Understanding the effects of anthropogenic impact on ecology, genetic diversity and population health of wildlife

Anthropogenic land-use often leads to shifts in species composition, alter species abundance and their genetic diversity. While there is strong awareness of the direct negative consequences of habitat loss, invasive species, pollution, overexploitation and climate change, only recently health issues have been recognized as an emerging cause of species decline. Changes in parasite and pathogen pressure due to microclimatic effects and increased contact rates between wildlife and human associated livestock potentially affect the transmission rate of pathogens and might be one reason for the increasing number of novel infectious diseases threatening our biodiversity. Additionally, loss of biodiversity has the potential to alter ecosystem services on which humans and wildlife depend.

One fundamental question in conservation genetics and functional biodiversity research is to understand what drives and limits a species’ ability to adapt to current environmental and climatic changes affecting pathogen and parasite pressure. Pathogens and parasites represent one of the major selective forces shaping host evolution, as they generally depend on ecological conditions of their host’s habitat. On the other side, the ability of a host population to resist pathogens depends, to a large extent, on its immunogenetic constitution. In vertebrates, genes of the Major Histocompatibility Complex (MHC) play a key role in the host’s adaptive immune response and are of central importance in pathogen and parasite defense. When human impact upon a population causes a loss of MHC diversity, the ability to present pathogen antigens to the immune system is strongly impaired. Moreover, MHC variation in mammals is intrinsically related to an individual’s unique odortype, which plays an important key role in social and reproductive behaviors. The MHC can directly shape olfactory cues (e.g. through the urinary presence of its gene products) or influence it indirectly: the MHC-dependent gut bacterial community, the so called microflora, is assumed to control variation in individual odor profiles.

In our research, we combine ecological field work with laboratory analyses (genetics, pathogen and parasite screening) in a wide range of different mammalian taxa, such as rodents, marsupials, lemurs, bats, lagomorphs and carnivores. We have ongoing projects in Africa, Central and South America, Asia, Australia and Europe. We apply genomic approaches using next-generation sequencing technologies (454, Illumina®) to investigate the mechanisms by which neutral (microsatellite, SNPs) and adaptive genetic diversity (MHC) act on evolutionary processes. We investigate the health status of wildlife individuals by monitoring ecto and endoparasite loads. As an example, gastrointestinal helminthes are very sensitive to microhabitat changes and influence the fitness of their hosts. They are known to facilitate co-infections and influence the resident gut bacterial community and the overall health of humans by modulating the immune response. Since virtually nothing is known for wildlife species we focus on the microbiome of different wildlife hosts in order to understand the effects of ecological, genetic and environmental factors on the ‘normal’ bacterial variation range.