Scielo RSS <![CDATA[Koedoe]]> vol. 56 num. 1 lang. es <![CDATA[SciELO Logo]]> <![CDATA[<b>Conservation of fishes in the Elands River, Mpumalanga, South Africa: Past, present and future</b>]]> In an isolated reach, between two large natural waterfalls in the Elands River in Mpumalanga, populations of a critically endangered Kneria sp., the endangered Chiloglanis bifurcus and a genetically unique population of Labeobarbus polylepis occur. The aim of this article was to evaluate past efforts to conserve these fishes, describe the current status and propose future conservation and management actions. The population status assessments were based on a series of fish community composition and population structure evaluations from surveys undertaken at 22 sites during seven surveys from 2002 to 2006. Although water-use activities have continued to increase in the area, impacts have been offset by conservation efforts initiated almost 30 years ago. The existing C. bifurcus population appears to be stable, which is reflected in the downgrading of the conservation status of the species from critically endangered to endangered. The abundance of the kneriid population appears to be increasing and spreading to other tributaries in the study area. The abundance of L. polylepis appears to be increasing but has still not reached historical levels. CONSERVATION IMPLICATIONS: Continued conservation efforts are required to protect these fishes. This case study presented a rare example of how the impacts associated with the use of aquatic resources in South Africa can successfully be offset by conservation efforts. <![CDATA[<b>Herbivores shape woody plant communities in the Kruger National Park: Lessons from three long-term exclosures</b>]]> The role of grazers in determining vegetation community compositions and structuring plant communities is well recognised in grassy systems. The role of browsers in affecting savanna woody plant communities is less clear. We used three long-term exclosures in the Kruger National Park to determine the effect of browsers on species compositions and population structures of woody communities. Species assemblages, plant traits relating to browsing and soil nutrients were compared inside and outside of the exclosures. Our results showed that browsers directly impact plant species distributions, densities and population structures by actively selecting for species with traits which make them desirable to browsers. Species with high leaf nitrogen, low total phenolic content and low acid detergent lignin appeared to be favoured by herbivores and therefore tend to be rare outside of the exclosures. This study also suggested that browsers have important indirect effects on savanna functioning, as the reduction of woody cover can result in less litter of lower quality, which in turn can result in lower soil fertility. However, the magnitude of browser effects appeared to depend on inherent soil fertility and climate. CONSERVATION IMPLICATIONS: Browsers were shown to have significant impacts on plant communities. They have noticeable effects on local species diversity and population structure, as well as soil nutrients. These impacts are shown to be related to the underlying geology and climate. The effects of browsers on woody communities were shown to be greater in low rainfall, fertile areas compared to high rainfall, infertile soils <![CDATA[<b>Tourists' perceptions and willingness to pay for the control of <i>Opuntia stricta</i> invasion in protected areas: A case study from South Africa</b>]]> Invasive alien plants have a long history of establishment in the national parks of South Africa. In particular, Opuntia stricta (sour prickly pear) has invaded several protected areas in the country, threatening the biodiversity conservation mandate of these conservation areas. This article focuses on the economic estimation of O. stricta's negative impacts in protected areas by using Contingent Valuation surveys conducted amongst a sample of tourists in the Pilanesberg National Park (North West Parks and Tourism Board, South Africa). Tourists' familiarity and awareness of selected invasive alien plants and their willingness to pay for the implementation of a control programme for O. stricta were assessed. The results show that many tourists are familiar with invasive alien plants and their (positive and negative) impacts and, in particular, perceived the presence of O. stricta to be negative, due to the impacts on aesthetics and recreation. Socio-demographic characteristics, as well as individual attitudes and biocentric beliefs, have an influence on the willingness to contribute financially to a control programme for O. stricta. The individual willingness to pay assessment found that the majority of respondents (78%) were willing to pay a higher entrance fee (an additional R57.30 or $7.00 per day) for a hypothetical programme to control the invasion of O. stricta in the Pilanesberg National