Drakensberg Research Articles

The impact of Nassella trichotoma (Nees) Hack. ex Arechav. on plant diversity, richness and soil properties in South Africa

Nassella trichotoma (Poaceae) is a highly invasive South American grass that is invading montane grasslands in the Eastern and Western Cape provinces of South Africa. Although N. trichotoma has been recognised as a major problem in these mountains for decades, the primary concern has been on impacts on rangeland productivity and management, while the impacts of invasions on plant biodiversity have not been considered. To understand the impact of N. trichotoma on local plant biodiversity, 81 pairs of plots (total of 162 plots) were laid out in the Sneeuberg and Eastern Cape Drakensberg mountains, Eastern Cape, in March 2020 and March 2021. At each site plots were located in grassland invaded by N. trichotoma and in nearby uninvaded grassland (control). A total of 20 N. trichotoma patches were sampled with two to four plot pairs per site. All vascular plant species were recorded in all plots, the cover abundance of each species per plot was visually estimated, and the topsoil was sampled and analysed for differences in nutrient and physical factors between invaded and uninvaded plots. Plant species diversity was 24 % higher in uninvaded areas, and the native grasses Pentameris airoides (Χ2 = 4.93, d.f. = 1, p < 0.01), Tenaxia disticha (Χ2 = 5.51, d.f. = 1, p < 0.01), and Themeda triandra (Χ2 = 9.28, d.f. = 1, p < 0.001) were significantly less abundant in invaded plots. Uninvaded areas had greater native species diversity (65 species) and fewer alien species (3) than invaded areas (47 and 9 respectively). Of the 18 soil variables measured, the following were significantly higher in invaded areas than uninvaded areas: boron (23 %), calcium (18 %), phosphorous (58 %), silt (10 %), total cations (12 %), and zinc (68 %). This suggest that N. trichotoma alters soil nutrients. The results indicate that N. trichotoma is a powerful driver of native biodiversity erosion in these montane grasslands and should be a cause for major concern by landowners and government.

HISTORICAL SPECIAL INTEREST TOURISM: THE EVOLUTION OF MOUNTAINEERING IN SOUTH AFRICA

Scholarship on special interest tourism has burgeoned since the 1980s. Although this expanding research interest is relatively new, the phenomenon of special interest tourism is not of recent origin as many of its forms, such as mountaineering, exhibit a long historical record. Most research on special interest tourism concentrates on contemporary issues. The objective is to present a historical perspective on special interest tourism. Using archival sources an analysis is undertaken of the evolution of mountaineering in South Africa as a recreational sport and incipient form of special interest tourism. Cape Town’s Table Mountain and the Drakensberg mountains provide the geographical focus of discussion. The results demonstrate that during the 1920s and 1930s tourism promoters in South Africa acknowledged the potential of special interest mountaineers to contribute to tourism growth. The documented experience of early mountaineering in South Africa provides an example of racism in recreation by showing that the country’s recreational practices became constructed around politicallyimposed racial hierarchies.

Past Niche Tourism: The First Chapter of Mountain Tourism in South Africa

Mountain tourism enjoys a long history in many countries, much of which is unrecorded. This paper addresses one dimension of the neglected past of recreation and tourism in the Global South. The focus is on the development of mountain tourism as a form of niche tourism in South Africa. The paper contributes to the limited international historical scholarship on niche tourism. In addition, it extends the literature in South African tourism scholarship on tourism’s past, tourism history and the historical geographies of tourism. Using the limited extant literature and with primary archival sources the early development of mountain tourism in South Africa is investigated. The time period covered is from the mid-19th century to the early 1950s. Arguably, the initial origins of mountain tourism in South Africa must be situated at Table Mountain in Cape Town. The focus shifts subsequently to the growth of mountain tourism in the high Drakensberg range. Although mountain tourism is dominated by domestic visitors it is argued that the South African Railways played a vital role in exposing South Africa — and especially the Drakensberg — as a potential destination for international mountain tourists.

