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13 Gd 3 Stormberg Plateau Grassland: Grasslands with prominent Themeda triandra, Eragrostis chloromelas, Cymbopogon pospischilii, Eragrostis gummiflua, Elionurus muticus, north of Jamestown (Eastern Cape).
Source publication
This is an extract of this Grassland Biome chapter from the pre-publication PDF of the book Mucina, L., & Rutherford, M.C. (eds). Reprint 2011. The Vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African Biodiversity Institute, Pretoria. ISBN: 978-1919976-21-1
Citations
... The soils are sandy clay loams classified as Westleigh and Mispah forms derived from Ecca group shale of the Karoo sedimentary sequence (Turner 2000). The vegetation is classified as Moist Midlands Mistbelt Grassland dominated by Themeda triandra (Mucina et al. 2006). The area has not been grazed by livestock for at least the past 63 years and has been burned approximately biennially during this time. ...
The importance of maintaining biodiversity in natural grasslands under livestock production systems has been recognised. Forbs contribute more to species richness than grasses in South African grasslands. However, little is known about the impact of grazing and grass competition on the population dynamics of forbs. The aim of this study was to determine the response of three mesic grassland perennial forb species to simulated intensive defoliation and interspecific competition from a neighbouring dominant grass, Themeda triandra, in a field experiment. Two of the selected forb species are sensitive to defoliation (Afroaster hispida and Gerbera ambigua) and one is potentially resistant to defoliation (Hypoxis hemerocallidea). Defoliation resulted in smaller plants of all three species following regrowth. Only A. hispida showed an interaction response to defoliation and competition. Thus, a competitive release was observed for A. hispida in that the height of defoliated plants was reduced by 45% compared with undefoliated plants under full competition, but there was no difference under partial or no competition. Gerbera ambigua was unaffected by competition. Hypoxis hemerocallidea was sensitive to competition irrespective of being defoliated or undefoliated. Findings of this study highlighted an individual response such that a general response cannot be predicted.
... E) is located at an altitude of 1633 m above sea level, 50 km north of the town Potchefstroom (North West province, South Africa), and is visited by a local caving club annually. The cave's entrance (facing South-East) is a sinkhole overgrown with cyanobacteria, algae, mosses, ferns, and trees, in contrast to the surrounding bioregion that consists of dry highland grassland classified as Carletonville Dolomite Grassland vegetation (Mucina et al., 2006). The geology of the surrounding area can be defined as dolomite, subordinate chert, minor carbonaceous shale, limestone, and quartzite (Burger, 2013). ...
... Bushmen Cave is a rock shelter (open North-West facing overhang) used by hikers as an overnight shelter. It is located in the Drakensberg grassland bioregion, which is classified as Lesotho Highland Basalt Grassland vegetation (Mucina et al., 2006). The geology of the area is characterized as sandstone, pink-weathering granular or augen quartz-feldspar gneiss (Johnson 1991;Burger, 2013). ...
There is a lack of knowledge on cyanobacteria and algae living in caves in the southern hemisphere. As a result, a pioneer study was undertaken to investigate cyanobacterial and algal community composition in two morphologically and geologically distinct caves in South Africa. Skilpad Cave is characterized by a large sinkhole entrance in a dolomitic
landscape. Three zones (light zone, twilight zone and dark zone) were identified based on differences in light intensity. Bushmen Cave, on the other hand, is a rockshelter overhang situated in a sandstone-dominated area and only presents a light and twilight zone. Cyanobacteria and algae were sampled twice, during the summer and winter of 2018 while abiotic factors of interest, i.e. light intensity, temperature and relative humidity, were also measured. A huge diversity of cyanobacteria (14 genera) and algae (48 genera) were identified in the two caves. While some genera were only present in one of the caves, other cosmopolitan genera were found in both caves. The most common genera encountered were Phormidium, Oscillatoria and Nostoc (cyanobacteria), Pinnularia and Luticola (diatoms), Chlorella and Chlorococcum (green algae). Cyanobacteria, green algae and diatoms were also the richest groups (taxa) in terms of the number of genera. More genera were present in the warm, wet season compared to the dry, cold season. Genus richness was positively correlated with light intensity in Skilpad Cave, but negatively in Bushmen Cave. Petalonema alatum, a cyanobacterium encountered in Bushmen Cave, represented a new record for Africa, and therefore, further research on cyanobacteria and algal assemblages in caves in the southern hemisphere is strongly recommended.
