Towards understanding the effects of informal harvesting of Sand Forest in Maputaland, South Africa

Indigenous forests and savannah provide numerous benefits for rural communities and are utilised as a source of firewood, building material and for woodcraft production. Currently, there is insufficient information on the magnitude of human pressure affecting one such important forest community, namely Sand Forest, particularly in communal areas. Sand Forest is regarded as being critically endangered and is considered to hold various endemic species. The fragmented patch occurrence of this rare and valuable forest type, combined with the lack of necessary knowledge and prior interest in its management, has resulted in the Sand Forest being subjected to uncontrolled utilisation within communal areas. The temporal monitoring of the spatial structures of forest areas, such as Sand Forest, within landscapes has been recommended in order to detect and model deteriorating trends in the forest structures and functioning. Remote sensing is critical in the generation of data that enables the identification and quantification of degraded and deforested areas. This study aims to contribute towards understanding the effects that could emerge from trends of informal Sand Forest wood harvesting, quantified through a spatial-temporal analysis. Quantifying the impact of a declining canopy closure resulting from selective wood harvesting required the use of remote sensing techniques and procedures that could potentially account for this effect. In addition, the study envisaged predicting the future changes of Sand Forest that will take place as a result of continued informal wood harvesting. The ability of trajectory analysis to predict potential changes based on observed and quantified trends provides a new dynamic to conservation and management strategies. In understanding where and how much Sand Forest will be lost in the forthcoming years, more appropriate and accurate recommendations on conservation and management can be made. Furthermore, priority areas can be more readily identified for both conservation and for management intervention

Remote sensing and biophysical monitoring of vegetation, terrain attributes and hydrology to map, characterise and classify wetlands of the Maputaland Coastal Plain, KwaZulu-Natal, South Africa

