Red fox population decrease in hungary: Competition or carrying capacity limitation?

Abstract

In the last two decades the Hungarian red fox (Vulpes vulpes) population (POP) has grown significantly. The growing trend was broken in 2002. We tested two hypotheses: (1) the POP falling due to a fox POP size that is above the carrying capacity (CC) that initiates internal control mechanisms (H1); or (2) a fall in the POP due to competition from the expanding golden jackal POP (H2). Data was collected in one of three ways: (1) voluntary questionnaire survey from Game Management Units regarding estimated (EST) fox POP size; (2) country and countywide hunting (HUNT) bag data from the National Wildlife Database; and (3) POP dynamics (DYN) data obtained from 1,352 dissected fox carcasses. For H1, the pop density was calculated from the EST fox POP size, the hunt mortality (MORT) was calculated from the hunt bag data, and the natural mortality was calculated from the difference between the following year’s EST POP size and the average litter size and stock of the current year. For H2 we examined data from three counties (Baranya, Bacs-Kiskun, Somogy) where a considerable breeding golden jackal POP exists. The county data have been compared with each other and with data for the whole of Hungary. The average POP DYN parameters have increased significantly from 1998 to 2002. In 2002, density was 9.47 sp/1,000 hectares, HUNT MORT was 8.2 sp/1,000 hectares, litter size was 7.1 sp, the reproductive (REP) rate for bitches was 55.14%, and the overall reproductive rate was 22.04 sp/1,000 hectares (the natural MORT rate was 15.36). In 2002, the natural mortality rate was nearly two times the HUNT bag rate. The Bacs-Kiskun county data parallels the average country’s data. Some differences in Baranya county’s data were noticeable when compared to the country’s data POP DYN parameters were of larger magnitude. In 2002 the POP density was 19.23 sp/1,000 hectares, the HUNT MORT was 9.8 sp/1,000 hectares, the REP rate was 44.77 sp/1,000 hectares, and the natural MORT rate was 42.96 in Baranya county. H1 seems to be supported by our results. POP size was above carrying capacity and internal control mechanisms were at work. The rodent POP decline in 2003 may have assisted in Dogs and other canines in the wild 63