Abstract

The dynamics of rangeland vegetation are products of spatial and temporal land use that determine rangeland productivity and conservation of biodiversity. This study examined effects of site, elevation, land use and season on vegetation attributes at three sites in Dida-Hara, southern Ethiopia. Herbaceous plant attributes (that is, above-ground herbaceous biomass, basal cover, plants’ density, species richness, diversity index and evenness), as well as woody plants characteristics such as density and species richness were measured. Herbaceous and woody vegetation variables were examined by season and land use types (that is, enclosures vs. open-grazed areas) across three sites and two altitudes. The results showed that all vegetation attributes were greatly affected by site, land use type and season. Herbaceous vegetation attributes such as biomass, basal cover and herbaceous species richness were more affected by land use types and season. Elevation affected herbaceous vegetation characteristics such as basal cover, herbaceous species diversity and woody richness. Effects of site differences in terms of herbaceous biomass were common during the dry season. Grass diversity was significantly affected by site, elevation, land use type, season and altitude across spatial and temporal scales. Herbaceous biomass was significantly higher in enclosure than in the communal land use type whereas herbaceous biomass showed a declining trend with increased density of woody plants.

Key words: Vegetation attributes, rangeland, grazing pressure, elevation, site, land-use, season.