Ph.D. - Zoology (Ecology, Evolution and Conservation Biology)
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Item Phylogeography And Evolution Of Mesophotic Coral Ecosystems(University of Hawaii at Manoa, 2020) Copus, Joshua M.; Bowen, Brian R.; ZoologyIn this dissertation, I begin to address the phylogeography and evolution of the unique reef fish fauna of the mesophotic zone, generally regarded as beginning at 30 - 150 m depth. Chapter 1 is an introduction to the topic and background for subsequent chapters. As the field of mesophotic research matures, we can move beyond descriptive studies and begin to construct hypotheses for the origins and evolution of mesophotic reef fishes. Accordingly, Chapter 2 describes the habitat persistence hypothesis (HPH), which postulates that mesophotic reef fish communities are older and more stable than their shallow water counterparts. This hypothesis is based on two fundamental observations; 1) Mesophotic communities are extend below the surface waters that are subject to glacial sea level changes on a scale of 106 years, and 2) The shallow water biodiversity gradient, extending from the Coral Triangle (between Philippines, Indonesia, and New Guinea) to Rapa Nui in the eastern Pacific, may not apply to mesophotic communities. This chapter is a formal description of the HPH, and outlines a set of testable hypotheses to evaluate the validity of the HPH. Chapter 3 is a description of the mesophotic fish species Neoniphon pencei. Chapter 4 is a description of the mesophotic fish species Luzonichthys seaver, and Chapter 5 is a description of the mesophotic fish species Prognathodes geminus. These data will provide some of the first descriptions of MCE fishes, and provide a beginning point for testing phylogenetic hypotheses about the origins of mesophotic fishes. Chaper 6 provides a brief conclusion.Item Genomics Of The Globally Distributed Echinoid Genus Tripneustes(University of Hawaii at Manoa, 2018-05) Laruson, Aki Jarl; Zoology (Ecology, Evolution, and Conservation Biology)Understanding genomic divergence can be a key to understanding population dynamics. As global climate change continues it becomes especially important to understand how and why populations form and dissipate, and how they may be better protected. To this effect, the globally distributed sea urchin genus Tripneustes has been highlighted as an ideal group for studying patterns of genomic divergence as the global distribution is split into two physically separated species (T. ventricosus in the Atlantic and T. gratilla the Pacific), and cryptic divergence in the absence of hard physical barriers has been suspected within each ocean. Molecular signatures of population divergence can be affected and skewed by a number of different biological realities. In the case of lower fitness of a heterozygous individual (underdominance), the degree as well as network shape of the connectivity between populations can determine wether rare alleles persist between populations, muddying population divergence signals, or are driven to fixation at one end of the population range while going extinct in the other, giving a signal of parapatric speciation. In order to address questions regarding the more nuanced molecular differences and broader evolutionary trajectories within the genus Tripneustes a draft transcriptome for the species T. gratilla was generated. In addition to showing an expansion in tumor suppressor genes when compared to the genome enabled sea urchin Strongylocentrotus purpuratus, and sex-specific gene expression differences in Sex determining Region Yassociated High Mobility Group box (SOX) genes, the transcriptome allowed for easy recovery of the full mitochondrial genome. Following isolation and sequence confirmation, the mitochondrial genome of T. gratilla was next compared to all previously published sea urchins mitochondrial genomes. A phylogenetic comparison validates the morphologically proposed superfamily Odontophora, with an estimated genesis of the group during the Eocene-Oligocene epoch transition. Estimates of selection via proportional non-synonymous to synonymous site substitution ratios suggest that purifying selection is the primary force acting on echinoid mitochondria.Item A Single Trait Drives Incipient Ecological Speciation in Sympatric Color Morphs of the Arceye Hawkfish(University of Hawaii at Manoa, 2016-05) Whitney, JonathanCoral reef fishes represent the most diverse assemblage of vertebrates on the planet, yet our understanding of the mechanisms driving this diversity remains limited. There is growing recognition that ecological adaptation shaped by natural selection may be a major driver of diversification on coral reefs. However, few examples of ecological speciation in nature currently exist. I integrate research on ecology, behavior and genetics to outline a novel case of incipient ecological speciation in sympatric color morphs of the arceye Hawkfish (Paracirrhites arcatus). First, I demonstrate that color morphs are exploiting different niches along a steep ecological gradient, likely