Statewide Analysis of Brook Trout (Salvelinus Fontinalis ) Population Status and Reach-Scale Conservation Priorities in West Virginia Watersheds
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Graduate Theses, Dissertations, and Problem Reports 2008 Statewide analysis of brook trout (Salvelinus fontinalis ) population status and reach-scale conservation priorities in West Virginia Watersheds Jason W. Clingerman West Virginia University Follow this and additional works at: https://researchrepository.wvu.edu/etd Recommended Citation Clingerman, Jason W., "Statewide analysis of brook trout (Salvelinus fontinalis ) population status and reach-scale conservation priorities in West Virginia Watersheds" (2008). Graduate Theses, Dissertations, and Problem Reports. 2606. https://researchrepository.wvu.edu/etd/2606 This Thesis is protected by copyright and/or related rights. It has been brought to you by the The Research Repository @ WVU with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you must obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in WVU Graduate Theses, Dissertations, and Problem Reports collection by an authorized administrator of The Research Repository @ WVU. For more information, please contact [email protected]. Statewide Analysis of Brook Trout (Salvelinus fontinalis) Population Status and Reach-Scale Conservation Priorities in West Virginia Watersheds Jason W. Clingerman A Thesis Submitted to the Davis College of Agriculture, Forestry, and Consumer Sciences at West Virginia University in partial fulfillment of the requirements for the degree of Master of Science In Wildlife and Fisheries Resources J. Todd Petty, Ph.D., Chair Patricia M. Mazik, Ph.D. Mike Shingleton, M.S. Wildlife and Fisheries Program of the Division of Forestry and Natural Resources Morgantown, West Virginia 2008 Keywords: Brook Trout, GIS, Landscape, Predictive Modeling, Classification Trees, Restoration, Ecology Abstract Statewide Analysis of Brook Trout (Salvelinus fontinalis) Population Status and Reach-Scale Conservation Priorities in West Virginia watersheds Jason W. Clingerman The Eastern Brook Trout Joint Venture (EBTJV) was formed to implement range-wide strategies that sustain healthy, fishable brook trout populations. Hudy et al. (2006) recently completed a comprehensive analysis of eastern brook trout distributions representing a critical first step towards fully integrating brook trout conservation efforts in this region. This study was designed to supplement and complement existing data on brook trout distributions and status within West Virginia. We examined recently obtained data for the entire state to update the EBTJV distributional map published in Hudy et al. (2006). We then used fish sample data along with GIS-acquired landscape data to create models to predict and extrapolate brook trout distributions and population types within the historical distribution of brook trout within West Virginia. We also used these data to identify critical reach scale priorities for brook trout protection, restoration and enhancement. iii Executive Summary Introduction Brook trout (Salvelinus fontinalis) in the Appalachians have a long history of decline and range reduction from physical, chemical, and biological alterations of habitat due to anthropogenic perturbations (Marschall and Crowder 1996, Yarnell 1998, Boward et al. 1999). In the Appalachians, many contributing impacts have combined to cause reduction in brook trout populations and distribution (Marschall and Crowder 1996). Habitat fragmentation (Belford and Gould 1989, Gibson et al. 2005, Poplar-Jeffers 2005), sedimentation (Curry and MacNeill 2004), increased water temperature (Johnson and Jones 2000, Curry et al. 2002), agriculture and forestry practices (King 1938, Curry et al. 2002, Nislow and Lowe 2003, Baldigo et al. 2005), acid rain (Baker et al. 1996, Van Sickle et al. 1996, Baldigo and Murdoch 1997, Driscoll et al. 2001, Baldigo et al. 2005), acid mine drainage, urbanization, poor riparian habitat/management, and the introduction of exotics (King 1938, Larson and Moore 1983, Waters 1983, Larson et al. 1995, Southerland et al. 2005) have all contributed to declines in native brook trout across their native range. Recently, studies by Hudy et al. (2005), and Theiling (2006) analyzed eastern brook trout populations at the “subwatershed” scale. A subwatershed was a 12-digit Hydrologic Unit Code (HUC). These large watersheds (average size = 86.3 km2) provided coarse-scale population status for the entire region, but lacked the resolution necessary to provide detailed information about brook trout population status. Dunning et al. (1992) emphasized the development of intermediate or landscape scale