Surprisingly fast recovery of biological soil crusts following livestock removal in southern Australia

Question: Biological soil crusts (BSCs) exist in arid and semi-arid ecosystems worldwide, and their recovery following the removal of a disturbance agent is integral to the rehabilitation of degraded landscapes. We asked: what is the likelihood of success and time frame of BSC recovery in vegetation remnants of southeast Australia, following livestock exclusion by fencing. Location: Dryland agricultural region of northwest Victoria, Australia. Methods: We conducted a space for time study of BSC recovery across 21 sites where livestock have been excluded by fencing between 1 and 450 years ago, and used boosted regression tree models to explore the response of BSCs to livestock exclusion while controlling for the influence of environmental variables on BSC abundance. Results: Our results show a relatively rapid, passive recovery of BSCs following livestock exclusion, with cover stabilizing after 20 years. Sites heavily disturbed by livestock grazing at the time of fencing stabilized at a lower cover. In contrast to studies from other countries, our results suggest mosses, not cyanobacteria, are the important colonizers in our study region. Conclusions: Ecosystem function in degraded remnants of southern Australia can be improved in a relatively short time frame through passive recovery alone. This knowledge will benefit land managers choosing between restoration options in disturbed and fragmented arid-landscapes.