Northern Namaqualand Research Articles

A preliminary report of the excavation at Spitzkloof D rockshelter, Namaqualand, South Africa

This paper describes the first excavations of Spitzkloof D rockshelter located in the semi-arid desert of northern Namaqualand, South Africa. The site is in a dry river valley 30 km south of the Orange River, which currently acts as a lifeline for pastoralists with mixed sheep and goat herds. A surface survey of the site revealed pottery, lithics, domesticate remains, ostrich eggshell (OES) fragments and jewellery, glass beads and iron fragments. The stratigraphy is complex reflecting multiple occupations with six layers consisting of large hearths, ash deposits, and multiple pits, some with potential votive (faunal) offerings in their base. Faunal analysis reveals a broad subsistence strategy consisting of low-intensity sheep-keeping combined with the hunting of wild species found on the landscape today. The presence of Equus zebra, a locally extinct water obligate species, suggests occupation during a climatic period that was more humid than today. Radiocarbon dates from the upper layers confirm a Little Ice Age occupation between AD 1667-1936, when the region was cooler and wetter, and a peak in radiocarbon dates indicates a population pulse in the region. Glass trade beads, iron implements, OES beads, as well as fish remains and a limpet shell, potentially indicate that the people occupying Spitzkloof D were part of an extensive trade/interaction network. Future analysis will include increasing sample sizes through continued excavation, detailed lithic analysis, and further radiocarbon dating.

New species of Hessea and Strumaria (Amaryllidaceae: Amaryllideae) from Namaqualand in Northern Cape and Western Cape, South Africa

Described are two new species in the southern African subtribe Strumariinae (Amaryllidaceae: Amaryllideae). In Hessea the new species H. pallida (subg. Hessea) from Toringberg, Western Cape, on the westernmost edge of the southern Namaqualand Hardeveld, is known on the edges of a seasonal pan within Namaqualand Granite Renosterveld. The whitish to pale pink flowers have crisped tepal edges in common with three species known exclusively from fire-prone fynbos in the Core Cape Floristic Region. Hessea pallida is inferred to be most closely related to H. monticola. The two species differ in the size, colouring and markings of the flowers, shape of the tepals and flowering habit. Hessea monticola is a fire obligate whereas H. pallida flowers regularly in a habitat free of fire. The recognition of Toringberg as a minor refugium for core Cape plants is briefly discussed. In Strumaria the new species S. crystallina (subg. Strumaria) is described from the Nama shales of the Skaaprivier gorge on the northern Namaqualand Escarpment. The widely campanulate flowers have sculptured stamens and style like those of S. bidentata, but S. crystallina stands out in having soft, narrow leaves unlike the firm, upright leaves spread into a flattened fan as in most other species in the subgenus, apart from S. prolifera in northern Namaqualand. Both new species are known only from the type locality.

Tylecodon ectypus, a New Cliff Dwelling Species from the Skaaprivier, Northern Namaqualand (Northern Cape Province), South Africa

Tylecodon ectypus (Crassulaceae) is a new species originating from the upper reaches of the Skaaprivierspoort, west of Steinkopf (northern Namaqualand). It is at once distinguished by its geophytic growth form, orbicular glossy leaves bearing thick reticulated veins, candelabriform inflorescences and trumpet-shaped pink-striped white corolla. Vulnerable status (IUCN red list criteria) is justified by its restricted and fragmented distribution, especially considering its scarcity in two of the three known populations.

Othonna koos-bekkeri, a new succulent shrub from northern Namaqualand and southern Richtersveld, (N. Cape Province, South Africa)

Othonna koos-bekkeri is a new shrubby Othonna from the mountains of the western escarpment in the Northern Cape. It is immediately recognized by its ascending rod-like stems and lateral ascending spreading spur-shoots and sub-umbellate yellow flower heads, the latter flowering during autumn when the plants are leafless. In the past, it was often confused with Othonna arbuscula, a smaller species widespread in the Succulent Karoo Biome.

