Scielo RSS <![CDATA[Koedoe]]> http://www.scielo.org.za/rss.php?pid=0075-645820110001&lang=en vol. 53 num. 1 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Sandstone geomorphology of the Golden Gate Highlands National Park, South Africa, in a global context</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100001&lng=en&nrm=iso&tlng=en The Golden Gate Highlands National Park (GGHNP) is well known for its impressive sandstone formations. While previous geoscience research in the park has focused on geology, palaeontology, slope forms and the prominent lichen weathering, remarkably little has been written on the diversity and possible origins of sandstone phenomena in the region. The objectives of this study were (1) to present a geomorphological map of prominent and interesting landforms for particular portions of the park and (2) to document the variety of macro- and microscale sandstone formations observed. During field work, we undertook global positioning system measurements to map landforms and, in addition, measured the dimensions of several landform types. A Schmidt hammer was used to conduct rock hardness tests at a variety of localities and lithologies for comparative purposes. We indentified and mapped 27 macro- and microscale sandstone landforms, of which 17 are described in detail. It is demonstrated that for the most part, the landforms are a likely product of surface lithological reactions to a regional climate characterised by pronounced multitemporal temperature and moisture shifts, recently and in the past. However, many of the geomorphological processes producing landforms are controlled by microclimates set up by factors such as macro- and microtopography. CONSERVATION IMPLICATIONS: The GGHNP is best known for its geological, geomorphological and palaeontological heritage. This paper highlights the diversity of sandstone geomorphological phenomena, many of them rare and 'unique' to the region. Not only are these landforms of aesthetic interest to tourists, but they also provide microhabitats for biota. Thus, conservation of biota requires associated conservation of geo-environments where they are established. <![CDATA[<b>Population size, structure and habitat features of <i>Haworthia koelmaniorum</i> var. <i>mcmurtryi</i>, an endemic plant from Mpumalanga Province, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100002&lng=en&nrm=iso&tlng=en Haworthia koelmaniorum Oberm. & D.S. Hardy var. mcmurtryi (C.L. Scott) M.B. Bayer is an endemic plant restricted to the high-lying areas of Mpumalanga Province in South Africa. There is a serious lack of information on this species; it was known from only two populations at the time of the study but this information did not include population sizes and structures or its habitat requirements. A total count was conducted of one of the two populations to determine its size. Recorded plants were classified into age groups - according to their size and number of leaves - to determine the population structure. A detailed investigation of the habitat features of the studied population was also conducted. It was found that the studied population consisted of 1284 individuals and comprised approximately 4% seedlings, 12% juveniles and 84% mature plants. The species was found to have specialised habitat requirements, occurring only on red rhyolite of the Selons River Formation. The plants were also found to select very specific habitat features within their range of occurrence. The species also seems to be adapted to fire and has developed strategies to survive fire events. It is recommended that future research projects on this species use the same methods and age groups as this study to facilitate comparison. It is also recommended that more research be initiated to determine the population and seed viability, specific pollinators and the optimum fire frequency and intensity for this species. CONSERVATION IMPLICATIONS: This article provides baseline information related to the size, structure and habitat features of one of two known populations of Haworthia koelmaniorum var. mcmurtryi. This information will contribute to the understanding of the ecology of this plant, thus contributing to better management decisions to enhance its in situ conservation. <![CDATA[<b>Stem growth of woody species at the Nkuhlu exclosures, Kruger National Park: 2006-2010</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100003&lng=en&nrm=iso&tlng=en An important aspect of managing African conservation areas involves understanding how large herbivores affect woody plant growth. Yet, data on growth rates of woody species in savannas are scarce, despite its critical importance for developing models to guide ecosystem management. What effect do browsing and season have on woody stem growth? Assuming no growth happens in the dry season, browsing should reduce stem growth in the wet season only. Secondly, do functional species groups differ in stem growth? For example, assuming fine-leaved, spiny species' growth is not compromised by carbon-based chemical defences, they should grow faster than broad-leaved, chemically defended species. Dendrometers were fixed at 20 cm in height on the main stems of 244 random plants of six woody species in three plots (all large herbivores excluded, partial exclusion, and control) and observed from late 2006 to early 2010. Average monthly increment (AMI) per dendrometer and season (dry, wet) was calculated and the interaction between plot and season tested per species, controlling for initial stem girth. AMIs of Combretum apiculatum, Dichrostachys cinerea and Grewia flavescens were zero in the dry season, whilst those of Acacia