Population structure variations of wild boar Sus scrofa in central Italy

Abstract

The study has been carried out on a wild boar Sus scrofa population in southern Tuscany (Italy). We aimed to estimate the trend in population structure and productivity of a harvested and high-density population. From 1990 to 1996 we examined 2773 harvested wild boars, assessing age, sex, and number of foetuses per females. We highlighted an increase of the proportions of yearling following a season with a peak of two-year individuals. Neither significant differences in mean foetus numbers among age classes nor among seasonal variations have been pointed out. Productivity peaks seemed to be related to peaks in sub-adult females in previous seasons, while food availability and harvest could have been responsible for fluctuations of sub-adult females. Fluctuations seemed more likely linked to an alternation of high and low frequency in the recruitment of females in the breeding pool than to individual differences in prolificity. Massive harvesting could bring sub-adult females and males to reproduction when adult individuals are scarce, incrementing the overall productivity, but young individuals are possibly more sensitive to environmental variations. We suggest that these studies should last longer and be strictly associated to a contemporary monitoring of trophic resources.