IGLECIA, MONICA N. Occupancy Models and Strategic Habitat Conservation for Avian Species in the Southeastern Coastal Plain of the United States. (Under the direction of Jaime

IGLECIA, MONICA N. Occupancy Models and Strategic Habitat Conservation for Avian Species in the Southeastern Coastal Plain of the United States. (Under the direction of Jaime A. Collazo). Rapidly expanding lists of priority species has increased the need for a framework that can utilize existing datasets to inform landscape-scale conservation strategies. This is evident in the South Atlantic Coastal Plain of the United States where no fewer than 91 avian species are considered high priority for conservation. It is believed that the process of urbanization is a contributing factor. This process transforms natural habitats into impervious surfaces and semi-permanent structures, threatening many avian species. We used single-season occupancy models, coupled with regional land cover and Breeding Bird Survey data from 2001, to address two objectives aimed at informing conservation planning in the region. The first objective addressed two questions: (1) do occupancy patterns correspond with purported species-habitat associations at two thematic resolutions of habitat classification, and if so, which of two thematic resolutions of habitat classification provided the best support? and (2) does the composition of the matrix of habitat surrounding a sampling unit influence species occurrence? The second objective addressed whether: (1) species richness differed between sampling units containing high and low levels of urban habitat, and (2) a species’ response conformed with expected sensitivity to urbanization. To address the first objective, we focused on three priority species: brown-headed nuthatch, red-headed woodpecker and eastern wood-pewee. Model results supported knowledge-based hypotheses for the nuthatch and wood-pewee; occupancy probabilities were strongly associated with predicted vegetation classes ranked as optimal habitat. This was not so for the woodpecker; vegetation regarded as marginal habitat received greater support. Results affirmed the woodpecker’s designation as a generalist. The influence of landscape-matrix composition on occupancy was consistent with species-habitat relationships at the BBS route-segment scale. Generally, the influence of amount of habitat on occupancy was inversely related to distance. To address the second objective, we used three groupings to categorize species according to their observed sensitivity to urban habitats: exploiters, adapters, and avoiders. We used occupancy models and gauged the sensitivity of 16 focal species based on the direction and strength (95%CIs did not overlap estimates) of the beta parameter relating percent urban habitat along BBS route-segments to occupancy probability. We expected the relationship to be positive and strong for exploiters, and negative and strong for avoiders. As predicted, species richness was higher in low-urban route-segments than in high-urban segments. Also as predicted, 2 of 3 urban exploiters were positively and strongly associated with increasing urbanized landscapes. In contrast, there was no support for a strong, negative relationship for urban avoiders. Results suggest that urban adapters and avoiders are adept at using the low-levels of urbanized habitat characterizing BBS routes. Options to relocate BBS routes will diminish with increasing urbanization. Thus BBS routes provide opportunities in the future to assess responses of urban avoiders, a sensitivity group that contains many species of conservation concern in most states. Our data-driven models can be used to test knowledge-based models and estimate the consequences of conservation actions in a structured-decision framework. Breeding bird surveys will continue to be a source of landscape scale data to assess changes in species composition and their relative sensitivities to habitat alteration. The potential to inform conservation design could benefit from estimating patterns of local extinction and local colonization rates. However, spatio-temporal inferences derived from the application of such modeling frameworks will require the availability of land cover data over short time intervals, which is not presently available. Occupancy Modeling and Strategic Habitat Conservation for Avian Species in the Southeastern Coastal Plain of the United States by Monica Nicole Iglecia A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science