Snail mucus increases the CO2 efflux of biological soil crusts

Biological soil crusts (hereafter, biocrusts) are communities of microorganisms that regulate key ecosystem processes such as water distribution, soil erosion, and nutrient cycling in drylands worldwide. The nature of biocrust function can be influenced by multiple environmental factors, including climatic conditions (e.g., precipitation), interactions with plants, and anthropogenic disturbances. Animal regulation of biocrust function has received less research attention, focusing primarily on livestock trampling and to a much lesser extent on biocrust consumption by mesofauna. Deposition of animal waste products, carcasses, and other body secretions such as mucus may also affect biocrust function. Yet, this novel regulatory pathway, to our knowledge, has never been empirically tested. Our goal was to begin bridging this knowledge gap by exploring how snail mucus affects biocrust CO2 efflux— using two distinct biocrust communities and three snail species. We found that snail mucus incre...