Semester

Fall

Date of Graduation

2009

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Wildlife and Fisheries Resources

Committee Chair

J. Todd Petty.

Abstract

Large scale surface mining in southern West Virginia causes significant alteration of headwater stream networks. It is unclear, however, the extent to which mining interacts with other stressors to determine physical, chemical, and biological conditions in aquatic systems downstream. Through a watershed scale assessment of Pigeon Creek, the specific objectives of this study were to: (1) quantify the direct and interactive effects of mining and residential development on in-stream conditions; and (2) identify landscape thresholds above which biological impairment occurs. Our results indicate high levels of impairment to habitat, water quality, and benthic invertebrate communities within this watershed. Statistical analyses indicate that degraded conditions were linked to both mining and residential development; however, residential development appeared to exhibit a stronger individual effect. Both mining and residential development resulted in a significant decrease in sensitive taxa. The impacts associated with residential development, however, also resulted in the proliferation of tolerant taxa. Both mining and residential development resulted in significant alterations to water chemistry, primarily through increases in dissolved ion concentrations and specific conductance. Changes in water quality resulting from mining, however, were more acute. Conversely, residential development resulted in more acute alterations to physical habitat, primarily through decreases in habitat complexity. Our results further suggest that the individual impacts associated with mining and residential development are additive, leading to highly degraded conditions downstream. The combined effects of mining and residential development were almost always worse than the individual effects of mining, but never worse than the individual effects of residential development. Thus, residential development appears to be the limiting factor in determining ecosystem impairment. Lastly, several community metrics exhibited potential threshold responses to relatively low levels of both total mining (∼25%) and parcel density (∼14 parcels/km 2). These change points corresponded to conductivities of approximately 100 uS/cm and 60 uS/cm, respectively. This study shows that effectively managing impacts from new mine development and watershed restoration efforts must address the prevalence of non-mining related impacts throughout this watershed.

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