상세정보
Export to Refworks부가기능
Foundation Species Across Environmental Gradients: Refugia, Adaptation, and Undiscovered Populations
상세 프로파일
| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Foundation Species Across Environmental Gradients: Refugia, Adaptation, and Undiscovered Populations. |
| 개인저자 | Hollarsmith, Jordan Ann. |
| 단체저자명 | University of California, Davis. Ecology. |
| 발행사항 | [S.l.]: University of California, Davis., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 155 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-03B. Dissertation Abstract International |
| ISBN | 9781085795746 |
| 학위논문주기 | Thesis (Ph.D.)--University of California, Davis, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-03, Section: B.
Advisor: Grosholz, Edwin D. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Species that form habitat, known as foundation species, are crucial members of ecological communities. Their presence supports highly biodiverse species assemblages and their removal often triggers a phase change to an entirely different ecosystem, such as oyster reefs to mud flats, kelp forests to urchin barrens, or coral reefs to rubble fields. Changes in foundation species populations may be permanent or temporary, rapid or gradual, and wide-spread or spatially explicit, but the mechanisms that drive these different trajectories are largely unknown. In this dissertation, I examine the hypothesis that adaptation to and refugia within environmental gradients at multiple spatial scales can explain much of the variation observed in foundation species response to disturbance and global change. To test this hypothesis, I focus on three model systems: (1) oysters (Ostrea lurida and Crassostrea gigas, family Ostreidae) across seasonal estuarine gradients, (2) kelp (Macrocystis pyrifera, family Laminariaceae) across global latitudinal gradients of temperature and pH, and (3) mesophotic coral and algal communities across gradients of depth, light, and temperature. Together, the findings of this dissertation suggest that environmental gradients drive foundation species' distributions at local scales and evolutionary trajectories at global scales, but that associated communities respond more to the presence of foundation species than environmental gradients.Chapter one assesses the consequences of seasonal estuarine gradients on oyster growth and survival, with a focus on the consequences of estuarine acidification. Estuaries in Mediterranean climates feature strongly seasonal inputs of terrestrial freshwater from winter runoff and intrusion of deep water from summer upwelling which create spatially-predictable gradients of salinity, temperature, pH, and dissolved oxygen, among other parameters. Using field-based experiments along an estuarine gradient in Northern California, I find that seasonal processes significantly influence estuarine water chemistry and hydrography in ecologically relevant ways. Both native (O. lurida) and commercial (C. gigas) oyster species respond to these spatial and seasonal gradients, with reduced performance when exposed to cold, low-oxygen, low-pH upwelled water or low-salinity, low-pH runoff. The mid-bay provides a refuge for oysters, as it is least impacted by runoff or upwelling, and tends to have the highest concentration of food for the oysters. The results from this chapter suggest that the key to oyster growth and survival are seasonal and spatial refuges along the estuarine gradient, with consequences for oyster restoration and for understanding the future trajectory of oyster populations as upwelling and runoff events intensify with climate change.In the second chapter, I investigate giant kelp (M. pyrifera) population-level variation in response to warming and acidification across broad latitudinal gradients of temperature and pH in California and Chile. Using common garden laboratory experiments, I identify temperature-driven reproductive bottlenecks among high-latitude and Southern Hemisphere populations, and increased reproductive potential under low-pH conditions for populations from upwelling zones. Notably, I observe high survival of the haploid life stage among all populations and treatments tested, lending support to the gametophyte "seed bank" hypothesis. Overall, these findings strongly support the hypothesis that giant kelp is locally adapted along its range. Results have important implications for understanding and modeling the future range shifts of this widespread foundation species under a changing climate with projected declines in ocean pH and increases in ocean temperature.In chapter three, I assess the importance of foundation species in structuring mesophotic communities across gradients of depth and temperature in the eastern Pacific. Mesophotic ecosystems are found at the limits of the photic zone from 30 - 150 m depth and are notoriously understudied due to difficulties accessing these depths. Surveys in the eastern Pacific are especially rare. To fill this knowledge gap, I build a small and economical remotely operated vehicle to survey fish assemblages across a range of biogenic habitats in the El Bajo-Espiritu Santo National Park in the Bay of La Paz and the Revillagigedo National Park in the Mexican Pacific. In addition to identifying novel depth and geographic records for fish species and extensive undocumented rhodolith and coral habitats, the surveys reveal that foundation species are the best predictor of fish community composition, irrespective of depth and temperature. The results from this chapter highlight the importance of foundation species in structuring communities, even at mesophotic depths, and demonstrate the effectiveness of new ROV technology for conducting deep-water surveys in remote regions. My methods and results provide a framework that can be used to greatly increase the biogeographic and taxonomic scope of mesophotic research. |
| 일반주제명 | Ecology. Climate change. |
| 언어 | 영어 |
| 바로가기 | 
: 이 자료의 원문은 한국교육학술정보원에서 제공합니다. |
