Into thinner air : how pikas live on the roof of the world and implications for their persistence in the Anthropocene
Abstract/Contents
- Abstract
- The human-dominated epoch of the Anthropocene is putting new pressures on species, threatening the persistence of many. One such pressure is anthropogenic climate change. In many species, climate change is causing parts of their range, generally lower latitudes and lower elevations, to no longer be habitable. As a result, we are seeing a general movement of species to higher latitudes and higher elevations. However, as montane species move to higher elevations, they will encounter greater physiological stress due to high-elevation hypoxia -- the decrease of available oxygen at high elevations due to a reduction in barometric pressure. The limitations that hypoxic stress may put on species' ability to alter their distributions have never been explored. One montane organism particularly vulnerable to climate change and already experiencing elevational range shifts at up to ten times the global average are pikas, genus Ochotona. There are at least 28 pika species, each occupying a unique elevational range between 0 -- 6,100 m with at least 14 species inhabiting elevations above 4,000 m. Little is known about how pikas can tolerate the hypoxic stress of their high-elevation habitat. By learning more about the mechanisms underlying hypoxia tolerance in pikas, I aim to gain understanding of what role hypoxic stress may play in their future range adjustments in response to projected climate change. Through the utilization of museum tissue samples, extensive field work in the Indian Himalayas, and the only captive colony of pikas in the world, I have investigated hypoxia tolerance in pikas from three different angles: (1) molecular evolution in mitochondrial candidate genes; (2) variation in gene expression along an elevational gradient within a population between 3,600 and 5,000 m; and (3) changes in gene expression within an individual when exposed to varying levels of hypoxia for a 5-day period. Our results indicate that while different pika species have genetic adaptations seemingly specializing them to the general elevational range of the species, on a local and even individual scale, changes in gene expression may offer a mechanism by which pikas can rapidly acclimate to hypoxic conditions. Our findings suggest that pika species may be genetically adapted to the elevational range they occupy, potentially limiting range movement; however, changes in gene expression may enable rapid range shifts within a species' elevational envelope.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Solari, Katherine Andrea |
|---|---|
| Associated with | Stanford University, Department of Biology. |
| Primary advisor | Hadly, Elizabeth Anne, 1958- |
| Thesis advisor | Hadly, Elizabeth Anne, 1958- |
| Thesis advisor | Dirzo, Rodolfo |
| Thesis advisor | Palumbi, Stephen R |
| Thesis advisor | Ramakrishnan, Uma |
| Thesis advisor | Sherlock, Gavin |
| Advisor | Dirzo, Rodolfo |
| Advisor | Palumbi, Stephen R |
| Advisor | Ramakrishnan, Uma |
| Advisor | Sherlock, Gavin |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Katherine Andrea Solari. |
|---|---|
| Note | Submitted to the Department of Biology. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Katherine Andrea Solari
- License
- This work is licensed under a Creative Commons Attribution Non Commercial No Derivatives 3.0 Unported license (CC BY-NC-ND).
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