SEX-BIASED HARVESTING AND POPULATION-DYNAMICS IN UNGULATES - IMPLICATIONS FOR CONSERVATION AND SUSTAINABLE USE

The consumptive use of wildlife, in particular trophy bunting and game ranching of ungulates, has been advocated as a tool for conservation in Africa We show that these methods of harvesting differ significantl y from natural predation, with trophy bunting showing extreme selectio n for adult males and game ranching leading to disproportionate harves ts of young males. Little information, either theoretical or empirical , exists concerning the effect of these harvesting regimes on the long -term population dynamics of ungulate populations. Despite that, the p otential effects of sex-skewed harvests are numerous. In this paper, w e investigate one potentially deleterious effect of sex-skewed harvest s. Both theory and experimental data suggest that male ungulates are l imited in their absolute ability to inseminate females. Using a Leslie -Matrix model and published data on impala, we show that the interacti on between sperm limitation and harvests with highly male-biased sex r atios can lead to greatly reduced female fecundity (defined as the num ber of young born) and population collapse. These results are robust a nd suggest that present methods of harvesting may not be optimal, or v iable, in the long term.