Connect the dots – how does habitat expansion impact wildlife behavior and parasitism?

Connectivity and habitat expansion are key conservation tools; however, secondary effects, such as those on behavior and parasitism, are poorly understood. Furthermore, their interaction – how changes in behavior affect... [ view full abstract ]

Connectivity and habitat expansion are key conservation tools; however, secondary effects, such as those on behavior and parasitism, are poorly understood. Furthermore, their interaction – how changes in behavior affect parasitism – has rarely been studied. Our objective was to investigate the impact of expansion on movement, interactions, and parasitism in the critically endangered woylie (Bettongia penicillata), using social network models to assess the epidemiological consequences of behavioral changes. We expected; 1) access to new habitat will change woylie behavior, with reduced home range overlap and nest-sharing as the population spreads out; 2) these behavioral changes will reduce the connectivity of woylie social networks; and 3) reduced host network connectivity will lead to reduced parasitism.
In August 2014, tunnels were opened at the study site in Western Australia, connecting an original 50ha fenced reserve with a 150ha expansion. Since February 2014, woylies have been trapped seasonally, fitted with GPS collars (n≈30), and sampled for gastrointestinal, external, and blood-borne parasites. Pre- versus post-expansion comparisons will include: kernel home/nest ranges; weighted social networks reflecting different transmission modes (e.g., overlapping home ranges for environmentally-transmitted ticks, nest sharing for lice); and parasite prevalences and abundance. Within three months, 96% of animals began using the expansion; home range sizes increased accordingly. However, most individuals continued to nest in the original reserve. Parasitism by lice and ticks was not immediately affected. Other results are pending; changes in movement, social networks, and parasitism will be detailed. Understanding how habitat expansion impacts wildlife behavior and parasitism can aid conservationists in risk assessment for connectivity and expansion projects; it is particularly relevant for the woylie, in which parasites have been implicated in their dramatic decline and understanding how behavior relates to transmission is of particular interest. This study will also demonstrate the utility of social networks in wildlife epidemiology.