Figure 9 - uploaded by M.C. Rutherford
Content may be subject to copyright.
45 SVl 2 Nwambyia-Pumbe Sandy Bushveld: Open to closed broad-leaved woodland, largely occurring on sandy soils with Strychnos species, Crossopteryx febrifuga and Xeroderris stuhlmannii south of Nwambyia, Kruger National Park.
Source publication
Similar publications
New approaches to pre-‐Columbian raised-‐field agriculture: ecology of seasonally flooded savannas, and living raised fields in Africa, as windows on the past and the future.
A new species of Dolichurus Latreille (Hymenoptera, Apoidea, Ampulicidae) from Brazil. Dolichurus sensei Ferreira and Lopez sp. nov. is described based on a single female specimen from a Neotropical savanna fragment in São Carlos, São Paulo, Brazil. We include images of the holotype and provide an additional commentary on its coloration.
An assessment of the concentration of heavy metals in the liver, brain, kidney, bone, and lungs of African giant rats (AGRs) from three agro-ecological zones of Nigeria having different industrial activities was carried out using atomic absorption spectrophotometer. Twenty adult AGRs from cities in mangrove/freshwater swamp, rainforest, and woodlan...
Citations
... Th e terrain is gently undulating and the geology is dominated by granite with local Timbavati gabbro intrusions. Th e vegetation is Granite Lowveld dominated by Terminalia sericea , Combretum zeyheri and C. apiculatum on the sandy, dystrophic uplands and Acacia nigrescens , Dichrostachys cinerea and Grewia bicolor on the deep, clayey, high sodium lowlands with dense stands of T. sericea delineating the seep zones (Rutherford et al. 2006). Localized Timbavati gabbro intrusions are characterized by Gabbro Grassy Bushveld, a more open savanna with fewer scattered trees on dark clay soils which swell and shrink (Rutherford et al. 2006). ...
... Th e vegetation is Granite Lowveld dominated by Terminalia sericea , Combretum zeyheri and C. apiculatum on the sandy, dystrophic uplands and Acacia nigrescens , Dichrostachys cinerea and Grewia bicolor on the deep, clayey, high sodium lowlands with dense stands of T. sericea delineating the seep zones (Rutherford et al. 2006). Localized Timbavati gabbro intrusions are characterized by Gabbro Grassy Bushveld, a more open savanna with fewer scattered trees on dark clay soils which swell and shrink (Rutherford et al. 2006). ...
Humans have played a major role in altering savanna structure and function, and growing land-use pressure
will only increase their influence on woody cover. Yet humans are often overlooked as ecological
components. Both humans and the African elephant, Loxodonta africana, alter woody vegetation in savannas
through removal of large trees and activities that may increase shrub cover. Interactive effects of both humans
and elephants with fire may also alter vegetation structure and composition. Here we capitalize on a
macroscale experimental opportunity - brought about by the juxtaposition of an elephant-mediated landscape,
human-utilized communal harvesting lands and a nature reserve fenced off from both humans and elephants -
to investigate the influence of humans and elephants on height-specific treefall dynamics. We surveyed 6 812
ha using repeat, airborne high resolution Light Detection and Ranging (LiDAR) to track the fate of 453 685
tree canopies over two years. Human-mediated biennial treefall rates were 2-3.5 fold higher than the
background treefall rate of 1.5% treefall ha-1 yr-2, while elephant-mediated treefall rates were 5 times higher at
7.6% treefall ha-1 yr-2 than the control site. Model predictors of treefall revealed that human or elephant
presence was the most important variable, followed by the interaction between geology and fire frequency.
Treefall patterns were spatially heterogeneous with elephant-driven treefall associated with geology and
surface water, while human patterns were related to perceived ease of access to wood harvesting areas and
settlement expansion. Our results show humans and elephants utilize all height-classes of woody vegetation,
and that large tree shortages in a heavily utilized communal land has transferred treefall occurrence to shorter
vegetation. Elephant- and human-dominated landscapes are tied to interactive effects that may hinder tree
seedling survival which, combined with tree loss in the landscape, may compromise woodland sustainability.
The Southeastern Coastal Hinterland geomorphic province of South Africa is dissected by deep valleys created by tectonic uplift in the early Miocene and late Miocene/early Pliocene. We hypothesised that seedlings of Vachellia nilotica, V. tortilis and V. karroo grown from seeds from different valleys would differ in growth and spinescence because of geographical separation. Ninety seedlings (30 per species) were grown for three months in uniform conditions in a greenhouse. Mean height of V. nilotica and V. tortilis seedlings was greatest for the Phongolo populations and lowest for the Thukela populations. Maximum stem diameter of both species was attained by individuals from the Phongolo population. Mean spine dry mass of V. nilotica seedlings was greatest for the Phongolo population, suggesting a growth-defence trade-off, but did not differ for V. tortilis. Results suggested Phongolo populations of V. nilotica and V. tortilis maybe characterised by morphotypes clearly distinct from those in the other valleys. Unclear and inconsistent results for V. karroo in this study suggested subtly different morphotypes occur in each valley. We propose that distinct Phongolo morphotypes of V. nilotica and V. tortilis are explained as evolutionary adaptations to moderate fire and high browsing pressure compared to populations South of Phongolo.
