Scielo RSS <![CDATA[Koedoe]]> vol. 57 num. 1 lang. en <![CDATA[SciELO Logo]]> <![CDATA[<b>Distribution and impact of the alien anemone <i>Sagartia ornata</i> in the West Coast National Park</b>]]> Sagartia ornata is an alien anemone that occurs intertidally within the West Coast National Park (WCNP). Whilst baseline distributional data was gathered in 2001, the range and abundance of this alien has not been reassessed. The present study aimed to determine the current status and distribution of this anemone, to assess its diet so as to establish the role it may play as predator and to investigate its impact on sandy-shore communities. Sagartia ornata was found to be restricted to the WCNP, where it occurred in densities of up to 508 ± 218 individuals per m². Within the park the distribution of this anemone had changed. Populations were recorded in Nanozostera capensis seagrass beds for the first time and this alien was absent from two areas in which it had previously occurred. Diet analysis revealed indigenous polychaetes and amphipods as the dominant prey items consumed by S. ornata. This alien was found to significantly alter sandy-shore community structure, with differences caused primarily by increases in the abundance and biomass of the tanaid Anatanais gracilis and the polychaete Orbinia angrapequensis.Additionally, invaded areas supported significantly greater invertebrate diversity, density and biomass. It is concluded that whilst this anemone negatively affects native biota, its current dependence on restricted habitats precludes widespread impacts with the park. CONSERVATION IMPLICATIONS: With regard to conservation implications, this invasion should be routinely monitored outside the WCNP as in its native range S. ornata occurs on rocky shores and kelp holdfasts, suggesting a potential for spread along the west coast of South Africa. <![CDATA[<b>An inventory of epigeal ants of the western Soutpansberg Mountain Range, South Africa</b>]]> The distribution, abundance and sensitivity of invertebrates to habitat change are largely unknown. Long-term monitoring of ecological gradients with standardised and comparable protocols can form the basis of a better understanding. Altitudinal gradients are particularly relevant within this context. Here we provide a check list and baseline data for ant species collected over a 5-year period across the Soutpansberg Mountain Range, South Africa. Standardised pitfall surveys across 11 sites yielded a total of 133 species in 38 genera and 6 subfamilies. Sample coverage of epigeal ants was 0.98 for the transect as a whole. Of these species, 21% were restricted to the southern slope of the mountain and 14% to the northern slope. Extrapolated richness estimates reached an asymptote for all, except for three sites. These were the only sites impacted by bush encroachment. Observed richness was the highest at a low-altitude mesic site that is exposed to considerable disturbance by megaherbivores and mechanical clearing of woody vegetation. Structural classification of vegetation was predictive of a broad-scale ant assemblage structure. On a smaller scale, however, structure was a function of elevation, space and temperature. CONSERVATION IMPLICATIONS: Future monitoring should target indicator taxa associated with bush encroachment, particularly with reference to their impacts on grasslands. Bush encroachment could endanger several ant species associated with mesic grasslands and woodlands on the mountain, as well as ant diversity, as these were the habitats with the highest ant diversity. <![CDATA[<b>A phytosociology survey and vegetation description of inselbergs in the uKhahlamba-Drakensberg Park World Heritage Site, South Africa</b>]]> No previous scientific surveys have been conducted on inselbergs in the Drakensberg. The aim of this study was to collect specimens, identify, describe and name the vegetation clusters and assess biogeographical connections with other Afromontane regions. A total of 103 relevés where sampled from six inselbergs. The plant sampling was carried out according to the Braun-Blanquet method with the plant and environmental data entered in TURBOVEG and exported as a Cornell Condensed format file (CC!) into Juice. Classification was completed using TWINSPAN (Two-way Indicator Species Analysis) (modified), resulting in 4 major communities, 11 communities, 13 sub-communities and 18 variants. Ordination (indirect) was carried out using CANOCO (version 4.5) to investigate the relationship between species. The four major communities identified are Rhodohypoxis rubella (wetland grass and forblands), Scirpus ficinioides - Crassula peploides (sheet rock grass and forblands), Pentaschistis exserta (high-altitude alpine grassland), previously undescribed, and Merxmuellera drakensbergensis - Helichrysum trilineatum (high-altitude alpine fynbos grassland), described in other vegetation and floristic studies. Four habitats were identified, namely wetlands, sheet rock shallow soil, high-altitude alpine grassland and deep soil high-altitude fynbos grasslands. Substrate and moisture availability appeared to be the defining micro-climatic conditions determining the different vegetation clusters whilst altitude is the overriding environmental factor influencing all vegetation. CONSERVATION IMPLICATIONS: Rising temperatures as a result of carbon dioxide increase is predicted to drastically decrease the number of endemic and near-endemic montane species, whilst altering the composition of vegetation units which comprise the alpine vegetation. <![CDATA[<b>Foraging range and habitat use by