exuvialis, Acacia grandicornuta and Euclea divinorum were either positive or negative in the dry season. Wet-season AMI of D. cinerea and dry-season AMI of G. flavescens tended to be reduced by browser exclusion. Net AMI (sum of the seasonal AMIs) was tested per species, but results suggested that only D. cinerea tended to be affected by browser exclusion. The results also suggested that stem radial growth of some fast-growing species is more prone to reduction by browser exclusion than the growth of other species, potentially reducing their competitiveness and increasing their risk of extirpation. Finally, the usefulness of grouping woody species into simple functional groups (e.g. fine-leaved vs. broad-leaved) for ecosystem management purposes in savannas requires further consideration. CONSERVATION IMPLICATIONS: Growth rates of woody plants are important parameters in savanna models, but data are scarce. Monitoring dendrometers in manipulative situations over several years can help fill that gap. Results of such studies can be used to identify species prone to high risk of extirpation. <![CDATA[<b>The Grassland vegetation of Platberg, eastern Free State, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100004&lng=en&nrm=iso&tlng=en Platberg is an inselberg that presents a refuge for indigenous plants and animals. Uncontrolled human access to this area threatens this sensitive ecosystem. The vegetation of Platberg was investigated to obtain an inventory of the different plant species and communities present in this area. A hierarchical classification, a description and an ecological interpretation of the grassland communities of Platberg are presented. A total of 169 sample plots were placed on a stratified random basis within the study area. From a TWINSPAN classification a total of 27 different plant communities, which can be grouped into two major community types, nine communities, 18 sub-communities and six variants, were identified. A significant difference in species richness was found between the two major communities, with the higher-altitude communities having a higher species richness than the communities on the lower-lying slopes. A total of 26 endemic or near endemic Drakensberg Alpine Centre species were recorded. CONSERVATION IMPLICATIONS: Anthropogenic influences are felt globally on ecosystems. Highaltitude habitats and organisms will be affected first. Inselbergs have high levels of endemic organisms and are reservoirs and refugia for unique genetic material. This grassland plant community survey of Platberg provides valuable information on inselberg ecology for conservation planning. <![CDATA[<b>Pilanesberg National Park, North West Province, South Africa</b>: <b>Uniting economic development with ecological design - A history, 1960s to 1984</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100005&lng=en&nrm=iso&tlng=en In the late 1970s, a ground-breaking project began in the Pilanesberg district in what is now the North West Province of South Africa to create a wildlife conservation and eco-tourism venture from degraded marginal farmland in an aesthetically attractive extinct volcanic crater. The establishment of this national park was innovative in a number of respects, including a partnership between landscape and ecological designers, local community development and participation, regional tourist satisfaction, trophy hunting, environmental education, ecological restoration, and wildlife conservation and management. This paper briefly explored the park's early history, explaining its landscape, its early peopling and historical land use. The narrative then concentrated on the first five years of the park's existence, from its inception in 1977, under the aegis of Agricor, Bophuthatswana's rural development agency, to 1984, when responsibility for the park was given over to Bophuthatswana National Parks, a parastatal agency, and a new era began. The article contended that 1984 is an appropriate date on which to conclude the early history of the Pilanesberg National Park (PNP) because it was then that the experimental phase of the park ended: its infrastructure was sufficiently developed to offer a satisfactory visitor experience, the management plan was revised, its bureaucratic structures were consolidated and an attitude survey amongst the local community was undertaken. Embedding the originating period of the PNP in its historical, political and socio-economic context, the paper foregrounded those elements in the park's beginnings that were new in the southern African protected area arena. Thus, elements that relate to socio-politics, landscape and ecological design and restoration, and early relations with neighbouring communities were emphasised. This paper has been written by an historian and is therefore conceptual and historical, conforming in language and structure to the humanities style (environmental history). It relies on published and unpublished literature and oral information and the critical evaluation of these sources. CONSERVATION IMPLICATIONS: The pioneering example of the PNP as a protected area is relevant to the field of conservation science because, as human population densities increase, as the tourism sector develops, as marginal farmland becomes available for new uses, and as it becomes important to include neighbouring communities in conservation activities, a study of this park's early history and socio-political and economic context may be of assistance in the development of similar projects elsewhere in South Africa and beyond. <![CDATA[<b>Determinants of soil respiration in a semi-arid savanna ecosystem, Kruger National