A SOCIAL COST-BENEFIT ANALYSIS OF A SMALL-SCALE CLAM FISHERY IN THE EASTERN CAPE, SOUTH AFRICA

When a proposal was advanced in 1991 to harvest the wedge clam Donax serra in the Eastern Cape, South Africa, for commercial gain, it elicited a huge public outcry. In order to shed light on the issue, a social costbenefit analysis (CBA), based on a biologically sustainable extraction rate of 100 ton of clams per year, was carried out on its commercial exploitation. Because fishery activities might exact a price on society in the form of negatively altering the quality of people\'s recreation experience in the area, as well as damage the aesthetic and ecological attributes of the beach system, such external effects were identified and valuated. Results from the CBA yielded positive net present values (NPVs) for project options involving live clams being sold on the export market (to Hong Kong) for R24.70 kg-1 and negative NPVs for domestic market options (Johannesburg and Cape Town), where the clam would be sold for R6.50 kg-1. Assuming a discount rate of 8&#37, the highest NPV was obtained for the scenario in which total production was sold on the foreign market and the firm rented facilities of an existing organization. The external cost was the single largest component of the cost of the fishery. The conclusion drawn is that the social benefit of the project exceeds the social cost – a conclusion which supports commercial exploitation of clam stocks along the St Francis Bay beach, but one which does not include the osts associated with policing.Afr. J. mar. Sci. 25: 159–16

Connecting tiger (Panthera tigris) populations in Nepal: Identification of corridors among tiger‐bearing protected areas

Abstract Habitat fragmentation and isolation threaten the survival of several wide‐ranging species, such as tigers, through increased risk from diseases, disasters, climate change, and genetic depression. Identification of the habitat most likely to achieve connectivity among protected areas is vital for the long‐term persistence of tigers. We aimed to improve the mapping of potential transfrontier protected area corridors for tigers by connecting sites within the Terai Arc Landscape in Nepal and to those in India, highlighting targeted conservation actions needed along these corridors to maintain long‐term connectivity. We used least‐cost corridor modeling and circuit theory to identify potential corridors and bottlenecks in the study area. The landscape's resistance to tigers' movement was gathered from expert opinions to inform corridor modeling. We identified nine potential tiger corridors in the Terai Arc Landscape—Nepal that aligned strongly with the remaining intact habitats of the Siwalik landscape, which could facilitate tiger movement. Banke‐Bardia and Chitwan‐Parsa‐Valimiki complexes and Lagga‐Bhagga and Khata corridors were identified as high‐priority conservation cores and corridors. While our model exhibited congruence with most established corridors in the landscape, it has identified the need to enhance existing corridors to improve landscape connectivity. Several pinch points posing an increased risk to connectivity were identified. Most of these were located near the protected area boundaries and along the Nepal–India border. The Siwalik landscape holds the key to long‐term connectivity in the study area; however, immediate conservation attention is needed, particularly at pinch points, to secure this connectivity for tigers. Validation of identified corridors through empirical research and their conservation is a priority

A political ecology of community gardens in Australia: form local issues to global lessons

The local impacts of global urbanization (e.g. dwindling green spaces, food insecurity, land shortages, loss of biodiversity) have triggered resurgent interest in various forms of urban agriculture (Godfray et al., 2010; Evers and Hodgson, 2011). In many rapidly growing cities across the Global North (GN) and Global South (GS), residents are clamouring for better access to places to grow safe and healthy food, for spaces that foster social inclusion, and improved environmental quality (Guitart et al., 2015). Urban cultivation initiatives are often framed around the social benefits of local food growing and typically seek to be 'sustainable' (Chapters 8 and 9, this volume). These twin goals have important implications for land-use planning and policy, implications that we address in this chapter

From beans to breams: how participatory workshops can contribute to marine conservation planning

