Special issue  

Here we introduce the BIODESERT survey, the first systematic field survey devoted to evaluating the joint impacts of grazing by domestic livestock and climate on the structure and functioning of dryland ecosystems worldwide. We describe the major characteristics and the field protocols used in this survey and the organizational aspects followed to carry it out succesfully.

Biocrusts in arid and semiarid regions interact with soil microbes and plants. The knowledge of the spatial scale of the interactions adds value to crusts' use for plant and soil restoration. Soil sampling was confined to an area with Erica spp. shrubs interspaced by crust cover (Cladonia rangiformis) or uncovered at different distances from the base of the shrubs towards the periphery. The community composition and the microbial networks showed response to spatial heterogeneity.

Biocrusts are associations among drought-tolerant organisms and are crucial for maintaining the steady state of ecosystems subjected to high environmental stresses. The elaboration of sustainable plans for their preservation, restoration, and spreading is a recent strategy to combat land degradation and desertification. This review highlights the most relevant achievements and the critical points still open for the biotechnological application of cyanobacteria and mosses to soil restoration.

Biocrusts are a key component in Spanish drylands, where their ecological relevance has been widely studied. However, by doing a literature review, we found that the social dimension of their role still remains unexplored. This may hinder biocrusts and their benefits from being known and understood by the policy community and the general public. Thus, we identified social–ecological knowledge gaps and proposed new research areas that need to be addressed to advance towards biocrust conservation.

Can organisms other than vascular plants establish and develop on road slopes? Yes, biological soil crusts (or biocrusts) can. Here, we found that lichen biocrusts are common and relatively abundant in road slopes after ~20 years of construction with no assistance needed. These findings are of critical importance for dryland restoration because biocrusts can speed up ecosystem recovery by stabilizing soil surface, improving soil fertility and facilitating vascular plant establishment.

In the quest to understand how biotic interactions respond to climate change, one area that remains poorly explored is how interactions involving organisms other than vascular plants will respond. This study assessed how changes in water availability altered the biotic effects of biological soil crusts and pioneer shrubs in the early life-history stage of tree seedling growth. We found that water availability changed the magnitude of shrub effect and the magnitude and type of crust effect.