Thesis
Selective predation on native vs invasive zooplankton in the lower Columbia River
Washington State University
Master of Science (MS), Washington State University
2014
Handle:
https://hdl.handle.net/2376/101956
Abstract
Copepods are important prey for many aquatic predators such as fish and macroinvertebrates. The Asian calanoid copepod, Pseudodiaptomus forbesi, introduced to the Columbia River Estuary approximately 15 years ago, now regularly dominates the late-summer zooplankton community, but the impacts of this invader on food webs are currently unknown. I conducted predation experiments to see if native aquatic predators (three species of planktivorous fish and one species of mysid) exhibited stronger selectivity for native vs invasive zooplankton prey. In `single prey-type' experiments, designed to investigate selection preference independent of interspecific prey interactions, predators showed neutral selectivity between native cyclopoid copepods (Cyclopidae spp.) and the invasive copepod, P. forbesi. However, in `two prey-type' experiments, where interspecific interactions between both prey types and predator occurred, O. tshawytscha and P. oregonensis both strongly selected native cladocerans (Daphnia retrocurva) over P. forbesi, and moreover, P. oregonensis selectively fed on native Cyclopidae spp. over P. forbesi. Other predators showed no significant selection preference of native versus invasive copepods. My results indicate that some native aquatic predators select for native over invasive zooplankton, and that such predation may facilitate iv zooplankton invasions, while at the same time potentially having deleterious effects on native predator populations. On the other hand, some native predators exhibited neutral selectivity of native vs invasive prey, suggesting that both the population-level and broader food web impacts of zooplankton invasions may be species-specific and difficult to generalize.
Metrics
2 File views/ downloads
34 Record Views
Details
- Title
- Selective predation on native vs invasive zooplankton in the lower Columbia River
- Creators
- Jesse Brandon Adams
- Contributors
- Stephen M. Bollens (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525178801842
- Language
- English
- Resource Type
- Thesis