The fate of biological soil crusts after fire: A meta-analysis

Abstract

Fire is a global disturbance that is predicted to increase in frequency and severity in many parts of the world due to climate change. Biological soil crust (biocrust) communities are often overlooked in fire studies despite having a substantial effect on ecological function and the adjacent communities. The goal of this study is to synthesize and analyze existing data elucidating the recovery of biocrust cover following fire at the global-scale and suggest avenues for future research. We performed a meta-analysis of studies from 1984 to 2019 to address the response of biocrust after fire and determine the moderating factors governing their response. Overall, fire reduced biocrust cover by 50% and had a significantly negative effect on biocrusts classified as cyanobacteria or algal dominated. Additionally, as time since fire increased, total biocrust cover increased but this response was modulated by biocrust type indicating compliance with traditional biocrust successional models. However, there was significant unexplained heterogeneity within the meta-analysis. This reflects a critical need for more studies specifically addressing the effect of fire on biocrust communities as they are an ecosystem engineer in drylands around the world. We suggest more thorough characterization of biocrust organisms through field and laboratory studies to understand the mechanisms of biocrust response to fire. Additionally, research is needed across a broader geographic range to represent the known distribution of biocrust communities, particularly as fires increase in severity and scope.