Evolution of termite functional diversity: analysis and synthesis of local ecological and regional influences on local species richness

• Published in: Journal of biogeography 2003-06, Vol.30 (6), p.847-877
• Main Authors: Davies, Richard G., Eggleton, Paul, Jones, David T., Gathorne-Hardy, Freddy J., Hernández, Luis M.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Assemblage; Biogeography; Biological and medical sciences; convergence; Forest canopy; Forest soils; From Termite Diversity to Mammal Diversity; Functional diversity; functional species richness; Fundamental and applied biological sciences. Psychology; Habitats; Insecta; Invertebrates; Isoptera; rain forest; Soil ecology; Species; species richness; Synecology; Systematics. Geographical distribution; Termites; Terrestrial ecosystems; Tropical rain forests; Tropical regions
• ISSN: 0305-0270; 1365-2699
• DOI: 10.1046/j.1365-2699.2003.00883.x

Aim To (1) describe termite functional diversity patterns across five tropical regions using local species richness sampling of standardized areas of habitat; (2) assess the relative importance of environmental factors operating at different spatial and temporal scales in influencing variation in species representation within feeding groups and functional taxonomic groups across the tropics; (3) achieve a synthesis to explain the observed patterns of convergence and divergence in termite functional diversity that draws on termite ecological and biogeographical evidence to-date, as well as the latest evidence for the evolutionary and distributional history of tropical rain forests. Location Pantropical. Methods A pantropical termite species richness data set was obtained through sampling of eighty-seven standardized local termite diversity transects from twenty-nine locations across five tropical regions. Local-scale, intermediate-scale and large-scale environmental data were collected for each transect. Standardized termite assemblage and environmental data were analysed at the levels of whole assemblages and feeding groups (using components of variance analysis) and at the level of functional taxonomic groups (using correspondence analysis and canonical correspondence analysis). Results Overall species richness of local assemblages showed a greater component of variation attributable to local habitat disturbance level than to region. However, an analysis accounting for species richness across termite feeding groups indicated a much larger component of variation attributable to region. Mean local assemblage body size also showed the greater overall significance of region compared with habitat type in influencing variation. Ordination of functional taxonomic group data revealed a primary gradient of variation corresponding to rank order of species richness within sites and to mean local species richness within regions. The latter was in the order: Africa > south America > south-east Asia > Madagascar > Australia. This primary gradient of species richness decrease can be explained by a decrease in species richness of less dispersive functional taxonomic groups feeding on more humified food substrates such as soil. Hence, the transects from more depauperate sites/regions were dominated by more dispersive functional taxonomic groups feeding on less humified food substrates such as dead wood. Direct gradient analysis indicated that 'region' and other large-scal