In this study we investigate the timing and nature of moisture availability in the Late Holocene by examining a multiproxy paleoenvironmental record from Kathu Pan at the southern edge of the Kalahari. In a region where organic proxy records are scarce, Kathu Pan provides a unique record of changes in past environmental conditions. Pollen, spore, charcoal, and stable isotope records were obtained from organic deposits at Kathu Pan and examined within a radiocarbon-constrained chronological framework. The Kathu Pan record registers a relatively moist phase occurring between 4.8 ka and 2.5 ka cal BP. Local environmental conditions at Kathu Pan shift gradually beginning around the terminal Northgrippian ∼4.8 ka cal BP. Kathu Pan reaches maximum moisture availability with marsh-like conditions signaled by increased organic content, dominance of Cyperaceae pollen, presence of freshwater fungi, and δ13C values consistent with local C3 vegetation, around the inception of the Meghalayan Stage, although due to uncertainties in the age-depth model these changes may have taken place 1–2 centuries on either side of the formal date for the onset of the Meghalayan at 4.2 ka cal BP. This interval also corresponds with the highest charcoal concentrations, indicating the importance of adequate moisture conditions to support the growth of biomass which eventually becomes a fuel source. The moist phase lasts ca. 2000 years until a hypothesized shift to arid conditions occurs c. 2.5 ka cal BP leading to a change in local hydroclimate that may have terminated the accumulation of organic-bearing sediments.
We have reassessed the palynological record of Equus Cave in the Savanna Biome of the southern Kalahari, one of the longest Late Quaternary pollen records for the semi-arid central interior of South Africa. We combined published pollen results from the cave, derived from hyena coprolites and the rubified deposits in which they occur, into a single sequence. By re-considering the chronology of this sequence, we critically evaluated the palaeoenvironmental record for the site. We compared the pollen evidence from Equus Cave to that from the longer Wonderwerk Cave records (stalagmite, sediments and dung), also located in the Savanna Biome. Then, we contrasted Equus and Wonderwerk records with other previously published pollen sequences derived from a range of sources from several sites in central South Africa. These sites follow a broad northwest to southeast transect of c. 500 km through the Grassland and Nama Karoo Biomes of the Free State and Eastern Cape. Applying Principal Components Analysis to the pollen data, we derived climatic signals at a regional scale to refine reconstructions of Late Quaternary changes for central South Africa.
Waterfall Bluff, in Eastern Mpondoland (Eastern Cape Province, South Africa), is a recently excavated archaeological site with deposits spanning Marine Isotope Stage (MIS) 3 to the Middle Holocene. Here, we present preliminary results of a multi-proxy palaeoenvironmental study combining macro-botanical remains, charcoal, phytoliths, pollen and plant waxes derived from the same archaeological record. We aim to understand the interactions between hunter-gatherer plant foraging and climate and environmental change in coastal Mpondoland from MIS 3 to the Early Holocene at Waterfall Bluff. The charcoal and pollen records at Waterfall Bluff show the gathering of a variety of woody taxa characterised by their combustion and medicinal properties (e.g., Millettia grandis and Apodytes dimidiate). The leaves identified in the macrobotanics and in the phytolith record might belong to some of these taxa and it is likely that they were used for medicinal purposes. From a palaeoenvironmental perspective, our results indicate low precipitation and low rainfall seasonality under cool conditions during MIS 3 and the Last Glacial Maximum (LGM). Under these conditions, open woodlands interspersed with dry and hygrophilous grasslands and bushveld vegetation with significant representation of fynbos elements occurred in the local landscapes probably along Podocarpus/Afrocarpus forests. The latter could have been (1) present along river valleys and scarps on the Mpondoland exposed continental shelf towards the south and west of Waterfall Bluff, supported by palaeo-rivers and cool temperatures favouring low evapotranspiration, or (2) present in the interior with pollen grains possibly transported to the site by intensified westerly winds. These forests contracted as a result of the post-glacial marine transgression or reduced westerlies following the LGM. During the Early Holocene, the palaeoenvironmental signal points to higher summer rainfall and higher (summer) seasonality than during MIS 3, the LGM and the LGIT. These changes are coeval with an increase of coastal forests and C4 mesic grasslands with localized wetland vegetation around Waterfall Bluff. These multi-proxy archaeobotanical and biochemical data show that landscapes surrounding Waterfall Bluff changed in relation to marine transgressions/regressions and changes in rainfall intensity and seasonality. The people of Waterfall Bluff foraged the coasts during glacial periods to collect wood.
