Small-scale pattern in grassland communities in the Serengeti National Park, Tanzania

Abstract

Small-scale community gradients and patterns in four grassland communities in the Serengeti National Park, Tanzania, were analyzed by detrended correspondence analysis (DCA) and percentage distance ordination (PD). The main goals of the study were (1) to describe the vegetation patterns in the communities, (2) to identify the potential underlying causes of the patterns, and (3) to rank the communities by their relative levels of patchiness. Species cover in a small number (16–32) of discontinuous plots was estimated and soils were collected. DCA successfully identified community gradients and phases of discrete mosaics, and PD identified the relative heterogeneity of the sites. Results suggested that the two most arid sites were composed of weakly or strongly differentiated vegetational mosaics and the two most mesic sites were essentially homogeneous. Termite modification of water infiltration properties of the soils and clonal growth of dominant species were identified as two factors possibly causing the mosaic vegetation patterns.