... For instance, the endemic-rich vegetation dominated by C 3 grasses of the Drakensberg Grassland Bioregion occupies high altitude areas of the Drakensberg mountain range where precipitation is high (MAP 732 mm), and low temperature (MAT 10.8 C) results in high frost incidence (78 MFD). On the other hand, the Sub-Escarpment Grassland Bioregion, found at a lower altitude of the Drakensberg foothills, has similar precipitation (MAP 763 mm) but warmer temperatures (MAT 15.5 C) and lower frost incidence (21 MFD) (Mucina et al., 2006a). As such, Southern African vegetation representative of a particular biome or bioregion is linked to specific climatic conditions. ...
... Anthospermum (Rubiaceae) is an important taxon to the biome model (Fig. 4a). Anthospermum, a shrub closely resembling taxa typical of the Mediterranean-type vegetation of the Fynbos, is found in a variety of environments throughout South Africa including Indian Ocean Coastal Belt, Fynbos, as well as various types of grasslands (Mucina et al., 2006a), and savannas . In the modern pollen dataset Anthospermum is identified in 61 assemblages with highest abundances in Grassland biome and bioregions and to a lesser extent in Savanna biome and bioregions (Fig. 3). ...
Fossil pollen assemblages can assist in understanding biome responses to global climate change if there is reasonable probability that they represent specific biomes or bioregions. In this paper, we introduce a novel probabilistic presentation of pollen data and biome assignment. We apply a recently developed pollen-based vegetation classification method utilizing supervised machine learning to Southern Africa modern pollen assemblages. We present an updated modern pollen dataset from Southern Africa, linking the sites to previously defined vegetation units and ultimately, we generate probabilistic classification for fossil assemblages to reconstruct past vegetation. The modern pollen dataset (N = 211 sites) represents a long vegetation gradient, from desert to forest biomes, capturing broad climate gradients ranging from arid to subtropical. We validate two models using Random Forest algorithm to classify modern vegetation at different spatial resolutions: subcontinental (biomes) and regional (bioregions). When the modern pollen assemblages (N = 164 sites) are used to predict the vegetation types, the classification models are correct in a number of cases. In our dataset of 164 sites, the classification model correctly classifies pollen assemblages from savanna (91% correct), grassland (87%), and coastal forest (82%) vegetation types, while the best results for classification of regional vegetation are achieved for sub-humid savanna (95%), dry savanna (95%), coastal forest (91%), and wet grassland (90%). We apply the models to a fossil pollen sequence at Wonderkrater in the South African savanna, to reconstruct subcontinental and regional changes in past vegetation states over the last 60 000 years. The most probable vegetation state dominating the region since the Late Pleistocene is sub-humid savanna yet grassland occurred at times associated with high vegetation variability. Within the record, the most frequent and amplified variability in the inferred vegetation states occurred during the transitional phase between the Late Pleistocene and the Holocene. The machine learning approach for reconstructing past vegetation, offers a more complex and nuanced view of past vegetation dynamics and has the potential to support quantitative proxy-based techniques for palaeoclimatic reconstructions.
... It is a warm temperature region, with wet summers and dry winters. The mean annual temperature is ∼15°C, and mean annual precipitation ∼1120 mm (Mucina et al., 2006). Precipitation is mainly as thunderstorms in summer, but also cold fronts, snow and dense mist. ...
... Soils are generally well-drained. They are derived from dolerite, mudstone, sandstone and shale (Mucina et al., 2006). Afromontane grassland are very poorly protected (Carbutt et al., 2011), and so rely heavily on conservation initiatives on private land (such as ENs). ...
