Using Rapid Bio-assessment and Habitat Evaluation Methods to Understand the Effects of Different Land Uses on a Privately-owned River in Southwest Virginia

Abstract

Private lands comprise the majority of the land area in the United States and serve as reservoirs for biodiversity conservation. Rivers in watersheds containing privately owned agricultural land often experience agricultural disturbances resulting in increased erosion and siltation. It was hypothesized that stream reaches subjected to agricultural disturbance, primarily from livestock, would exhibit decreased habitat quality and increasingly stressed aquatic communities. This study was conducted in the North Fork of the Roanoke River in Montgomery County, Virginia, USA. The Qualitative Habitat Evaluation Index and Use Assessment (QHEI) was applied to measure habitat quality and the Virginia Stream Condition Index (VSCI) to assess ecological health. QHEI and VSCI scores were determined between parcels based on different land uses. The downstream mean QHEI score was 49.7 ± 3.7, compared to the upstream score 57.2 ± 6.5. Conversely, the downstream VSCI score was 74.9 ± 5.4, compared to the upstream score 60.8 ± 20.9. These score discrepancies are likely due to concentrated livestock river access, an upstream low water crossing, degraded banks and increased siltation at the study site which reduced macroinvertebrate abundance, especially pollution-sensitive groups. Management to reduce livestock entry and remove low-water crossing structures may reduce sedimentation and increase VSCI recovery potential. Increasing understanding of factors adversely affecting the ecosystems within private lands, as demonstrated by this research project, improves management efficacy and enhances the area's role in promoting biodiversity conservation. Future research to understand how ecological communities and habitat quality respond to different private land uses should be conducted in southwest Virginia to further advance private land conservation.