The Maputaland Coastal Plain is situated in north-eastern KwaZulu-Natal Province, South Africa. The Maputaland Coastal Plain and underlying aquifer are two separate but inter-linked entities. This area with high permeable cover sands, low relief and regional geology that slopes towards the Indian Ocean, hosts a variety of important wetlands in South Africa (e.g. 66% of the recorded peatlands). The wetlands overlie and in some cases also connect to the underlying regional water-table. The apparent distribution of wetlands varies in response to periods of water surplus or drought, and over the long-term has been reduced by resource (e.g. agriculture, forestry) and infrastructure (e.g. urbanisation) development. Accurate wetland mapping and delineation in this environment is problematic due to the ephemeral nature of wetlands and extensive land-use change. Furthermore the deep aeolian derived sandy soils often lacks soil wetness indicators in the soil profile. It is postulated that the aquifer is the source of water to rivers, springs, lakes and wetlands (and vice versa). However, the role of groundwater in the sustainability of hydro-ecological systems is unclear. Consequently this research attempted to determine spatial and temporal changes in the distribution of these wetlands, their susceptibility to human development, understand the landscape processes and characterise and classify the different wetland types. An underlying assumption of the hydrogeomorphic wetland classification concept in South Africa is that wetlands belonging to the same hydrogeomorphic unit share common features in terms of environmental drivers and processes. Given the above, the objectives of this thesis relating to the north-eastern corner of the Maputaland Coastal Plain are to: 1) Map the distribution of wetlands and their relation to other land-use; 2) Characterise the landscape processes shaping the dynamics of wetland type and their distribution; 3) Classify wetlands by applying hydrogeomorphic wetland classification system. This study used Landsat TM and ETM imagery acquired for 1992 and 2008 (dry) and Landsat ETM for 2000 (wet) along with ancillary data. Wetland type characteristics were described using terrain unit position in the landscape, SRTM DEM, land surveyor elevation measurements along with long-term rainfall records, in situ water-table levels with soil analysis and geology and vegetation descriptions. A conceptual model was used to account for the available data, and output from a hydrology model was used to support the interpretation of wetland distribution and function. Wetlands in the study area include permanent wetlands (swamp forests and reed/sedge wetlands), but the majority of sedge/moist grassland wetlands are temporary systems. The wetland distribution reflects the rainfall distribution and groundwater discharge in lower lying areas. The weathering of the Kosi Bay Formation is a key factor in wetland formation. Because of an increase in clay content with depth, the pore-space and hydraulic conductivity are reduced which causes water to impede on this layer. The nature of the aquifer and regional geology that slope towards the east along with extreme rainfall events in wet and dry periods are contributing drivers of wetland and open water distribution. In 2008 (a dry year) the smaller wetland extent (7%) could primarily identify “permanent” groundwater-fed wetland systems, whereas for the wet year (2000) with larger wetland extent (18%) both “temporary” and “permanent” wetlands were indicated. Comparison between both dry years (1992 and 2008) indicates an 11% decrease in wetland (sedge/moist grassland) and a 7% increase in grassland distribution over time. Some areas that appear to be grassland in the dry years were actually temporary wetland, based on the larger wetland extent (16%) in 2000. The 2008 Landsat TM dataset classification for the entire Maputaland Coastal Plain gave an overall 80% mapping accuracy. Landscape settings identified on this coastal aquifer dominated by dune formations consist of 3 types: plain (upland and lowland), slope and valley floor. Although the wetland character is related to regional and local hydrogeology as well as climate affecting the temporal and spatial variability of the wetlands this research confirms that the patterns and wetland form and function are predominantly shaped by the hydrogeomorphic setting and not the rainfall distribution. The following wetland types were identified: permanent wetlands such as peat swamp forests, peat reed and sedge fens; temporary wetland systems such as perched depressions, and sedge/moist grasslands. The Hydrogeomorphic wetland classification system was applied using a semi-automated method that was 81% accurate. The following hydrogeomorphic units could be identified: one floodplain, i.e., Siyadla River Floodplain, channelled valley-bottoms, unchannelled valley-bottoms, depressions on modal slope values <1%, seepage wetlands on modal slope values 1-2%. However, evaluation of the hydrogeomorphic classification application results suggests that the “flat” hydrogeomorphic class be revised. It did not fit meaningfully on the upland plain area. This research finding concludes wetland function does depend on landscape setting and wetland function is not truly captured by the hydrogeomorphic type classification. Not all depression on the coastal plain function the same way and three types of depressions occurs and function differently, i.e., perched depression with no link to the regional water-table vs. depressions that are linked with the regional water-table on plain, slope and valley floor landscape settings. Overall, this research study made a useful contribution in characterising and classifying wetland type and distribution for a high priority wetland conservation area in South Africa. Applying similar methods to the broader Maputaland Coastal Plain will particularly benefit from the research findings. The importance of using imagery acquired in wet and dry periods as well as summer and winter for a more comprehensive wetland inventory of the study area, is stressed. To manage the effects of climate variability and development pressure, informed land-use planning and rehabilitation strategies are required based on landscape analysis and interpretation

Remote Sensing of Human–Environment Interactions in Global Change Research: A Review of Advances, Challenges and Future Directions

The role of remote sensing and human–environment interactions (HEI) research in social and environmental decision-making has steadily increased along with numerous technological and methodological advances in the global environmental change field. Given the growing inter- and trans-disciplinary nature of studies focused on understanding the human dimensions of global change (HDGC), the need for a synchronization of agendas is evident. We conduct a bibliometric assessment and review of the last two decades of peer-reviewed literature to ascertain what the trends and current directions of integrating remote sensing into HEI research have been and discuss emerging themes, challenges, and opportunities. Despite advances in applying remote sensing to understanding ever more complex HEI fields such as land use/land cover change and landscape degradation, agricultural dynamics, urban geography and ecology, natural hazards, water resources, epidemiology, or paleo HEIs, challenges remain in acquiring and leveraging accurately georeferenced social data and establishing transferable protocols for data integration. However, recent advances in micro-satellite, unmanned aerial systems (UASs), and sensor technology are opening new avenues of integration of remotely sensed data into HEI research at scales relevant for decision-making purposes that simultaneously catalyze developments in HDGC research. Emerging or underutilized methodologies and technologies such as thermal sensing, digital soil mapping, citizen science, UASs, cloud computing, mobile mapping, or the use of “humans as sensors” will continue to enhance the relevance of HEI research in achieving sustainable development goals and driving the science of HDGC further