Habitat degradation is a major concern in transformed landscapes, as it reduces complexity by removing species, interactions, and ultimately biodiversity. Degradation is also of concern for ecological networks (ENs) composed of an interconnected system of conservation corridors among South Africa's commercial forestry compartments. These corridors are predominantly grasslands, and used as rangeland, so managed to optimize grazing conditions. Yet, how this management approach influences biodiversity remains unknown. Here, we studied how butterfly assemblages respond to local differences in rangeland quality (low, high and reference sites), and how this effect compared to that of local environmental variables (e.g. rockiness and bare ground), meso environmental gradients (e.g. topographic position and aspect), and landscape composition (i.e. proportion of different land cover types in the surrounding matrix). We calculated species richness and composition, Shannon's diversity index (H′), and the Butterfly Conservation Index (BCIn) representing the proportion of sensitive and range-restricted butterfly species per site. Rangeland quality was considered less important for butterflies than other environmental variables, but it was also significantly confounded with other environmental variables. At the landscape scale, proportion of grassland in the landscape matrix influenced butterfly assemblage composition, while proportion of thicket had a significant positive effect on BCIn. Moreover, the effect of elevation on assemblage composition emphasizes the value of maintaining environmental gradients within these conservation corridors. At the meso spatial scale, butterfly species richness and diversity (H′) declined with increased dominance by a single plant species, which usually occurs late in a normal fire cycle. This suggests a reliance by butterflies on recurring natural disturbances for long-term persistence. We recommend moderate patch burning and grazing, as well as occasional hot burns to reduce thicket in Afromontane grassland. This approach would improve local scale vegetation patterns, and increase heterogeneity across the landscape for conserving these butterflies into the future.
... This study was undertaken in the sub-escarpment Grassland Bioregion (Mucina et al., 2006) in the KwaZulu-Natal Midlands (29°42 S; 29°59 E) in South Africa. Sampling was done in two commercial forestry plantations (Pinus patula) ( Fig. 1), of which 47% of the land surface is natural, remnant grassland in the form of conservation corridors. ...
... Sampling was done in two commercial forestry plantations (Pinus patula) ( Fig. 1), of which 47% of the land surface is natural, remnant grassland in the form of conservation corridors. The study area falls within the ecotone between two structurally similar vegetation types: endangered Midlands Mistbelt Grassland (MMG, 760-1 400 m above sea level (m asl)) and Drakensberg Foothill Moist Grassland (DFMG, 880-1 860 m asl) (Mucina et al., 2006). Situated to the south and south-west of the EN is Impendle Nature Reserve. ...
... Elevation, vegetation type and rockiness were included as surrogates of background environmental heterogeneity (Crous et al., 2013;Pryke and Samways, 2015). Although previous work has found DFMG and MMG to have similar plant species composition within this EN (Joubert et al., 2014), the vegetation types differ regarding underlying abiotic variables (specifically soil type) and were retained in the data as surrogates for these differences (Mucina et al., 2006). Corridor width, soil hardness, and invasive alien plant density (American bramble, Rubus cuneifolius) were included as possible surrogates of local habitat quality (Pryke and Samways 2001;Cingolani et al., 2003;de Andrade et al., 2014;van Hengstum et al., 2014). ...
