This study aims at explaining the distribution and composition of the southern Cape forests, the largest forest complex in southern Africa. These are the only forests in southern Africa which are actively and scientifically managed for their products and values. Population growth due to forestry, agricultural and economic development and a growing tourism industry exerts increasing pressures on the natural environment of the southern Cape coast and therefore affect the dynamics and conservation of the forests. Conservation and sustained utilization of the forests require a sound knowledge of the composition, structure and dynamics of the forests. This study was aimed at an understanding of the biogeography of the forests at the landscape level in order to isolate those variables which contributed to the present distribution and composition of the forests. Determinants of the forest location pattern in the southern Cape were identified as rainfall above 500 mm, which determines the potential limits of the forests, and the bergwind fire pattern, which determines the actual forest distribution. Fires driven by the hot, dry, northwesterly, föhnlike bergwinds interacted with the terrain physiography since prehistorical times and the forests persisted in topographic shadow areas. The largest forests in the area therefore occur on the coastal platform at the foot of the mountains, in the river valleys and on the coastal scarp. Forests in the mountains, with high rainfall, are small and scattered. The results have shown that the bergwind driven fires control the distribution of forests which have important implications for the understanding of forest dynamics and for conservation management of forests in multiple-use management systems. Forest composition at the landscape level was studied by means of plant species lists. A species list for the southern Cape forests was annotated with information on the growth form, breeding system, propagule type, forest type, moisture tolerance, abundance and spread in the study area, and the distribution range in southern Africa, of each species. Analyses of the list showed that the species/family ratios for the southern Cape forest flora are very low, that woody plants have mostly fleshy propagules and herbaceous plants mostly dry propagules, and that several species have adaptations to adverse conditions. The species richness and composition, and floristic similarity and relationships were compared between the southern Cape forest flora and the floras of 13 other forests representing particular geographic regions in southern Africa. Forest size explained relatively little of the variation in species richness of the forests. Stepwise multiple regression analyses indicated that the number of dispersal corridors, the proximity to other forests and mean altitude explained most of the variation in number of woody species, whereas the number of landscape types and dispersal corridors explained most of the variation in number of herbaceous species. The high similarity between the southern Cape forest flora and those of the forests along the escarpment from the eastern Cape to northern Transvaal, and the southern attenuation of species suggest that the forests were once continuous. It is suggested that the Sundays river valley east of Port Elizabeth isolated the southern Cape forests from those to the east already during the Pliocene or earlier.

Bibliography: pages 71-83. / A variety of studies have shown the problems of energy supply faced by low-income communities in southern Africa. Most of these communities are dependent upon indigenous fuelwood supplies. In addition, many of these communities use indigenous wood for construction. This largely uncontrolled utilisation imposes severe threats on woody vegetation communities. The Eastern Cape/Ciskei region is an area where energy supply problems are particularly severe and impacts on woody vegetation correspondingly severe. This study aimed to investigate the feasibility of using remote sensing techniques to monitor the the impact caused by collection of wood in the Eastern Cape/Ciskei forest and thicket communities. A variety of remote sensing techniques for landcover analysis were investigated. In all cases, visual interpretation was used because it is considerably cheaper and demands less technical expertise than would computer processing. In addition, many studies have shown visual interpretation to be superior. Maps were drawn from multitemporal aerial photograph sequences and from Landsat and SPOT satellite images. These maps showed that there has been relatively little change in area of woody vegetation in the study area since 1956. However, field studies showed that vegetation community structure had been degraded as a result of intense and sustained human impact. This qualitative decline also reflected a decline in usefulness of the woody vegetation of the area to local communities. This substantial degradation was not visible on any of the remote sensing imageries. This emphasises that field-based checks to monitor human impacts on forest and thicket formations are essential. Strategies for reducing the dependence of low-income communities on indigenous vegetation for energy supplies and constructional timber have been reviewed from the literature and these are descibed in Appendix 1. Most successful strategies in other parts of the world have been the result of a national commitment to tree planting, recognition of a multiplicity of constraints and the voluntary involvement of the communities the strategies are intended to assist.

Ectomycorrhizal (ECM) associations are important elements of forest biomes, connecting and transferring nutrients through an intricate and complex system of hyphal networks, ensuring plants of the nutrients they require, in nutrient poor soil. ECM research and particularly investigations into the diversity of the fungal partners has not received much attention in South Africa, hindering the advance of research in this field. This has been attributed to the difficulty of identifying the mycobionts involved in the symbiosis. The objectives of this study were to examine the ECM fungal diversity associating with Pinus patula, in selected forest plantations in Mpumalanga, South Africa. Both morphological and molecular techniques were used to identify specimens of both sporocarp collections and ECM root tip morphotypes. Morphological analysis of the ECM root tips involved characterisation of root morphology such as colour, branching and texture, and anatomical analysis examined hyphal arrangement in the root mantle and rhizomorphs. Molecular analysis involved sequencing of the Internal Transcribed Spacer (ITS) region and comparative BLAST analysis. Twenty-four sporocarp species were identified from 13 genera, namely: Amanita, Boletus, Clavulina, Inocybe, Lactarius, Rhizopogon, Russula, Scleroderma, Suillus, Tricholoma, Thelephora, Tomentella and Xerocomus. ECM root tip analysis led to the characterisation of 7 wild-type morphotypes identified as an Albatrellus sp., 2 Amanita species, a Rhizopogon sp., Thelephora terrestris, a Tomentella sp. and Scleroderma citrinum. A secondary objective was to determine whether fertilisation treatments within the study sites were responsible for differences in fungal species community structure. No evidence of a change in species diversity or shift in species composition was encountered. It is envisaged that these comprehensive ECM descriptions will be used as reference material to stimulate continued research in this field in South Africa.

