Scielo RSS <![CDATA[Koedoe]]> http://www.scielo.org.za/rss.php?pid=0075-645820150001&lang=pt vol. 57 num. 1 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Distribution and impact of the alien anemone <i>Sagartia ornata</i> in the West Coast National Park</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582015000100001&lng=pt&nrm=iso&tlng=pt 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>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582015000100002&lng=pt&nrm=iso&tlng=pt 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>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0075-64582015000100003&lng=pt&nrm=iso&tlng=pt 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.