We used a distance-based test of independence to measure the association between concurrent distributions of radio-collared grizzly bears (Ursus arctos) and calving caribou (Rangifer tarandus) of the Porcupine caribou herd (PCH) on the Arctic National Wildlife Refuge (ANWR), Alaska. The analysis utilized 552 grizzly bear and 585 caribou radio relocations recorded during 5 consecutive time intervals between 29 May and 22 June, 1988-90. Correlation coefficients of bear and caribou distributions tended to be positive in 1988 and negative in 1990. Those trends corresponded with annual variations in snowmelt in the Alaska portion of the PCH calving grounds and mortality for calves of radio-collared PCH cows. Concurrent distributions of bears and caribou were positively correlated (P < 0.05) during time intervals 29 May-2 June and 8-12 June 1989. We hypothesize that positive correlations were the result of extensive overlap and a high degree of interspersion between bear and caribou distributions. The majority (13/15) of concurrent distributions of bears and calving caribou were not significantly correlated. We hypothesize this occurred because the ANWR bear population did not respond to the availability of calving caribou in a homogeneous manner. The distance-based test of independence appeared to be an acceptable technique for quantifying associations between discrete, but interacting, populations of wildlife.
- Volume 9
- Issue
- Pages 435-442
- Publication Date 1 January 1994
- DOI 10.2307/3872730
- File Size 289.56 KB
- Download