The vegetation of the proposed coastal National Botanic Garden, East London

The vegetation of the proposed National Botanic Garden in East London was sampled in 79 100-m2 quadrats and classified using TWINSPAN. Seven plant communities were identified, namely Acacia savanna, riverine forest, riverine thicket, coastal forest, coast scrub, dune margin scrub and a xerophytic community associated with the rocky promontories. DECORANA was used to determine the relationship between these communities and identified a gradient from the rocky promotories through dune margin scrub and coastal scrub to forest on the first axis and a gradient from Acacia savanna to forest on the second axis. Studies of aerial photographs and an old painting of the beach front showed that in this windy coastal environment the vegetation has remained stable for some time. Of the 71 families recorded, Poaceae and Asteraceae dominate the area in terms of genera and species numbers, although woody plants total more than 45% of the species. The trees and shrubs are distributed among the many families of the Tongoland – Pondoland floristic region, thus the area is floristically more subtropical than Cape. Alien vegetation covers a small area and with sound management can easily be eradicated. Recommendations are made for the conservation of the region, the construction of parking facilities, tea-rooms, picnic spots and carefully designed paths and boardwalks for the public to visit and learn more about the indigeous coastal flora

Regeneration of grassy fynbos near Grahamstown (eastern Cape) after fire

The regeneration of grassy fynbos was studied for a period of 13months after the original vegetation had been totally destroyed by fire. Because the fire was preceded by a very dry spell and succeeded by months of high rainfall, regeneration proved to be rapid and the growth of some of the species was clearly related to rainfall. Species recolonization was very rapid and in a particular order. The classification of the species into regeneration type and phenological groups relates well to other studies on fire regeneration in the fynbos. After 13months over 100 species had returned to the area, the plants showing a progressive increase in height, basal and aerial cover

The effect of salt spray on the growth of Scirpus nodosus

Field studies suggested that salt spray may have a detrimental effect on the growth of Scirpus nodosus plants. In a controlled greenhouse experiment plants of three different height classes were sprayed with varying concentrations of salt water. It was found that only plants in the seedling stage were significantly affected by the salt spray. The amount of chloride ions received by the treated plants was equivalent to that deposited by wind-borne salt on plants growing on the foredunes. Thus the position on the shore where S. nodosus seedlings become established may be controlled by the amount of salt spray that they receive

The pattern of the woody species of the Nylsvley Savanna Ecosystem Project area.

A recent survey of the woody plants in the Naboomspruit area of the Northern Transvaal has borne out the fact that plants rarely occur at random in an ecosystem. The densities of all the woody species in five localities of Burkea-Ochna Savanna were recorded in contiguous quadrats and the data subjected to a pattern analysis. The trees and shrubs showed different patterns in the five sample areas depending on the type of savanna vegetation characterising the area.Keywords: botany; northern transvaal; nylsvley; pattern analysis; savanna ecosystem project; shrubs; south africa; survey; trees; vegetation; woody plants; woody specie

The distribution of algae epiphytic on pneumatophores of the mangrove, Avicennia marina, at different salinities in the Kosi System

Samples of algae epiphytic on the pneumatophores of Avicennia marina (Forssk.) Vierh. were collected at different seasons of the year. The distribution of this mangrove, which extends from the mouth of the estuary to Wankute island, approximately 6.5km upstream, covers a salinity range from 35‰ to 7‰ at its upper limits, and includes the Ukhalwe inlet in which the surface water of the upper reaches is 0‰. Thirty-six species of epiphytic algae were collected across this distribution range, of which there were 11 rhodophycean, 17 cyanophycean (cyanobacteria), 7 chlorophycean and 1 phaeophycean. Most of the red algae were restricted to the high (>25‰) salinity areas, while the blue-green algae generally appeared to have a wider salinity and exposure tolerance. Six algal species were found to have a distribution covering the entire salinity range, 10 species were recorded in waters ranging from 35‰ to 7‰, 16 and 2 species were limited to high (>25‰) and lower (5-18‰) salinity areas, respectively, while one species occurred only in freshwater. The ecological implications of these results are discussed. The need for additional collections from localities to the north is stressed to establish the affinities of this community with those in more tropical areas