在线查找
与期刊/刊物的链接
在图书馆查找
正在查找有这资料的图书馆...
详细书目
| 文件类型: | 文章 |
|---|---|
| 所有的著者/提供者: | Neil F Payne |
| ISSN: | 0022-541X |
| OCLC号码: | 479999468 |
| 语言注释: | English |
| 奖励: |
摘要:
Mortality rates of beaver (Castor canadensis) were studied in Newfoundland from 1964-65 to 1970-71. The average annual mortality rate was 27%, but was 52% during the first 6 months of life, 4% between 0.5 and 1.5 years, and 40% between 1.5 and 2.5 years. The survival rate was constant from 4.5 to 10.5 years. Average annual adult (2.5 years and older) mortality was 32%. Annual harvest mortality for sustained-yield management varied from 8 to 29%. Adult harvest mortality varied from 11 to 36% and natural mortality from 0 to 24%. Some compensatory natural mortality probably operates in the absence of harvest mortality. An annual harvest of less than 20-25% from stationary beaver populations will result in economic loss to trappers when fur prices are high.
