'''' GSSA-Publications-1986-1990

Abstract: Data from stalagmites in the Makapansgat Valley, South Africa, document regional climatic change in southern Africa in the Late Pleistocene and Holocene. A new TIMS U-series dated stalagmite indicates speleothem growth from 24.4 to 12.7 ka and from 10.2 to 0 ka, interrupted by a 2.5 ka hiatus. High-resolution oxygen and carbon stable isotope data suggest that postglacial warming was first initiated ~17 ka, was interrupted by cooling, probably associated with the Antarctic Cold Reversal, and was followed by strong warming after 13.5 ka. The Early Holocene experienced warm, evaporative conditions with fewer C4 grasses. Cooling is evident from ~6 to 2.5 ka, followed by warming between 1.5 and 2.5 ka and briefly at ~AD 1200. Maximum Holocene cooling occurred at AD 1700. The new stalagmite largely confirms results from shorter Holocene stalagmites reported earlier. The strongest variability superimposed on more general trends has a quasi-periodicity between 2.5 and 4.0 ka. Also present are weaker ~1.0 ka and ~100-year oscillations, the latter probably solar induced. Given similarities to the Antarctic records, the proximate driving force producing millennial- and centennial-scale changes in the Makapansgat record is postulated to be atmospheric circulation changes associated with change in the Southern Hemisphere circumpolar westerly wind vortex.

Abstract: Two vibrodrill and six core drill cores were recovered in Lake Assom near Tibati, south of Adamawa. From eight radiocarbon ages on samples from the two vibrodrill cores and on the basis of sedimentological analysis, a reconstitution of the environmental history of this site for the late Holocene has been done. These results suggest the Lake Assom has remained swampy or even dry since 2800 years BP. Spectacular deposition of compact muddy intraclasts strongly suggests that this situation was suddenly interrupted close to [approximate]1700 years BP when the lake was inundated by water. This deposition can be compared to that of coarse materials observed at the base of the erosion profile "Basse Terrasse". In spite of this present filling trend, the lacustrine state of the site seems to still pertain. Observations done on the lake banks and the occidental swampy plain, compiled with those from the well in the centre of the small adjacent depression of Ngwana, enable us to better understand the recent functioning of the lake. The Mandjara river certainly played a major role in the sedimentation of sandy gley, and later in the high energy reworking of older coarse intraclasts at [approximate]1700 years BP. Lake Assom seems to have originated from the dissolution of a more extensive iron crust covering the hole region of Mbella Assom. The presence today of two adjacent depressions is due to local morphology following changes in the lake during the dry period. On the other hand, palynologic studies show no indication of the proximity of any humid forest to this wooded savannah over the past 4500 years BP.

Abstract: This study investigates the practical and financial implications of alternative strategies for meeting explicit conservation goals on the Agulhas Plain, South Africa. This is an area of exceptional biodiversity increasingly threatened by alien plant infestation, urbanisation, and agricultural expansion. In addition to traditional on-reserve protection, we identify two types of property-rights agreements (conservation easements and management agreements) and two types of financial incentives (land management assistance and tax relief) as appropriate for encouraging off-reserve conservation on targeted lands in the area. Specifically, we suggest actions to offset the costs facing landowners under new pieces of legislation, such as alien-clearing requirements and a property tax. After refining an existing GIS database of cadastral units targeted for conservation, we assigned on- or off-reserve conservation status to properties on the basis of a simple decision system, which took the irreplaceability of the area into account. Three implementation scenarios were designed: an entirely [`]on-reserve' approach, a mixed on- and off-reserve approach, and the mixed approach in conjunction with financial incentives. The conservation costs, to both the public and private sector (including expanded obligations from new legislation), were first modelled and then analysed in a Geographic Information System. We found that a traditional on-reserve approach would cost the state about R240M in acquisition costs, whereas both mixed approaches, using the decision rules developed in this study, would involve leaving 40% of targeted areas in private hands, saving the state 80% in acquisition costs. Of the subsequent conservation costs, which total R401M (present value @ 6% discount rate; Scenario 1), most are alien clearing costs. Since landowners are now compelled to put up these costs, the state could make further savings (44-51%) under a mixed management scenario. Using Property Rate relief as an additional financial incentive is relatively efficient in that it may save targeted private landowners 32% in Property Rates, at a cost of 5.5% of expected tax revenue to the state. Given the prohibitive costs, realising conservation goals in the Agulhas Plain will probably depend upon the establishment of institutions, mechanisms, and incentives for private participation in conservation.

