A phytosociology survey and vegetation description of inselbergs in the uKhahlamba-Drakensberg Park World Heritage Site, South Africa

Abstract

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, highaltitude 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.

Chrysocoma ciliata L. (Asteraceae) in the Lesotho Highlands: an anthropogenically introduced invasive or a niche coloniser?

“…These findings are in direct conflict with a the majority of the existing literature, that assumes, if not argues, that the species is an invasive to the eastern Lesotho Highlands (Table 1). In particular, on the basis of this evidence, we dispute the claims that the species was anthropogenically introduced into the region from c. AD 1890, the time from which the highlands were used more extensively for livestock grazing, and which was assumed to be the cause of the introduction of the species (Van Zinderen Bakker 1981; Grab and Deschamps 2004;Showers 2005;Brand et al 2015). While Parker et al (2011) present archaeological evidence for livestock in the eastern Lesotho Highlands dating back considerably further to 1,070 cal.…”

“…In the contemporary environment, Chrysocoma ciliata proliferates in areas which have been severely environmentally degraded, including landscapes subject to over-grazing, gullying and trampling, and in desiccated wetlands (cf. Beverly 1980;Killick 1990;Grab and Deschamps 2004;Du Preez and Brown 2011;Brand et al 2015;Kopij 2015). As hypothesised above, this may be due to Chrysocoma ciliata requiring a decrease in the surrounding vegetation cover to thrive (Quinlan & Morris, 1994).…”

Global patterns and drivers of alpine plant species richness

“…Datasets from different sources were standardized by identifying a minimum common set of plot attributes, including size, elevation and geographical coordinates. When the geographical coordinates were missing for small, clearly delimited areas, we estimated plot locations from maps (i.e., Mount Jaya; Hope et al., 1976) or by randomly assigning the coordinates of raster cells with the same elevation (±10 m) as the plots in that area (i.e., Mount Wilhelm and Drakensberg; Brand et al., 2015; Wade & McVean, 1969), using the SRTM‐3 digital elevation model at 30 m resolution (Farr et al., 2007; NASA & JPL, 2013). Species cover values with discrete scales were transformed to the mean value of the corresponding percentage interval.…”

The alpine flora on inselberg summits in the Maloti–Drakensberg Park, KwaZulu-Natal, South Africa

“…The study area is described in detail in a companion paper dealing with the phytosociology of the same inselberg summits (Brand et al 2015). Consequently, only a brief summary of salient environmental features is given here.…”

“…Although the flora of the DAC has been relatively well described (Carbutt & Edwards 2004Hilliard & Burtt 1987;Killick 1963), to our knowledge the flora of Drakensberg inselbergs had never been sampled before this study was initiated. (Companion papers are Brand, Collins and Du Preez [2015] and Armstrong & Brand [2012].) A general aim of this study was therefore to establish whether inselbergs supported a representative sample of DAC flora in terms of species, genera and families, as well as species of conservation concern including endemic and near endemic species.…”