Park, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100006&lng=en&nrm=iso&tlng=en Soil respiration, which is a combination of root respiration and microbial respiration, represents one of the main carbon fluxes in savannas. However, it is remarkable how little is known about these components - regarding either process-level mechanisms or quantitative estimates, especially in savanna ecosystems. Given the extensive area of savannas worldwide, this limits our ability to understand and predict the critical changes in the global carbon budget that underlie the phenomenon of global climate change. From May 2000 to April 2001, bi-weekly soil respiration measurements from two savanna types were made in 14 sampling collars (diameter = 100 mm), using a PP Systems EGM-2 respirometer. Results indicated that there was a difference in the rate of respiration between the more clayey Acacia and sandier Combretum savanna soils (p = 0.028). The mean (± s.d.) soil respiration in the Acacia savanna was 0.540 g/m²/h ± 0.419 g/m²/h, whilst it was 0.484 g/m²/h ± 0.383 g/m²/h in the Combretum savanna. We also found that soil respiration was sensitive to soil moisture and soil temperature. The rate of soil respiration at both sites rose to a maximum when soil temperature was at 28 °C and declined at higher temperatures, despite different temperature sensitivities. Soil respiration increased approximately linearly with an increase of soil moisture. In both savanna sites soil is subject to a combination of high temperature and water stress, which controls the fluxes of soil carbon dioxide. We found that the two sites differed significantly in their soil moisture characteristics (p < 0.0001) but not with regard to temperature (p = 0.141), which implies that soil moisture is the main factor responsible for the differences in respiration between Acacia and Combretum savannas. CONSERVATION IMPLICATIONS: It is argued for many protected areas that they perform a climate change buffering function. Knowing the soil respiration rate and determining its controlling factors contribute to improved understanding of whether protected areas will be net sources or sinks of carbon in the future. <![CDATA[<b>Guiding conservation efforts in the Hantam-Tanqua-Roggeveld (South Africa) using diversity parameters</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100007&lng=en&nrm=iso&tlng=en The Hantam-Tanqua-Roggeveld subregion falls within the Succulent Karoo and Fynbos Biomes, which are both recognised as global biodiversity hotspots that should be conserved. The objective of this study was to gather baseline biodiversity information that can be used to guide conservation efforts. A total of 40 Whittaker plots were surveyed in the subregion and the various diversity parameters calculated from the data were compared across the subregion and to available data for the Succulent Karoo and Fynbos Biomes. Species richness per 1000 m² ranged from nine to 100 species across the subregion. Species richness for all plot sizes < 1000 m² was significantly lower for the Tanqua Karoo than for both the Winter Rainfall Karoo and Mountain Renosterveld. The latter two areas did not differ significantly from each other with regard to species richness. Species richness was significantly higher only at the 1000 m² scale in the Mountain Renosterveld compared to the Winter Rainfall Karoo. Evenness and Shannon and Simpson indices did not differ significantly between the Mountain Renosterveld and Winter Rainfall Karoo; however, these values were significantly higher than for the Tanqua Karoo. A principal coordinate analysis of species richness data at seven plot sizes produced three distinct clusters. One cluster represented the Tanqua Karoo, with low species richness, evenness, and Shannon and Simpson indices. Another cluster represented mostly Mountain Renosterveld vegetation, which was characterised by a high species richness, evenness, and Shannon and Simpson indices. The third cluster was formed by the remaining Mountain Renosterveld plots as well as the Winter Rainfall Karoo plots. The high species richness values found in the various vegetation units can add valuable information to the conservation planning arena by providing information on biodiversity parameters and their spatial distribution. This information can assist with conservation efforts in the Hantam, Tanqua and Roggeveld areas. CONSERVATION IMPLICATIONS: Conservation and development of the Hantam-TanquaRoggeveld subregion is hampered by a lack of information on floristic diversity. The results of the current study indicated areas of low diversity and contrasting areas of high diversity. These data can be used to guide effective conservation and management of the floristic diversity. <![CDATA[<b>The avifauna of Kwandwe Private Game Reserve, Eastern Cape, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100008&lng=en&nrm=iso&tlng=en A protected area since 1999, Kwandwe Private Game Reserve incorporates several former farms, for which past records of bird occurrences are available. No bird species appear to have been lost from the area. Between 2001 and 2005, a group of observers conducted systematic bird surveys in most months, which allowed the status (resident, migrant or irregular visitor) of most bird species to be determined. At least three species have established breeding populations in the reserve over the past 10 years. Of 302 species reliably recorded to date, 182 (60.3%) appear to be resident, 46 (15.2%) are seasonal migrants and 74 (24.5%) are vagrant visitors. Eight vulnerable and eight near-threatened bird species have been recorded; Blue Crane, Kori Bustard and African Crowned Eagle have bred