Vegetation characterization and large herbivore population changes at IL N'gwesi community conservancy, Laikipia district, Kenya

Abstract

This study was carried out at IL N'gwesi Community Conservancy in Mukogodo division of Laikipia District, between January and August 2001 and in September 2006. The overall objective of the study was to establish plant species diversity, herbaceous layer standing crop yield and large herbivore population changes at IL N'gwesi Community Conservancy. Herbaceous vegetation sampling was done in four different sites namely; open bushland, wetland, riverine and community grazing area using a square quadrat measuring 0.25m2. Trees and shrubs were sampled using belt transects in the above four study sites. Harvest method was used in estimation of herbaceous layer standing crop yield. Herbivores were counted using road count sample method. Trees and shrubs density ranged between 1000+/-84.3 plants/ha estimated in the riverine and 560+/_84.3plants/ha 'estimated in the open bushland habitat and there was no significant difference among the four study sites. The mean monthly herbaceous layer density ranqed between 90+/-13.13/m2 estimated in the bushland and 43+/-22.73/m2 estimated in the community grazing area and there was no sIgnificant di.fference among the four study sites. The highest . mean monthly .herbaceous layer standing crop yield was estimated in the wetland while community grazing area had the lowest and there was a significant difference among the four habitats. The highest mean monthly standing crop yield was recorded in April while the lowest was realized in June. The wet period had a mean monthly standing crop yield of 190.91+/-15.79g/m2 while in the dry period it was 109.69~8.8g/m2 and there was a significant difference between the periods. The highest mean monthly large herbivores population density estimated at 11.9+/-3.8/km2 was noticed in the riverine while open bushland habitat had the lowest estimate of 3.1+/-0.5/km2 and there was a significant difference among the habitats. These densities were pooled for dikdik, elephant, .gerenuk, giraffe, impala, warthog and waterbuck. The study recommends that pasture management in ..the community grazing area should be improved; for instance through reducing grazing stock.