Soil Microbiodiversity's Role in Wild Mammal Gut Health and Immunity
The gut microbiota, a diverse community of bacteria and fungi residing in the intestinal tract, plays a crucial role in host health by aiding in digestion, preventing pathogen colonization, and regulating the immune system. Its assembly is influenced by ecological processes such as dispersal, selection, drift, and diversification. Early-life colonization, particularly through maternal inheritance, significantly impacts the long-term composition of the gut microbiota. While the gut microbiota in murines stabilizes post-weaning, wild animal gut communities face additional selective pressures from pathogens, pollution, and human land use, which can either enhance resilience or lead to dysbiosis.  In humans, the "biodiversity hypothesis" suggests that urbanization and reduced microbial exposure contribute to inflammatory diseases. Interventions involving contact with microbially rich soils have shown promise in mitigating these effects by enhancing regulatory T cell maturation and increasing the abundance of key microbial taxa. However, the functional roles of different soil microbial communities in gut microbiota assembly remain unclear.  This study investigates the impact of soil exposure on the gut microbiota of captive-born progeny of wild bank voles. By comparing voles exposed to sterile environments versus soils from Finnish national parks and urban areas, we aim to determine if natural forest soils promote healthier gut microbiomes with higher alpha diversity and reduced dysbiosis. We also explore whether sterile environments lead to reduced or increased community dispersion and assess the stability of bacterial versus fungal communities. This research seeks to elucidate the effects of environmental biodiversity on wild gut microbiota development and host health.