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Mechanisms driving postfire abundance of a generalist mammal


Zwolak, R.; Pearson, D. E. ; Ortega, Y. K.; Crone, E. E. 2012. Mechanisms driving postfire abundance of a generalist mammal. Canadian Journal of Zoology. 90: 51-60.

doi: 10.1139/Z11-111

Changes in vertebrate abundance following disturbance are commonly attributed to shifts in food resources or predation pressure, but underlying mechanisms have rarely been tested. We examined four hypotheses for the commonly reported increase in abundance of deer mouse (Peromyscus maniculatus (Wagner, 1845)) following forest fires: source-sink dynamics, decreased predation, increased food resources, and increased foraging efficiency. We found that reproduction of deer mouse was considerably higher in burned versus unburned forests and survival did not differ between habitats, indicating that burned forests were not sink habitats. Comparable survival also suggested that predation rates were similar between habitats. Increased reproduction in burned versus unburned forest suggested better resource conditions, but abundance of seeds and arthropods (the primary food resources for mice) either did not differ between habitats or were higher overall in unburned forest. Foraging experiments indicated that seed removal from depots was substantially higher in burned versus unburned forests after controlling for mouse density. Additionally, in both habitats, mice were captured more often in open microhabitats and the odds of individual insect removal increased with decreasing cover during certain sampling periods. Of the four hypotheses tested, greater foraging efficiency provided the best explanation for elevated populations of deer mouse. However, predation risk may have influenced foraging success.

Keywords: vertebrate abundance, forest fires, mechanisms, source-sink dynamics, decreased predation, food resources, foraging efficiency


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http://www.fs.fed.us/rm/pubs_other/rmrs_2012_zwolak_r001.pdf

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Title: RMRS Other Publications: Mechanisms driving postfire abundance of a generalist mammal
Electronic Publish Date: March 20, 2012
Last Update:
March 20, 2012

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