The influence of microclimate and local adaptation for a climate-sensitive species (Aplodontia rufa)
Graduation Date
Summer 2018
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Wildlife
Committee Chair Name
William Bean
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Joseph Szewczak
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Micaela Szykman Gunther
Third Committee Member Affiliation
HSU Faculty or Staff
Fourth Committee Member Name
William Zielinski
Fourth Committee Member Affiliation
Community Member or Outside Professional
Keywords
Aplodontia, Microclimate, Species distribution model, Point Arena mountain beaver
Subject Categories
Wildlife
Abstract
Climate change models and analyses predict a disproportionate impact on climatically sensitive species such as the mountain beaver (Aplodontia rufa). Mountain beavers have physiological constraints that limit their distribution to cool, moist climates. While mountain beavers have persisted through past periods of climate change, increasing temperature since the last glacial maximum is believed to have had a strong influence in reducing their range. This is particularly true for the Point Arena subspecies (A. r. nigra, “PAMB”), found towards the southwestern edge of their range on the coast of California. Here, I examined the climatic niche of mountain beavers at four scales: range-wide; by clade; PAMB rangewide; and PAMB microclimates to test whether PAMB exhibit different climatic requirements than other subspecies.
I examined the climatic space occupied by mountain beavers at four scales using the machine learning method MaxEnt and occurrence points from museum records, previous surveys conducted by USFS, and personal survey data. First, I modeled the distribution of mountain beaver range-wide and the distributions of the five individual genetic clades (Coastal, Californica, Olympica, Pacifica, and Rufa). To examine the microclimate use of PAMB, I developed fine-scale climate surfaces using temperatures recorded from dataloggers and topographic variables calculated from LiDAR data. These layers were incorporated with PAMB occurrence data to model distribution. Finally, I examined pairwise differences in microhabitat use between burrows and available space.
At all scales high temperatures were a limiting factor in distribution. Despite a low level of niche overlap at broad scales, mountain beavers appear to display some level of niche conservatism. PAMB does seem to exist in a warmer climate than other mountain beavers; however, they apparently persist by selecting the coolest places within that range. This suggests that niche overlap between the Coastal clade and all other clades may be higher than what is detected at the coarser scale. Further research is needed to understand the mechanisms limiting this distribution, but it may be that mountain beavers in marginal habitat are more adaptable to changes in climate.
Citation Style
Journal of Wildlife Management
Recommended Citation
Jones Scherbinski, Jennie K., "The influence of microclimate and local adaptation for a climate-sensitive species (Aplodontia rufa)" (2018). Cal Poly Humboldt theses and projects. 192.
https://digitalcommons.humboldt.edu/etd/192