Accelerational Implications of Hummingbird Display Dives

Integrative Biolog

Aspects of genetic and morphological variation in selected new world land birds

Thesis (M.S.) University of Alaska Fairbanks, 2000The objective of this thesis is to examine variation in certain New World land birds, focusing on morphological difference at the intraspecific level and genetic differences at the intra- and interspecific levels. First, I investigate sexual dimorphism in the Wilson's Warbler (Wilsonia pusilla), a Nearctic-Neotropic migrant parulid. Using museum specimens, I quantify the degree of dimorphism and devise a method to distinguish the sexes using morphological measurements. Second, I outline a new method of approximating Weir and Cockerham's 0 (1984, 1993), an unbiased estimator of genetic population structure. The method uses commonly published parameters and obviates the need to recode existing allozyme data sets to calculate 0. The estimation algorithm is shown to be useful for both model populations and real-world avian populations

BIOMONITORING OF CONTAMINANTS IN BIRDS FROM TWO TROPHIC LEVELS IN THE NORTH PACIFIC

Abstract-The presence and accumulation of persistent contaminants at high latitudes from long-range transport is an important environmental issue. Atmospheric transport has been identified as the source of pollutants in several arctic ecosystems and has the potential to severely impact high-latitude populations. Elevated levels of contaminants in Aleutian Island avifauna have been documented, but the great distance from potential industrial sources and the region's complex military history have confounded identification of contaminant origins. We sampled bird species across the natural longitudinal transect of the Aleutian Archipelago to test three contaminant source hypotheses. We detected patterns in some polychlorinated biphenyl congeners and mercury that indicate abandoned military installations as likely local point sources. Carbon isotopes were distinct among island groups, enabling us to rule out transfer through migratory prey species as a contaminant source. The long-range transport hypothesis was supported by significant west-to-east declines in contaminant concentrations for most detected organochlorines and some trace metals. Although relatively low at present, concentrations may increase in Aleutian fauna as Asian industrialization increases and emitted contaminants are atmospherically transported into the region, necessitating continued monitoring in this unique ecosystem

Comparing Genetic Diversity Along Populations of Rock Sandpipers (Calidris ptilocnemis)

Rock Sandpipers (Calidris ptilocnemis) are a shorebird species only found in the North Pacific Basin (Ruthrauff, et al. 2019; Fig. 1, 2). There are four subspecies of Rock Sandpipers, C. p. couesi, C. p. quarta, C. p. tschuktschorum, and C. p. Ptilocnemis (Gibson & Withrow, 2015). Of these four subspecies, three have an overall conservation category of moderately high with a current unknown status and high biological vulnerability due to environmental disturbances (ACCS at UAA, 2018). The three subspecies compared for differences in their genetic diversity and population relatedness were C.p. couesi, C.p. tschuktschorum, and C.p. ptilocnemis. The subspecies differed in their primary migratory and breeding locations: C.p. couesi is found in the Aleutian Islands, C.p. tschuktschorum is found on the Seward Peninsula and Cold Bay, and C.p. ptilocnemis is found on the Pribilof Islands. The subspecies are further distinguished through their morphological differences among populations. C.p. ptilocnemis is of the greatest conservation size due to the differing population size of its two island populations

Systematics of Beringian threespine sticklebacks

Thesis (M.S.) University of Alaska Fairbanks, 2000In Pleistocene Beringia, large-scale glaciations exposed high latitude species to variable environmental conditions that created disjunct populations of terrestrial and marine species. The general nature of the dynamic biogeographic history of Beringia can be assessed by studying genetic patterns across many Beringian organisms. Mitochondrial DNA sequences were used to study the phylogenetic and phylogeographic structure of the threespine stickleback, Gasterosteus aculeatus. A 714 bp fragment of the cytochrome b gene was sequenced from 66 individuals from 17 locations extending from southeast Alaska northwest to coastal Siberia. These data were combined with 36 homologous cyt-b sequences from a previous study to provide a preliminary assessment of patterns of genetic variation in threespine stickleback- with a particular emphasis on Alaskan populations. Cytochrome b data show the existence of two major clades in the Pacific, with an extensive zone of overlap that spans the Bering Straits