Biological soil crusts in a changing world: introduction to the special issue
Soil surface communities comprised of cyanobacteria, mosses, liverworts, fungi, eukary-otic algae and lichens (biological soil crusts or biocrusts) are a conspicuous and importantbiotic component of many terrestrial ecosystems worldwide, from the tropics to the poles,in which they strongly inﬂuence ecosystem structure and processes (Belnap and Lange2003). Biocrusts show the resistance and resilience of life under extreme conditions as wellas a remarkable adaptation to the combinations of different climatic factors throughout alllatitudes. As such, it is not surprising that multiple aspects of the biology and taxonomy ofbiocrust constituents have been studied for many years (Belnap and Lange 2003). How-ever, the interest of the scientiﬁc community in biocrusts has grown exponentially over thelast two decades, and a new wave of research on the ecological roles of biocrusts has beenconducted during this period (e.g. Lindo and Gonzalez 2010; Castillo-Monroy and Maestre2011; Maestre et al. 2011; Mager and Thomas 2011; Pointing and Belnap 2012; Bu et al.2013 for recent reviews). Research on all aspects of biocrust biology and their inﬂuence onecosystems, traditionally performed by researchers in a few countries, such as the USA,Australia, Israel, and Germany has become a truly global research endeavor, with theemergence of many groups in countries such as China, Spain, and Mexico (Castillo-Monroy and Maestre 2011).The biocrust research community is more interconnected than ever before, as evidencedby the multiple collaborations that are being established among the different groups, by theongoing preparation of a new book on the status of the ﬁeld featuring authors from all the