The proposed site for the construction of a new dam (Laleni Dam) on the Tsitsa River in the Eastern Cape, South Africa falls within a high soil erosion zone, which is expected to affect the lifespan of the dam. Estimating the sediment yield of the catchment is important from a management perspective, and thus we designed this study to assess the applicability of the Modified Universal Soil Loss Equation (MUSLE). The original MUSLE was applied to the Inxu River sub catchment, upstream of a proposed dam, over a summer rainfall period extending from October 2016 to April 2017. A modified version of the MUSLE, incorporating a storage module, was later applied over the same period. Model calibration of the MUSLE with and without a storage model was tested against 7 months of recorded daily suspended sediment discharge data. With a storage model, we achieved a percentage bias, coefficient of efficiency and R2 of 2%, 0.83 and 0.83, respectively, while without storage the performance statistics were markedly lower. These results suggest that a calibrated MUSLE can provide estimates of sediment yield that are valuable for regional planning, and that the inclusion of a storage component further improves the MUSLE application. Given the complexity of sediment generation and transport processes, a relatively simple empirical MUSLE model is a useful tool for initial sediment yield estimation for planning purposes.
# The publishing journal is open access , to access the paper please click the DOI below the title or use this link: https://doi.org/10.1016/j.iswcr.2020.10.003
This study investigates the population structure and life history traits of the Critically Endangered cycad, Encephalartos latifrons. Populations of E. latifrons have been considered functionally extinct because no natural recruitment has been observed in the wild for almost 30 years. The discovery of a previously undocumented population of E. latifrons has made it possible to build on previous research into the life history and regeneration capabilities of the species. This new population was censused annually over 5 years; between 2013 and 2017. Population characteristics of this 'new' population were compared to earlier studies in 2010 of a well-known and intensively managed population. Results of the censuses show that the newly discovered population of E. latifrons appears to be increasing under current environmental conditions through natural recruitment. The discovery of a 'new' E. latifrons population has uncovered many more questions and further research is needed. Information on the life history of E. latifrons, particularly its response to fire, should be used to inform conservation management decisions at a time where the impact of climate change is predicted to have a major influence in the Fynbos Biome.
Bush thickening (shrub encroachment) is a major ecological and economic threat in southern African savannas. Different types and intensities of bush control (BC) are applied to counteract and mitigate bush thickening. However, woody vegetation response to BC and possible ecological side effects can be manifold. Land users therefore require solid knowledge about the associated structural and compositional changes, helping to apply an informed BC strategy that preserves multiple ecosystem services and functions. The present study addresses this need in a South African thornbush-type savanna. We sampled 41 rangeland sites with a known history of BC in comparison to benchmark conditions. The BC treatments included a selective and non-selective arboricide application and a selective stem burning. We identified each woody species in belt transects and measured the size and canopy of all individuals. The data were used to calculate measures of diversity, cover and density and to describe the population structure of key species. Marked differences in woody species composition and abundance patterns as well as significant alterations of the horizontal and vertical woody vegetation structure clearly reflected the intensity and level of selectivity with which BC had been conducted. While population trends displayed regeneration of key species, important structural elements (large mature trees) were often at risk of being lost from the savanna ecosystem. Results suggest varying degrees of ecosystem functional integrity following the BC treatments. It is concluded that selective BC treatments should be preferred as they allow to create open and well-structured savannas in benefit of the stability and biodiversity of the system. Yet, for improved predictions further research is needed into species-specific population dynamics and trait-related plant-plant interactions. In addition, there is still uncertainty about possible long-term ecological effects associated with the use of arboricides in this type of savanna, which should receive special attention in future research.
Vachellia farnesiana was in cultivation in South Africa as an ornamental tree as early as 1858. The first non-cultivated specimen was collected in 1888 and the first naturalised population in 1952. We surveyed 4.5 km along a seasonal watercourse near Albert Falls Dam in KwaZulu-Natal, South Africa, where a V. farnesiana population was identified in 2016. We found a total of 1203 trees of V. farnesiana, of which 82% of the trees produced fruit. Field observations suggest that this species has the potential to become invasive in South Africa.
We describe a new prostrate species of Deverra (Apiaceae), D. rapaletsa Magee & Zietsman, from the Ghaap Plateau in the Griqualand West Centre of endemism, South Africa. This is the third species of Deverra in southern Africa and brings the total number of species in the genus to 10. The three southern African species are separated from the rest of the species in northern African and Arabia by an arid disjunction. The new species is distinguished by the prostrate habit, densely warty ovaries and slender branches with short internodes. Deverra rapaletsa is known from two populations and favours limestone outcrops.