Impacts of climate hazards on households along the Drakensberg Mountains in the Free State Province of South Africa

Mountains are climate change hotspots and their ecosystems are key components in the supply of ecosystem goods and services to local communities. Low-income communities that directly depend on mountain resources are highly vulnerable to the harsh impacts of climate change. Using rainfall and temperature trends, and data collected from a household questionnaire survey, the objective of this study is to assess the impact of climate change on low-income households living in the Maluti-a-Phofung Municipality part of the Drakensberg Mountains. Climatic data were obtained from Climate Explorer while the household data were collected from a sample of 383 households in the villages of Qwaqwa. The results show that temperature and rainfall changes have significantly increased over a period of 120 years. About 51 percent of the respondents experienced extreme weather events which has the greatest impact on their households followed by drought (25.5%). Employment status was found to be significantly associated with the perception that hazards negatively impact natural resource availability, with 54% of those who had this perception being unemployed. In addition, income was found to have a significant relationship with extreme weather impacts on households and 60% of those households had a low monthly income of ZAR 2000 or less. Based on these findings, mountain households along the Drakensberg Mountains in Qwaqwa villages are already experiencing the negative impacts of climate change and their socio-economic characteristics indicate very low levels of adaptation capacity.

Let's get high: Cladogenesis in freshwater crabs (Decapoda: Potamonautidae: Potamonautes) supports the mountain gradient speciation hypothesis in the Cape Fold and Drakensberg Mountains, South Africa.

During the present study, the evolutionary relationship within a clade of mountain clade of freshwater crabs (Potamonautes) was examined using mtDNA sequence data for species from the Cape Fold Mountain (CFM) and Great Escarpment (Drakensberg Mountain range). We undertook phylogenetic analyses, divergence time estimation, and an ancestral area reconstruction to explore the period of cladogenesis and understand the biogeographic history in this high-altitude clade. Furthermore, we applied four species delimitation methods using ASAP, bPTP, bGMYC, and STACEY on the latter clade. Bayesian phylogenetic analyses retrieved a monophyletic freshwater crab clade comprised of two major sister clades, one comprised of the Cape Fold (clade A) and two comprised of Drakensberg Mountains (clade B) species. Divergence time estimation indicated that the two clades underwent Mio/Pliocene cladogenesis. Within the CFM clade (A), P. amathole (Amathola Mountains) was sister to P. parvispina (Cederberg and Kouebokkeveld Mountains) and the latter species were sister to P. parvicorpus (Cape Peninsula, Jonkershoek, and Helderberg Mountains) sister to P. tuerkayi (Overberg Mountains) and P. brincki (Hottentots Holland Mountains). Within the Drakensberg Mountain clade (B), we observed in situ diversification. Specimens from the southcentral Drakensberg Mountains (Dargle Forest, Injasuti, Karkloof, and Impendle) represent a new undescribed lineage Potamonautes sp. nov. 1. The second clade from the northern Drakensberg, representing P. clarus, was sister to a central Drakensberg Mountain clade that comprised P. depressus that was in turn sister to P. baziya from the Eastern Cape Province. The application of species delimitation methods generally overestimated the number of species. The biogeographic analyses indicated that the Eastern Cape Province is the most likely ancestral range area. Ecological niche modelling of representative species in clades A (Cape Fold Mountains) and B (Drakensberg Mountains) demonstrated that temperature and rainfall were the major abiotic drivers that differentiated the two clades. Our data favours the mountain gradient speciation hypothesis.

The “eco-story” of a mountain range: the development of Socio-Ecological Disturbance Regimes in the northern Drakensberg and consequences for grassland-plant diversity

The phenomenal level of biodiversity in the Drakensberg mountains was shaped by and depends on the disturbance regimes which prevailed before the intensification of human settlement in the region. Global change has, however, changed these disturbance regimes leaving an uncertain future for biodiversity. In order to reduce uncertainty around the influence of human society on biodiversity, we propose the Socio-Ecological Disturbance Regime (S-EDR) construct, which implicitly considers the effects of interactions between society, ecosystems, and associated disturbance regimes. We aimed to provide insight into how disturbance regimes have deviated from their “natural” range of variation, and developed into novel S-EDRs that are increasing uncertainty around the fate of plant diversity in the region. Drakensberg grasslands house high levels of indigenous grassland-plant species, many of which only occur in this mountain range. To achieve this we present findings from palaeoecological, through to more recent history, to establish the context of disturbance regimes in this landscape. Over the last 150–200 years there have been rapid and large changes in disturbance regimes, and these novel S-EDRs are demonstrated to have been shaped by interactions between the dominant “social systems” in the study area, that is, communal, private, and protected areas, and the nature of the ecosystems they inhabit. Owing to their prevalence in the landscape the disturbance regime components, fire and herbivory, and land transformation, are focused on. Understanding the nature of developed S-EDRs will be important for understanding contemporary research, guiding future investigations, and the maintenance of plant diversity in Drakensberg grasslands.