Abstract: The formulation of a strategic plan for the conservation of terrestrial biodiversity in the Cape Floristic Region (CFR; 87,892 km2) requires an objective and spatially explicit assessment of the representativeness of major habitat categories (surrogates for biodiversity) currently under protection. A GIS layer of statutory and non-statutory conservation areas was used, along with layers of many biological and physical features, to explore the configuration of conserved areas relative to key biological and physical indicators. Three analyses were performed. (1) Recursive partitioning, a classification-tree analysis technique, was used to contrast features of protected areas with non-protected areas. (2) The conservation status of 16 primary and 88 secondary Broad Habitat Units (BHUs; derived on the basis of topography, geology, homogeneous climatic zones, and floristic composition) was assessed in terms of prescribed conservation targets. (3) The extent to which protected areas are able to sustain ecological and evolutionary processes was explored by assessing the extent of spatial components of these processes for all conservation areas. About 20% of the CFR is protected in some form of conservation area, mostly concentrated on sandstone substrates, and areas with high altitude and steep slopes. The reservation bias towards upland areas has seriously constrained representation of biodiversity pattern and processes. Most of the habitat diversity is poorly represented in the current conservation area system with only 9% of the remaining primary BHUs in the lowlands conserved. However, almost 50% of the Mountain Fynbos Complex is conserved (largely exceeding its conservation target). Spatial components of the ecological processes identified are poorly captured by the conservation area network although faunal and floral migration is possible in the uplands due to the strong spatial connectivity of the protected network.

Abstract: The lack of realistic estimates of the costs of protected area establishment and effective management can hinder conservation planning and result in under-funded "paper parks" that fail to meet conservation goals. This study comprises the first comprehensive and systematic estimate of the costs of conserving a globally recognised biodiversity hotspot, the Cape Floristic Region. To our knowledge, it is also the first study to use specific relationships between protected area attributes and management costs to estimate the long-term costs of implementing a regional conservation plan. We derived a configuration for an expanded protected area system and two off-reserve mechanisms (contractual reserves and other incentive mechanisms) that achieve explicit conservation targets for biodiversity pattern and process identified in a systematic conservation planning process. Using a costing model, we then estimated the costs of establishing and maintaining this reserve system. Although the reserve system is one of many potential configurations that may achieve the designated conservation targets, the results indicate that the costs of conservation are substantial. An expenditure of $45.6 million per year, assuming a 20-year implementation horizon, is required to develop a representative reserve system, while the annual costs of maintaining this system are $24.4 million. Owing to the economies of scale, especially the marked increase in unit management costs when protected area size <600 ha, the predicted cost of managing the expanded system was only 1.2 times that of the existing system. Overall, the level of expenditure required to effectively conserve the region's biodiversity is low relative to its regional and global significance.

Abstract: The hillslope erosion model (HEM) was developed to describe erosion and sediment yield on rangelands and is based on mathematical relationships among sediment yield, runoff, hillslope characteristics, and a relative soil erodibility value. It is available on the web site, http://www.eisnr.tucson.ars.ag.gov/HillslopeErosionModel. Currently, HEM has had limited application outside the USA. Our aim was to test the utility of the model with data from (a) a sandy loam at Hyderabad, India; (b) a clay loam at Pukekohe, New Zealand; and (c) a heavy red clay soil in northern Australia. Calibration showed that derived relative soil erodibility values for Indian and Australian locations differed from those determined for the USA datasets, however the default value appeared to be applicable for the New Zealand data with some variability. Our testing suggests that further calibration and analysis are necessary before default values can be identified for all sites. We also suggest however, that cautious use with derived soil erodibilities is possible at these locations, as further model testing occurs.

