A natural resource assessment of Chapungu Ranch, Save Valley Conservancy, Zimbabwe

Abstract

An assessment of the natural resources on Chapungu Ranch, Zimbabwe, was undertaken for the purpose of incorporating this ranch into the larger Sango Ranch. The geological description was based on literature, whilst the soils were classified using the soil taxonomic system described for Zimbabwe. The seven soils types on Chapungu Ranch were from the Amorphic, Calcimorphic and Natric orders and varied considerably in terms of depth, texture and chemical composition. Most soils were fertile and supported a herbaceous layer generally referred to as sweetveld. A phytosociological classification and structural analysis of the vegetation identified nine plant communities and 15 subcommunities on Chapungu Ranch. Separation of plant communities was mostly influenced by the geological formations and soils. Each community was described in terms of its species composition and structure. The dry mass of the herbaceous layer was quantified using the disc pasture meter and the composition of the herbaceous layer using the step-point method. The veld condition ranged from moderate (30.1%) to very good (60.4%) and the biomass production ranged from very low to high. The browsing capacity was determined using the BECVOL method. On Chapungu only 15.4% of the total browse was available to browsers, 5.0% of the browse was available for herbivores up to 2 m and 10.4% of the browse was available to browsers feeding between >2 – 5 m in height. Grazing capacity of different plant communities ranged from 7 GU/100 ha to 38 GU/100 ha with a mean of 25 GU/100 ha. The browsing capacity ranged from as low as 0.3 BU/100 ha to 13 BU/100 ha with a mean of 9 BU/100 ha. In 2003,Chapungu Ranch had the capacity to carry 3 331 GU and 1 169 BU whereas the stocking density was 2 199 GU and 3 029 BU. After the integration of Chapungu Ranch into Sango Ranch seven management units were identified. Animal populations were described in terms of population size and their spatial and temporal trends for the entire Sango Ranch. The populations of bushbuck, bushpig, Livingston’s eland, hippopotamus, impala, greater kudu, warthog, leopard, cheetah, baboon and vervet monkey were already at ecological capacity when monitoring commenced, however, populations of black rhinoceros, common duiker, African elephant, klipspringer, sable antelope, Sharpe’s grysbuck, waterbuck, blue wildebeest, Burchell’s zebra, black-backed jackal and wilddog reached ecological capacity within the past 14 years. The populations for African buffalo, giraffe, nyala, white rhinoceros, lion and spotted hyena had still not reached ecological capacity. Evaluation of the long-term monitoring program indicated that the stocking density for the grazer units (GU) exceeded the grazing capacity during the 2006/2007 season whilst the browsing capacity has been exceeded since the inception of the monitoring program in 2000. Recommendations are made towards improving artificial water provision, erosion control and road management. Additionally, recommendations are presented on fire management, alien plant control, stocking density, elephant impact, vegetation harvesting, waste management and wildlife utilization. Finally, four research priorities were identified which included studies on sable antelope, lion, spotted hyena and brown hyena and small mammals on Sango Ranch.