the richtersveld cultural and botanical landscape - SAHRA

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Richtersveld Cultural and Botanical Landscape World Heritage Site Nomination 45 The vegetation is very sparse in this unit and further monitoring is required to assess grazing and erosion threats. No endemic species are known from this unit. 98.5% of this unit falls within the Richtersveld Community Conservancy. Upper Annisvlakte Succulent Shrubland 19180.8018 total ha 2013.2221 ha in Richtersveld Community Conservancy = 10.5% This shrubland is found in the southern parts of the Annisvlakte north and northwest of the Goariep Mountain from near Kuboes to the region southeast of Arrisdrif. The westernmost section, southeast of Arrisdrift, is virtually separated from the main area by a northwards moving duneveld of red sand (part of Richtersveld Red Duneveld), which at its northern margin fades out to form a shallow sand sheet, which crosses the main road between Alexander Bay and Khubus. The landscape is mainly a very wide tilted plain, formed by the huge pediment of the Goariep Mountain, towards the Orange River. Some river courses are deeply incised into this plain. On the plains, habitats are controlled by soil salinity and texture, and by different states of degradation by overgrazing. The granite of the Kuboos Pluton of the Cambrian Kuboos-Bremen Suite is largely covered by alluvium loamy sandy gravel soils, mainly derived from granite and superficial calcrete deposits. The altitude ranges from 150 to 500 m. The predominantly winter rainfall varies between 55 to70 mm per annum. Light frost is a very rare event, but the unit receives sea fog from a southwesterly direction as well as “Malmokkie” fog. Strong winds to very strong storms occur and cause severe dust and sand storms with consequentially strong erosion of topsoil material and sandblasting. The present state of the vegetation is interpreted as result of strong grazing pressure over the past 100 years. At present, very sparse, dwarf vegetation cover, mainly Galenia fruticosa, Drosanthemum hispidum, Euphorbia gummifera, Galenia crystalline and Psilocaulon subnodosum and all indicators of disturbance, is observed. Another indicator of disturbance is the high numbers of annuals and
Richtersveld Cultural and Botanical Landscape World Heritage Site Nomination 46 geophytes after good rains. Very high numbers of annual or bi-annual succulent species of Mesembryanthemum hypertrophicum and Mesembryanthemum squamulosum characterize this unit (Figure 2). In the past this unit was probably covered by Northern Richtersveld Scorpionstailveld and partly by the Ruschia senaria. None of this unit is conserved in any other conservation area and a small proportion falls within the Richtersveld Community Conservancy. Comparison of recent historical photographs shows that soil and vegetation have been severely altered since the early 20 th century. The export of topsoil material negatively affects neighbouring areas such as the Cornellskop to the east with its population of Aloe pillansii. Endemic plant species In addition to numerous species endemic to the Succulent Karoo or the Gariep Centre, the Richtersveld Community Conservancy has a high number of plant species endemic to just the Conservancy area’s East Gariep Centre itself. There are a total number of 33 endemic plant species found in the Richtersveld Community Conservancy (Table 1) and Appendix F indicates which endemic species are found in each vegetation unit (note: some are found in more than one specific unit within the Conservancy). The Conservancy is especially important for the conservation of one of the world’s most endangered plants, Aloe pillansii, with one of the most important localities for its survival being the Rooiberg Mountains in the Conservancy where there are a number of these ancient plants. This attractive and impressive plant that towers over the hilly slopes can easily become a flagship species for the area. The highest number of endemic species is found in the Central Richtersveld Mountain Shrubland (13), the Rooiberg Quartz Vygieveld (9), the Kahams Mountain Desert (8) and the Lekkersing Succulent Shrubland (8). Only 5 of the 13 vegetation units have no observed Richtersveld endemic species (Table 2).
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the richtersveld cultural and botanical landscape - SAHRA

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