Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains ix, 85 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references.

Geographic Information Systems (GIS) and remote sensing technologies were used to identify and describe potential habitat for three species endemic to the Southwestern United States; the Golden-cheeked Warbler (Dendroica chrysoparia), the Black-capped Vireo (Vireo atricapillus), and the Texas kangaroo rat (Dipodomys elator). For each species, the computerized classification of digital satellite imagery was integrated with ancillary spatial information (e.g. soils, geology, and land use) to construct a data base to be used for ecological evaluation as well as habitat protection and management measures.

Over the past 100–150 years Texas rangelands have dramatically changed from native open savannahs to dense woodlands. On the Edwards plateau, a major management concern is the increasing encroachment of Ashe juniper (Juniperus ashei). Preceding an anticipated brush management program, I investigated the presence, co-occurrence, and habitat relationships of 7 breeding bird species in the Leon River Watershed in central Texas, USA: black-capped vireo (Vireo atricapillus), golden-cheeked warbler (Dendroica chrysoparia), northern bobwhite (Colinus virginianus), white-eyed vireo (Vireo griseus), Bell’s vireo (Vireo bellii), painted bunting (Passerina ciris), and brown-headed cowbird (Molothrus ater). Vegetation characteristics were compared between sites occupied by each species and unoccupied sites using univariate analysis. Models for predicting species site occupancy were developed (using logistic regression) based on habitat characteristics correlated with the presence of each species. Two species of special concern, the endangered black-capped vireo and golden-cheeked warbler occupied 5.6% of sites and 13.8% of sites respectively, while the brood parasite brown-headed cowbird was the most widespread, occupying 86.8% of sites. Species co-occurrence patterns revealed significant associations between the golden-cheeked warbler and each of 5 other species. For most species, variables included in habitat models could be explained by knowledge of species known habitat associations. For example, the black-capped vireo was positively associated with increasing low-growing (<1.5 m) hardwood cover and with Low Stony Hill ecological sites. The golden-cheeked warbler was positively associated with increasing density of larger juniper trees, increasing variability in vertical vegetation structure, and decreasing midstory canopy of deciduous nonoaks (e.g., cedar elm [Ulmus crasifolia]). It also preferred Low Stony Hill and Steep Adobe ecological sites. Site occupancy seemed to be driven by variables that describe overall vegetation structure. In particular, cover of low-growing non-juniper vegetation and juniper tree density appeared to be important in determining site occupancy for several species. Although the models constructed were not very robust, resource managers can still benefit from such models because they provide a preliminary examination of important controlling variables. Managing rangelands to maintain or restore a mosaic of juniper patches and open shrublands are likely to help meet the habitat requirements of these bird communities.

Doctor of Philosophy / Department of Biology / Brett K. Sandercock / The reproductive strategies of avian brood parasites and the behavioral responses of their hosts have served as a model of co-evolution in nature. Host adaptations to reduce the costs of parasitism are countered with novel parasite behaviors that increase the success of the parasite and thereby decrease host productivity. Not all host species possess anti-parasite defense behaviors, and parasitism by Brown-headed Cowbirds (Molothrus ater) may cause population declines in some species. Bell’s Vireo (Vireo bellii) is a small-bodied cowbird host that fails to fledge young if successfully parasitized. Although vireos desert naturally parasitized nests, the cues that cause desertion have not been identified. Understanding how parasitism affects vireo productivity is important because cowbird removal is an integral component of the recovery efforts for the endangered Least Bell’s Vireo (V. b. pusillus) in California. However, it is generally unknown how cowbird removal affects vireo productivity. To address these issues, I monitored the productivity of vireos nesting in Kansas at the Konza Prairie Biological Station, conducted a clutch manipulation experiment, and experimentally removed cowbirds. In addition, I used stable isotope analysis to determine if recently fledged cowbird young could be assigned to habitats or host species. I found that vireos did not desert nests due to the presence of a cowbird egg; rather egg removal by cowbirds caused desertion, which is a generalized response in many taxa of birds. Cowbird removals decreased parasitism of vireo nests by approximately 36% and led to a 2-fold increase in vireo productivity per pair. Cowbird productivity from vireo pairs increased because fewer parasitized nests were deserted and parasitized nests on removal plots had a higher probability of success. No cowbird removal study has reported an increase in cowbird productivity in response to trapping. Cowbird nestlings from prairie plots and shrub plots differed in carbon and nitrogen isotope compositions, and 87% of locally produced juvenile cowbirds were classified with nestlings from shrub plots. Thus, the continued expansion of woody plants into tallgrass prairie may result in local increases in cowbird productivity.

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One major lesson derived from the implementation of the Endangered Species Act (ESA) over the past 30 years is that direct regulation is not the only nor the optimal way to protect endangered species on working lands because of an undue burden imposed on private landowners. The role of a voluntary conservation program is to rearrange incentives so that society bears the cost rather than the landowner. Employing a survey research methodology, I used theories of reasoned action and random choice to explore landowners? stated preferences for conservation programs. I found landowners? stated interest in compensation programs to be moderate at best. For those willing to consider programs involving endangered species, associating land management requirements for species conservation with direct benefits to the landowner is important, but perhaps not as important as ensuring that the program provides adequate financial incentives, consideration of the term of the program, and a level of certainty regarding the landowner?s future obligations under the ESA. Landowners are not a homogenous group. I identified two classes of landowners according to preferences for program structure. One group was highly sensitive to program structure, aside from financial incentives, while the other was likely to participate if adequately compensated with financial and technical assistance. These differences related to opinions on endangered species protection and dependence on their land for income. Voluntary incentive programs increasingly are a popular tool to maintain and enhance conservation; however, these programs are only successful insofar as landowners choose to enroll. This research demonstrates that improving recovery efforts on private lands requires program administrators to have a more complete understanding of landowners? views on endangered species and conservation programs in general, as well as their motivations for owning and operating their land. By doing so, programs with broader appeal and greater efficacy can be designed and implemented.