Forb diversity and community similarity of kopjes in the Serengeti National Park, Tanzania

The forb communities of kopjes (rock outcrops) in the Simba, Maasai and Loliondo areas of the Serengeti National Park were examined to determine differences in species composition from surrounding grassland communities, and among sites within kopje and grassland communities. Species diversity measures and multivariate ordination techniques were used to examine the community similarity and species turnover between sites. All measures of forb species diversity were higher on the kopje sites with the exception of one grassland site, and the community composition significantly differed between these two habitat types, with more species and families exclusive to the kopje habitat. Species turnover was very high in grassland habitats, with two of the three areas (Simba and Loliondo) exhibiting a complete change in species composition. Kopjes, on the other hand, had remarkably similar forb communities, suggesting that the populations of the species present on these rock outcrops form patch structures. The distinct flora and higher diversity of kopje forbs raise interesting questions regarding distribution, dispersal and patch dynamics.