Land degradation and settlement intensification in Umhlathuze Municipality

Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: The multifaceted land degradation problem and its associated manifold impacts have attracted research from different disciplines, resulting in varying definitions of the concept. However, most researchers agree that human intervention that deteriorates the state of the environment is the central element. Among the anthropogenic activities that exacerbate land degradation, land cover has been singled out as the salient element. Rapid and unplanned land cover changes are primary manifestations of this problem. UMhlathuze Municipality, the study area which has superior biodiversity richness, is one of fastest growing municipalities in South Africa and is the locale of significant land modifications in recent decades because of a variety of industrial and residential developments. Using Landsat TM imagery acquired for 1984, 1996 and 2004, this study mapped and quantified land cover change and manifestations of land degradation in the uMhlathuze Municipality in conjunction with settlement intensification computed from orthophotographs acquired for 1984 and 2004. Census population statistics were analysed as a reflection of population dynamics and further to gauge related causes of land cover change. Geographical information technology (GIT) was applied as an analytical tool. The results revealed the anthropogenic influences that led to changes in land cover over the 20- year period between 1984 and 2004. The dominant natural cover classes in 1984 declined continuously and human-dominated land categories had increased sharply by 2004. Much of grasslands, forest and wetlands were converted to monotypical agroforestry (sugar cane and forestry plantations), built-up settlement and mining. These changes engendered complete loss of biodiversity (floral and migration of fauna). Bare ground, signifying land degradation, was noticeable although it exhibited a fluctuating trend which could be attributable to differences between the various imagery used. Along with population growth, the area of settlements increased over the study period and spatially sprawled from urban areas. Settlements showed a fairly stable spatial configuration over the 20-year period, but became magnified in medium- and high-density areas. Grassland and wetlands occurring around Richards Bay, as well as indigenous forest near Port Durnford, were identified as critically threatened ecosystems. The proposed industrial development zone and port expansion were recognized as having adverse ecological implications for wetlands. The study concluded that significant land cover changes occurred in the form of natural land cover giving way to monotypical agroforestry, built-up settlements and mining - all to the detriment of pristine natural habitat.AFRIKAANSE OPSOMMING: Die veelvlakkige probleem van omgewingsdegradasie en die gepaardgaande veelsoortige impakte lok navorsing uit verskillende dissiplines, wat lei tot verskillende definisies van die konsep. Tog is die meeste navorsers dit eens dat menslike invloede die sentrale element is wat die toestand van die omgewing verswak. Van die vele menslike aktiwiteite is grondgebruikverandering uitgesonder as die belangrikste beïnvloeder van agteruitgang van die omgewing. Veral vinnige en onbeplande grondgebruikveranderinge verteenwoordig die primêre manifestasies van hierdie probleem. UMhlathuze Munisipaliteit, die studiegebied met 'n hoë biodiversiteitsrykdom, is een van die vinnigste groeiende munisipaliteite in Suid-Afrika, waar 'n verskeidenheid nywerheids- en residensiële ontwikkelings beduidende grondgebruikverandering oor die afgelope dekades dryf. Met behulp van Landsat TM beelde van 1984, 1996 en 2004, is hierdie studiegebied gekarteer en oppervlaktes gekwantifiseer om grondgebruikverandering en verwante manifestasies van die agteruitgang van landbedekking in die uMhlathuze Munisipaliteit te konstateer. Tesame hiermee is die verdigting van nedersettings ook met behulp van ortofoto’s van 1984 en 2004 aangeteken. Bevolkingsensusstatistieke is ontleed as weerspieëling van die gepaardgaande bevolkingsdinamika en om moontlike oorsake van verandering in grondbedekking te bepaal. Vir hierdie doel is geografiese inligtingstegnologie (GIT ) as analitiese instrument toegepas. Die resultate toon antropogeniese invloede lei tot veranderinge in grondbedekking oor die tydperk van 20 jaar tussen 1984 en 2004. Die dominante natuurlike dekkingsklasse in 1984 het voortdurend verminder en menslik-gedomineerde kategorieë het teen 2004 skerp gestyg. Baie van die grasvelde, woude en vleilande is daadwerklik omskep tot monotipiese agro-bosbou (suikerrieten bosbouplantasies), beboude nedersetting en mynbou. Hierdie veranderinge behels 'n volledige verlies van biodiversiteit (plantegroei en migrasie van fauna). Kaalgrond, wat dui op die agteruitgang van grondbedekking, was ook opvallend, hoewel dit 'n wisselende tendens toon wat ook kan wees as gevolg van die verskille tussen die beeldmateriaal wat gebruik is. Saam met die groei van die bevolking is bevind dat nedersettings oor die studieperiode toegeneem het en in tipiese spreipatrone weg van die stedelike gebiede uitbrei. Nedersettings het 'n redelik stabiele ruimtelike liggingsopset oor die tydperk van 20 jaar getoon, maar het in medium- en hoë- digtheid gebiedeverdeel. Die voorkoms van grasveld en vleiland rondom Richardsbaai, asook inheemse woud naby Port Durnford, is geïdentifiseer as krities-bedreigde ekosisteme. Die voorgestelde nywerheidsontwikkelingsone en hawe-uitbreiding is geïdentifiseer as ontwikkelings met nadelige ekologiese implikasies vir vleilande. Daar is dus tot die gevolgtrekking gekom dat beduidende voortgaande grondbedekkingveranderinge in die gebied voorkom, waarin natuurlike landdekking transformeer tot monotipiese agrobosbou, beboude nedersettings en mynbou - alles tot nadeel van die ongerepte natuurlike habitat

