Graduation Date
Fall 2020
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Wildlife
Committee Chair Name
Dr. Richard Brown
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Dr. Daniel Barton
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
David Garcelon
Third Committee Member Affiliation
Community Member or Outside Professional
Keywords
Felis catus rattus, Invasive feral cat, Ship rat micronesia, Island mark-recapture, Oceania, Mesopredator, Release, Pacific
Subject Categories
Wildlife Management
Abstract
The colonization by rats (Rattus spp.) and cats (Felis catus) on islands are known to contribute to the decline of native birds. On the island of Rota, Commonwealth of the Northern Mariana Islands, cats are being lethally removed to conserve two endangered bird species. Although cats are controlled to reduce impacts on birds, they can also prey heavily on sympatric rats. Of euthanized feral cats on Rota, 60% had ≥1 rat in the stomach. Predation by cats could be a mechanism of top-down control of rats. Removing feral cats may reduce the magnitude of that control, leading to increased rat abundance and, in turn, predation on native birds. To determine if the level of cat control being conducted on Rota is positively influencing rat abundance, I conducted a robust design capture-mark-recapture of rats, using a before-after-control-impact design, in two areas where the ongoing cat removal was not being conducted. Between primary rat trapping occasions, feral cats were removed from one of the two rat trapping areas. Using program MARK to model the data and Akaike information criterion to rank the models I determined that there was no effect of cat removal on the apparent survival of rats and that the estimated abundance did not change significantly in either the control or treatment groups after cat removal.
Citation Style
Journal of Wildlife Management
Recommended Citation
Page, Douglas A., "The effects of feral cat removal on rat abundance in an insular, tropical ecosystem" (2020). Cal Poly Humboldt theses and projects. 435.
https://digitalcommons.humboldt.edu/etd/435