Palaeoecology of giraffe tracks in Late Pleistocene aeolianites on the Cape south coast

Until now there have been no reliable historical or skeletal fossil records for the giraffe (Giraffa camelopardalis) south of the Orange River or northern Namaqualand. The recent discovery of fossil giraffe tracks in coastal aeolianites east of Still Bay, South Africa, significantly increases the geographical range for this species, and has implications for Late Pleistocene climate and vegetation in the southern Cape. Giraffe populations have specialised needs, and require a savanna ecosystem. Marine geophysical and geological evidence suggests that the broad, currently submerged floodplains of the Gouritz and Breede Rivers likely supported a productive savanna of Vachellia karroo during Pleistocene glacial conditions, which would have provided a suitable habitat for this species. We show evidence for the hypothesis that the opening of the submerged shelf during glacial periods acted as a pathway for mammals to migrate along the southern coastal plain.
 Significance: 
 
 The identification of fossil giraffe tracks on the Cape south coast, far from the area in which giraffe have previously been known to occur, is unexpected; conclusions about prehistoric conditions and vegetation can be drawn from this discovery.

A review of the Geissorhiza namaquensis (Iridaceae: Crocoideae) group with the new species G. namaquamontana from Northern Cape, South Africa

The Geissorhiza namaquensis (Iridaceae) group of species from Namaqualand, Northern Cape, South Africa, has until now included two species, the short-tubed G. namaquensis from the western escarpment of central and northern Namaqualand, and the long-tubed Geissorhiza kamiesmontana from high elevations in the Kamiesberg. Two collections of short-tubed plants from the Kamiesberg currently included in G. namaquensis are shorter than normal and have unusually small flowers for that species, and are now matched by a new collection from Grootberg, some 21km southwest of Kamieskroon. This has led us to revise the concept of G. namaquensis, which we now restrict to taller plants up to 300mm tall, with comparatively larger flowers with tepals 14–18×±4mm and anthers 4.5–5.5mm long. The shorter plants from the Kamiesberg and Grootberg, 80–160(–250) mm tall, with smaller flowers with tepals 8–10×±2mm and anthers 2–3mm long, are described as the new species Geissorhiza namaquamontana.

Tylecodon florentii, a new cliff dwelling species from the Kookrivier cliffs, Richtersveld (Northern Cape Province), South Africa

Tylecodon florentii is described as a new distinctive obligate cliff dwelling species endemic to the upper south-facing reddish sandstone cliffs of the Kookrivier, NW of Eksteenfontein. It belongs to a group of Tylecodon species with tuberous roots and extended phyllopodia that occur in the northern Namaqualand (North Cape) parts of South Africa, confined to winter rainfall.

Early Maritime Desert Dwellers in Namaqualand, South Africa: A Holocene Perspective on Pleistocene Peopling

ABSTRACTSouth Africa's northern Namaqualand coastal desert is the southern extension of the Namib. Today, this region is semi-desert with patchy subsistence resources and scarce, unpredictable rainfall. Yet this ancient desert landscape possesses residues of human activity stretching back into the Middle Pleistocene, evidenced by heavily weathered surface finds, including handaxes and Victoria West cores. Such old finds in so harsh an environment raise important questions: how do human movements into this area relate to local palaeoenvironmental changes, and how has this relationship changed through time? While no dated Middle Pleistocene sites presently exist to reconstruct the earliest hominin dispersals, several late Pleistocene sites now have chronostratigraphic sequences that can be brought to bear on these questions. This article presents chronological and subsistence-settlement data for one such site, Spitzkloof A Rockshelter in northern Namaqualand's rugged Richtersveld. Humans are shown to have visited the site very sporadically between ∼50,000 and 17,000 cal BP. Unlike most of the subcontinent, the most intensive occupations occur during early Marine Isotope Stage 2, when multiple proxies suggest enhanced humidity associated with intensified winter rainfall. We examine these data using the region's better-developed Holocene archaeological record to create predictions about the earliest coastal desert dwellers.

Notes onRuschia dichroa(Aizoaceae): An Endemic to the Arid Mountain Fynbos of the Western Cape, South Africa

Abstract: Ruschia dichroa (Rolfe) L.Bolus is endemic to a semi-arid, mountainous region within the Western Cape, South Africa. This species has often been confused with Ruschia marianae (L.Bolus) Schwantes and Astridia longifolia (L.Bolus) L.Bolus, since all three species have a similar chunky leaf morphology, are fairly large-flowered and may have reddish petaloid staminodes. Astridia longifolia only occurs in northern Namaqualand and is thus geographically well separated from the others, which are both found in the Wuppertal district of the Western Cape. The flowers of Ruschia dichroa differ from those of R. marianae by the presence of filamentous staminodes, which are collected into a cone around the stamens. In addition, the two species flower at different times, with R. marianae flowering from July to September and R. dichroa earlier in winter, from May to July. If not in flower, the two species can be separated by their different habit, R. marianae forming an erect shrub, whereas R. dichroa has a lo...