Systematic conservation planning and South Africa's Forest Biome: An assesment of the conservation status of South Africa's forest and reccomdentations for their conservation

This thesis reports on the first substantial data collation, analysis and interpretation for a systematic conservation plan for the entire South African forest biome. This was done by addressing the following questions: What is the current state of the forest biome? How well are forests protected? How threatened are they? What are the conservation priorities, and what needs to be done to improve forest conservation? The study is broad and integrative, using information from various published and unpublished sources, as well as expert judgements. The general framework of systematic conservation planning was used along with the software tools typically used for irreplacebility analysis. Rule based modelling, expert judgements and GIS modelling, were used to develop indices of threat, vulnerability, fragmentation, degradation, connectivity and irreplacebility, at the scale of forest patches, forest clusters and forest types. An index of subsistence resource use of forests was modelled using population density, extent of electrification, forest accessibility and the buffering effect of plantations and woodlots. Using these indices, priorities for conservation were identified. Species richness and numbers of red data and endemic species, were also evaluated for each forest type. Forest patches as well as forest clusters were used as planning units, while forest types were used as surrogates to represent forest biodiversity . South African forests have by far the highest number of tree species per unit area of any temperate forest in the world. A high proportion of species occurring in forests are threatened and endemic. At least 56 forest occurring vascular plants and approximately 88 forest occurring faunal species are listed as IUCN red data species. The current forest protected area network of South Africa, does not adequately protect representative samples of forest biodiversity pattern and process. Approximately 25 % of the total forested area occurs within formal statutory protected areas, but most of this is made up of just a few forest types. Of the 21 forest types assessed, six have less than 10% formal protection. Three forest types, Eastern Scarp, Pondoland Scarp and Kwazulu-Natal Dune forests stand out as being highly vulnerable to biodiversity loss, of these; Pondoland Scarp forests have the lowest level of formal protection, and the highest number of endemic species, making this forest type, the highest conservation priority in the country. 10 PhD thesis: Forest conservation planning: Derek Berliner The limitations of the mathematical selection algorithms (C-plan and MARXAN) to incorporate ecological heuristics and context specific information within reserve selection were recognised. In response to this, a rule based modelling approach was used, that enables ecological heuristics to guide the selection of priority forests, This provided pragmatic, but not necessary mathematically optimal solutions to network reserve design. The traditional (largely silvicultural) focus of forest management and reserve planning in South Africa, has tended to view forests as geographically and functionally distinct ecosystems, without adequate consideration of landscape scale processes and requirements for connectivity. For long term conservation of forest biodiversity, planning requires to occur across multiple scales, and with a broader and longer term view than what has been the traditionally focus. Forest conservation needs to involve both on, and off-reserve strategies. This should include: expansion of the formal protected area network (so as to adequately represent all forest types), improvements in management of existing reserves, and regulation of land use change within forested catchments and catchments linked to forests. This should form part of integrated land management strategy that directly involves communities in forest conservation programmes

