Graduation Date

Fall 2024

Document Type

Thesis

Program

Master of Science degree with a major in Natural Resources, option Wildlife

Committee Chair Name

Richard Brown

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Barbara Clucas

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Ho Yi Wan

Third Committee Member Affiliation

HSU Faculty or Staff

Keywords

Activity patterns, American pika, Behavior, California, Camera traps, Community structure, Small mammals

Subject Categories

Wildlife

Abstract

COMPOSITION, SPATIAL CO-OCCURRENCE, AND TEMPORAL OVERLAP OF SMALL MAMMAL SPECIES AT AMERICAN PIKA (OCHOTONA PRINCEPS) ACTIVITY CENTERS

Understanding how spatial, temporal, and behavioral factors play a role in shaping the structure of small mammal communities can provide insights into the extent to which species can coexist. I investigated the community structure of American pikas (Ochotona princeps) and sympatric small mammals at lower elevations in Lassen National Forest, California, U.S.A. Camera trapping stations were installed at 35 activity centers of pikas across three study sites in Lassen National Forest from June - October 2023. I assessed differences in composition, spatial co-occurrence, and temporal overlap in communities of pikas and sympatric small mammals. A total of 11 small mammal species were detected. Community compositions differed significantly across sites, with California ground squirrels (Otospermophilus beecheyi) and a muskrat (Ondatra zibethicus) only occurring at one site. Observed spatial co-occurrence frequencies mostly did not deviate from expected co-occurrence frequencies among small mammals, except Douglas’s squirrels (Tamiasciurus douglasii) were positively associated with golden-mantled ground squirrels (Callospermophilus lateralis) and long-tailed shrews (Sorex sp.), and no negative associations were detected. The following temporal activity patterns were observed: bushy-tailed woodrats (Neotoma cinerea), deer mice (Peromyscus sp.), and long-tailed shrews were nocturnal while western chipmunks (Neotamias sp.), golden-mantled ground squirrels, and California ground squirrels (Otospermophilus beecheyi) were diurnal, and pikas and Douglas’s squirrels were crepuscular. Pikas temporally overlapped the least with bushy-tailed woodrats and the most with Douglas’s squirrels. Pikas and all small mammals temporally overlapped the least when pikas were haypiling. Behaviors displayed by pikas that had the highest temporal overlap with sympatric small mammals were mostly territorial. The type of territorial behavior used by pikas was associated with whether small mammals were diurnal or nocturnal. This study demonstrates that spatial, temporal, and behavioral factors play a role in shaping the community structure of pikas and sympatric small mammals. Findings from this study suggest that temporal partitioning and behavioral mitigation facilitate coexistence between pikas and sympatric small mammals.

Citation Style

Journal of Wildlife Management

Collaboration

1

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