What is a biocrust? A refined, contemporary definition for a broadening research community.

Studies of biological soil crusts (biocrusts) have proliferated over the last few decades. The biocrust literature has broadened, with more studies assessing and describing the function of a variety of biocrust communities in a broad range of biomes and habitats and across a large spectrum of disciplines, and also by the incorporation of biocrusts into global perspectives and biogeochemical models. As the number of biocrust researchers increases, along with the scope of soil communities defined as 'biocrust', it is worth asking whether we all share a clear, universal, and fully articulated definition of what constitutes a biocrust.

Temporal and abiotic fluctuations may be preventing successful rehabilitation of soil-stabilizing biocrust communities.

Land degradation is a persistent ecological problem in many arid and semiarid systems globally (drylands hereafter). Most instances of dryland degradation include some form of soil disturbance and/or soil erosion, which can hinder vegetation establishment and reduce ecosystem productivity. To combat soil erosion, researchers have identified a need for rehabilitation of biological soil crusts (biocrusts), a globally relevant community of organisms aggregating the soil surface and building soil fertility.

Spectrally monitoring the response of the biocrust moss Syntrichia caninervis to altered precipitation regimes.

Climate change is expected to impact drylands worldwide by increasing temperatures and changing precipitation patterns. These effects have known feedbacks to the functional roles of dryland biological soil crust communities (biocrusts), which are expected to undergo significant climate-induced changes in community structure and function. Nevertheless, our ability to monitor the status and physiology of biocrusts with remote sensing is limited due to the heterogeneous nature of dryland landscapes and the desiccation tolerance of biocrusts, which leaves them frequently photosynthetically inactive and difficult to assess.