Environmental factors relating to the distribution of terricolous bryophytes and lichens in semi-arid eastern Australia

Bryophytes and lichens associated with soil crusts were sampled over 500,000 km(2) of rangelands in semi-arid eastern Australia. Canonical Correspondence Analysis (CCA) was used to examine the relationships between a range of environmental variables and the distributions of these species from a subset of 130 samples from 87 sites. CCA revealed that bryophytes were related to total annual rainfall, soil pH, calcium carbonate levels, plant cover, texture, organic carbon, and soil texture. Lichens were related to annual rainfall, pH, calcium carbonate levels, plant cover, sheet erosion, organic carbon, and crust cover. Rainfall is a primary determinant of plant cover, which in turn affects light, nutrient availability and litter levels, and therefore bryophyte and lichen distribution. On the basis of the first two ordination axes, bryophytes and lichens clustered infer loose arrangements of species, based on their responses to the environmental variables.