A comparison of termite assemblages from West African savannah and forest ecosystems using morphological and molecular markers

Termites (Isoptera) are important ecosystem engineers of tropical ecosystems. However, they are notoriously difficult to identify, which hinders ecological research. To overcome these problems, we comparatively studied termite assemblages in the two major West African ecosystems, savannah and forest, both under natural settings and along disturbance gradients. We identified all species using morphological as well as molecular markers. We hypothesized species richness to be higher in the forest than the savannah and that it declines with disturbance in both ecosystems. Overall we found more species in the forest than in the savannah. However, alpha diversity per site did not differ between both ecosystems with on average around ten species. For both ecosystems, species diversity did not decrease along the studied disturbance gradient but encounter rates did. For the forest, we did not detect a decline in soil feeding termites and an increase of fungus grower Macrotermitinae with disturbance as some other studies did. Yet, soil feeders were generally rare. Strikingly, the set of morphologically difficult-to-identify Macrotermitinae (Microtermes and Ancistrotermes) was as high in the forest as in the savannah with little species overlap between both ecosystems. Using phylogenetic community analyses, we found little evidence for strong structuring mechanisms such as environmental filtering or interspecific competition. Most local assemblages did not differ significantly from random assemblages of the regional species pool. Our study is the most comprehensive of its kind. It provides the most reliable termite species list for West Africa that builds the basis for further ecological studies.