干旱区生态环境知识资源中心

Human impact causes land degradation with negative effects on both density and genetic variability of animal populations. Recent studies indicate that host genetic diversity plays an important role in buffering populations against widespread epidemics. Within the mammalian immune system the highly variable major histocompatibility complex (MHC) plays a central role in pathogen defence. In this study we used two common African rodent species, the hairy-footed gerbil (Gerbillurus paeba) and the striped mouse (Rhabdomys pumilio), as model organisms to investigate effects of different land use on (1) vegetation structure and population density, (2) parasite burden and (3) the importance of the MHC-constitution for resistance to parasites by comparing two sites on a private nature reserve and one site on a commercially used farm in the Southern Kalahari/South Africa. Both rodents were significantly more abundant and showed more helminths infections in the two less degraded nature reserve sites, although the MHC diversity was not significantly different between sites. Either higher parasite species richness or the increased host population density in the more diverse nature reserve sites might be responsible for the higher parasite prevalence. In both species significant associations were found between specific alleles and infection status, giving evidence for the significance of the MHC in the defence of pathogens.