Distribution of unionid mussels in tributaries of the Lower Flint River, Southwestern Georgia: an examination of current and historical trends

The historically diverse assemblage of freshwater mussels in the Flint River Basin (FRB) has shown declines in abundance and distribution. The mid-reaches of the major tributaries of the Flint River contained one of the richest assemblages of mussels in the southeastern Coastal Plain. Declines in mussel assemblages were accelerated by the recent drought that occurred during 1999-2001. Following the drought, we surveyed mussel populations at selected sites in the major tributaries of the Flint River to determine if declines in abundance and distribution were continuing. Many populations of common, rare, and endangered species were stable in their distribution but exhibited declines in numbers. One survey site in particular, on Spring Creek, contains a rich assemblage of mussels unique to this basin, and surveys from this site also suggest population declines. Possible explanations for declines include poor water quality, loss or degradation of instream habitat, competition from the exotic Asiatic clam, and inadequate instream flows.Sponsored by: Georgia Environmental Protection Division U.S. Geological Survey, Georgia Water Science Center U.S. Department of Agriculture, Natural Resources Conservation Service Georgia Institute of Technology, Georgia Water Resources Institute The University of Georgia, Water Resources Facult

Effects of Flooding on the Longleaf Pine-Wiregrass Ecosystem

Proceedings of the 1995 Georgia Water Resources Conference, April 11 and 12, 1995, Athens, Georgia.Flood waters associated with Tropical Storm Alberto inundated 21 km2 of uplands at Ichauway, a 115 km 2 ecological reserve located in southwestern Georgia. At the landscape scale, sink holes were formed, landslides and erosion occurred along riverine bluffs and terraces, and sediment deposition occurred along all riparian corridors. Xeric habitats, dominated by longleaf pine-wiregrass and scrub-shrub, were disproportionately affected by flooding on an area basis. Longleaf pine seedlings and saplings with apical meristems above high water always survived. Mortality of submerged longleaf pine and wiregrass was positively related to flooding depth and duration. Treefall in bluff riparian zones and hardwood hammocks reflected species composition within the two habitats although oaks and southern red cedar were the most commonly downed trees in both habitats. Higher treefall was observed in bluff riparian zones and may be related to constrained stream channel geomorphology. Although infrequent, flooding appears to be important in governing the structure and function of the longleaf pine-wiregrass ecosystem and, along with other disturbances, should be explicitly incorporated into reserve and riparian corridor planning and design.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Carl Vinson Institute of Government, The University of Georgia, Athens, Georgia 30602 with partial funding provided by the U.S. Department of Interior, Geological Survey, through the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1990 (P.L. 101-397). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of the University of Georgia or the U.S. Geological Survey or the conference sponsors

Elevated aluminium concentration in acidified headwater streams lowers aquatic hyphomycete diversity and impairs leaf-litter breakdown.

Aquatic hyphomycetes play an essential role in the decomposition of allochthonous organic matter which is a fundamental process driving the functioning of forested headwater streams. We studied the effect of anthropogenic acidification on aquatic hyphomycetes associated with decaying leaves of Fagus sylvatica in six forested headwater streams (pH range, 4.3-7.1). Non-metric multidimensional scaling revealed marked differences in aquatic hyphomycete assemblages between acidified and reference streams. We found strong relationships between aquatic hyphomycete richness and mean Al concentration (r = -0.998, p < 0.0001) and mean pH (r = 0.962, p < 0.002), meaning that fungal diversity was severely depleted in acidified streams. By contrast, mean fungal biomass was not related to acidity. Leaf breakdown rate was drastically reduced under acidic conditions raising the issue of whether the functioning of headwater ecosystems could be impaired by a loss of aquatic hyphomycete species

Using Adopt-A-Stream in the coastal plain: a look at the macroinvertebrate index

As major threats to Georgia’s waterways continue, volunteer-based monitoring groups such as Georgia Adopt-A-Stream (GA AAS) have become a vital source of information on aquatic ecological condition. Biological monitoring is an important component of the program, with macroinvertebrates serving as the primary tool for assessing water quality. We evaluated the validity and applicability of the GA AAS macroinvertebrate index on three impacted and two reference streams within an agricultural landscape in the Coastal Plain region of southwest Georgia. We compared these findings to a concurrent study that examined the condition of streams impacted by grazing livestock, through water quality, physical and vegetative parameters as well as macroinvertebrate metrics. The GA AAS index for macroinvertebrates proved to be effective in separating sites with different impacts, showing similar results as most invertebrate indices, and appears to be a valid tool to assess the ecological condition of Coastal Plain streams.Sponsored by: Georgia Environmental Protection Division U.S. Geological Survey, Georgia Water Science Center U.S. Department of Agriculture, Natural Resources Conservation Service Georgia Institute of Technology, Georgia Water Resources Institute The University of Georgia, Water Resources Facult

Current Conditions of Historical Mussel Habitat in the Flint River Basin, Georgia

