Does spatial pattern matter to ecosystem functioning? Insights from biological soil crusts

1. Theoretical and modelling studies highlight the importance of the spatial patterns of organisms for ecosystem functioning, stability and dynamics. However, there is little empirical evidence as to their importance as drivers of such ecosystem attributes. 2. We evaluated the relationships between different biological soil crust attributes (spatial pattern, cover and diversity) and ecosystem functioning in two semiarid areas differing in the developmental stage of these crusts. 3. We found a significant direct relationship between spatial pattern and both soil bulk density and respiration (surrogates of ecosystem infiltration and nutrient cycling, respectively) at one of our study sites. However, the strength of such a relationship was lower than that found between attributes such as cover and evenness and the same ecosystem functioning surrogates. 4. Our results represent, to our knowledge, some of the first empirical evidence linking the spatial pattern of a community and ecosystem functioning. They also suggest that the importance of spatial pattern as a driver of ecosystem functioning may depend on community attributes such as cover and diversity, and that its importance may be lower than that of these attributes.