Cape Vulture <i>Gyps coprotheres</i> from the Msikaba colony, Eastern Cape province, South Africa</b>]]> <![CDATA[<b>Resilience of imperilled headwater stream fish to an unpredictable high-magnitude flood</b>]]> Headwater stream fish communities are increasingly becoming isolated in headwater refugia that are often cut off from other metapopulations within a river network as a result of non-native fish invasions, pollution, water abstraction and habitat degradation downstream. This range restriction and isolation therefore makes them vulnerable to extinction. Understanding threats to isolated fish populations is consequently important for their conservation. Following a base-flow survey, a high-magnitude flood (peak flow of 1245 m−3s−1) provided an opportunity to investigate the response of endangered Eastern Cape redfin Pseudobarbus afer populations to a natural disturbance in the Waterkloof and Fernkloof streams, two relatively pristine headwater tributaries of the Swartkops River system within the Groendal Wilderness Area, Eastern Cape Province, South Africa. Pseudobarbus afer had limited distributions, occupying 3 km in both the Fernkloof and Waterkloof streams. Fish population assessments before and after the flood event indicated that there were no longitudinal trends in P. afer abundance before or after the flood, but overall abundance post-flooding in the Fernkloof stream was higher. There were no noticeable changes in P. afer size structure pre- and post-flood. Pseudobarbus afer showed resilience to a major flooding event most likely related to evolution in river systems characterised by environmental stochasticity. CONSERVATION IMPLICATIONS: This research provides insight into the population level responses of native headwater stream fishes to unpredictable natural disturbance. Of particular relevance is information on their ability to withstand natural disturbances, which provides novel information essential for their conservation and management especially as these fishes are already impacted by multiple anthropogenic stressors. <![CDATA[<b>Artisanal Fisheries in the Ndumo Area of the Lower Phongolo River Floodplain, South Africa</b>]]> The aim of this study was to investigate the status of artisanal fisheries in the lower Phongolo River floodplain in northern KwaZulu-Natal, South Africa. A cross-sectional quantitative survey design was used that included the development of a questionnaire and a systematic survey among the five villages bordering the Ndumo Game Reserve. Data were collected over a 5-day period by a group of 16 fieldworkers and analysed using the Statistical Package for the Social Sciences, version 21. The results revealed that fish was the third most consumed protein in the area, that people consumed fish on average twice a week, that at least six fish species (and one recently introduced crayfish species) were consumed regularly, and that most fish were obtained from local vendors, who in turn bought it from local fishermen and -women. Fishing activities also appeared to occur predominantly along the river system and targeted mainly red-breasted tilapia (Tilapia rendalli) and Mozambique tilapia (Oreochromis mossambicus) and, to a slightly lesser extent, African sharptooth catfish (Clarias gariepinus) and brown squeaker (Synodontis zambezensis). CONSERVATION IMPLICATIONS: Given that Ndumo residents predominantly catch fish by means of non-commercial methods, that they do so for reasons of personal consumption and subsistence, and that they mostly target rivers and dams rather than the ecologically sensitive pans in the region, it would seem likely that fishing in the region might be sustainable for the moment. However, it is recommended that studies on the local fish populations and their reproductive rates be conducted so that the actual impact on local fish populations can be determined more accurately. This study serves to provide the necessary baseline data on fish utilisation in the region, which would enable the impact of artisanal fishing on fish reserves in the Ndumo region to be determined once population studies have been completed. <![CDATA[<b>Aerial surveys conducted along the Garden Route coastline, South Africa, to determine patterns in shore fishing effort</b>]]> Coastal environments provide a wide range of leisure opportunities, including recreational fishing. Understanding spatial and temporal fishing patterns is important in ensuring wise management and sustainable use. To provide information on shore angler effort and distribution, randomised aerial surveys of the Garden Route coast between the eastern border of the Tsitsikamma Marine Protected Area and the Kaaimans River mouth in the west were undertaken between December 2008 and November 2009. A total of 15 flights were conducted, with six flights taking place over weekends, two on public holidays and the balance on normal week days. Angler effort was not uniformly distributed along the coastline, and spatial analysis highlighted coastal areas both inside and outside marine protected areas that had increased angler effort. In general, fishing effort was highest around more densely populated areas and concentrated in areas with easy access. Although angler counts were highly variable, the seasonality of shore angling effort showed a slight increase during autumn and winter and angling effort was significantly higher on weekends. CONSERVATION IMPLICATIONS: Data obtained during these surveys can assist management with future conservation planning exercises, whilst also guiding daily law enforcement patrols to maximise angler encounters.