in the reserve. Together with other state-owned and private protected areas in this region, this reserve holds a significant portion of the inland bird species recorded from the Eastern Cape. CONSERVATION IMPLICATIONS: The varied thicket vegetation types of the Great Fish River Valley support a considerable diversity of bird species. If these habitats are managed for biodiversity conservation, they can support a large component of the terrestrial avifauna of the Eastern Cape region. <![CDATA[<b>Spiders (Arachnida</b>: <b>Araneae) of the vegetation layer of the Mkambati Nature Reserve, Eastern Cape, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100009&lng=en&nrm=iso&tlng=en The Pondoland region of the Eastern Cape province, South Africa is very poorly studied with regard to invertebrate diversity, particularly in the case of arachnids. Accordingly, and in view of proposed infrastructural and mining developments in this ecologically sensitive area of high plant endemism, baseline data are provided on spiders (Araneae) of the vegetation layer (i.e. excluding the ground-dwelling fauna) of the Mkambati Nature Reserve (MNR). Spiders were collected at 26 sites (six forest and 20 grassland sites) in the MNR over an eight-day period, using sweep sampling and active searching of flowers in grassland and tree beating in forests, as part of a broader biodiversity survey. Additional specimens were collected with Malaise and pan traps. A total of 1275 specimens were sampled, representing 132 species (6.6% of the total number recorded in South Africa) in 103 genera and 29 families. Theridiidae and Araneidae were the most diverse spider families in the reserve, represented by 22 species each (16.7% of the total), followed by Thomisidae with 19 species (14.4%) and Salticidae with 18 species (13.6%). Grassland and forest had distinct spider faunas, with only 24.2% of species being recorded from both biomes. The average number of species sampled per site in grassland and forest was 26 species for both habitats, although values for the two biomes are not directly comparable because different sampling methods were used. All 132 species are new records for the reserve, of which 20 were new records for the Eastern Cape and at least eight spider species may be new to science. The spider diversity captured despite temporal and methodological limits indicates that many additional species are likely to occur in the reserve. CONSERVATION IMPLICATIONS: If the MNR is not adequately conserved at least five new species, which may be confined to the area, would be at high risk of extinction and 15 other species endemic to the Pondoland and KwaZulu-Natal region would have their risk of extinction increased. <![CDATA[<b>Alien species in South Africa's national parks</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100010&lng=en&nrm=iso&tlng=en The Pondoland region of the Eastern Cape province, South Africa is very poorly studied with regard to invertebrate diversity, particularly in the case of arachnids. Accordingly, and in view of proposed infrastructural and mining developments in this ecologically sensitive area of high plant endemism, baseline data are provided on spiders (Araneae) of the vegetation layer (i.e. excluding the ground-dwelling fauna) of the Mkambati Nature Reserve (MNR). Spiders were collected at 26 sites (six forest and 20 grassland sites) in the MNR over an eight-day period, using sweep sampling and active searching of flowers in grassland and tree beating in forests, as part of a broader biodiversity survey. Additional specimens were collected with Malaise and pan traps. A total of 1275 specimens were sampled, representing 132 species (6.6% of the total number recorded in South Africa) in 103 genera and 29 families. Theridiidae and Araneidae were the most diverse spider families in the reserve, represented by 22 species each (16.7% of the total), followed by Thomisidae with 19 species (14.4%) and Salticidae with 18 species (13.6%). Grassland and forest had distinct spider faunas, with only 24.2% of species being recorded from both biomes. The average number of species sampled per site in grassland and forest was 26 species for both habitats, although values for the two biomes are not directly comparable because different sampling methods were used. All 132 species are new records for the reserve, of which 20 were new records for the Eastern Cape and at least eight spider species may be new to science. The spider diversity captured despite temporal and methodological limits indicates that many additional species are likely to occur in the reserve. CONSERVATION IMPLICATIONS: If the MNR is not adequately conserved at least five new species, which may be confined to the area, would be at high risk of extinction and 15 other species endemic to the Pondoland and KwaZulu-Natal region would have their risk of extinction increased. <![CDATA[<b>Meeting the challenges of game ranch management</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100011&lng=en&nrm=iso&tlng=en The Pondoland region of the Eastern Cape province, South Africa is very poorly studied with regard to invertebrate diversity, particularly in the case of arachnids. Accordingly, and in view of proposed infrastructural and mining developments in this ecologically sensitive area of high plant endemism, baseline data are provided on spiders (Araneae) of the vegetation layer (i.e. excluding the ground-dwelling fauna) of the Mkambati Nature Reserve (MNR). Spiders were collected at 26 sites (six forest and 20 grassland sites) in the MNR over an eight-day period, using sweep sampling and active searching of flowers in grassland and tree beating in