Semester

Fall

Date of Graduation

2012

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Wildlife and Fisheries Resources

Committee Chair

James T. Anderson.

Abstract

Riparian zones serve to maintain high water quality, low water temperatures, and structural complexity in aquatic and terrestrial environments, among other beneficial services. Riparian buffers provide habitat and corridors linking forest patches for terrestrial wildlife. High riparian vegetative structure and complexity attract a high diversity of wildlife, including birds, herpetofauna, and small mammals. Devegetated riparian zones, often a result of developmental and agricultural practices, lose their beneficial functions and require restorative actions to regain them. The Cacapon River watershed in West Virginia is agriculturally-dominated with many areas of riparian zone degradation. A section of the Cacapon River was selected for natural stream channel design restoration during 2009 to 2011. Our objectives were to: (1) monitor birds, small mammals, anurans, and vegetation along the restoration reach, 2 control (impaired) sites, and 2 reference (unimpaired) sites following a before-after control-impact design along the Cacapon River; (2) survey natural history characteristics of wood turtles (Glyptemys insculpta) using the riparian zone along the Cacapon River; and (3) assess factors limiting wood turtles along the southern extent of their geographic range along the Lost and North rivers, tributaries of the Cacapon River. We expected (1) the diversity of the riparian wildlife to remain stable or increase post-restoration, (2) wood turtles to undergo all natural history aspects within the riparian zone, and (3) geographical and environmental features to limit wood turtles along the southern border of their range in the Cacapon River watershed.;Monitoring of riparian wildlife along the Cacapon River occurred pre- (April 2009 to April 2010) and post-restoration (May 2010 to August 2011). Overall, 6 small mammal species, 79 bird species, 8 anuran species, and 96 plant species were recorded. Small mammal abundance declined initially in the restoration reach post-impact, but began to recover. Overall bird abundance, richness, and diversity increased along the restoration reach post-impact. The anurans were unaffected by the restoration activities, but showed species-specific timing of reproductive activities across the sites. Shrub and tree diversity, richness, and evenness increased over time, possibly indicating that the restoration reach began improving in vegetative complexity post-impact. The restoration was considered a success because the diversity of the riparian wildlife remained stable or increased post-restoration.;Monitoring of wood turtles along the Cacapon River occurred during spring 2009 to summer 2011. The turtles were observed primarily using the riparian zone (80.7%) instead of the surrounding agricultural land (19.3%). Adult males and females were larger than juveniles. Reproductively active males were longer, thicker, and heavier than reproductively active females. Home ranges were 0.62 -- 36.97 ha. Low bare ground and rock cover and high vertical density differentiated the turtles' habitat from random vegetation plots. The turtles were typically terrestrial during spring and summer and aquatic in autumn and winter. Mating occurred in autumn (64.3%) after 1300 hrs (75%), sometimes terrestrially (35.7%). Nesting attempts were made on sandy substrate in the early mornings and early evenings of spring. Basking occurred at 45°, angled to the sun, on a variety of surfaces. Dietary preference was for slugs (67%), although other invertebrates, plant matter, and animal matter were consumed. The riparian zone provided the wood turtles with all of their natural history needs.;Monitoring of wood turtles along the Lost and North rivers in the Cacapon River watershed was conducted during summer 2010. Habitat characteristics, potential dispersal barriers, and the approximate southern geographic boundary of the species in the watershed were assessed. Sixty-four of 100 randomly-selected sites contained wood turtles. Increasing stream depth, canopy cover, soil temperature, and proximity to the Cacapon River, and low elevation and slope positively influenced presence of the turtles. Field layer (woody and herbaceous plants <1 m tall) species richness and diversity were greater in sites with wood turtles than without the turtles. Witch-hazel (Hamamelis virginianus) and ironwood (Ostrya virginiana) weakly separated sites without turtles from sites with them. The factors limiting wood turtles at the southern limits of their range in West Virginia included (1) inability to disperse over high elevations, (2) agricultural influences decreasing habitat availability and turtle survivorship, and (3) an intolerance to high temperatures. In agricultural areas bordering waterways, riparian buffers should be restored if they are degraded, managed to promote structurally complex vegetation, and monitored to determine whether the buffers are providing essential habitat for a diverse array of terrestrial wildlife that should promote adult survivorship and population stability.

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