The Australian Termite Diversity Anomalys Effect on Termite Mound Abundance and Dead Wood Occupancy

In tropical ecosystems, termites can be responsible for more than half of decomposition. Through their activities breaking down wood, soil, grass and leaf litter, they contribute up to 1-3% of the global methane budget each year. Additionally, as termites move and redistribute soil to build their nests, they generate hotspots of biological activity in dry habitats. Across the tropics, termites comprise up to 10% of animal biomass with highest abundance and species diversity usually in lowland tropical rainforests. However, the Australian termite diversity anomaly indicates that Australian rainforests contain exceptionally low termite diversity and abundance compared to lowland rainforests on other continents. In this study, we compared termite abundance, activity, diversity and feeding group assemblages across a rainfall gradient in North Queensland, Australia. We sampled termites from five sites within 100km of each other with annual rainfall ranging from 800 to 4260mm including a dry savanna, a Eucalyptus woodland/savanna, a wet sclerophyll forest and upland and lowland rainforests. We found dramatic decreases in termite abundance in both mounds and dead wood from dry to wet habitats. The low precipitation savanna sites had more termites and more species of termites than the high precipitation rainforest sites . Feeding group richness was also highest in savanna sites where we encountered termites from wood-, litter-, grass-, dung-, and soil-feeding groups, while only wood-feeding termites were encountered in rainforest and wet sclerophyll sites. These quantitative estimates paired with data from termite surveys in rainforests in other continents suggest that termites are playing a smaller role in Australian rainforests compared to other tropical rainforests. More work in understanding continental differences in termite community assemblages is needed to properly incorporate termites into global models of decomposition and biogeochemical cycling.