Abstract: This paper provides an introduction and overview for the special issue on systematic conservation planning in the species-rich and highly vulnerable Cape Floristic Region. Firstly, we outline the three major problems that created the need for a systematic conservation plan and implementation programme in the region, namely an existing reserve system that is not representative of biodiversity patterns and processes, escalating threats to biodiversity, and diminishing institutional capacity. Secondly, we present the framework used for the planning and implementation process, place the contributions to the special issue in this context, and summarise current implementation initiatives. Thirdly, we extract from these studies and our own experience a number of lessons that were learnt during the planning process. Foremost amongst these lessons is a requirement for effective incorporation of implementation issues at all stages of the planning process. Other lessons include the need to consult and involve stakeholders at the local (municipal) level, the importance of a common planning framework for all teams contributing to the plan, the importance of mainstreaming biodiversity concerns as an implementation mechanism, the requirement for a critical level of home-grown capacity for undertaking ecoregional planning, and the value of expert knowledge when incorporated into a systematic planning framework. We conclude by suggesting that the approach used in this planning process, modified by accommodating the lessons learnt, has general applicability.

Abstract: We produced a conservation plan that achieved conservation targets for biodiversity pattern and process in the species- and endemic-rich Cape Floristic Region of South Africa. Features given quantitative conservation targets were land classes, localities of Proteaceae and selected vertebrate (freshwater fish, amphibians and reptiles) species, population sizes for medium- and large-sized mammals, and six types of spatial surrogates for ecological and evolutionary processes. The plan was developed in several stages using C-Plan, a decision support system linked to a geographic information system. Accepting the existing reserve system as part of the plan, we first selected spatially fixed surrogates for biodiversity processes; then we included those planning units that were essential for achieving targets for land classes, Proteaceae and vertebrate species; next we included areas required to accommodate population and design targets for large and medium-sized mammals; we then selected planning units required to conserve entire upland-lowland and macroclimatic gradients; and finally we resolved the options for achieving remaining targets while also consolidating the design of conservation areas. The result was a system of conservation areas, requiring, in addition to the existing reserve system, 52% of the remaining extant habitat in the planning domain, as well as restorable habitat, that will promote the persistence and continued diversification of much of the region's biota in the face of ongoing habitat loss and climate change. After describing the planning process, we discuss implementation priorities in relation to conservation value and vulnerability to habitat loss, as well as socio-economic, political and institutional constraints and opportunities.

Abstract: Expert-based and systematic, algorithm-based approaches to identifying priority areas for conservation are sometimes posited as alternatives. While both approaches have pros and cons, the systematic approach does have the advantage of providing a region-wide assessment of the options for achieving explicit conservation targets. A distinct advantage of the expert-driven approach is its incorporation of expert knowledge on biodiversity persistence and pragmatic management and implementation issues not normally included in biodiversity feature-site data matrices. Given the widespread application of both approaches, surprisingly little research has been undertaken to evaluate their conservation planning outcomes. Here we compare priority conservation areas in South Africa's Cape Floristic Region identified by park managers and reserve-selection software. Managers identified 29 areas (a wishlist) that together, comprised 31% of the planning domain and had 40% of its area under some form of conservation management. This wishlist was assessed for the extent to which it achieved targets for biodiversity pattern and process over and above the existing conservation system, and its incorporation of priority areas identified in terms of conservation value and vulnerability to processes that threaten biodiversity. Overall, the wishlist reflected a desire by managers to improve management efficiency and facilitate rapid implementation by expanding existing, largely montane reserves into low-priority areas where land tenure is sympathetic to conservation. Consequently, it was not very effective and efficient in achieving pattern and process targets, and it excluded large areas of vulnerable and inadequately conserved lowland habitat--the areas currently in most need of conservation action. Further, it provided no basis for scheduling implementation or for exploring alternative areas to achieve the same goals, unlike systematic approaches. Nonetheless, the manager's wishlist did include many highly innovative and feasible projects that make important contributions to the conservation of the region's biodiversity. Rather than emphasize the dichotomy between expert and systematic approaches, conservation planners should devise ways of integrating them. In particular, priority areas identified by experts should be carefully considered against the backdrop of the outcomes of systematic conservation planning.