Understanding how common vs. rare species contribute to species richness patterns, and are differentially affected by landscape features, is essential for effective conservation monitoring and planning. Using common vs. rare dung beetles and ants, we test how species rarity shapes richness patterns across a timber plantation mosaic with remnant natural grassland conservation corridors as a mitigation measure. We then determine how environmental and spatial factors shape assemblage composition of common and rare grassland species, and how matrix-derived species influence these patterns. For each taxon, species were ranked from common-to-rare, and from rare-to-common. This ranking gave sequences of species richness patterns for increasing numbers of species. Along each stage of these two sequences, species richness of the sub-assemblage was correlated with that of the whole assemblage. This was repeated with matrix-derived species excluded. Deconstructing the species response matrices according to species traits, variation in composition of common vs. rare grassland specialists, as well as in matrix-derived species, were related to environmental (natural environmental heterogeneity and habitat quality) and spatial factors. For both taxa, common species reflected overall species richness patterns better than rare species. Matrix-derived species reduced the contribution of rare species to species richness patterns of dung beetles. Environmental variables were relatively more important for rare species than for common species composition, especially rare ants. We found that in a fragmented landscape: 1) common species reflect overall species richness patterns better than rare species, 2) overall species richness patterns do not reflect those of rare species, 3) the relative influence of regional-and local-scale factors are determined by an organ-ism's scale of life function, 4) rare species are especially affected by habitat quality, 5) knowledge of ecological processes governing communities in landscape mosaics are crucial for conserving grassland species diversity within these corridors.
... In South African grasslands, woody plants are largely restricted to woodlands/shrublands, hillsides and along water bodies, but only rarely form dense, closed canopy assemblages in the latter two habitats. Generally trees and shrubs in the open, lower-lying plains occur isolated within the grassland matrix (Mucina et al., 2006). In this study we investigated the potential habitat and microhabitat factors influencing the litter-dwelling spider assemblages associated with Searsia lancea (L.f.) F.A.Barkley (Anacardiaceae), a common and widespread tree species in grasslands, hillsides and riparian habitats of central South Africa (Venter and Joubert, 1984;Malan et al., 1995Malan et al., , 1998Malan et al., , 2001. ...
... The study was carried out at the Free State National Botanical Gardens (FSNBG) on the outskirts of Bloemfontein in the central Free State, South Africa (29°08′S, 26°10′E). The property has an extent of approximately 70 ha, comprising large tracts of undisturbed grassland, hills, wetlands and the horticultural gardens themselves, and falls within the endangered Bloemfontein Dry Grassland vegetation type of the South African Grassland Biome (see Mucina et al., 2006 for details). The FSNBG falls within the summer rainfall region of central South Africa, with mean annual rainfall falling in the 400-500 mm isohyet. ...
... In contrast, hilltops in central South African grasslands are often associated with rocky terrain and woody vegetation that are protected against fire (Neke and Du Plessis, 2004;Mucina et al., 2006;Carbutt et al., 2011) and serve as thermal refugia for invertebrates during winter (Samways, 1990), and therefore harbour floristic and faunistic components of conservation significance, including butterflies (Henning et al., 2009), grasshoppers (Gebeyehu and Samways, 2006;Crous et al., 2013Crous et al., , 2014 and spiders (Haddad and Butler, 2018). As such, the low levels of disturbance in hillside habitats and their rich and unique fauna highlight their importance to invertebrate conservation in the grassland biome. ...
Spiders are a prominent component of leaf litter assemblages, where they function as critical predators of other invertebrates. We investigated the influence of habitat, cardinal directions and position on Searsia lancea litter-dwelling spider assemblages in central South Africa. A total of 1521 spiders were collected, representing 27 families and 77 species. Species richness, abundance and coverage per tree were highest in the grassland, followed by the hillside and riparian habitats. Neither of the finer scale filters, direction nor position, had significant effects on species richness or abundance, although there was weak evidence for an increase in spider abundance toward the periphery of a tree (p = 0.09) and a decrease in abundance towards the western cardinal direction (p = 0.08). Species composition, though, was significantly affected by habitat (p = 0.001) and direction (p = 0.014), as well as a three way-interaction between habitat, direction and position (p = 0.01). Hillside assemblage structure is intermediate between the other two habitats. Species abundance distributions of all three habitats were multimodal, indicating disturbance. Particularly, the log-series distribution of both the grassland and riparian woodland point to more disturbed assemblages than the hillside (Poisson log-normal distribution). Habitat therefore played a significant role in affecting richness, abundance and assemblage structure (composition and abundance). Although finer scale variables only had a weak effect on abundance, spider assemblages were influenced by direction, particularly for the climatically more variable habitats of the grassland and hillside. The significantly higher evenness and less disturbed nature of the hillside emphasize the conservation significance of this habitat.
