Ecological importance of large fishes
Abstract/Contents
- Abstract
- In this dissertation I explore how ecosystems change when their largest faunal residents are removed. Specifically I consider how coral reef ecosystems respond to the removal or depletion of a variety of functionally and taxonomically unique large reef fish. There are seven chapters in this thesis. Chapter 1 critically examines the performance of four methods for estimating coastal shark abundance. I compare outputs from field survey trials conducted at Palmyra to results from computer simulations to evaluate the efficacy of these selected methods. In Chapter 2 I present the results of an experiment conducted at our near-pristine reef site where I excluded large fish and tracked the effects of their absence. I observed that the removal of these larger ecosystem constituents affected a variety of responses including algal growth, fish behavior, and invertebrate recruitment. These changes occurred rapidly and were observed to interact in complex ways with one another. Chapter 3 relies on the use of stable isotopes to identify how large fish build linkages across ecosystems. I use isotopes of C and N and mixing models to determine what energy sources large reef predators rely upon and to infer how these utilization patterns influence ecosystem connectivity and functioning. In Chapter 4 I examine some provocative observations made in unfished and fished reefs which suggest that large fish predators control the temporal niche structure of their prey. I observed that the removal of day-time active predators from fished reefs appears to have caused an increase in the abundance of nocturnal prey fishes. Chapter 5 is an investigation of the functional ecology of the world largest parrotfish B. muricatum. Using this animal as a model, I consider how ecologically dominant animals affect the functioning of ecosystems. Conclusions are drawn from intensive field observation and simulation exercises. Chapter 6 utilizes a diversity of research approaches (biogeochemical tools, ecological surveys, animal tracking) to chronicle a long ecological interaction chain that links forests to manta rays. By contrasting processes in disturbed and undisturbed study sites I consider how anthropogenic disturbance more generally affects the length of ecological interaction chains. Finally, in chapter 7 I discuss the importance of protecting remote ecosystems that often harbor intact communities of large animals. I argue that extremely remote environments are critically important and yet vulnerable repositories of biodiversity and I review how existing conservation strategies may be adapted to help protect these special environments.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2011 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | McCauley, Douglas J |
|---|---|
| Associated with | Stanford University, Department of Biology |
| Primary advisor | Micheli, Fiorenza |
| Thesis advisor | Micheli, Fiorenza |
| Thesis advisor | Dirzo, Rodolfo |
| Thesis advisor | Dunbar, Robert B, 1954- |
| Thesis advisor | Estes, J. A. (James A.), 1945- |
| Thesis advisor | Palumbi, Stephen R |
| Advisor | Dirzo, Rodolfo |
| Advisor | Dunbar, Robert B, 1954- |
| Advisor | Estes, J. A. (James A.), 1945- |
| Advisor | Palumbi, Stephen R |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Douglas Jon McCauley. |
|---|---|
| Note | Submitted to the Department of Biology. |
| Thesis | Ph.D. Stanford University 2011 |
| Location | https://purl.stanford.edu/mm765qn1476 |
Access conditions
- Copyright
- © 2011 by Douglas Jon McCauley
- License
- This work is licensed under a Creative Commons Attribution Non Commercial Share Alike 3.0 Unported license (CC BY-NC-SA).
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