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Evaluating Bat Roost Abundance: A Comparison Of Drone-Acquired Thermal Imagery And Acoustic Estimates With Visual Observations, Karah Jaffe Aug 2022

Evaluating Bat Roost Abundance: A Comparison Of Drone-Acquired Thermal Imagery And Acoustic Estimates With Visual Observations, Karah Jaffe

Electronic Theses and Dissertations

Roosts provide an opportunity to census philopatric populations of bats. Comparing the efficacy of traditional methods with novel methods can provide guidance on the use of new technologies in the field. This project aims to compare the count efficacy of external emergence methodologies, i.e., drone-acquired thermal imagery, acoustic estimates, and visual counts. Surveys were conducted ten nights at two emergence sites and synchronized to compare counts. Acoustic estimates could not be established as there was a weak prediction of the linear relationship between root-mean-square pressure and emergence count; therefore, this method was removed from the comparative analysis. A linear mixed-effects …


Detection, Occupancy, Abundance, And Mercury Accumulation Of The Alligator Snapping Turtle (Macrochelys Temminckii) In Texas, David Rosenbaum May 2022

Detection, Occupancy, Abundance, And Mercury Accumulation Of The Alligator Snapping Turtle (Macrochelys Temminckii) In Texas, David Rosenbaum

Electronic Theses and Dissertations

Land use practices and physical alterations of ecosystems result in habitat loss and fragmentation, while chemical alterations, such as pollutant input, reduce habitat quality and health of exposed organisms. Here, I investigated the effects of watershed- and local-scale environmental variables on the occupancy, abundance, and mercury accumulation of a threatened aquatic species (Macrochelys temminckii, i.e., alligator snapping turtle) within the southwestern periphery of its distribution. Hierarchical modeling suggested the distribution of the species is more affected by watershed-scale land-cover than local habitat, and provided a baseline estimate of average species abundance across its range in eastern Texas. Abundance …