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Faculty of Science University of Witwatersrand Johannesburg SOUTH AFRICA / A three-year study was undertaken In the province of Mpumalanga, South Africa to Investigate the competitive effects of the grass Setaria megaphylla on the growth of the tree species Pinus patula. A replacement series field trial, where six different competition regimes were Implemented, clearly demonstrated the suppressive effects of S. ( Abbreviation abstract ) / AC2017

A thesis submitted in the Faculty of Science, University of Witwatersrand, Johannesburg for the degree of Doctor of Philosophy. Johannesburg, 1996. / Litter accumulates on the forest floor in Pinus patula plantations in Mpumalanga, South Africa and as a result nutrients become immobilized and site productivity is reduced. Studies have correlated litteraccumulation with abiotic factors, such as high altitude sites, high rainfall soils derived from the timeball series (shale) have thick litter layers. This study focuses on the biotic factors involved in litter accumulation. [Abbreviated Abstract. Open document to view full version] / GR 2017

Dominant understorey species, such as herbs, ferns, palms and shrubs may influence forest tree species diversity and dynamics. Their influence may be through shading the forest floor, thereby affecting regeneration of shade-intolerant species and reducing species diversity, or it may be through competition with seedlings for space and belowground resources, thus modifying or changing the structure of the forest. These effects may be compounded if the life cycle of the understorey species consists of synchronized reproductive and mortality events. This study examines the influence of a dominant understorey species, Isoglossa woodii (Acanthaceae), on regeneration of trees in Indian Ocean subtropical coastal dune forest in southern Africa. The species is a semiwoody herb and has population-wide synchronous reproduction at 4-7 year cycles after which it dies and regenerates from seed. In this thesis I examine three aspects of the ecology of this suppressive herb: (i) the ecological and environmental correlates of the distribution of I. woodii; (ii) the evolutionary advantages of synchronous monocarpy; and (iii) the ecological effects of the extensive cover and putative recruitment window caused by I. woodii on forest tree seedling dynamics and diversity. Isoglossa woodii covered 65–95 % of the understorey, while gaps in this understorey cover occupied the remaining 5–35 % of the area. The spatial distribution of I. woodii was strongly related to tree canopy structure, with the species excluded from sites with dense canopy cover. Woody seedling establishment was inhibited by low light availability ( / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

This study investigates environmental factors influencing ecotonal changes in the Dontsa Forest Management Unit (FMU) of the Keiskammahoek Estate Forest which is located in the Amatole Mountains of the Eastern Cape in the Republic of South Africa. The patterns of forest edge movement were analysed to show trends of forest edge movement from 1975 to 1985, 1975 to 1992, 1975 to 2002, 1975 to 2014, 1985 to 1992, 1985 to 2002, 1985 to 2014, 1992 to 2002, 1992 to 2014 and 2002 to 2014 by digitizing and assessing the scale of forest edge movement using georeferenced aerial photographs. Belt transects were established in six sites that were selected on the basis of physiographic elements for determination of the driving forces of forest ecotonal changes. The results of the study show that the forest edge moved positive towards the grassland biome while in other sites there was contraction of the forest edge from 1975 to 2014. The findings of the study show that some forest patches moved with few individual pioneer species towards the grassland while indigenous species dominated in the ecotone area of the forest in other research sites. D whyteana, A latifolius, R melanophloes, A facultus, R prenoides, C aurea, C bispinosa, C inerme, and S martina are the plant species with high density in the forest ecotone while A latifolius, R prenoides, R melanophloes were highly distributed along the grassland area. The results also show that harvesting of Pinus patula and illegal harvesting of understory species are major factors that result in ecotonal changes of Dontsa FMU. The research sites adjacent to residential areas have experienced reduction of ecotone area as compared to the research sites in high altitude areas of the Amathole Mountains where there is less disturbance. The eastern facing aspect of the forest exhibited a high density of plants in the forest ecotone as compared to the west facing slope.