forests, as part of a broader biodiversity survey. Additional specimens were collected with Malaise and pan traps. A total of 1275 specimens were sampled, representing 132 species (6.6% of the total number recorded in South Africa) in 103 genera and 29 families. Theridiidae and Araneidae were the most diverse spider families in the reserve, represented by 22 species each (16.7% of the total), followed by Thomisidae with 19 species (14.4%) and Salticidae with 18 species (13.6%). Grassland and forest had distinct spider faunas, with only 24.2% of species being recorded from both biomes. The average number of species sampled per site in grassland and forest was 26 species for both habitats, although values for the two biomes are not directly comparable because different sampling methods were used. All 132 species are new records for the reserve, of which 20 were new records for the Eastern Cape and at least eight spider species may be new to science. The spider diversity captured despite temporal and methodological limits indicates that many additional species are likely to occur in the reserve. CONSERVATION IMPLICATIONS: If the MNR is not adequately conserved at least five new species, which may be confined to the area, would be at high risk of extinction and 15 other species endemic to the Pondoland and KwaZulu-Natal region would have their risk of extinction increased. <![CDATA[<b>Review of Environmental Risk Management in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100012&lng=en&nrm=iso&tlng=en The Pondoland region of the Eastern Cape province, South Africa is very poorly studied with regard to invertebrate diversity, particularly in the case of arachnids. Accordingly, and in view of proposed infrastructural and mining developments in this ecologically sensitive area of high plant endemism, baseline data are provided on spiders (Araneae) of the vegetation layer (i.e. excluding the ground-dwelling fauna) of the Mkambati Nature Reserve (MNR). Spiders were collected at 26 sites (six forest and 20 grassland sites) in the MNR over an eight-day period, using sweep sampling and active searching of flowers in grassland and tree beating in forests, as part of a broader biodiversity survey. Additional specimens were collected with Malaise and pan traps. A total of 1275 specimens were sampled, representing 132 species (6.6% of the total number recorded in South Africa) in 103 genera and 29 families. Theridiidae and Araneidae were the most diverse spider families in the reserve, represented by 22 species each (16.7% of the total), followed by Thomisidae with 19 species (14.4%) and Salticidae with 18 species (13.6%). Grassland and forest had distinct spider faunas, with only 24.2% of species being recorded from both biomes. The average number of species sampled per site in grassland and forest was 26 species for both habitats, although values for the two biomes are not directly comparable because different sampling methods were used. All 132 species are new records for the reserve, of which 20 were new records for the Eastern Cape and at least eight spider species may be new to science. The spider diversity captured despite temporal and methodological limits indicates that many additional species are likely to occur in the reserve. CONSERVATION IMPLICATIONS: If the MNR is not adequately conserved at least five new species, which may be confined to the area, would be at high risk of extinction and 15 other species endemic to the Pondoland and KwaZulu-Natal region would have their risk of extinction increased. http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582011000100013&lng=en&nrm=iso&tlng=en The Pondoland region of the Eastern Cape province, South Africa is very poorly studied with regard to invertebrate diversity, particularly in the case of arachnids. Accordingly, and in view of proposed infrastructural and mining developments in this ecologically sensitive area of high plant endemism, baseline data are provided on spiders (Araneae) of the vegetation layer (i.e. excluding the ground-dwelling fauna) of the Mkambati Nature Reserve (MNR). Spiders were collected at 26 sites (six forest and 20 grassland sites) in the MNR over an eight-day period, using sweep sampling and active searching of flowers in grassland and tree beating in forests, as part of a broader biodiversity survey. Additional specimens were collected with Malaise and pan traps. A total of 1275 specimens were sampled, representing 132 species (6.6% of the total number recorded in South Africa) in 103 genera and 29 families. Theridiidae and Araneidae were the most diverse spider families in the reserve, represented by 22 species each (16.7% of the total), followed by Thomisidae with 19 species (14.4%) and Salticidae with 18 species (13.6%). Grassland and forest had distinct spider faunas, with only 24.2% of species being recorded from both biomes. The average number of species sampled per site in grassland and forest was 26 species for both habitats, although values for the two biomes are not directly comparable because different sampling methods were used. All 132 species are new records for the reserve, of which 20 were new records for the Eastern Cape and at least eight spider species may be new to science. The spider diversity captured despite temporal and methodological limits indicates that many additional species are likely to occur in the reserve. CONSERVATION IMPLICATIONS: If the MNR is not adequately conserved at least five new species, which may be confined to the area, would be at high risk of extinction and 15 other species endemic to the Pondoland and KwaZulu-Natal region would have their risk of extinction increased.