Spatio-temporal dynamics of woody vegetation structure in a human-modified South African savanna

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. 25 October 2016 in Johannesburg, South Africa.Ecosystem services, nature’s benefit to people, contribute to human well-being. Extensive reliance on, and unsustainable use of, natural resources is typical of the rural poor in developing countries and can lead to ecosystem degradation, decreased ecosystem service provision, and increased vulnerabilities of rural populations. Most ecosystem services are intangible or difficult to quantify, but fuelwood provisioning can be measured directly and can serve as a proxy for the status of other ecosystem services (e.g. aesthetic and spiritual services, nutrient cycling, carbon sequestration). South African rural communities have a high reliance on fuelwood despite extensive access to electricity. Within this context, live wood harvesting occurring around rural settlements in increasing amounts has been deemed unsustainable. However, the ‘fuelwood crisis’ of the 1970s, and subsequent predictions of woodland collapse through fuelwood supply-demand models, has still not occurred despite substantial population growth in developing countries. Hypothesised reasons for modelled supply-demand mismatches are based on underestimation of fuelwood supply and woodland regeneration, as well as overestimation of fuelwood demand by discounting behavioural adaptability of users. It is likely that the spatial configuration of fuelwood use allows for the co-adaptability of both humans and ecosystems. A lack of understanding of the spatial configuration of these social-ecological dynamics limits our insights into current and future adaptive responses and thus, the degree of sustainability. This thesis aimed to assess woody biomass stocks and vertical structure changes, as a proxy for provisioning ecosystem services, in a spatially and temporally explicit manner, to describe the status and impact of wood extraction in semi-arid, savanna communal lands. Using repeat, airborne light detection and ranging (LiDAR) data from 2008 and 2012, we surveyed three-dimensional woodland structure in Bushbuckridge Municipality communal lands – the grazing and harvesting areas for densely populated rural settlements in former Apartheid ‘homelands’ in South Africa. Woody biomass in 2008 ranged from 9 Mg ha-1 on gabbro geology to 27 Mg ha-1 on granitic geology. Land-use pressure was associated with compensatory regrowth of savanna tree species through post-harvest coppice in the 1-3m height class. Woody biomass increased at all sites, contrary to previous fuelwood models of the area. Change detection in the vertical canopy structure revealed that biomass increases were almost solely attributable to the 1-3m and 3-5m height classes. These changes were exacerbated by wood extraction intensity in the communal lands – the communal land with the highest wood extraction pressure experienced the greatest biomass increases, likely a strong regrowth response to high harvesting levels. Within communal lands, areas closest to roads and settlements experienced substantial biomass increases as a result of shrub level gains. This relationship was mediated by the usage gradient – the greater the wood extraction pressure on the communal land, the larger and more spatially coalesced the ‘hotspots’ of shrub-level increases were in relation to ease of access to the communal land. However, biomass increases are not necessarily indicative of woodland recovery, as shrub-level increases were coupled with losses of trees >3m in height. To explore these tall tree dynamics further, we tracked >450 000 individual tree canopies over two years over contrasting landscapes – a private reserve containing elephants, two communal lands under different wood extraction pressures, and a nature reserve fenced off from both elephants and humans. Humans are considerable drivers of treefall (defined here as a ≥75% reduction in the maximum height of each tree canopy) in communal lands. Humanmediated biennial treefall rates were 2-3.5 fold higher than the background treefall rate of 1.5% treefall ha-1 (in the control site – the reserve containing neither elephants nor humans). Elephant-mediated treefall was five fold higher than the background rate. Rate and spatial patterns of treefall were mediated by geology and surface water provision in the elephantutilised site where relative treefall was higher on nutrient-rich geology, and intense treefall hotspots occurred around permanent water points. Human-mediated rates and spatial patterns of treefall were influenced by settlement and crop-land expansion, as well as ease of access to communal lands. Frequent fires facilitated the persistence of trees >3m in height, but was associated with height loss in trees <3m. The combined loss of large trees and gain in shrubs could result in a structurally simple landscape with reduced functional capacity. Shrub-level increases in the communal lands are likely an interactive combination of newly established woody encroachers and strong coppice regrowth in harvested species. The more intensely used the communal land, the greater the bush thickening and the stronger the relationship between biomass gains and structural changes in the lowest height classes. The exacerbation of bush thickening in natural resource-dependent communities has critical implications for ecosystem service provision. There is potential for coppice regrowth to provide fuelwood to communities using ‘tree thinning’ programmes, but there is a lack of data on the quantity and quality of the regrowth, as well as the sustainability of coppice, the impacts of different harvesting methods, and the potential feedbacks with changing climate and CO2 fertilisation. Woody resource spatial distribution in communal lands is centred around settlement-level wood extraction pressure, as well as natural resource accessibility in the woodlands. In highly utilised areas, woodland regenerative capacity has been underestimated. Additionally, natural resource extraction is still highly localised, even at the communal land scale, with major structural changes occurring around the periphery or close to existing infrastructure. However, it is these underrated coupled adaptive responses in social-ecological systems that explain the failure of fuelwood supply-demand models’ predictive abilities. Nevertheless, loss of large trees in the landscape and the persistence of ‘functionally juvenile’ coppice stands will have implications for seedling production and establishment in the landscape with repercussions for the future population structure and ecosystem service provision. I discuss the implications of increased natural resource reliance in an African development context and the positive feedback between rural poverty and environmental impoverishment. Potential constraints to the data are unpacked, together with opportunities for further research in this area.LG201

