Local distribution of C and C grasses in sites of overlap on Mount Kenya.

A zone of C-C grass overlap has been identified on the northern slopes of Mount Kenya at elevations of 2,800-3,200 m. At higher elevations, C grasses predominate; below, C grasses predominate. At each of three elevational sites of overlap, a series of transects was surveyed for C and C grass composition. All transects were located in structurally similar vegetation (high elevation grassland) within 150 m of each other. Transects were run in a variety of topographic situations. Within each transect, several environmental parameters were measured. Both unweighted (species presence/absence) and weighted (by frequency) measures of %C composition were significantly correlated with dry season soil moisture. Drier transects contain significantly more C species, in greater frequency, than wetter transects. Other correlations of C composition (e.g. factors which tend to parallel soil moisture) were also found. This local trend parallels the larger scale tendency of C grasses to replace C grasses with increasing elevation. Finer scale habitat partitioning may account for C-C overlap within transects.