driven by disruptive selection favoring color patterns that are better camouflaged in contrasting microhabitats. Second, mate preference experiments show that females prefer individuals of their own morph, indicating color morphs are mating assortatively. Third, I provide genetic evidence that these premating barriers have resulted in at least partial reproductive isolation between ecologically differentiated sympatric color morphs. Taken together, these results suggest that reproductive isolation between morphs may be arising as a by-product of divergent selection on ecological differences and enhanced by the isolating effects of assortative mating. I conclude that color alone is driving incipient divergence in this species, despite high gene flow and no geographic isolation. I argue that the characteristics of this system could be quite common and thus widely applicable to thousands of reef organisms. This dissertation emphasizes the role natural selection plays in initiating speciation and should help bring us one step closer to understanding the processes driving high biodiversity in tropical seas.Item Invasion Ecology and Control Feasibility of the Jackson Chameleon (Trioceros jacksonii xantholophus) in Hawai‘i(University of Hawaii at Manoa, 2016-05) Van Kleeck, MelissaBiological invasions provide opportunities to investigate micro-evolutionary change and the relative roles of key factors that lead to differentiation. Following introduction, release from native selective pressures and exposure to novel evolutionary forces can reduce morphological and physiological constraints and impose new ones, resulting in rapid micro-evolutionary changes. Studying ecosystem and geographic variation in invasive taxa on an ecological time scale can help provide conservation relevant information for management. I investigated ecological and evolutionary questions involving adaptation and ecomorphological variation and the roles of habitat characteristics on form, function and behavior of an invasive lizard in Hawaii. In Chapters 1 and 2 I evaluate substantial variation in head-size and horn-length among and within islands, and between native and introduced ranges. Larger heads are associated with low precipitation, and consumption and higher availability of hard prey, while longer horns are exhibited by chameleons in their native range and are associated with fight success and higher precipitation in the introduced range. Results may suggest rapid ecomorphological adaption to introduced microhabitats and release from natural selective pressures influencing sexually dimorphic characters in the native range. Chapter 3 examined predatory behavior in chameleons in response to prey size and type. Instead of the well-documented lingual prehension mechanism in Chamelaeonidae, a novel feeding mechanism is described, in association with both prey/predator size and prey type. Finally, for Chapter 4, I present the first proposed control strategy for T.j. Xantholophus in Hawaii. We tested a method based on an approach using acetaminophen deployed by resource managers to control the invasive brown tree snake on Guam. We determined minimum dosage necessary to cause >95% mortality in <48 hours. Additionally, I propose methods of field delivery, including use of introduced snail shells as a vessel for ingestion. Although there is a massive and increasing body of invasion ecology research, this study provides new insights into trait adaptation of invasive predators and how this information can help develop management strategies. In addition, this study presents a framework by which biological invasions can be used to examine evolutionary questions on an ecological rather than evolutionary time-scale.Item Assessing Reproductive Biology of Hawaiian Reef Fishes: The Importance of Fisher and Community Participation(University of Hawaii at Manoa, 2015-12) Schemmel, EvaSmall-scale fisheries management is moving towards a more holistic and integrated approach, that of ecosystem–based management. This management philosophy incorporates life history, biological and physical processes, and people as integral components of the ecosystem. Although ecosystem-based management is complex, significant progress can be made by incorporating people and communities into resource monitoring and management. This research used a participatory approach and incorporated fishers and community members in research on the biology of several fish of management importance in Hawaiʻi. A fish species of ecosystem-based management importance that is often overlooked is the small pygmy goby (Eviota epiphanies). This research found that E. epiphanies exhibits fast growth and high generational turnover rates, likely contributing significantly to the bioenergetics of coral reef ecosystems. By working with fishers, reproductive biology was collected for the invasive peacock grouper (Cephalopholis argus), and the herbivorous convict tang, (Acanthurus triostegus sandvicensis). Collaborative research helped increase the number of samples collected across locations and time, improving