Park. CONSERVATION IMPLICATIONS: The willingness of tourists to pay for O. stricta management provides useful insights in the decision-making process of park management. The results are encouraging, since, in general, tourists are aware of the problem and are in support of providing additional economic input for preventing future alien plant invasions. <![CDATA[<b>Exploring an extensive dataset to establish woody vegetation cover and composition in Kruger National Park for the late 1980s</b>]]> Woody plant cover and species composition play an important role in defining the type and function of savanna ecosystems. Approximately 2000 sites in the Kruger National Park (KNP) were surveyed by F.J. Venter over a period from 1985 to 1989, recording vegetation, soil and topological characteristics. At each of these sites (approximately 20 m × 20 m each), woody vegetation cover and species were recorded using a rapid, Braun-Blanquet classification for three height classes: shrub (0.75 m - 2.50 m), brush (2.50 m - 5.50 m) and tree (> 5.50 m). The objective of this study was to re-analyse the vegetation component of the field data, with a specific focus to provide a spatially explicit, height-differentiated, benchmark dataset in terms of species occurrence, species richness and structural canopy cover. Overall, 145 different woody species were recorded in the dataset out of the 458 species documented to occur in the park. The dataset describes a woody layer dominated by a relatively small number of widely occurring species, as 24 of the most common woody species accounted for all woody species found on over 80% of all sites. The less common woody species (101) were each recorded on 20 sites or less. Species richness varied from 12 to 1 species per site. Structural canopy cover averaged 9.34%, 8.16% and 2.89% for shrub, brush and tree cover, respectively. The dataset provides a useful benchmark for woody species distribution in KNP and can be used to explore woody species and height class distributions, as well as comparison with more recent or future woody vegetation surveys. CONSERVATION IMPLICATIONS: The results provided evidence that large-scale, woody vegetation surveys conducted along roads offer useful ecosystem level information. However, such an approach fails to pick up less common species. The data presented here provided a useful snapshot of KNP woody vegetation structure and composition and could provide excellent opportunities for spatio-temporal comparisons. <![CDATA[<b>Rocky shores of a major southern African Marine Protected Area are almost free from intertidal invertebrate alien species</b>]]> A major threat to marine ecosystems is the establishment and proliferation of invasive alien species. This study addresses gaps in our knowledge regarding marine alien invertebrate species in the Kogelberg Biosphere Reserve (KBR) and adjacent Betty's Bay Marine Protected Area (MPA) in the Western Cape of South Africa, together a potentially important area for south-coast marine conservation. Understanding the distribution and geographical expansion of these species is critical for conservation planning. A quantitative systematic survey of the intertidal rocky shore region was undertaken. The mytilid Mediterranean mussel, Mytilus galloprovincialis, and the bryozoan Watersipora subtorquata were the only alien species recorded along the coastline, which included the MPA. The abundance of M. galloprovincialis was significantly higher outside the MPA, and the abundance of W. subtorquata was significantly higher inside the MPA. With only two alien species recorded, the Betty's Bay MPA and its surroundings support relatively few marine alien species with regards to rocky shore invertebrate biodiversity. CONSERVATION IMPLICATIONS: It is important that the Betty's Bay MPA and its adjacent coastline maintain its current status as an area with relatively few marine alien species. The conservation implications on management require routine surveys of this region to detect early introductions of any additional species. <![CDATA[<b>Vegetation of the eastern communal conservancies in Namibia: I. Phytosociological descriptions</b>]]> The establishment of communal conservancies aims to have the local communities share in the benefits especially of wildlife resources, in this way spearheading the conservation of the environment. The Desert Margins Programme in Namibia aimed to develop vegetation resource data for the Otjituuo, Okamatapati, Ozonahi, African Wild Dog, Otjinene, Epukiro, Otjombinde, Omuramba Ua Mbinda, Eiseb and Ondjou communal conservancies, in order to assist with natural resource planning. For this purpose, a phytosociological survey of this area, with 422 relevés, was conducted during 2004. The data was captured in Turboveg and forms part of the Namibian phytosociological database (GIVD AF-NA-001). The data was split into two, representing two major land forms, the 'hardeveld' and the 