Abstract: In many South African catchments, water is an increasingly limited and highly fluctuating resource. Accurate prediction of low flows is especially vital if water resource managers are to successfully balance the growing needs of agriculture, industry and rural and urban populations, while maintaining the ecological health of aquatic and riparian ecosystems. Existing hydrological models in use in South Africa suffer from a number of disadvantages. They are complex, over-parameterised, data demanding and expensive to use. IHACRES, a lumped conceptual model requiring minimal input data, is less limited by these problems, and has the potential to advance our understanding of streamflow patterns and predict how these may be altered by land-use change. The purpose of this paper is to evaluate IHACRES performance for two South African catchments: Lambrechtsbos A (a 31 ha research catchment) and Groot-Nylrivier (74 km2). IHACRES predicted streamflow at Lambrechtsbos A with useful accuracy (pre-afforestation period, R2>0.81; bias <26 mm/yr; post-afforestation period, R2=0.81, bias=8.4 mm/yr). With prior knowledge of changes in annual evapotranspiration, predictions of land-use impacts on flow regime may be satisfactorily predicted. Simulations of flows in the Groot-Nylrivier catchment were found to be of useful accuracy for relatively short periods of 2-3 yr, but performance over longer time periods was reduced by poor predictions in certain years. We ascribe this primarily to poor catchment-average rainfall estimation following certain storms in some years. Our simulations highlighted a tendency for IHACRES to underestimate quick flow events, especially at times when the greater part of a catchment is dry. Further model development is required to overcome these problems. IHACRES shows great potential in linking proposed land-use change to altered flow regimes, and efficiently describing the flow characteristics within catchments. However, poor estimation of average rainfall in larger catchments is a limitation that needs to be overcome before long-term flow regimes of non-research catchments may be predicted with confidence.

Abstract: A multivariate analysis of the current South American Land-Mammal Ages is used to reanalyse the recognized "faunistic (mammal) units" or chronofaunae that appear related to radical environmental and climatic changes, which we characterize as Faunistic Cycles and Subcycles. The compositional changes recorded in the successive Faunistic Cycles reflect regional environmental and climatic variations, thus patterns of climatic change. Basically we used cheek teeth of ungulates--natives and immigrants--as an indicator of dietary preference. We then try to infer the structure of successive fossil ungulate communities to deduce the structure of their associated vegetation, and thus the prevailing climatic conditions. We also used other native mammals that followed similar dental modifications, e.g., some rodents and some marsupials, and various types of biological and/or geological evidence. These include climate-sensitive or ecologically specific animals or plants, changes of regional distribution and lithological features of the mammal-bearing formations, diastrophic events, changes in global marine temperatures, and sea-level changes, to contrast those climatic and environmental inferences. We conclude that: (1) From the oldest to the youngest cycles the ungulates changed from browser sylvan types to predominantly open country and grazer types as warm, humid sylvan environments became drier and more temperate. (2) The earliest mammal communities (Paleocene-Eocene), excluding the peculiar Cochabambian Cycle, show a higher diversity but are composed of taxa with less extreme morphological differences. Even mammals placed in different orders were not nearly as dissimilar as their later counterparts. This relationship gradually became reversed within the later communities, i.e., lower diversity but taxa with more extreme morphological differences; that is, mammals placed in separate orders became more divergent. (3) According to the record of mammals as well as other climate-sensitive organisms, warm and relatively humid forested environments had a wider latitudinal range, stretching at the very least to the northern part of the Antarctic Peninsula. (4) With some regional range fluctuations, Palcogene and Early Miocene tropical to subtropical environments remained very well represented as far as the southern tip of the continent. (5) The Middle Miocene mammals (beginning of the Panaraucanian Faunistic Cycle) indicate that favorable environments were shifted to northern Patagonia and that many climate-sensitive mammals (including platyrrhine monkeys) disappeared from Patagonia, in correlation with the waning or extinction of many taxa related to subtropical woodlands. (6) Mammals of the Panaraucanian Cycle and the Pampian Subcycle clearly indicate that this was the time of the most extensive open-country environments, progressively ranging from wetter subtropical savannas to cold-temperate steppe-like habitats. Most of the mammals of this time were savanna-adapted or steppe-adapted elements. (7) Mammals representing the Postpampian Subcycle attest to the wide swings and cyclicity of the Cenozoic climates. (8) According to the Brazilian mammal records, as well as other biological evidence from the isthmian region, the rainy forested areas characterizing those regions evolved quite recently, by the latest Pleistocene to Recent times.

