small watersheds of the upper Bay.

The U.S. Geological Survey’s (USGS) Water, Energy, and Biogeochemical Model (WEBMOD) was used to simulate hydrology, weathering, and isotopic fractionation in the Andrews Creek watershed in Rocky Mountain National Park, Colorado and the Icacos River watershed in the Luquillo Experimental Forest, Puerto Rico. WEBMOD includes hydrologic modules derived from the USGS Precipitation Runoff Modeling System, the National Weather Service Hydro-17 snow model, and TOPMODEL. PHREEQC, a geochemical reaction model, is coupled with the hydrologic model to simulate the geochemical evolution of waters as...

In Grant Parish, LA, increases in overstory basal area, canopy cover, and development of understory woody plants reduce over the last 50 years, the Apalachicola-Chattahoochee- Flint (ACF) Basin in Alabama, Florida, and Georgia has undergone extensive development of water resources for municipal and industrial supplies, power generation, and agriculture. Concurrent with this development, there has been increasing conflict over the use of water in the ACF system, resulting in legal battles over the rights to this valuable resource.

The degree of hydrological connectivity between wetland systems and downstream receiving waters can be expected to influence the volume and variability of stream discharge. The Prairie Pothole Region contains a high density of depressional wetland features, a consequence of glacial retreat. Spatial variability in wetland density, drainage evolution, and precipitation patterns as well as interannual and interdecadal variability in climate can be expected to result in variable degrees of wetland-stream connectivity within the region.

Many coastal ecosystems along the south Atlantic are transitioning from forested wetlands to marsh due to increasing tidal inundation and saltwater intrusion primarily attributed to global climate change processes. In 2004, we established long-term research sites in Georgia, South Carolina, and Louisiana to understand how climate factors (temperature, precipitation, streamflow, sea-level rise, droughts, and hurricanes) interact to elevate soil salinities and flooding that collectively foster forest dieback and habitat conversion in tidal freshwater forested wetlands of the Southeast.

Coastal forested freshwater wetlands are sentinel sites for salinity intrusions associated with large, tidally influenced, storm-driven or drought-induced incursions of estuarine waters into freshwater ecosystems. These incursions may also be exacerbated by rising sea levels associated with climate change.

Hydrology is recognized as one of the principal factors regulating soil biogeochemical processes in forested wetlands. However, the consequences of tidally mediated hydrology are seldom considered within forested wetlands that occur along tidal water bodies. These tidal water bodies may be either fresh or brackish, and the tidal streams function as a reservoir to sustain a shallow water table depth as compared to nontidal stream reaches. Accordingly, both the hydrology and water chemistry are expected to affect the forest carbon cycle; however, there are few studies to support this...

Non-point source pollution from stormwater runoff associated with large-scale land use changes threatens the integrity of ecologically and economically valuable estuarine ecosystems. Beaufort County, SC implemented volume-based stormwater regulations on the rationale that if volume discharge is controlled, contaminant loading will also be controlled.