Nearest-neighbor contingency table analysis of spatial segregation for several species

Spatial segregation of species occurs when a species is more likely) to be located in the vicinity of conspecifics. This can be investigated by mapping and identifying all locations in a study area, then analyzing the nearest-neighbor contingency table. where each location is classified by its species and the species of its nearest neighbor. Nearest-neighbor contingency tables for two species call be analyzed using the methods in Dixon (1994). Here, I present methods to analyze contingency tables for any number of species. Calculation and interpretation of the multispecies contingency table are illustrated by two examples: spatial segregation of species in a swamp forest. with five types of points (Fraxinus caroliniana. Nyssa sylvatica, Nyssa aquatica, Taxodium disticum and other species). and spatial segregation in the gamodioecious tree Nyssa aquatica. with three types of points (male, female. and juvenile). Two issues that affect the results and their interpretation are the choice of randomization (random labelling or toroidal rotation) and the choice of test (pairwise or multispecies).