knowledge of fish reproductive biology in Hawaiʻi across multiple scales. Findings from this research show that size at maturity and temporal shifts in spawning seasons is variable by location. These findings suggest that stewardship and management is best conducted at the local level in order to understand and respond to the variability within the ecosystem. To meet these needs, I worked with fishers, communities, NGOs, and state natural resource managers to develop community-based fishery monitoring programs to assess the reproductive biology of harvested reef fishes. These monitoring programs combined traditional Hawaiian ecological knowledge and scientific assessments to better understand local spawning seasons and optimal harvest sizes for reef fishes. By directly monitoring their resources, fishers have the information needed to track changes in their resources, and therefore the ability to respond to changing resource conditions, allowing for informed decisions on the species that are targeted and times that harvest takes place. Lastly, this research demonstrates the power of participatory approaches for collecting information need for ecosystem-based management and the social and ecological benefits of empowering fishers and communities to be monitors and stewards of their resources.Item The importance of food and scale in the ecology of tropical seabirds(University of Hawaii at Manoa, 2008) Hebshi, Aaron J.Birds breeding in areas with large colonies experienced low fledging success and chick growth. This density-dependent pattern, on the scale of the birds' foraging area, supports the argument that reproductive rates are driven by food limitation. Shearwater populations are currently limited by breeding habitat availability due to human development and introduced predators, but as land managers protect more main-island breeding sites, food-limitation and its effects on reproductive rates may play an increasing role in population regulation. Food availability also appears to influence how Hawaiian seabirds time their breeding. Species with large foraging ranges were found to breed at a more predictable time of year presumably because they are able to buffer against small-scale variation in prey abundance.Item An ecological comparison of Cephalopholis argus between native and introduced populations(University of Hawaii at Manoa, 2008) Meyer, Amanda LeilaniThe blue-spotted grouper, Cephalopholis argus, was introduced to the Hawaiian islands from Moorea, French Polynesia in the late 1950s in an attempt to establish a grouper fishery in Hawaii. C. argus was introduced from a region of high grouper diversity into an environment with little competition from other large sedentary piscivorous species, and has flourished over the last 50 years. Total length, weight, and body condition were each significantly greater in introduced populations of C. argus in Hawaii than in native populations in Moorea. Both regions showed significant positive relationships between C. argus total length and: (1) prey total length, and (2) prey body depth. There were significant regional differences in diet; in Moorea C. argus consumed significantly deeper-bodied prey than their counterparts in Hawaii. These differences are consistent with competitive release experienced by C. argus in Hawaii. Active and passive tracking confirmed that C. argus are diurnal and highly site attached. In Moorea, home range size ranged from 230 to 1389 m2, mean = 700 m2 in, and 425 to 2300 m2, mean = 1236 m2in, in Hawaii. There was a significant positive correlation between the size of C. argus and home range size, and C. argus in Hawaii held significantly larger home ranges than C. argus in Moorea. C. argus in both regions spent the majority of their time in core use areas which corresponded with areas of high rugosity and reef complexity. Differences in home range area and habitat utilization between regions may be due to the lack of competing species, especially other groupers, in Hawaii. C. argus is known in Hawaii for causing ciguatera fish poisoning (CFP). CFP is caused by Gambierdiscus toxicus, which produces ciguatoxins (CTX) that are incorporated into the fish tissues. Standard length of C. argus and CTX score were positively correlated, however, small fish could be strongly positive, and cause CFP. At all sites, the majority of C. argus tested contained CTX levels at or above those considered unsafe for consumption. C. argus of a given length in Hawaii had lower CTX scores than fish of the same size in Moorea.Item Community ecology of the invasive intertidal barnacle Chthamalus Proteus in Hawaiʻi(University of Hawaii at Manoa, 2005) Zabin, Chela JulietItem Local and regional influences on arthropod community structure and species composition on Metrosideros polymorpha in the Hawaiian Islands(University of Hawaii at Manoa, 2004) Gruner, Daniel S.Item The cephalic lateralis system of cardinalfishes (Perciformes: Apogonidae) and its application to the taxonomy and systematics of the family(University of Hawaii at Manoa, 2004) Bergman, Laura M. Rodman