Projected changes in precipitation characteristics over the Drakensberg Mountain Range

AbstractThis study examines the potential impacts of climate change on the characteristics of precipitation over the Drakensberg Mountain Range (DMR) at different global warming levels (GWLs: 1.5, 2.0, 2.5 and 3.0°C) under the Representative Concentration Pathway 8.5 (RCP8.5) scenario, using dynamical and statistical downscaled datasets. The dynamical datasets consist of 19 multi‐model simulations datasets from the Coordinated Regional Climate Downscaling Experiment (CORDEX), whereas the statistical downscaled datasets comprise 19 multi‐model simulations from the National Aeronautics and Space Administration (NASA) Earth Exchange (NEX) Global Daily Downscaled Projections (NEX‐GDDP, hereafter NEX). The capacity of the CORDEX and NEX datasets to represent past characteristics of extreme precipitation over the DMR was evaluated against eight observation datasets. The precipitation characteristics were represented by eight precipitation indices. Both CORDEX and NEX realistically capture the characteristics of extreme precipitation over the Drakensberg and, in most cases, their biases lie within the observation uncertainty. However, NEX performs better than CORDEX in reproducing most of the precipitation characteristics, except in simulating the threshold of extreme rainfall. The ensemble means of CORDEX and NEX agree on a future increase in the intensity of normal precipitation, in the frequency and intensity of extreme precipitation, as well as an increase in widespread extreme events, with a decrease in the number of precipitation days and continuous wet days. However, they disagree on the projected changes of annual precipitation, for which CORDEX projects an increase over most parts of the DMR, whereas NEX indicates a decrease. The self‐organizing‐map analysis, which reveals diversity in the projection patterns hidden in the ensemble means, shows the most probable combinations of projected changes in the annual precipitation and extreme precipitation events (in terms of intensity and frequency): (a) increase in both annual precipitation and extreme precipitation events; (b) decrease in both annual precipitation and extreme precipitation events; (c) decrease in annual precipitation but increase in extreme precipitation events. The results of this study can thus provide a basis for developing climate change adaptation and mitigating strategies over the DMR.

Testing the efficacy of bat monitoring methods for identification and species surveys in KwaZulu-Natal province, South Africa

Multi-method sampling approaches are becoming increasingly popular for investigating species occurrence at specific sites, as there is a need to accurately monitor species with limited time and resources. In this study, a multi-method comparative approach was used to survey bat species in the foothills of the Drakensberg Mountain range in KwaZulu-Natal province, South Africa. We used historical museum records and species distribution modelling (SDM) to predict which species would likely occur in our study area. We then compared physical capture (by deploying mist nets) with acoustic surveys (using an Anabat bat detector) to assess the bat species assemblages present. Species distribution models predicted eight bat species to occur from the historical checklist of 28 species recorded in the broader region, as no museum records existed for the specific study area. Species detection by acoustic data yielded the highest number of detected species ( n = 11) while active trapping yielded nine species from 54 individuals of four families, namely, Laephotis botswanae, L. capensis, Myotis tricolor, Pipistrellus hesperidus, Rhinolophus clivosus, and Tadarida aegyptiaca with molecular confirmation required for Miniopterus fraterculus, R. darlingi and R. swinnyi. These complementary sampling methods may be necessary for accommodating the limitations of each individual method for a more inclusive assessment of bat species richness in a targeted landscape. The present study could be used as a model approach to assess the biodiversity and demographics of other taxa and in other habitats.

