Effect of Human Settlement and Altitude on Rangeland Herbaceous Species Biodiversity and Productivity in Kafta-Humera Woreda, Tigray, Ethiopia

Abstract

This research was conducted in Kafta-Humera districts of the Northern Ethiopia with the objective to determine the effect of human settlement on rangeland productivity and biodiversity under three altitudinal ranges (600-1000, >1000-1400 and >1400-1800 m.a.s.l.) and along three distance intervals near (0-2 km), middle (2-4 km) and far (4-6 km) from settlement. Vegetation and soil data was analyzed by Statistical Package for Social Sciences.  In the study districts, a total of 39, 30 and 15 species of grasses, forbs and herbaceous legumes species were identified, respectively. Species diversity and species richness in higher altitude were significantly higher than middle and lower altitudes. Species diversity and species richness were lower near to settlement than far distance from settlement. Grass biomass of near, middle and far distance from settlement were 113.59, 622 and 1102.56 kg ha^-1 respectively. Similarly, grass biomasses of the low, middle and upper altitude were 349.8, 542.7 and 945.7 kg ha^-1, respectively. Far distance from settlement had significantly higher in organic matter, available phosphorus and available potassium than middle and near distance from settlement. The upper altitude had significantly higher in organic matter, available phosphorus and available potassium than the lower and middle altitude. Generally, the study area was highly dominated by the annual herbaceous species. This implies that there is undergoing reduction in soil quality, biodiversity and productivity degradation. Therefore, appropriate plan of soil and biodiversity conservation such as establishing, designing and implementations of watershed management for physical and biological conservation should be planned to minimize loss of biodiversity.

Keywords: Settlement, plant Species composition, plant species abundance, plant Species diversity, biomass production, basal cover, soil properties