title: Local distribution of C3and C4grasses in sites of overlap on Mount Kenya.
abstract: A zone of C3-C4grass overlap has been identified on the northern slopes of Mount Kenya at elevations of 2,800-3,200 m. At higher elevations, C3grasses predominate; below, C4grasses predominate. At each of three elevational sites of overlap, a series of transects was surveyed for C4and C3grass 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 %C4composition were significantly correlated with dry season soil moisture. Drier transects contain significantly more C4species, in greater frequency, than wetter transects. Other correlations of C4composition (e.g. factors which tend to parallel soil moisture) were also found. This local trend parallels the larger scale tendency of C3grasses to replace C4grasses with increasing elevation. Finer scale habitat partitioning may account for C3-C4overlap within transects.
authors.affiliation: Department of Ecology and Evolution, State University of New York at Stony Brook, 11794, Stony Brook, NY, USA.
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Young
authors.affiliation: Department of Biology, University of Pennsylvania, 19174, Philadelphia, PA, USA.
authors.forename: Truman P
authors.initials: TP
authors.lastname: Young