Change in the Urban Landscape of the Drakensberg Mountain Region, South Africa: A Case Study of Phuthaditjhaba

The settled landscape in the Drakensberg Mountain region of South Africa is characterized by increasing urbanization. Some of the supposedly rural settlements in the region have experienced increasing change in their landscapes over the last 3 decades, resulting in significant land use and land cover (LULC) changes. Among such settlements, Phuthaditjhaba and its environs are slowly becoming a metropolitan area. Based on conceptual considerations regarding sustainable urban development, we assessed LULC change using 4 Landsat images from 1989, 1999, 2009, and 2019 and a combination of unsupervised and supervised classification methods. The images were classified into 4 LULC classes. Between 1989 and 2019, the urban built-up area in Phuthaditjhaba increased from about 5% to 19%, representing a total increase of 270%. However, the greatest increase in land cover was in bare surface at the expense of vegetated areas, including farmland, which decreased from about 45% to 15%. The increase in bare surface could be due to fires. Built-up areas also increased due to a consistent increase in population density in the study area. We further described spatial patterns in LULC using selected landscape metrics. A decrease in patch density (PD) and cohesion, coupled with constant edge density (ED) and an increase in the fractal dimensional index (FDI), indicates fragmentation and less connectivity between 1989 and 1999; we interpret this as a sign of unsustainability. An increase in PD and cohesion and fluctuations in ED and FDI show that land patterns were more aggregated between 2009 and 2019. At the class level, an increase in PD, cohesion, and ED also showed more aggregated land patterns, which was confirmed by the mean patch size. The FDI revealed greater connectivity, which we also interpreted as unsustainable because of the increase in bare surface and built-up areas. Integrative coplanning and comanagement of land use and allocation are needed to ensure sustainable development.

MAPPING BASUTOLAND: CORRESPONDENCE BETWEEN GEOLOGISTS GORDON MURRAY STOCKLEY AND ALEXANDER LOGIE DU TOIT (1938–1946)

ABSTRACT Basutoland is a former British Protectorate (now the Kingdom of Lesotho) nestled in the Maluti and Drakensberg mountains, surrounded by South Africa. Geological knowledge about Basutoland started with the activities of French missionaries in the 1830s and continued to accumulate throughout the nineteenth century. Systematic geological mapping began in 1902–1904 with the work of Ernest Schwarz and Alexander du Toit, who, while working for the Geological Commission of the Cape of Good Hope, extended their mapping activities into Basutoland. In 1905 Samuel Dornan from Morija started studying the geology of that region of Basutoland. In the 1930s rumours about the finds of diamonds prompted the British Government to map the country geologically. Gordon Stockley, a geologist experienced in mapping for the Geological Survey of Tanganyika, was seconded to Basutoland in late 1938. Stockley mapped the whole country in 11 months in 1939, and then returned to Tanganyika. His geological map, at a scale of 1:380,160 was published in 1946, and the report appeared in 1947. At the start of his mapping, Stockley wrote to du Toit asking his advice on various matters related to the geology, geomorphology and palaeontology of Basutoland. Their correspondence lasted until 1946. Stockley’s map and report on Basutoland geology laid the foundation for all future exploration and led to the discovery of several diamondiferous kimberlite pipes in the 1960s, and to the establishment of several diamond mines that contribute significantly to the economy of modern Lesotho.

The Limpopo–Mpumalanga–Eswatini Escarpment—Extra-Ordinary Endemic Plant Richness and Extinction Risk in a Summer Rainfall Montane Region of Southern Africa

