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详细书目
| 文件类型: | 文章 |
|---|---|
| 所有的著者/提供者: | Douglas W Smith; David R Trauba; Raymond K Anderson; Rolf O Peterson |
| ISSN: | 0003-0031 |
| OCLC号码: | 477464034 |
| 语言注释: | English |
| 奖励: |
摘要:
Beavers (Castor canadensis) were studied on two Lake Superior islands; one (Stockton) had black bears (Ursus americanus), while the other (Outer) did not. Both islands were colonized by beavers during the late 1940s or early 1950s in the absence of bears, and bears immigrated to Stockton Island in the 1970s. Active beaver colonies on Outer Island increased during the study whereas they declined on Stockton Island. Bears ate five beavers in live-traps and disturbed twelve other sets. Six of 90 bear scats found had beaver hair in them, and 18 of 26 beaver lodges were dug into by bears. Compared to Outer Island, beavers on Stockton Island cut fewer food trees relative to their availability, and cut few trees >30 m from water, whereas beavers on Outer Island traveled >200 m inland to forage. Mainland studies have not reported such intense beaver/bear interactions, nor is the behavioral or population response of beavers as significant where they are preyed upon by wolves (Canis lupus), a more typical beaver predator.