studies. They define a landscape as a mosaic of habitat patches in which a particular patch (focal patch) is embedded. Landscapes would be of different sizes for different organisms, but would iv be of a size between an organism’s normal home range and the species’ regional distribution (Dunning et al. 1992). This scale of study links local microscale studies with large regional or global assessments. A study of this scale focusing on brook trout could give managers essential information on the viability and status of populations across this landscape scale. For the brook trout this could enable further development of management and restoration strategies as well as pinpoint strategic areas to implement these methods for maximum recovery of the landscape- scale population. In order to more effectively address recovery of brook trout populations, we must address the differences in brook trout populations across the landscape scale. Petty et al. (2005) studied spatio-temporal variation in the distribution of brook trout within the upper Shavers Fork, a 12- digit HUC located in east-central West Virginia found that throughout the study watershed, population structure differed from reach to reach. They found that small, alkaline tributaries were nonsubstitutable, source habitats (Schlosser and Angermeier 1995) that acted as spawning areas where abundances of juvenile brook trout were high and seasonally stable. They found that large adult brook trout were substantially more mobile and utilized the larger stream habitats during spring and summer but moved back into small streams to spawn. Understanding these processes and identifying population types across the landscape are critical steps to fully understand brook trout population dynamics and for restoration at a landscape scale. Given the above concerns, we designed this study to supplement and complement existing data on brook trout distributions and status within West Virginia. We decided to use landscape-scale variables to assess and predict brook trout status at the local (reach) scale. We assessed brook trout population types, presence/absence, densities, and conservation priorities. v Methods First, we examined recently obtained data for 265 sites from across the entire state to update the EBTJV distributional map published in Hudy et al. (2005). We then used this fish sample data along with GIS-acquired landscape data (landcover, geology, drainage area, elevation) to create models to predict and extrapolate brook trout distributions and population types within the historical distribution of brook trout within West Virginia. We also analyzed landscape data to detect thresholds important in determining brook trout presence/absence. Lastly, we also used these data to identify critical reach scale priorities for brook trout protection, restoration and enhancement. Results EBTJV Status Update We found that the majority of the time, the EBTJV status was correct, but were able to reclassify 9 of the 29 subwatersheds we sampled that were previously deemed extirpated. For the remaining 20 subwatersheds, we confirmed that brook trout were indeed extirpated. From this sampling, we conclude that of the original 454 subwatersheds believed to have supported brook trout populations historically, brook trout are now extirpated from 281, present at highly reduced levels in 144, present in reduced levels in 19, and intact in only 5 subwatersheds. We used the results of this study to produce a final updated map of brook trout population status at the 12-digit HUC scale throughout the state of West Virginia. Brook Trout Population Status We found that we were able to correctly classify brook trout presence/absence in approximately 75% of independently sampled streams. Cross-validated models predicting brook trout population types and densities were also effective. The model predicting population types vi had a 61% average cross-validated misclassification rate, but had a cross-validated error rate of less than 1 (0.973) which indicates the model improved up choosing population types at random. The density models had explained 18.8 – 94% of the variation in the data; the average variance explained was 47.1%. Threshold Analysis We analyzed landscape data and found the following threshold ranges important in determining brook trout presence/absence: > 80 – 92% forest, < 2 – 12% agriculture, < 5 – 7% developed, < 45 km2 drainage area, > 400 – 700 m minimum elevation, and < 4% mining intensity. Brook Trout Conservation Priorities We found that 15% of the study area was assigned a protection priority, 3% was assigned a restoration priority and <1% of the study area was classified as a reintroduction priority. We also assessed the