'sandveld', respectively. A classification was undertaken using the Modified two-way indicator species analysis (TWINSPAN) procedure. Further refinements, based on field observations and literature sources, were performed using Cocktail procedures. Thirteen vegetation associations were formally described in this article, of which two were subdivided into subassociations. These associations can broadly be grouped into broad-leaved savanna types typical of the central and northern Kalahari of Namibia and microphyll savannas found on the transitions to the Central Plateau. One association, the Burkeo africanae-Pterocarpetum angolensis, forms the southern fringe of the Zambesian Baikiaea Woodlands ecoregion of the World Wildlife Fund, whilst all the other associations fall within the Kalahari Acacia-Baikiaea Woodlands ecoregion. The Combreto collini-Terminalietum sericeae is the most widespread association and dominates the landscape. Threats to the vegetation include overutilisation and regular fires, both of which could easily lead to desertification. This threat is aggravated by global climate change. CONSERVATION IMPLICATIONS: This article described 13 plant associations of the central Kalahari in eastern Namibia, an area hitherto virtually unknown to science. The information presented in this article forms a baseline description, which can be used for future monitoring of the vegetation under communal land use <![CDATA[<b>Vegetation of the eastern communal conservancies in Namibia: II. Environmental drivers</b>]]> The eastern communal conservancies are situated along the western fringe of the Kalahari basin. Under a very short rainfall gradient, the vegetation abruptly changes from microphyllous Acacia-dominated savannas to mesophyll savannas, dominated by Terminalia sericea and Combretum spp. We hypothesise that this is caused by changes in soil moisture availability brought about by changes in soil texture from loamy soils to deep sands (the 'inverse texture effect'). For this analysis, we used vegetation and soils data derived from a recognisance survey of the natural resources of the study area. As the sites in the soil and vegetation surveys did not overlap, it was decided to use only synoptic data for the plant associations in the analysis. Non-metric multidimesional scaling ordination was utilised as ordination technique of the vegetation data and various environmental parameters, including soil texture, soil hydraulic parameters, climatic and fire regime parameters, were overlaid as biplots onto the resulting graph, as were various plant functional attributes particularly related to climatic conditions. The main environmental gradient identified within the study area is the rainfall gradient. This relatively short gradient, however, does not explain the marked change in vegetation observed within the study area. This change is attributed to the change in soil type, in particular, the soil texture and the associated soil hydraulic parameters of the soil. This gradient is closely correlated to leaf size, explaining the change from microphyll savannas to mesophyll savannas along the change from loamy to sandy soils. One of the lesser understood mechanisms for the survival of these mesophyll plants on sandy soils seems to be a deep root system, which is actively involved in water redistribution within the soil profile - by hydraulic lift, inverse hydraulic lift and stem flow. CONSERVATION IMPLICATIONS: Understanding these mechanisms will greatly assist in understanding savanna dynamics. With the threat of global climate change, we postulate that the vegetation will gradually change from the present mesophyll to a microphyll savanna, but that the grass sward will probably not develop very well. Shrub and tree removal ('bush harvesting') is likely to speed up the desertification process within this area <![CDATA[<b>The diet of brown hyaenas (<i>Hyaena brunnea</i>) in Shamwari Game Reserve, Eastern Cape, South Africa</b>]]> Brown hyaenas (Hyaena brunnea) were introduced to Shamwari Game Reserve in the Eastern Cape Province during 2002, but their feeding ecology is poorly understood. Feeding observations of brown hyaena by field guides and the collection of 31 scats from the study area took place over an 11 month period. Standard techniques were used to analyse the scats and identify prey items present. Ten dietary categories were identified from the scats, with a mean of 3.2 dietary categories per scat. Large mammal remains were found in 30 of the 31 scats, with kudu being the most abundant (61.0% of scats). Overall the two methods indicated at least 14 mammal species being fed on by the brown hyaena. The presence of mainly large mammal remains and invertebrates (in 38.7% of all scats), together with the feeding observations of mainly large mammals by field guides, suggests that brown hyaena in Shamwari are mainly scavengers and that sufficient carrion is available, thereby reducing the need for them