Effects of goat pastoralism on ecosystem carbon storage in semiarid thicket,Eastern Cape,South Africa |
| |
Authors: | A J MILLS R M COWLING M V FEY G I H KERLEY J S DONALDSON R G LECHMERE‐OERTEL A M SIGWELA A L SKOWNO P RUNDEL |
| |
Abstract: | Abstract Intensive pastoralism with goats transforms semiarid thicket in the Eastern Cape, South Africa from a dense vegetation of tall shrubs to an open landscape dominated by ephemeral grasses and forbs. Approx. 800 000 ha of thicket (which prior to the introduction of goats had a closed canopy and a Portulacaria afra Jacq. component) have been transformed in this manner. Ecosystem C storage in intact thicket and loss of C due to transformation were quantified. Carbon storage in intact thicket was surprisingly high for a semiarid region, with an average of 76 t C ha?1 in living biomass and surface litter and 133 t C ha?1 in soils to a depth of 30 cm. Exceptional C accumulation in thicket may be a result of P. afra dominance. This succulent shrub switches between C3 and CAM photosynthesis, produces large quantities of leaf litter (approx. 450 g m?2 year?1) and shades the soil densely. Transformed thicket had approx. 35% less soil C to a depth of 10 cm and approx. 75% less biomass C than intact thicket. Restoration of transformed thicket landscapes could consequently recoup more than 80 t C ha?1. |
| |
Keywords: | biomass carbon stocks goats pastoralism soil carbon thicket |
|
|