Neighbour diversity is the diversity of other plant species contacting a reference species. The expected value and confidence intervals of neighbour diversity assuming random contacts can be found using bootstrapping. In general, frequent species have higher expected neighbour diversities with narrow confidence intervals than infrequent species. In fixed sand dunes dominated by lichens and bryophytes most species have lower than expected neighbour diversity. However, the fixed sand dunes seem to be a mixture of two patch types, with the species in lichen-rich patches having higher diversities than the species in bryophyte-rich patches. In hay pastures, nearly all species have lower than expected neighbour diversities. The more frequent the species is, the more below the expectation is its neighbour diversity. This implies that the frequent species are selective in their neighbours, and so they drive a biological formation of spatial pattern.
Keywords: Bootstrapping; Contact sampling; Fixed sand dune; Hay pasture; Plotless sampling; Spatial scale