Effects of landscape characteristics on water quality and fish assemblages in the Tallapoosa River Basin, Alabama

摘要

To maintain and improve water quality, there is an increasing need to understand relationships between current land-use practices (e.g., agriculture, forested/silviculture, and urban) and stream ecosystems. In this study, we investigated the relationships among water quality, habitat composition, fish assemblages, and current land-use practices in the Tallapoosa River Basin in eastern Alabama. Within the six streams investigated, all fish metrics were significantly higher for forested watersheds compared to agricultural watersheds, with total nitrogen and total phosphorus being the variables most descriptive of fish biotic integrity (i.e., total nitrogen and total phosphorus were negatively related to fish biotic integrity). In addition, we found that nutrient concentrations (especially total nitrogen and total phosphorus) increased as percent agricultural land use increased. When looking at a larger scale (Tallapoosa River Basin), anthropogenic impacts such as eutrophication of Lakes Martin and Harris were related to agricultural land practices and the percentage of the basin these practices occupy. Because current land-use practices appear to be negatively impacting stream water quality and biota, it is important to decrease the amount of fertilizer, pesticides, and animal waste that runoff into streams and to protect riparian zones in order to preserve or improve biotic integrity.