The Potential of Cephalophyllum inaequale (L. Bolus) for the Restoration of Degraded Arid Landscapes in Namaqualand, South Africa

Abstract

The potential of Cephalophyllum inaequale was investigated for use in initiating ecosystem restoration in degraded landscapes of Namaqualand, South Africa. Cephalophyllum inaequale, a perennial shrub, is a member of the succulent Mesembryanthemaceae family, typical of the Succulent Karoo Biome and in particular of the Namaqualand area. A bioclimatic envelope was modeled to establish the area in which this species might feasibly be used. The regional bioclimatic potential for C. inaequale proved to be extensive, covering approximately 17,500 km 2 . An examination of the functional role of C. inaequale showed it to facilitate early seedling survival in this community. A nearest-neighbor study found no evidence of interspecific competition between C. inaequale and its dominant co-occurring species, possibly due to vertical stratification of rooting structures. Cephalophyllum inaequale significantly reduced wind speed and soil erosion. Experiments to test the feasibility of propagating, reintroducing, and establishing this species showed that it easily germinates from seed, and transplanted cuttings have a high survival rate. This study demonstrates that C. inaequale has potential for use in initiating the restoration of degraded lands in South Africa.

Analysis and evaluation of ecological restoration experiments in the Succulent Karoo (South Africa)

“…Since the cold upwelling waters of the Benguela Current temper and buffer climatic extremes the climate is relatively mild with a mean annual temperature of 16.8° (Mucina et al 2006) and rare frost events. Strong prevailing southerly winds during summer months (Anderson et al 2004) and strong easterly berg winds during winter and spring are prominent features of the climate (Carrick & Krüger 2007). Because of its outstanding insect, vertebrates and plant species diversity with more than 1940 endemic plant species (Myers et al 2000), the Biome is rated to be the only arid of 25 global biodiversity hotspots identified by Myers et al (2000).…”

“…In the past the grazing system of the area was pastoral but displaced by a period of fenced commercial sheep farming use by the De Beers mining company from 1986 to 1999 (Petersen 2008, Labitzky 2009). In 1999 (Anderson et al 2004) the community got the utilization right for 15,000 ha land back and uses it today for small stock farming with goats and sheep plus some rain-fed crop production. The current stocking rates are below the recommended ones and access to the land is strongly controlled (Petersen 2008), but due to the history of overgrazing by the former land use practices Anderson et al (2004) state that more than a third of the Soebatsfontein community area are degraded with evidence of soil erosion.…”

“…In arid and thus fragile rangelands, degradation is a common problem (Hoffman & Ashwell 2001, Snyman 1999 and has been ascribed mainly to overgrazing (Kraaij & Milton 2006, Hoffman & Ashwell 2001, mining activities (Botha et al 2008) and changes in the rainfall regime and is seen as a severe threat to Namaqualand's exceptionally high biodiversity and endemism (Desmet 2007, Cowling et al 1999, Anderson et al 2004. With the arrival of European settlers the former pastoralists' (i.e., Khoekhoen of Namaqualand) practices to move with their stocks around to take advantage of summer and winter rainfall areas changed and they were forced to move into smaller communal areas and had to stop their transhumant strategies (Boonzair et al 1996In: Samuels et al 2007).…”

“…While some authors attributed the severe degradation which became apparent within the last centuries, primarily to overgrazing (Todd 2006, Anderson et al 2004, Yeaton & Esler 1990) others state that the observed patterns are natural, caused by short-term fluctuations of rainfall and that the influence of grazing might only become apparent in the long term (O`Connor & Roux 1995, Wiegand et al 1998, Wiegand & Milton 1996. Wiegand et al (1998) simulated the vegetation dynamic of five typical dominant Karoo shrubs and showed slow turn-over rates of the vegetation which can be explained by the persistence of long-living species which occupy sites that would otherwise be free for the establishment of new species (Rahlao et al 2008).…”

“…There has been an enormous increase of interest in restoration techniques to reverse degradation world-wide (Hobbs & Norton 1996, Anderson et al 2004) and in the Succulent Karoo Biome (Burke 2008, Snyman 1999, where the restoration of former mining areas of the Namaqualand is statutory since 1992 (Carrick & Krüger 2007, Hälbich 2003. Thus, the development of appropriate and effective restoration methods is of great importance.…”