... Three study sites were selected for testing and validating the algorithm. These included two sites in the grassland biome, one in the Southern Drakensberg Highland Grassland (Truro farm) and the other in the East Griqualand Grassland (Mucina et al. 2006), i.e. Somerton farm in the northern Eastern Cape province, South Africa ( Figure 1, Table 1). ...
... Wu et al. (2015) found that even shallow-rooted plants such as grasses can use groundwater by exploiting the capillary rise fluxes. The study sites are underlain by Beaufort Series sandstones of the Karoo Supergroup (Mucina et al. 2006) and hence the accompanying shale and mudstones could be creating peached water tables, causing capillary action to be significant and this possibly leads to groundwater becoming available to even short-rooted vegetation. Therefore, these factors may introduce minor errors in the subsequent f values calculated. ...
In a context of water scarcity, efforts to increase landscape production should focus on improving water productivity. This requires an appreciation of the various components of evapotranspiration (ET), including soil evaporation (Es) because the latter reflects ‘unproductive’ water loss. Both complex and simple algorithms have been developed to determine ET. In data scarce areas, developing and testing parsimonious algorithms is useful. This study sought to improve a simple single layer ET model by incorporating an Es component. Empirical methods were also explored to predict ET from vegetation indices (VIs), leaf area index (LAI) and reference evapotranspiration (ET0). A large aperture scintillometer and an eddy covariance (EC) system were used to validate the proposed algorithm at three sites over Grasslands and Albany Thicket biomes in the Eastern Cape, South Africa. There was good agreement between the observed and predicted ET with RMSE of 0.30–0.58 mm d⁻¹ when average daily observed ET was 0.43–3.24 mm. The VIs had moderate correlations with the observed data due to the significant role played by Es (65%–84%) across the sites and stomatal conductance at the Albany Thicket site. The simple algorithms developed would make determining ET easier in data scarce regions.
... In South Africa, grassland comprises about 27.9% of the total area of biomes and is the second largest after the Savanna Biome . About 30% of the South African Grassland Biome has been permanently modified (Mucina et al. 2006) and this affects livestock and wildlife production. Invasion by woody plants is one of the pervasive drivers of grassland transformation in South Africa and influences rangeland production. ...
An understanding of factors modulating water and energy fluxes partitioning over vegetated surfaces is important in a context of global environmental changes. The study evaluated the patterns of water vapour and energy fluxes to enable the development of biome scale predictive evapotranspiration (ET) models over the Albany Thicket vegetation. Environmental constraints to ET were assessed by examining the response of ET to biotic and abiotic factors with the latter accounting for >50% variability in ET. Bulk parameters were used to evaluate the integrated impact of biophysical factors on fluxes. The surface conductance (Gs) for use in the Penman‐Monteith equation and the Priestley‐Taylor coefficient (α) for application in the modified Priestley‐Taylor model were modelled as a function of environmental variables. A predictive ET equation developed for the area was validated. On an annual scale, 62% of net radiation was consumed by sensible heat flux and α was < 1, indicating that the area was water limited. The decoupling factor (0.005) suggested strong connection between the canopy and the boundary layer. The patterns of ET and vapour pressure deficit suggest strong ET control through stomatal conductance. The prediction of ET as a function of leaf area index and reference evapotranspiration was able to simulate observed ET (RMSE 0.28 day‐1) than application of the Penman‐Monteith equation using modelled Gs (RMSE of 0.59 – 0.62 mm day‐1) when average ET was 0.87 mm day‐1. The modified Priestly‐Taylor equation did not perform well since ET was strongly coupled to vapour pressure deficit and surface conductance.