Climatic, edaphic, and topographic differences between mountains and surrounding lowlands result in mountains acting as terrestrial islands with high levels of endemic biota. Conservation of mountains is thus key to successful biodiversity conservation. The Limpopo–Mpumalanga–Eswatini Escarpment (LMEE) in South Africa and the Kingdom of Eswatini is one of the largest components of southern Africa’s Great Escarpment. Despite botanical collecting effort over 150 years, there has never been a holistic and comprehensive synthesis of plant endemics data for the LMEE. For the first time, we define the LMEE as an orographic entity, covering 53,594 km2; it forms a contiguous highland area from the Pongola River in the south, north to the Woodbush area, and includes rugged western Eswatini. Using exhaustive literature mining, coupled with combined decades of fieldwork by the authors, and up-to-date taxonomic assessments of the 46 undescribed species, we provide the first robust list of plant endemics for the LMEE. The LMEE has 496 endemic plant taxa, comprising 10.7% of the provisional flora (4,657 taxa). This is more than double the endemic plant taxa in the Drakensberg Mountain Centre (DCM), and may be the richest concentration of montane endemics in southern Africa outside of the Core Greater Cape Floristic Region. Grassland hosts the largest number of endemics (74.2%), followed by Savanna (26.6%), then Forest (7.7%). Most endemics of conservation concern occur in Grassland (68.4%), in which one is Extinct and two are Extinct in the Wild. Evolutionary partitioning between Grassland, Savanna and Forest is suggested by low introgression of Biomes at family and genus level, and by a dominance of life-forms adapted to open habitats. High threat statuses for Grassland endemics can be attributed to the historical transformation of almost 20% of Grassland to forestry pre-1990, and ongoing degradation of primary Grassland. With conservation area coverage only 11.1% of the LMEE, the exceptional richness of the endemic flora—combined with major conservation threats—suggest that the LMEE should become a major focus of conservation effort between South Africa and Eswatini as a matter of urgency.

1019. GLADIOLUS MICROCARPUS: Iridaceae

SummaryGladiolus microcarpus G.J. Lewis is a striking, summer‐flowering cremnophyte, with a strongly weeping habit, endemic to the Drakensberg Mountain Centre in southern Africa. A description and details of its history, taxonomy, habitat and cultivation are given.

Interpreting unusual imagery: a rare rock art depiction of a bushbuck in the southeastern mountains of South Africa

ABSTRACT A rare, painted depiction of a bushbuck (Tragelaphus scriptus) is reported from the Drakensberg Mountains of the Eastern Cape Province, South Africa. The painting is located outside the known distribution range of the species. It is identified based on the close correlation between details of the painting and the colouration of the animal. Differences between the painting and animal are noted. These differences are discussed in terms of San views on anomalous individual animals. How depictions of such animals may act as symbols is also discussed.

Seasonal evapotranspiration over an invader vegetation (Pteridium aquilinum) in a degraded montane grassland using surface renewal

Study regionCathedral Peak Research Catchments, uKhahlamba Drakensberg mountain range, South Africa. Study focusThe focus was to determine the seasonal pattern of evapotranspiration (ET) over a bracken canopy, which is a product of degradation within the montane grasslands of the uKhahlamba Drakensberg mountains. Surface renewal (SR) was investigated as a viable alternative to eddy covariance for long-term estimation of ET within a remote high rainfall montane landscape. The SR dissipation method was used to observe ET over the bracken canopy for 23 months, across two consecutive years with variable seasonal rainfall timing and amounts. Besides ET, rainfall and energy flux components were observed. New hydrological insights for the regionThe SR dissipation method was shown to be adequate for the long-term estimation of evapotranspiration over a bracken canopy within a remote high summer rainfall montane landscape. The bracken canopy was found to have a distinct seasonal cycle. Autumn was most sensitive to rainfall amount and timing, as late annual rainfall during autumn decreases bracken ET compared to higher summer rainfall followed by a lower autumn rainfall. Comparing the evapotranspiration of bracken from this study to the evapotranspiration of natural grassland in previous studies, the largest difference in evapotranspiration between the canopies occurs in winter.

Modelling potential range expansion of an underutilised food security crop in Sub-Saharan Africa

Despite substantial growth in global agricultural production, food and nutritional insecurity is rising in Sub-Saharan Africa. Identification of underutilised indigenous crops with useful food security traits may provide part of the solution. Enset (Ensete ventricosum) is a perennial banana relative with cultivation restricted to southwestern Ethiopia, where high productivity and harvest flexibility enables it to provide a starch staple for ∼20 million people. An extensive wild distribution suggests that a much larger region may be climatically suitable for cultivation. Here we use ensemble ecological niche modelling to predict the potential range for enset cultivation within southern and eastern Africa. We find contemporary bioclimatic suitability for a 12-fold range expansion, equating to 21.9% of crop land and 28.4% of the population in the region. Integration of crop wild relative diversity, which has broader climate tolerance, could enable a 19-fold expansion, particularly to dryer and warmer regions. Whilst climate change may cause a 37%–52% reduction in potential range by 2070, large centres of suitability remain in the Ethiopian Highlands, Lake Victoria region and the Drakensberg Range. We combine our bioclimatic assessment with socioeconomic data to identify priority areas with high population density, seasonal food deficits and predominantly small-scale subsistence agriculture, where integrating enset may be particularly feasible and deliver climate resilience. When incorporating the genetic potential of wild populations, enset cultivation might prove feasible for an additional 87.2–111.5 million people, 27.7–33 million of which are in Ethiopia outside of enset’s current cultivation range. Finally, we consider explanations why enset cultivation has not expanded historically, and ethical implications of expanding previously underutilised species.