Expansion of Schlechteranthus (Ruschioideae, Aizoaceae) to include Polymita, with a new species from Namaqualand, South Africa

The species of Polymita N.E.Br. and Schlechteranthus Schwantes are compact, highly succulent shrubs endemic to the arid, winter-rainfall region of northern Namaqualand, South Africa. The two genera are closely related, and this is reflected in their overall similarity. Characters formerly believed to separate Polymita and Schlechteranthus are shown to vary considerably and therefore we include Polymita within Schlechteranthus. Schlechteranthus diutinus (L. Bolus) Klak, previously included under Polymita albiflora (L. Bolus) L. Bolus, exhibits consistent differences from P. albiflora in the leaves and is reinstated. We describe a new species, Schlechteranthus holgatensis Klak, which is known from a single, very prolific locality along the Holgat River in northern coastal Namaqualand. The new species is unusual for its velvety leaves: all other Schlechteranthus have smooth and somewhat shiny leaves. The habit and fruits, however, firmly place this species in Schlechteranthus. Altogether, six species are recognized and a revised generic description is provided. The ranges of the species rarely overlap and they mostly inhabit distinct soil types and occur at different altitudes. Species which occur close together flower at different times.

Cheiridopsis alba-oculata (Aizoaceae: Ruschioideae, Ruschieae) — A new quartz-endemic from southern Namaqualand, South Africa

Cheiridopsis alba-oculata Klak & N.A. Helme is a new species known from two populations in the Garies region of southern Namaqualand, where it appears to be restricted to patches of quartz-gravel. The species belongs to the Cheiridopsis–Odontophorus alliance because of its papillate leaves and the 9- or 10-locular fruits with large closing bodies. The isophylly and globose fruits with raised tops suggest that it is closely related to C. subg. Odontophoroides and Odontophorus. C. alba-oculata is geographically isolated in this group, whose other members are restricted to northern Namaqualand. C. alba-oculata resembles Cheiridopsis ponderosa and Cheiridopsis pilosula in its densely papillate leaves but is distinguished from them by its strongly keeled, apically toothed leaves.

Taxonomy of the Moraea saxicola complex (Iridaceae: Iridoideae) of arid, western southern Africa, with the new species, M. acocksii, M. geminifolia, M. quartzicola and M. teretifolia

Included in Moraea subg. Polyanthes sect. Deserticola Goldblatt, species of the M. saxicola complex have one or two basal foliage leaves, a typical Moraea-type flower with well-developed style branches and crests, nectar guides present only on the limbs of the larger outer tepals, and an ovary included in the inflorescence spathes. The complex extends from southwestern Namibia in the north to the slopes of the Gifberg near Klawer in Western Cape, South Africa, in the south. Examination of plants in the field and herbarium specimens collected since the group was last studied taxonomically shows that the complex includes four undescribed species: 1. terete-leaved Moraea acocksii Goldblatt & J.C.Manning; 2. two-leaved M. geminifolia Goldblatt & J.C.Manning; 3. terete-leaved M. teretifolia Goldblatt & J.C.Manning [all from northern Namaqualand in Northern Cape]; and 4. diminutive M. quartzicola Goldblatt & J.C.Manning from the southern Knersvlakte of Western Cape. The circumscriptions of Moraea bolusii Baker and M. namibensis Goldblatt are adjusted in light of new information and the range of the latter is expanded to include the Richtersveld of South Africa. We also expand the circumscription of M. saxicola, previously a Namibian endemic, to include plants from southern Namaqualand and the Richtersveld. The complex now includes eight species, and we provide a complete revision of all species, with distribution maps and illustrations of three of the new species.

