M.S. - Zoology (Ecology, Evolution and Conservation Biology)

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Now showing 1 - 5 of 11
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    Gonad Morphology And Social Influence On Gonad Development Of The Juvenile Divine Dwarfgoby, Eviota Epiphanes(Teleostei: Gobiidae)
    ( 2018-05) de Souza Brasil Barreto, Helena ; ZOOLOGY (ECOLOGY, EVOLUTION, AND CONSERVATION BIOLOGY)
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    Evaluating Population Viability and Conservation Options for The Endangered Puaiohi
    ([Honolulu] : [University of Hawaii at Manoa], [December 2016], 2016-12) Fantle-Lepczyk, Jean
    Evolution in the Hawaiian Islands has produced a unique assemblage of forest birds. Unfortunately, many of these species are highly endangered or extinct. Despite numerous threats and great effort aimed at saving endemic birds, we lack basic science necessary for understanding many species of concern, including the endangered puaiohi (Myadestes palmeri). Currently, the puaiohi’s breeding population is estimated at 500 birds restricted to the Alaka‘i Wilderness Preserve on Kaua‘i. Given its small population and restricted range, understanding the conditions that affect the species’ population dynamics is essential. Hence, the goals of this dissertation were to: investigate links between precipitation and temperature in the puaiohi’s range and reproductive success; represent puaiohi population dynamics under current and potential management scenarios to determine management’s potential efficacy in aiding species recovery; and, investigate which management activities might supply the most cost-effective species management. Management scenarios included rat management, habitat improvement (habitat restoration or supplemental feeding), provision of nest boxes, and translocation of an additional population to another island. Total rainfall in the previous wet season and mean rainfall during the breeding season positively correlated with most nest success variables. Female and juvenile survival most influenced puaiohi population viability, indicating that management should focus on increasing female and juvenile survival. Rat control, even at conservative levels, was the most effective method of increasing puaiohi abundance. While translocation offers hope of increasing puaiohi population and decreasing extinction risk, success depends on the conditions established at the release site. In addition, re-establishment of the puaiohi captive breeding program may be necessary to provide enough birds to translocate. Management costs over the 25 years modeled ranged from $378,701 to $245,213,905, with translocation being one of the most cost-effective means of managing puaiohi and supplemental feeding the least. Cost-efficiency of rat control varied based on scale and method, and restoration of habitat was moderately cost-effective. Findings indicate that practical, attainable management activities can increase puaiohi and bring it back from the brink of extinction. These findings provide a model for other endangered species conservation efforts.
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    Invasion Ecology of the Plague Skink (Lampropholis delicata) in Hawai‘i
    ([Honolulu] : [University of Hawaii at Manoa], [December 2016], 2016-12) Smith, Thomas
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    Movement and Sexual Dimorphism of the Endangered Hawaiian Coot, (Fulica alai), on Oahu
    ([Honolulu] : [University of Hawaii at Manoa], [December 2016], 2016-12) Riggs, Randi
    The endangered Hawaiian Coot, Fulica alai, is one of only six native waterbird species remaining in the Hawaiian Islands. Most of its population is concentrated in the wetlands of the islands of Kauai and Oahu. Oahu also has the most wetland loss and fragmentation. This study aimed to determine if the species exhibits sexual dimorphism, if shield size of either sex exhibits seasonal variation, and if morphometric measurements could be used to predict sex accurately, as an alternative to molecular sexing. It also sought to determine if wetland loss and fragmentation prevents movement between wetlands and how common intraisland and interisland movements are. Sixty coots were captured from five Oahu wetlands, tagged with neck collars, and standard morphometric measurements and blood samples (for molecular sexing) were taken. Resight data were collected from ten Oahu wetlands from November 2011 to December 2013. The sex ratio was heavily male biased. No morphological character tested differed significantly between the sexes when assessed independently. However, stepwise binary logistic regression indicated tarsus length, bill height, tail length, and wing length in combination differed between the sexes. Shield size of males exhibited a significant declining trend over the year, being larger in males captured during the pre-breeding and breeding season and smaller in those captured during the post-breeding season. Female shield size did not vary significantly among seasons. The accuracy of predicting sex based on regression models of morphometric measurements was insufficient to substitute for molecular sexing. Habitat fragmentation did not preclude movement, intraisland movement was common and even the widest channels between islands did not impede interisland movement. Movement was not associated with sex, wing length or wing loading. Analysis of resight histories indicated encounter probability was lower during the pre-breeding and early breeding seasons than the late and post-breeding seasons.
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    Genetic diversity, population structure, and demographic history of the Hawaiʻi akepa
    ( 2007) Reding, Dawn M.
    As a result of disease, habitat destruction, and other anthropogenic factors, the Hawaii Akepa (Loxops coccineus coccineus) currently occupies less than 10% of its original range and exists in five widely separated populations, raising concerns about what effect such reduction and fragmentation has had on the connectivity and diversity of Akepa populations. In this study, both historical and contemporary samples were utilized to assess genetic diversity and structure in this endangered Hawaiian honeycreeper. Sequence data from ND2, control region, and two nuclear introns were obtained from three of the five current populations, and control region sequence data were obtained from museum specimens collected over 100 years ago throughout the historical range of the bird. Results indicate that despite recent declines and fragmentation, genetic diversity has not yet been lost. No clear phylogeographic breaks were observed across the historical range of Akepa, but rather genetic differentiation was modest and seemed to follow a pattern of isolation-by-distance. Low levels of differentiation between the contemporary populations observed with mtDNA but not nuclear sequences indicate that not much divergence, if any. has occurred post-fragmentation. Rather, the present structure seen likely reflects historical isolation-by-distance. Ironically, this declining species exhibits the genetic signal of an expanding population, demonstrating that earlier demographic events are outweighing the effects of recent changes in population size, and genetic estimates of N., though crude, suggest Hawaii Akepa were at least an order of magnitude more abundant prior to the decline.