IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Slough, B.G.; Mowat, G. | |
| Lynx population dynamics in an untrapped refugium | |
| 1996 Journal of Wildlife Management (60): 946-961 | |
Refugia from trapping are believed to be important to support a long-term sustainable harvest of Canada lynx (_Lynx lynx_), but long-term studies in unharvested areas are lacking. We studied lynx population characteristics in relation to snowshoe hare (_Lepus americanus_) densities in a 301 kmę refugium in the Yukon Territory between 1986 and 1994. Lynx carcasses were collected from adjacent trapping concessions for analysis of attributes of the harvested population. Hare density peaked in summer 1990 and began to decline in the winter of 1990-91. Lynx density in March varied with hare density from 2.7/100 kmę in 1987 to 44.9/100 kmę in 1991-92. The lynx population doubled annually for 4 years when reproduction and kit and adult survival were high, and immigration balanced or exceeded emigration. High mortality and emigration characterized the lynx decline. Proportions of breeding adults were 100% most years, including the first year of declining hare densities, but zero in the following 2 years. Yearling females reproduced only in the 2 years of highest hare numbers. Kit survival, which was 0% in 1986-87, peaked at 75% for kits of adult females and 26% for kits of yearlings in 1990-91. Emigration peaked annually from March-June, was lowest Sept.-Oct., and was not sex-biased. At least 16% (n = 22) of emigrants were trapped or shot. Seventeen lynx (14M, 3F) emigrated 100-1100 km. Annual natural mortality rates were under 11% for the first 6 years of study, including 2 years of hare decline, 60% in 1992-93 and 25% in 1993-94. The carcass sample contained 36% fewer kits, 40% more yearlings, and 4% fewer adults than were present on the study area, reflecting the lower birth and survival rates of kits of yearling females and trapping bias. Mean annual lynx home range size did not vary with hare density, until 1992-93 when male ranges increased markedly, and 1993-94 when female ranges increased. We recommend a network of permanently assigned untrapped areas to facilitate normal lynx population responses to changing snowshoe hare densities, to prevent local extinctions, and to maximize lynx harvests over a complete population cycle. |
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