Testing for a decline in secondary productivity under desertification in subtropical thicket, South Africa, using Angora goats: lessons for experimental design
AbstractThere are few tests of the predicted decline of econdary productivity in desertified rangelands, espite this being one of the major concerns around desertification. Subtropical thicket, largely used for goat pastoralism, suffers extensive transformation typical of desertification. We measured body growth and mohair production of Angora goats in both untransformed and desertified thicket paddocks over one year. Body growth and mohair length and diameter did not differ between the two treatments. We interpret the lack of responses in terms of the above-average rainfall during the study. In contrast, mohair mass was lower in the untransformed paddock, resulting in a decline in mohair production. We suggest that this counterintuitive result reflects the combing out, and therefore loss, of hair in the densely vegetated site. This study failed to demonstrate a decline in secondary productivity in desertified thicket and highlights the importance of replicating such studies in space and time.
African Journal of Range & Forage Science 2009, 26(2): 107–110