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OKES DU TOIT, J. C., O'CONNOR, T.G. & VAN DEN BERGAC, L. (2015)

Photographic evidence of fire-induced shifts from dwarf-shrub- to grass-dominated vegetation in Nama-Karoo.

South African Journal of Botany 101 (November 2015): 148-152. https://doi.org/10.1016/j.sajb.2015.06.002

Abstract:

The Nama-Karoo is a semi-arid inland biome in South Africa dominated by dwarf shrubs with grasses, shrubs, geophytes and herbs at varying levels of abundance. The position of the Nama-Karoo/grassland boundary is determined in part by rainfall amount, and in recent years there has been an increase in grassiness, correlated with good rains. This has allowed wildfires, an unusual occurrence, to burn at several sites in the central and eastern regions of the biome. The general effect of fire has been to convert dwarf shrublands to grassland with the extirpation of several nonsprouters species. A collection of photographs describes this effect. It is anticipated that these nonsprouters will recolonise by seed over time, but could be eliminated if fire frequency is high enough to eliminate their seedbank. It is predicted that if grassy conditions persist in the Nama-Karoo, then fire will be an important factor that shapes the Nama-Karoo/grassland boundary.

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