Systematic conservation planning is increasingly being used in the marine environment, but the relative paucity of data on marine patterns and process still presents a problem, particularly in developing countries. For example, along the south-eastern component of the Agulhas marine bioregion of South Africa, current data regarding the habitat availability, distribution and abundance of 10 seabream species (Sparidae) were insufficient to design a regional-scale conservation plan. We report on how this data void was filled using information provided by marine resource users, managers and scientists during participatory workshops. Participants described the distribution of reefs, and then scored not only the relative abundance of each of the sparid species, but also benthic biodiversity, by arranging beans into piles on paper matrices. Reef positions were verified both by discussions within individual workshops and by subsequent comparisons of outputs among workshops. Similarly, extensive discussions provided an element of verification of relative abundance and biodiversity data. Although the free-scoring method employed in quantifying relative abundance and biodiversity meant that comparisons among workshops were problematic, this was resolved by assigning data to categories according to a simple five-level abundance index. After compiling results from all workshops, relative abundance data reflected conservation status of each species. Opinions by the participants regarding the reasons for recent declines in fish abundance tallied well with explanations from the literature. Biodiversity data were less comprehensive and more difficult to verify. Nevertheless, because participatory workshops provided relatively accurate data regarding fish abundance, were cost effective to run and generated a good level of buy-in from participants, they represent a valuable new tool for marine conservation planning.Keywords: marine conservation planning; participatory mapping and scoring methods; Sparidae; workshopsAfrican Journal of Marine Science 2008, 30(3): 475–48

Options for the conservation of large and medium-sized mammals in the Cape Floristic Region hotspot, South Africa

We assessed options for conserving the large- and medium-sized mammals indigenous to the Cape Floristic Region, South Africa, using systematic conservation planning, the first such attempt for an entire ecoregion. The potential distributions and abundances of the 41 extant species for the entire region prior to anthropogenic transformation of habitats were estimated. This was particularly useful as it obviated any reliance on records of occurrence for conservation planning. Areas that had not been transformed through agriculture or other developments were considered available for conservation. The fragments of untransformed habitat were identified as being large enough to support communities at least 25 individuals of the smallest herbivore species. Smaller fragments were not considered suitable for mammal conservation. Transformation and fragmentation had significant impacts on potential populations, and this was asymmetrical across species, being higher for lowland than montane species. The existing reserve system was estimated to effectively conserve only half the mammal species, using the criteria applied here. Two conservation goals were compared; first, either conserving only CFR endemics and threatened species; and second, conserving all the mammals (with some exceptions for marginally occurring species). Options for protected area systems were assessed using C-Plan, a decision support system designed for systematic conservation planning. The irreplaceability of the planning units varied only slightly under the two goals, and the more inclusive goal was used to develop a proposed reserve network in which targets for all the species were achieved. The CFR endemics and threatened species effectively function as umbrella species for the remaining mammals. This study demonstrates that the incorporation into systematic conservation plans of conservation targets adequate for the persistence of populations comprising communities across entire ecoregions is feasible. (C) 2003 Elsevier Science Ltd. All rights reserved

The expert or the algorithm? - comparison of priority conservation areas in the Cape Floristic Region identified by park managers and reserve selection software

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. (C) 2003 Elsevier Science Ltd. All rights reserved

Genetic and morphological variation in four populations of the surf clam Donax serra (Röding) from southern African sandy beaches

The surf clam Donax serra (Bivalvia, Donacidae) dominates sandy beach communities of two southern African biogeographical regions, a cold (Benguela current) and warm province (Agulhas current). Morphometric and behavioural differences led to a controversial discussion of whether or not populations from the two provinces belong to the same species. Shell size measurements confirmed morphological differences: clams from the cold province were significantly rounder, flatter and less wedge-shaped than clams from the warm province. In this study a genetic approach was used to relate phenotypic differences to genetic variability of four populations of D. serra separated by up to 2 500 km of shoreline. Genetic analysis of twenty-two protein-coding loci was carried out by starch-gel electrophoresis. Populations studied are conspecific (genetic distances range from 0.003 to 0.044) and possess genetic variation (alleles per locus: 1.73 - 1.91; mean heterozygosity: 18 - 22%; percentage polymorphism: 45.5 - 59.1%) in the range of most other marine bivalves, which allows for potential adaptation to environmental changes. Wrights fixation indices show little to moderate genetic divergence among the subpopulations relative to the limiting amount under complete fixation (FST = 0.016 - 0.089), moderate divergence of individuals relative to the total population (FIS = 0.265 - 0.452), and comparably high divergence of individuals relative to the compound population (FIT = 0.300 - 0.473). The effective number of individuals exchanged between populations in each generation is high enough (1.44 - 8.65) to counteract genetic drift. We propose that the observed differences represent phenotypic plasticity enabling this species to inhabit different biogeographic regions. Gene flow, balanced selective pressure and evolutionary inertia are discussed as explanations for similarities of the two outlying populations. The substantial subdivision of the two Namibian populations indicates a potential biotic barrier and requires separate studies of the population dynamics