Evaluation of Gully Erosion Susceptibility Using a Maximum Entropy Model in the Upper Mkhomazi River Basin in South Africa

Soil erosion is one of the most challenging environmental issues in the world, causing unsustainable soil loss every year. In South Africa, several episodes of gully erosion have been documented and clearly linked to the presence of Quaternary colluvial deposits on the Drakensberg Mountain footslopes. The aim of this study was to identify and assess the triggering factors of gully erosion in the upper Mkhomazi River basin in KwaZulu-Natal, South Africa. We compiled a gully inventory map and applied remote sensing techniques as well as field surveys to validate the gully inventory. The gullies were subdivided into slope gullies and fluvial gullies. We derived susceptibility maps based on the spatial distribution of gully types to assess the most important driving factors. A stochastic modeling approach (MaxEnt) was applied, and the results showed two susceptibility maps within the spatial distribution of the gully erosion probability. To validate the MaxEnt model results, a subset of the existing inventory map was used. Additionally, by using areas with high susceptibilities, we were able to delineate previously unmapped colluvial deposits in the region. This predictive mapping tool can be applied to provide a theoretical basis for highlighting erosion-sensitive substrates to reduce the risk of expanding gully erosion.

A rapid biodiversity assessment of Lesotho’s first proposed Biosphere Reserve: a case study of Bokong Nature Reserve and Tšehlanyane National Park

Background: Two of Lesotho’s protected areas, namely Bokong Nature Reserve and Tšehlanyane National Park, form the core area of the country’s first proposed Biosphere Reserve. Biodiversity is a key aspect needed to justify nomination of a Biosphere Reserve under UNESCO’s Man and the Biosphere Programme. Previously documented biodiversity of the two protected areas is limited in terms of coverage and scope as well as being outdated. The aim of the current study was to conduct a rapid assessment of the biodiversity, including endemism, of the proposed Biosphere Reserve to inform the formal nomination process.Methods: A field survey was undertaken over 112 033 ha in the core, buffer and transition zones of the proposed Biosphere Reserve during which species of both flora and fauna were documented. Purposeful recordings were made during different seasons to incorporate various flowering seasons of the plants, as well as faunal species that may hibernate or migrate seasonally.Results: A total of 380 plant species was recorded, 30 of which are legally protected in the country, 60 endemic to the Drakensberg Mountain Centre, and two species (Aloe polyphylla and Glumicalyx lesuticus) are endemic to Lesotho. The former is the national flower of Lesotho and is under threat due to illegal trade. Sixteen mammal species were recorded, seven of which are legally protected in the country, as well as 53 bird species (including the IUCN Red Listed vulture species, Gyps coprotheres and Gypaetus barbatus). Two fish species were also recorded including Pseudobarbus quathlambae, which is Lesotho’s only known endemic vertebrate species, as well as seven reptile and three amphibian species (two of which are near endemic namely Amietia delalandii and A. vertebralis).Conclusion: This survey has provided valuable baseline information on the biodiversity (particularly regarding the flora and avifauna) of the proposed Biosphere Reserve, which includes two protected areas namely Bokong Nature Reserve and Tšehlanyane National Park. The findings reflect the biodiversity value of the area and will contribute towards its nomination as Lesotho’s first Biosphere Reserve.

