Impact of Site Characteristics on Vegetation Cover and Rangelands Management in South Kordofan State

Abstract

The study was conducted at Eldebeibat area in El Dilling locality- South Kordofan State. It aimed to study the impact of site’s characteristics on vegetation cover and rangelands management process. The study area was divided into the three sites namely; sandy, clay and gardud. The vegetation attributes for herbaceous: plant composition, relative species composition, plant cover, frequency, biomass and litters and trees and shrubs density in the tree sites were measured for the two rainy seasons (2013/2014) in addition to soil organic matter, soil seed bank and socio-economic survey for sedentary and the nomads. The remote sensing used to study dynamic of plants growth in the different sites and interval. Eight transects (100m length) were laid out randomly in each site and then ten quadrats (1x1m) were taken along each transect and vegetation measurements were taken at 10m interval. Ten soil samples from each site were taken to determine soil organic matter and to assess soil seed bank for herbaceous. Remote sensing was used to estimate value of Normalized Difference Vegetation Index (NDVI) at the three sites from 2010 up to 2014. The socio-economic information was collected from sedentary and the nomads by questionnaires and the samples size were taken about 10% of total population for the nomads and sedentary group. There were variations between the three sites in vegetation attributes. Sandy had the highest plant composition, lowest bare soil and lowest plant litters compared to the clay and gardud sites. Nevertheless the three sites recorded low plant cover, low biomass production, low soil organic matter and dominated by different plant species. Sandy dominated by unpalatable species: Zornia glochidiata and Guiera senegalensis, clay dominated by Schoenfeldia gracilis and Acacia oerfota and gardud was dominated by Vossia cuspidata and Acacia mellifera.

The nomads and sedentary respondents confirmed to occurrence invasion of unpalatable species in the area and disappearance of more palatable species such as Blepharis linariifolia and Andropogon gayanus. The dominant species indicating that the sandy site is deteriorating compared to clay and gardud. Most the nomads 58% entering to sandy site early in (June) and majority of them existing from gardud site in early in (October) and both respondents preferred sandy for grazing. The both respondents confirmed existence of conflicts between them around farms and both of them settled the conflicts by local administration and leaders of their tribes. The results of NDVI values in the three sites in each month within each year were different and all sites in each month and year showed NDVI with a peak in September. The gardud site showed NDVI value earlier than other sites (sandy and clay). The results showed the NDVI value in sandy site reached the peak early and the values declined rapidly. According to the results obtained the study recommended that the rangelands management process should be based on sites characteristics and conditions when applying different rangelands management approaches. Nevertheless seed broadcasting of more palatable species, should be done in the sandy site with proper measure to control the unpalatable species invasion. The plant cover in the clay site should be increased and gardud site needs apply water harvesting techniques to control erosion hazards particularly water erosion.