to hunt. A 52.0% occurrence of plant matter was found in the scats, suggesting that plant material is an important component of their diet. Further studies are underway to investigate the feeding ecology of brown hyaena in Shamwari and surrounding areas. CONSERVATION IMPLICATIONS: Comprehensive scat analysis over a number of years, monitoring of individual movement patterns and population numbers of brown hyaena in and around conservation areas will be beneficial in quantifying resource use of this species. <![CDATA[<b>Soil water retention curves for the major soil types of the Kruger National Park</b>]]> Soil water potential is crucial to plant transpiration and thus to carbon cycling and biosphere-atmosphere interactions, yet it is difficult to measure in the field. Volumetric and gravimetric water contents are easy and cheap to measure in the field, but can be a poor proxy of plant-available water. Soil water content can be transformed to water potential using soil moisture retention curves. We provide empirically derived soil moisture retention curves for seven soil types in the Kruger National Park, South Africa. Site-specific curves produced excellent estimates of soil water potential from soil water content values. Curves from soils derived from the same geological substrate were similar, potentially allowing for the use of one curve for basalt soils and another for granite soils. It is anticipated that this dataset will help hydrologists and ecophysiologists understand water dynamics, carbon cycling and biosphere-atmosphere interactions under current and changing climatic conditions in the region. <![CDATA[<b>Impact of elephant on two woody trees, <i>Boscia oleoides</i> and <i>Pappea capensis</i>, in an arid thicket-Nama Karoo mosaic, Greater Addo Elephant National Park</b>]]> Despite extensive evidence of the influences of elephant on woody trees in savannah habitats, effects on trees in the succulent thickets of the Eastern Cape are relatively poorly described. Our study investigates the role and intensity of elephant impacts on Pappea capensis and the relatively rare Boscia oleoides in an arid thicket-Nama Karoo mosaic habitat of the Greater Addo Elephant National Park. We show that roughly 19% of the B. oleoides and nearly half of the P. capensisindividuals recorded showed signs of elephant impact. Elephant often toppled our study trees, and where these individuals were uprooted, mortalities occurred: B. oleoides ∼ 44% of the impacted trees (4 individuals); P. capensis ∼ 22% of the impacted trees (29 individuals). CONSERVATION IMPLICATIONS: Whilst this study is restricted by limited spatial and temporal replication, P. capensis mortalities caused by elephant occurred at a rate exceeding that of other processes. Our results provide insight into the severity of the measured changes and the need to reduce the impacts. However, it would be critically important to establish the specific driver of elephant-tree interactions before any management intervention is implemented <![CDATA[<b>Plant nematodes in South Africa. 12. Checklist of plant nematodes of the protected areas of the Eastern Cape Province</b>]]> Soil-inhabiting nematodes, including plant-parasitic nematodes, are considered to be the most abundant multicellular organisms in the soil, and of particular interest since they are an integral part of the interlocking chain of nutrient conversions. Because of their abundance and relative susceptibility to both physical and chemical changes, these organisms are used as indicator organisms. The National Collection of Nematodes (NCN) consists of a core collection, the Meloidogyne Collection and the Juan Heyns Collection, which are housed at the Plant Protection Research Institute of the Agricultural Research Council in Pretoria. Vast amounts of biodiversity data are contained in NCN, and the digitising of the collection from 2007 to 2014 yielded unpublished locality information, especially datasets of plant nematodes reported from protected areas of the Eastern Cape. Two hundred and thirty plant nematode species belonging to 36 genera were reported from the Eastern Cape. Of these, only 80 were from protected areas, whilst 163 were from uncultivated areas (outside protected areas) and 148 from cultivated areas. Ten species were described from protected areas, namely Criconemoides silvicola, Meloinema silvicola, Ogma tuberculatum, Paralongidorus cebensis, Paralongidorus hanliae, Scutellonema tsitsikamense, Trichodorus vandenbergae, Xiphinema erriae, Xiphinema ornatizulu and Xiphinema simplex. Only M. silvicola, O. tuberculatum, P. cebensis and S. tsitsikamense were not reported from other provinces, suggesting endemism. CONSERVATION IMPLICATIONS: The diversity of nematode fauna is not adequately protected as most nematode biodiversity in the Eastern Cape lies outside protected areas, with only 80 of the 230 plant-feeding nematode species in the province being reported from protected areas