Stratigraphy of late Quaternary mountain slope landforms and deposits in southern Africa and their significance for the dynamics of mountain sediment systems

AbstractMountains are areas of high potential sediment yield due to their steep slopes and generally cool, wet climates. Mountain sediments are moved by gravity-driven and often cryogenically-influenced processes, and captured within valleys or footslopes in the form of screes, alluvial/colluvial fans and terraces, or on hillslopes in the form of solifluction sheets, debris lobes/ridges and openwork block deposits. This study critically examines the geomorphic, sedimentary, stratigraphic and dating evidence from cryogenically-influenced late Quaternary slope deposits found along the highest sectors of the Great Escarpment in the Eastern Cape Province (South Africa) and Maloti–Drakensberg range (Lesotho, and KwaZulu-Natal Province, South Africa). This evidence is set in the context of mountain weathering and erosion/transportation processes during the late Quaternary, and the dynamics of such sedimentary systems. Despite many general reports and observations, there is little detailed and quantitative evidence for late Quaternary slope processes, products and stratigraphy in southern Africa. This study integrates the existing morphological, sedimentary and dating evidence to examine mountain slope evolution in southern Africa based on the conceptual framework of sediment cascades. Application of this framework can help explain the spatial and temporal differences in sediment supply and dynamics observed in different sectors of the Great Escarpment during the late Quaternary.

Reproductive strategies in the rare and endangered Killickia grandiflora (Lamiaceae) – implications for its urgent conservation

Populations of rare and restricted species are commonly challenged due to risks associated with reduced genetic diversity, environmental variation, and demographic stochasticity. Killickia grandiflora (Lamiaceae) is one of three Killickia species endemic to the Drakensberg Mountain Centre in KwaZulu-Natal, South Africa. Its confirmed distribution is restricted to a firebreak between two catchments in the Cathedral Peak region of the Ukhahlamba Drakensberg Transfrontier Park, where it is threatened by habitat transformation. In this study, we aimed to understand factors that promote or inhibit gene flow within this highly restricted K. grandiflora population, to estimate inbreeding, and to assess its status as a potentially threatened species. Exclusion and hand pollination trials indicate that K. grandiflora cannot autonomously self-pollinate and is dependent on pollinators for outcrossing. Germination trials and tetrazolium staining suggest that the seeds may have dormancy breaking requirements or are inviable. Inbreeding and genetic diversity analyses show that the K. grandiflora population nonetheless maintains a high level of genetic diversity, likely through outcrossing, despite the small population size and apparent poor reproductive success. We recommend that the IUCN conservation status of K. grandiflora be changed from Vulnerable to ‘Critically Endangered’ based on observed reductions in population size, limited extent of occurrence, small number of mature individuals, and threats by woody competitors. We strongly recommend that the known population(s) be monitored and the habitat patches be conserved regardless of size and maintained through regular burning to enable the species’ survival and conservation. Ex situ propagation and reintroduction to its historical habitat should be explored as additional conservation measures for this species.

New records of alien and potentially invasive grass (Poaceae) species for southern Africa

Background: The grasses (Poaceae) of the Flora of Southern Africa (FSA) region (i.e. Botswana, Eswatini, Lesotho, Namibia and South Africa) are relatively well documented, for both native and non-native species. Visiting taxonomic expertise nevertheless reveals new FSA and in-country records, particularly of non-native species. Such records provide an opportunity for improving biosecurity relating to potentially invasive but hitherto undetected non-native Poaceae in the FSA region.Objectives: To improve floristic data for non-native Poaceae occurring in theFSA region.Method: Field collections were made, herbarium collections, databases and relevant literature were studied.Results: New records are presented for non-native grasses that were encountered as locally common populations in the Drakensberg Mountain Centre of Floristic Endemism (DMC, Lesotho and South Africa). Festuca rubra and Agrostis capillaris are newly reported for sub-Saharan Africa and southern Africa and are also the first verified specimens reported for the African continent, with previous reports from northern-most Africa (Morocco, Algeria and/or Tunisia) uncertain. Jarava plumosa, introduced from South America and previously known for the whole of Africa from a single population in the Western Cape, South Africa, is newly reported from the border between the Eastern Cape, South Africa and Lesotho. The ecological implications, including the potential to become invasive, are discussed for each species, with taxonomic notes given to help differentiate them from closely resembling taxa.Conclusion: These new records of alien grass species raise concerns over their potential ecological impact, particularly as they are found in an area of conservation importance. Future efforts to monitor their distribution are of importance.