Partitioning the impact of abiotic factors and spatial patterns on species richness and community structure of ground ant assemblages in four Bornean rainforests

Contrasting theories have been proposed to explain the structure of ecological communities. Here, we studied the impact of environmental factors and spatial patterns on ground-foraging ant communities in four different forest types of Gunung Mulu National Park in Sarawak, Borneo, Malaysia. Forest types differed in their environmental parameters and were inhabited by distinct ant communities, with various indicator species characteristic for single forest types. Three environmental parameters, soil volume, number of trees and amount of leaf litter, had the most influence on ant communities. Spatial patterns were correlated with environmental parameters and also influenced ant communities. Environmental parameters influenced community composition only moderately (r 2 = 0.14), but had a high impact on species richness (r 2 =0.44). Spatial patterns explained only a small fraction of the total variance in species patterns, while much of the residual space in the ordination space of ant community patterns remained unexplained. We conclude that environmental parameters shape the number of niches within a tropical soil habitat, but identities of species that occupy those niches are accounted for by other factors like competition, traits and neutral processes that may further reduce unexplained variance in species ordination.