SPATIAL PATTERN IN COMMUNITIES OF CRUSTOSE SAXICOLOUS LICHENS

This paper describes two versions of a new method for detecting and ex amining spatial pattern in communities of crustose saxicolous lichens. One version is based only on the shapes of the lichen thalli and the second on the identity of their species. These methods are useful for examining the spatial structure of a lichen community for the presence of anisotropy, the phenomenon of having different scales of pattern i n different directions. If present, the nature of the anisotropy has i mplications for our understanding of the processes that give rise to s patial pattern. Preliminary results from communities in the Canadian R ockies suggest that while individual species show some evidence of ani sotropy, when all species are considered together, or when only the sh apes of the thalli and their boundaries are considered, anisotropy is reduced or absent. (C) 1995 The British Lichen Society