Spatial-temporal variation of biomass production by shrubs in the succulent karoo, South Africa

Abstract

Forage production in arid and semi-arid rangelands is not uniform but varies with seasons and in various landscapes. The aim of this study was to investigate the spatial and temporal variation in forage production in RNP. Plants sampling was carried out in 225 plots distributed in each of the five vegetation types. In each vegetation strata, sampling points was based on proximity to an occupied stock post, a rain gauge, a foothill and flat plains. A total of were measured in the 5 study sites. Line Intercept Method in combination with harvest method were used in ground measurement of biomass production. To assess biomass production using remote sensing technique, par values were obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) imageries which consisted of 8 days composite images at spatial resolution of 1km² pixel size. There was positive correlation between line intercepts and biomass production Biomass production was higher in succulent Karoo biome than in desert biome. There was a strong relationship between biomass production with rainfall and with fpar values. Since leaf and stem succulents’ plants were found to contribute the highest amount of forage production in RNP, they should be given conservation priority.