... KwaZulu-Natal is a province on the east coast of SA. It has high levels of biodiversity and forms part of the Maputaland-Pondoland-Albany biodiversity hot spot with several centres of endemism [Maputaland, Pondoland (Mucina et al. 2006b), Midlands and Drakensberg Alpine (Mucina et al. 2006a)]. The KZN vegetation map provides greater detail on vegetation types and is mapped at a finer scale than the national vegetation map of Mucina and Rutherford (2006) and was used in this analysis. ...
Background: Systematic conservation planning aims to ensure representivity and persistence of biodiversity. Quantitative targets set to meet these aims provide a yardstick with which to measure the current conservation status of biodiversity features and measure the success of conservation actions.
Objectives: The conservation targets and current ecosystem status of vegetation types and biomes occurring in KwaZulu-Natal (KZN) were assessed, and their level of formal protection was determined, to inform conservation planning initiatives in the province.
Method: Land cover maps of the province were used to determine the amount of natural habitat remaining in KZN. This was intersected with the vegetation map and assessed relative to their conservation targets to determine the ecosystem status of each vegetation type in KZN. The proclaimed protected areas were used to determine the level of protection of each vegetation type.
Results: In 17 years (1994–2011), 19.7% of natural habitat was lost to anthropogenic conversion of the landscape. The Indian Ocean Coastal Belt and Grassland biomes had the least remaining natural habitat, the highest rates of habitat loss and the least degree of formal protection.
Conclusion: These findings inform conservation priorities in the province. Vegetation type targets need to be revised to ensure long-term persistence. Business-as-usual is no longer an option if we are to meet the legislative requirements and mandates to conserve the environment for current and future generations.
... Average minimum and maximum temperatures range from 14 to 25°C, in summer, and 7 to 18°C, in winter. Mean annual rainfall of the period of interest (2005-2010 when clearing of invasions was undertaken) has been generally higher than the long term average (calculated for 40 years).The dominant vegetation type found here is Amathole Montane Grassland (Mucina et al. 2006) characterised as short grassland with a high species richness of forbs (especially Helichrysum and Senecio species). The dominant grass species include Themeda triandra (Forssk.), ...
... are also prevalent. The most prominent invaders into this vegetation type include A. mearnsii (De Wild.) and Acacia dealbata (Link) (Mucina et al. 2006) . Geologically, the soils are derived from sedimentary rocks of the Beaufort Group and are characterised by weakly developed lithosols, solonetzic soils interspersed with red clay (Mucina et al. 2006). ...
... The most prominent invaders into this vegetation type include A. mearnsii (De Wild.) and Acacia dealbata (Link) (Mucina et al. 2006) . Geologically, the soils are derived from sedimentary rocks of the Beaufort Group and are characterised by weakly developed lithosols, solonetzic soils interspersed with red clay (Mucina et al. 2006). Land use within this region is dominated by livestock production with numerous cattle and sheep stud farms, commercial livestock farms as well as communally based livestock (Kopke 1961). ...
The degree to which invasive Acacia species affect South Africa’s livestock production has received little attention. We investigated the ecological impacts of Acacia mearnsii invasion on forage quality and quantity and on soil resources, along A. mearnsii invasion gradients, on South African rangelands and the subsequent conditions following clearing. Grazing capacity was reduced by 72% in densely invaded sites, whereas clearing improved grazing capacity by 66% relative to densely invaded sites within 5 years. In densely invaded sites total grass species basal cover was reduced by up to 42%. As a result, A. mearnsii reduced grazing capacity, from 2 to 8 ha required to support one large stock unit (ha/LSU) in uninvaded and densely invaded sites, respectively. Soil moisture content was lower in densely invaded sites compared with lightly invaded and cleared sites. Plant litter increased from 1.3% to 4.2%, carbon content of the soil increased from 2.0% to 4.0% and nitrogen concentrations increased from 0.1% to 0.2% in response to invasion by A. mearnsii. Clearing resulted in improved grazing capacity within 5 years. These results also showed that, if left uncontrolled, wattle species can reduce livestock carrying capacity within montane grasslands in South Africa.EDITED BY James Aronson
