Modern non-pollen palynomorphs from East African lake sediments

This paper presents an illustrated guide to the identification of non-pollen palynomorphs (NPPs) preserved in lake-sediment archives from equatorial East Africa. Modern NPPs were recovered from recently deposited surface sediment in 20 small crater lakes in western Uganda, located along environmental gradients of vegetation (moist evergreen and semi-deciduous forest, wooded and open grass savannah), land use (pastoralism, crop agriculture, plantations) and lake characteristics (basin morphometry, water chemistry and aquatic production). We analyzed 9700 NPP specimens, which could be assigned to 265 distinct morphotypes, of which 239 belong to six major taxonomic groups: spores and other remains of fungi (198 morphotypes), spores of ferns and mosses (19 morphotypes), microscopic zoological remains (14 morphotypes), colonies, coenobia or zygo-/aplanospores produced by filamentous algae (7 morphotypes) and microscopic aquatic plant remains (1 morphotype). The remaining 26 morphotypes could not be assigned to a specific taxonomic category. Using primary taxonomic and molecular phylogenetic literature, 73 (28%) of the recovered morphotypes could be identified at the species, genus or family level, thereby conferring ecological indicator value to them. This study may facilitate the use of fossil NPPs to help reconstruct past climatic and anthropogenic impacts on African ecosystems, as already broadly established in other study regions outside Africa.

Research Highlights
► Illustrated guide of 187 non-pollen palynomorphs from East African lake sediments.
► 28 % of the recovered 265 morphotypes are identified and ecologically classified.
► NPPs may shed light on past climatic and human impacts on African ecosystems.