<i>Maireana brevifolia</i> (Chenopodiaceae: Camphorosmeae), a new naturalized alien plant species in South Africa

We describe and discuss the distribution of a new, naturalized alien species, Maireana brevifolia (R.Br.) Paul G.Wilson (Chenopodiaceae), a native of Australia, in the western regions of South Africa. First discovered near Worcester, Western Cape in 1976, the species is now established in disturbed karoo shrubby rangelands, along dirt roads and on saline alluvia, from northern Namaqualand to the western Little Karoo. In the South African flora, M. brevifolia is most easily confused with the indigenous Bassia salsoloides (Fenzl) A.J.Scott, from which it is distinguished by the flat to cup-shaped and almost glabrous perianth with woolly-ciliate lobes, and the hardened and winged fruiting perianth.

LANDSCAPE CHANGE AND ECOLOGICAL PROCESSES IN RELATION TO LAND-USE IN NAMAQUALAND, SOUTH AFRICA, 1939 TO 2005

ABSTRACT This paper examines the consequences of land use on vegetation over a sixty-six year period, within various agrarian landscapes across the winter/summer rainfall ecotone in northern Namaqualand. We employ repeat ground and aerial photography and interviews with land users to elucidate the causal factors that explain environmental change and stability. Ecological literature on landscape change in Namaqualand has suggested that communal land-use is detrimental to vegetation cover and species richness. Our study shows that there have been very few changes in vegetation cover and species richness in cultivated and grazed communal areas during the last 65 years, but that there has been a regeneration process in the private and protected areas. We demonstrate that these different vegetation responses reflect different land management histories. This evidence suggests that the potential for increased vegetation cover and species richness in response to land-use change is higher than was previously assumed and provides a new perspective on the latent capacity of communal landscapes to regenerate from changes caused by cultivation and grazing pressure. The environmental history presented in this paper spans a temporal and spatial scale that elucidates the complex relationship between land-use, climate, soils and vegetation change.

A MORPHOLOGICAL PHYLOGENY OF THE GENUS CONOPHYTUM N. E. BR. (AIZOACEAE)

In this paper I present a cladistic evolutionary hypothesis for 83 taxa of Conophytum, a genus of leaf-succulent xerophytes endemic to South Africa and Namibia. My analysis is based primarily upon anatomical and micromorphological characters. The genus as a whole, and some of its traditional sections such as Ophthalmophyllum and Pellucida, is shown to be monophyletic, with bootstrap support, though many other branches are not well supported. Within Conophytum, nocturnal flowering and the embedded window-plant life form appear to have originated several times in separate lines of evolution. The most basally-diverging lineages in the genus are native to the Richtersveld in northern Namaqualand, suggesting an origin in that area. A trend towards the loss of anatomical adaptations to drought, such as sunken stomata, and the gain of adaptations in gross morphology, such as growth embedded in soil, is evident in many of the more recently derived lineages.

A new variety of Euphorbia filiflora Marloth from the Northern Cape Province of South Africa

Euphorbia filiflora is distributed on the high plateau of northern Namaqualand from Brakdam to north and north west of Steinkopf to Umdaus. A new variety is described, E. filiflora Marloth var. nana G.Williamson. This plant is a miniature and has a restricted distribution.

Plant induced fertile islands as possible indicators of desertification in a succulent desert ecosystem in northern Namaqualand, South Africa

Zones of nutrient enrichment beneath shrubs, the so called 'fertile islands', are the result of a range of interacting physical and biotic concentrating mechanisms. These concentrating mechanisms lead to specific spatial patterns of soil properties across a landscape and it has been suggested that disruption of the normal patterns into more aggregated 'fertile islands' might be a useful index of desertification in semi-arid regions. The objective of this paper was to determine whether 'fertile islands' are as characteristic a feature of succulent deserts as they are of shrub dominated deserts. Results indicate that, even in a community dominated by succulent species fertile islands develop under extremely arid conditions and that the degree of development is dependent on plant dynamics. Long-lived species showed greater concentration effects. However, the patterns of nutrient accretion in islands are very different to shrub invaded grasslands in North America. In particular nitrogen accretion dominated the 'fertile islands' in Namaqualand, and we suggest that these islands are more ephemeral than carbon and phosphorus dominated islands reported for other systems. These more dynamic islands are a consequence of rapid community dynamics since the Namaqualand region is characterised by many short-lived perennials which turnover generations very rapidly in response to environmental conditions. Using the development of 'fertile islands' to assess desertification as applied elsewhere might be inappropriate in Namaqualand because of the different patterns of community dynamics underlying the formation and characteristics of these islands.