Photorealistic visualisation of urban greening in a low-cost high- density housing settlement.

Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.Apartheid housing policies of the pre-1994 South African government, and the low-cost highdensity housing programmes of the post-1994 government, has given rise to numerous urban environmental problems, some of which could be addressed in a cost-effective and sustainable manner through urban greening, while simultaneously promoting biodiversity. Public participation in the planning of urban greening has been identified as being of vital importance, without which urban greening projects run a high, and expensive, risk of failure. Previous studies indicate that the greening priorities of residents in low-cost high-density housing settlements may differ considerably from those of managers and experts tasked with the protection and extension of the natural environment resource base. A system of participatory decision support is therefore required to reconcile the greening requirements of the community, and the ecological benefits of biodiversity. If language, literacy, map literacy and numeracy difficulties are to be avoided, and a sense of place or belonging is to be invoked, such a participatory decision support system should, ideally, be visually based, and capable of generating realistic eye-level depictions of the urban landscape. New computer-based landscape visualisation applications, which can directly utilise GIS, CAD and DEM data to produce detailed photo-realistic viewsheds, were deemed better suited to the task of visualising urban greening than existing GIS based mapping systems, CAD and traditional landscape visualisation methods. This dissertation examines the process of constructing a 3D computer model of the Mount Royal low-cost high-density housing settlement, situated in the eThekwini Municipality, KwaZulu-Natal, South Africa. Visualisations including terrain, natural features, indigenous vegetation, houses and roads were produced and submitted, with a questionnaire, to experts from different disciplines, Mount Royal residents and neighbors. Results from the expert survey indicate moderate support for visualisation in professional decision-making. However, both experts and residents expressed strong support for the accuracy and credibility ofthe visualisations, as well as for their potential in a participatory decision support system