Abstract: Information from the literature about forage conservation losses in the field has been reviewed, contrasted and analysed in the categories respiratory loss, leaching loss and mechanical loss. An attempt has been made to summarise the information in terms of relationships with various climatic, crop and machinery factors, suitable for incorporation in an operational research model of forage conservation. An equation developed to relate respiratory loss to the temperature, moisture content and water soluble carbohydrate content of forage material gives a good representation of results of a range of laboratory studies, and is in reasonable agreement with less accurate field studies. A relationship between leaching loss for a given quantity of rain and moisture content is proposed, but on the basis of very limited information. It was found helpful to regard mechanical loss as the sum of two processes, namely true shatter loss and pick-up loss for windrowing, baling and forage havesting operations. An equation relating shatter loss to moisture content and severity of mechanical treatment is proposed. It is suggested that a roughly constant level of pick-up loss per unit area of stubble cleared by the operation might be assumed, because this is the only conclusion justified on the basis of the rather varied information available.

Abstract: Information from the literature about forage conservation losses in the field has been reviewed, contrasted and analysed in the categories respiratory loss, leaching loss and mechanical loss. An attempt has been made to summarise the information in terms of relationships with various climatic, crop and machinery factors, suitable for incorporation in an operational research model of forage conservation. An equation developed to relate respiratory loss to the temperature, moisture content and water soluble carbohydrate content of forage material gives a good representation of results of a range of laboratory studies, and is in reasonable agreement with less accurate field studies. A relationship between leaching loss for a given quantity of rain and moisture content is proposed, but on the basis of very limited information. It was found helpful to regard mechanical loss as the sum of two processes, namely true shatter loss and pick-up loss for windrowing, baling and forage havesting operations. An equation relating shatter loss to moisture content and severity of mechanical treatment is proposed. It is suggested that a roughly constant level of pick-up loss per unit area of stubble cleared by the operation might be assumed, because this is the only conclusion justified on the basis of the rather varied information available.

Abstract: A general description and a map of the agricultural systems in Ethiopia have previously been published, but the approach and methodology used to arrive at this classification was not adequately described. The two dominant agricultural systems in Ethiopua are the mixed agriculture of the humid and sub-humid highlands and pastoralism in the arid and semi-arid lowlands covering 40 and 60% of the country respectively. These divergent systems are clearly a result of agro-climatic differences and their sub-systems indicate, in part, the range of climatic situations. The approach used to distinguish and describe the agricultural systems in Ethiopia is described and two examples are provided to illustrate the process; one being a synthesis of present land use systems in the Ethiopian Highlands, and the other, a land capability survey for a range lands development project in the southeastern Ethiopian Lowlands.

Abstract: Map of grassland biome The Grassland Biome is found chiefly on the high central plateau of South Africa, and the inland areas of KwaZuluNatal and the Eastern Cape. The topography is mainly flat and rolling, but includes the escarpment itself. Altitude varies from near sea level to 2 850 m above sea level. Grasslands (also known locally as Grassveld) are dominated by a single layer of grasses. The amount of cover depends on rainfall and the degree of grazing. Trees are absent, except in a few localized habitats. Geophytes (bulbs) are often abundant. Frosts, fire and grazing maintain the grass dominance and prevent the establishment of trees. There are two categories of grass plants: sweet grasses have a lower fibre content, maintain their nutrients in the leaves in winter and are therefore palatable to stock. Sour grasses have a higher fibre content and tend to withdraw their nutrients from the leaves during winter so that they are unpalatable to stock. At higher rainfall and on more acidic soils, sour grasses prevail, with 625 mm per year taken as the level at which unpalatable grasses predominate. C4 grasses dominate throughout the biome, except at the highest altitudes where C3 grasses become prominent. Grass plants tolerate grazing, fire, and even mowing, well: most produce new stems readily, using a wide variety of strategies. Overgrazing tends to increase the proportion of pioneer, creeping and annual grasses, and it is in the transition zones between sweet and sour grass dominance that careful management is required to maintain the abundance of sweet grasses. The Grassland Biome is the mainstay of dairy, beef and wool production in South Africa. Pastures may be augmented in wetter areas by the addition of legumes and sweet grasses. The Grassland Biome is the cornerstone of the maize crop, and many grassland types have been converted to this crop. Sorghum, wheat and sunflowers are also farmed on a smaller scale. Urbanization is a major additional influence on the loss of natural areas - the Witwatersrand is centred in this biome. The Grassland Biome is considered to have an extremely high biodiversity, second only to the Fynbos Biome. Rare plants are often found in the grasslands, especially in the escarpment area. These rare species are often endangered, comprising mainly endemic geophytes or dicotyledonous herbaceous plants. Very few grasses are rare or endangered. The scenic splendour of the escarpment region attracts many tourists.