This study focused on assessing the condition and creating a carbon inventory of forests in the Matiwane area of the Transkei. This entailed the use of aerial photography in tracing forest cover change from 1942 to 2007 coupled with ground-truthing to assess whether the forests have in any way endured degradation over the years with a potential reduction in carbon stocks as a result. This study revealed both the loss and gain of biomass in the area with a general trend of forests being continuously converted to agricultural fields resulting in reduced forest area, stem density, tree density and carbon loss in different pools of the forests, reflecting that these forests are degraded. The conversion has resulted in the reduction in the number of species from a mean of 11±0.57 species/200m² in intact forests to 1±0.23species/200m² plot in degraded forests. It was also revealed that approximately 5.2 % (791 hectares) of 15 352 hectares of forest area was lost as a result of the conversion of forest land to agricultural fields from 1942 to 2007 with 99 % of the clearing occurring in the last 33 years (1974-2007) and of which 60 % ( 4 77 hectares) occurred from 1995 to 2007, indicating that forest degradation in these forests is on the increase. The assessment also revealed some areas that were nonforest in 1942 that have accumulated woody biomass (BAA), composed mainly of Acacia sp accounting for 51.18 MgC.ha⁻¹ (Megagrams of carbon per hectare) and total carbon stocks of 0.02 TgC (Teragrams of carbon). The degradation of these forests induced a reduction in carbon stocks from 311.68±23.69 MgC.ha⁻¹ (to a soil depth 0-50 cm) in intact forest to 73.46±12.34 MgC.ha⁻¹ in degraded forests. The total carbon stocks in the degraded forests were approximated at 0.06 TgC and the BAA areas 0.02 TgC with 4.7 TgC in intact forests. The degradation of these forests has resulted in the net carbon loss of 0.19 TgC between 1942 and 2007 but 4.76 TgC is still locked in these forests. The large difference in carbon stocks between intact and degraded forests indicated the need to reduce the degradation of these forests to prevent further carbon loss and reduction of the carbon sequestration potential of these forests.

The area studied at Fern Kloof, near Grahamstown, consists of a strip of vegetation approximately 260 yds. long and 50 yds. wide, in which there are two communities: 1) indigenous forest 2) exotic Pine forest (which has only one tree species Pinus pinaster). Throughout the thesis this species is referred to as the pine. The object of the investigation has been to determine whether these communities are natural or not. This has involved a study of the floristic composition, the life forms and the structure of the plant communities. In addition, various soil and environmental factors have been studied.

Human appropriation of natural resources, and the consequent loss of habitats, means that ecological restoration may in the future become a vital conservation tool. For this to happen, we have to understand the processes and factors that govern community assembly, and their management. Here I analyze data on community structure (richness, evenness, diversity, composition) of assemblages (millipedes, spiders, dung beetles, plants, birds, rodents), and on soil chemical and physical properties, to describe and evaluate post-disturbance dune forest regeneration patterns. Data were collected from program of a dune mining company), from post-mining rehabilitating dune forests, and from self-regenerating dune forests in northern KwaZulu-Natal. Both succession theory and community assembly theory predict that a species' niche will determine when it will colonize new sites, and by extension, what the eventual species composition will be. This type of control should result in deterministic regeneration patterns for a community. In support of this view, I found that the majority of habitat-age related changes in community structure and ecosystem function were either towards benchmark values (and will reach these values in less than 65 years post-disturbance), or were already equal to the benchmark. Age-related trajectories were repeatable between surveys and post-mining sites were changing as fast or faster than spontaneously regenerating sites. Moreover, detailed analysis of changes in community composition of millipedes, dung beetles, herbs, trees, birds and rodents showed that all of the taxa were also regaining the benchmark's species composition. However, community change was dependent on how it was measured - dung beetles recovered only species presence, but others relative abundances as well. Changes were almost never exponential, suggesting that colonization and extinction are not the orderly events foreseen by equilibrium biodiversity theory. Furthermore, the average abundances of birds, trees and millipedes in undisturbed dune forest patches were correlated with colonization success, suggesting that post-disturbance recovery through colonization may be controlled from outside the local community, rather than by species interactions. The recovery of the spider community appeared to be towards the benchmark forest community, but spider species composition was critically linked to microhabitat structure. Because microhabitat is not necessarily restored concurrently with forest community structure, the spider assemblage (and possibly other invertebrates) may not recover the desired pre-disturbance structure or composition. Dune forests thus seem to be resilient to mining disturbances, since most taxa were recovering structure and composition. However, classic successional and community assembly theories are unlikely to fully explain these community recovery mechanisms. More likely, post-disturbance recovery occurs because a new habitat passively "samples" the rain of dispersing propagules and individuals, leading to a high probability of capturing the average species composition of the region. A conceptual model of dispersal in the landscape suggested that species composition of new habitats might equilibrate to the composition of the closest habitat undergoing the least amount of species compositional change, although this may not apply to all taxa. This model may serve as the basis for directing future research and restoration management. / Thesis (DPhil (Zoology))--University of Pretoria, 2006. / Zoology and Entomology / unrestricted