Small Mammal Population Ecology and Ectoparasite Load: Assessing Impacts of Land Use and Rainfall Seasonality in the Serengeti Ecosystem, Tanzania

Abstract

Small Mammal Population Ecology and Ectoparasite Load: Assessing Impacts of Land Use and Rainfall Seasonality in the Serengeti Ecosystem, Tanzania.

Small mammals are members of a very diverse animal group that includes rodents, shrews and moles, besides other sub-groups. They play many critical roles in ecosystems, including dispersing seeds, transforming soils, providing traditional medicine, as well as food for other animals. They are also important as bio-indicators for monitoring ecosystem health. We studied how the number, species diversity, habitat selection, breeding and community demography of small mammals vary between seasons and between contrasting land uses in the Serengeti National Park and adjoining pastoralist and agricultural lands in northern Tanzania. Further, we explored how land use and habitat type impact the number of skin parasites on small mammals. Live traps were used to trap small mammals in 2017 and 2018. Small mammals were most abundant in the pastoralist land where the African grass rat contributed over 70% of all captured individuals. This is because livestock grazing in the pastoralist land promotes more uniform shrubs and shorter grasses that this species prefers. However, the park had higher species diversity, suggesting it provides safer habitats, than either the pastoralist or agricultural land. Most of the common species selected the park except for a few habitat generalists that also used the pastoralist and agricultural lands. The majority of the species started breeding in the wet season when water, plant cover and food, essential for successfully producing and rearing young, were plentiful. As a result, juveniles were most abundant in the early dry season. Additionally, individuals had more skin parasites in the pastoralist and agricultural lands than in the park, reflecting impaired habitats, hence posing greater risks to human and animal health and, potentially escalating human-wildlife conflicts. Promoting land uses compatible with conservation around protected areas is therefore essential to reducing human-wildlife conflicts, improving ecosystem health, mammal species diversity, breeding patterns and habitat selection.