M.S. - Zoology (Ecology, Evolution and Conservation Biology)
Permanent URI for this collection
Browse
Recent Submissions
Item 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)Item Evaluating Population Viability and Conservation Options for The Endangered Puaiohi([Honolulu] : [University of Hawaii at Manoa], [December 2016], 2016-12) Fantle-Lepczyk, JeanEvolution 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.Item Invasion Ecology of the Plague Skink (Lampropholis delicata) in Hawai‘i([Honolulu] : [University of Hawaii at Manoa], [December 2016], 2016-12) Smith, ThomasItem Movement and Sexual Dimorphism of the Endangered Hawaiian Coot, (Fulica alai), on Oahu([Honolulu] : [University of Hawaii at Manoa], [December 2016], 2016-12) Riggs, RandiThe 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.Item 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.Item Anthropogenic stress, bioerosion, and farming damselfish : potential interactions and effects on coral reefs in American Samoa(2007) McTee, Sarah A.Damselfish algal gardens are a prominent feature of coral reefs around the world, and can occupy, in some cases, up to 50 percent of the solid benthic substrate (Klumpp and Polunin, 1989; Sammarco and Williams, 1982). Therefore, the relationship between damselfish and coral, and their effects on the structural integrity of coral reefs, is an important aspect of coral reef ecology that deserves attention. Because farming damselfish can readily establish algal gardens on recently dead coral, eutrophication or other forms of anthropogenic stress that kill coral tissue are expected to be positively correlated with the abundance of damselfish and damselfish algal gardens. To date, the abundance and distribution of farming damselfish have not been correlated with eutrophic conditions or local anthropogenic activities. By examining the effects of anthropogenic stress on bioerosion and the abundance of damselfish and their algal gardens at a number of sites, this thesis suggests how human activities, specifically in coastal environments, may have direct and indirect effects on the structure of coral reef habitats and the diversity and composition of species found there.Item Reproductive biology of Eleotris sandwicensis, a Hawaiian stream gobioid fish(2006) Sim, Tara K.Spawning season, size at first reproduction, oocyte maturation, fecundity and spawning frequency of Eleotris sandwicensis, an amphidromous Hawaiian gobioid, were studied from July 2004 through December 2005 in Nuuanu stream, Oahu, Hawaii. The smallest male and female fish with mature gonads measured 54 mm standard length. Ripe individuals were collected in all months, and gonadosomatic index was highest in males and females from June 2004 through February 2005. Size-frequency distributions of measurements of vitellogenic oocyte diameters and microscopic observations of oocytes indicated this species has asynchronous oocyte development. Estimates of batch fecundity ranged from 5000 eggs to 55000 eggs. Batch fecundity was positively related to standard length, wet weight, and ovary weight, and inversely related to oocyte diameter. Eleotris sandwicensis appears to be capable of repeat spawning.Item The impact of transplanted sea urchins on alien and native flora(2006) Cunha, Tamar B. SaturenAfter fish, urchins are the most conspicuous herbivores on coral reefs in Hawai'i, as elsewhere. In Kane'ohe Bay, O'ahu, the native urchin Tripneustes gratilla is present in small numbers, but is easily transplanted to patch reefs with high algal cover. Because it readily consumes several of the invasive algae in the bay, it has been proposed as a biological control agent for these algae. To determine its usefulness as a control of invasive algae and to examine its impact on the native benthic invertebrate and algal communities, urchins were placed in 1m^2 cages on the reef flat in varying densities and the substrate composition was monitored over time. After three months, high densities of urchins (6 urchins m^-2) were able to significantly reduce high cover of Gracilaria salicornia and the medium density of urchins (3 urchins m^-2) were able to further reduce and control the invasive alga in sites where it had previously been brought down manually. Background herbivory by fishes was not able to reduce or control G. salicornia, even in sites where the algal cover had been reduced manually first. Fish, but not urchins, seem to have an effect on the community composition of native turf algae. On reefs where invasive algae competes with corals, transplanting urchins to that coral-algal interface holds promise for controlling and reducing algal cover, especially in cases where algal biomass is physically reduced first.Item Validating real-time PCR and field manipulations using the coral Montipora Capitata(2008) Hirst, Marissa BrettIn this study, qRT -PCR amplification of the gene encoding hsp70 from Montipora capitata and Symbiodinium were tested and normalized using the SMP method (Mayfield et al. accepted). The goal of this work was to confirm the utility of the exogenous spike as a reference gene for calculating SMP and as a housekeeping gene in qRT-PCR amplification of cDNA as well as to validate the general methods utilized for qRT-PCR using corals (the RNA extraction, cDNA synthesis, and amplification steps). Two field experiments were also designed to explore how the Symbiodinium residing in coral hosts responded to 1) fragmentation and recuperation and 2) transplantation by tracking symbiont photophysiological data and changes in Symbiodinium cell densities using qRT-PCR. Temperature and light intensity data collected from the transplantation experiment were used to determine whether control depth and experimental depth were statistically different. Coral fragments used in the field experiments were also used to test qRT-PCR methods.Item Diet dynamics and trophic relations of Laysan and Black-footed albatrosses associated with pelagic longline fishing(2008) Bisson, Jeremy R.Commercial fishing is a source of food for many types of seabirds, including albatrosses, but the importance of commercial fishing may vary between fishing methods, locations and affected species. Longline fishing in the north Pacific has expanded and affects Laysan Albatrosses and Black-footed Albatrosses through incidental bycatch, but the importance of longline fishing to the diets of these albatrosses is unknown. I analyzed fishery observer data to determine whether there are differences in fishery association behavior between Laysan and Black-footed Albatrosses and whether they differ in their amount of catch scavenging effort. I analyzed the digestive tract contents of tuna and swordfish longline-associated albatrosses to determine the fishery component of the albatross diets. Last, I analyzed the stable nitrogen isotopic compositions of longline associated birds and birds from colonies, as well as prey, to determine whether there might be broader, time-averaged effects on the albatross diets. Black-footed Albatrosses were more abundant around vessels than were Laysan Albatrosses and swordfish longline fishing attracted more birds than did tuna longline fishing. Black-footed Albatrosses also scavenged more swordfish catch, but not necessarily in greater proportion than expected. Laysan Albatrosses ate more fish bait and these two species also differed in their naturally acquired diets, with Laysan Albatrosses consuming more T. borealis. Albatross δ^15N values differed between species and Black-footed Albatrosses differed between fishing methods, but it is unclear whether these differences in nitrogen isotopic compositions were fishery related because of overlap in the δ^15N values among fishery and naturally acquired prey. Differential fishery resource use was evident, even when the albatrosses were exploiting the same resource, indicating that these species should not be given equal treatment in management decisions. Managers should consider the effect of longline fishing on the diets of Lay san and Black-footed albatrosses separately when making decisions that may change fishing practice. Black-footed Albatrosses should receive the most attention because they are the most affected species, while swordfish operations appear to have the greatest affect on the albatross diets.