Ecological and phylogenetic patterns of carbon isotope discrimination in the winter-rainfall flora of the Richtersveld, South Africa

Leaf tissues of vascular plant species from the arid Richtersveld of northern Namaqualand (Succulent Karoo), South Africa, show a great range of variation in carbon isotope discrimination. Analyses of Δ values for species with obligate C3 metabolism demonstrated that the water use efficiency indicated by these values varies between species and within a species population both between seedlings and mature shrubs and between sites along an aridity gradient. An expected pattern of increasing water use efficiency with greater longevity in these species was not present, however. Only among ephemerals were there taxa with high Δ values associated with low water use efficiency, but these high values were balanced by other ephemeral species with low Δ values comparable to those typical of moderate to long-lived shrubs. The extent to which putative CAM species in the succulent flora rely entirely on nocturnal carbon fixation is highly variable. Species of Crassulaceae and Aloe (Asphodelaceae) relied almost exclusively on CAM photosynthesis, although Crassulaceae from more mesic environments may be CAM-flexible. Succulent-leaved species of Senecio and leaves of stem-succulent Euphorbia were CAM-flexible in their Δ values, while shrubby species of Ceraria (Portulacaceae) appeared to rely primarily on C3 photosynthesis. Variable patterns of reliance on CAM photosynthesis were present in the ecologically dominant Mesembryanthema of the Aizoaceae. Shrubby species of the subfamily Mesembryanthemoideae, although capable of CAM-flexibility in less xeric habitats, relied largely on CAM fixation of carbon in our field sites. Within the subfamily Ruschioideae, there was a wide range of Δ values indicating species with CAM, CAM flexibility, and primary reliance on C3 photosynthesis. Low Δ values indicative of typical CAM fixation were associated with species with greater longevity, suggesting that a positive correlation may exist between the degree of reliance on CAM photosynthesis and plant life span.

The ecological status of Aloe pillansii (Aloaceae) in the Richtersveld with particular reference to Cornellskop

The precarious ecological status of Aloe pillansii L. Guthrie in the Richtersveld, northern Namaqualand, northwest corner of the northern Cape Province of South Africa, is examined. There is some concern over the condition of the aloe population occurring on the hill Cornellskop, the type locality. An attempt was made to recognise and analyse the main problems, natural and anthropogenic, threatening the conservation of the unique Cornellskop miniecosystem. During the research project a checklist of plants occurring on the hill was compiled. A map of Cornellskop is included (Figure 1). The general status of the aloe throughout the Richtersveld is dealt with and a map showing the overall distribution as is presently known is appended (Figure 2). The origins of the resident Richtersveld traditional herders is briefly outlined. It is postulated that future conservation of the species and the progressive degradation of the habitat is finely balanced between the restricted severe climatic niche within which the plants have evolved and ever present, progressive, attritional anthropogenic factors.

New species, chromosome cytology and notes on the southern African Iridaceae-Irideae: Moraea, Roggeveldia and Homeria

A new species for each of Moraea (120 species), Homeria (32 species) and Roggeveldia (2 species), African genera of Iridaceae–Irideae subtribe Homeriinae, is described. Moraea vlokii from the interior Swartberg Mountains of the southern Cape, is most closely related to the widespread winter rainfall area species M. gawleri, from which it differs by its short, crestless style arms, obtuse subequal tepals and solitary leaf. In Roggeveldia, until now monotypic, the new R. montana is a plant of low stature with a single long, terete and slender leaf, occurring locally in the Kamiesberg (central Namaqualand) and Swartberg Mountains. Although its flowers correspond closely to those of R. fistulosa in their free stamens and simple style branches that alternate with the stamens, the taller R. fistulosa has a short, straight and thick hollow leaf. Homeria serratostyla, restricted to the Richtersveld, northern Namaqualand, is assigned to section Homeria, and seems most closely related to H. patens. Notable additional populations, including significant range extensions, are reported for Moraea incurva, M. insolens, M. linderi, Homeria fenestrata, H. galpinii and H. schlechteri. Original chromosome counts for each of the new species and several more of Homeria are also included here.