Proceedings of the 2007 Georgia Water Resources Conference, March 27-29, 2007, Athens, Georgia.Streams of the Flint River Basin (FRB) remain as viable habitat for many freshwater species and harbor some of the most diverse mussel assemblages in the Southeast. However, land use changes, hydrologic alterations, and declines in native fish species have adversely affected mussel diversity and abundance throughout the region. Protection of rare and sensitive mussels requires the development of timely conservation strategies, supported by knowledge of current riparian and instream habitat conditions that impact their survival and recovery. We examined habitat conditions and selected water quality parameters at 81 stream sites that have historically supported populations of freshwater mussel species in the Basin. Higher nutrient, sediment, and bacterial concentrations were observed in the upper portion (Piedmont) of the Basin, which is characterized by higher gradient streams and percentages of urban land use. Sites in the lower section of the Basin (Fall Line Hills and Coastal Plain) maintained better quality riparian habitat including a larger buffer zone width, greater bank stability, and more vegetative cover. Overall, mussel habitat quality appeared good throughout the Basin. Physicochemical parameters and riparian habitat quality were influenced both by regional geologic differences and patterns of human activity.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, Natural Resources Conservation Service, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202. The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia, the U.S. Geological Survey, the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1990 (P.L. 101-397) or the other conference sponsors

Stream Flow Changes Associated With Water Use and Climatic Variation in the Lower Flint River Basin, Southwest Georgia

Proceedings of the 2007 Georgia Water Resources Conference, March 27-29, 2007, Athens, Georgia.In the 1970’s agricultural water use expanded rapidly in the lower Flint River Basin resulting from the introduction of center pivot irrigation technology. The rapid expansion has raised concerns about impacts on regional stream flows essential to support aquatic fauna. Using long-term stream gage records from the USGS and climate data, we analyzed trends in stream flow in two major sub-watersheds and regional patterns of rainfall from 1940 through 2004. We observed no change in annual rainfall but seasonality changed with winters being slightly wetter. Minimum flows showed substantial declines since the development of irrigation. We attribute altered stream flows to increased regional water demand however; the demand for water is also exacerbated by long-term variations in climate and rainfall distribution.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, Natural Resources Conservation Service, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Institute of Ecology, The University of Georgia, Athens, Georgia 30602-2202. The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia, the U.S. Geological Survey, the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1990 (P.L. 101-397) or the other conference sponsors

The economics of parasitic diseases: Research priorities

Parasitic diseases are primarily diseases of poverty. At serious risk are individuals, communities and countries least able to afford the costs of treatment of prevention. In turn, economic development projects which aim to increase income levels may lead to negative results because of increased transmission of parasitic diseases often results. In attempting to analyse the economic consequences of parasitic diseases and the economics of their control, economists have usually relied on the tools of cost-benefit analysis, cost-effectiveness analysis and financial analysis. These efforts are briefly reviewed in the paper. The results have been subject to considerable criticism because of conceptual and methodological problems. For example, most studies have not taken into account the epidemiology and natural history of the disease in estimating the associated economic losses, thereby leading to inappropriate conclusions. The UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases through its Social and Economic Research Scientific Working Group (SER-SWG) is promoting research on the economics of parasitic diseases. In an attempt to improve the usefulness and reliability of such studies, conceptual and methodological approaches have been suggested which are reported on here. To improve the research design of these projects, a conceptual framework is proposed which consists of four components: (1) baseline social, cultural and economic conditions influencing disease transmission; (2) resources already invested in the health system and investments in other related sectors such as agriculture, housing, water supply and sanitation; (3) health consequences resulting from (1) and (2); and (4) social and economic consequences resulting from (3). A key concern in relation to the framework is to determine the most useful basis for linking results from studies of one component to another so as to analyse more systematically the impacts of disease on individuals and society. Such studies are inherently interdisciplinary and close collaboration of economists with medical scientists and disease control programme staff is needed to ensure completeness and reliability of input data and results. Results from these studies could be used to inform national decision-makers about the social and economic consequences of the parasitic diseases and their control and, thus, should strengthen support for increased investment to reduce the parasitic disease burden in developing countries.

Stream macroinvertebrates and amphibians as indicators of ecosystem stress: a case study from the Coastal Plain, GA

Proceedings of the 2003 Georgia Water Resources Conference, held April 23-24, 2003, at the University of Georgia.Conservation buffers are one strategy adopted by various federal and state agencies to aid in the reduction of agricultural impacts on surface and ground water systems. A diversified row crop and beef cattle operation located on a tributary of the Lower Chattahoochee River in Early County, southwest Georgia was the selected site for this study. A suite of indicators were chosen to evaluate the impact of agriculture on three unfenced and two fenced stream sites. Preliminary results provide no discernible differences in herpetofaunal captures between sites, except for larval salamanders captured within bimonthly invertebrate samples, which were more abundant at fenced sites. Percentages of EPT, Coleoptera and Crustacea were also higher at fenced sites, which also showed lower levels of nitrate-N, suspended solids, and fecal coliforms. Exclusion sites, which had been fenced out three years prior to this study, suggest some recovery from cattle impacts