Suchergebnisse

The recognition of the economic consequences of alien invasive plants in terms of water-supply costs was pivotal in the establishment of the Working for Water programme, which has spent over R3 billion in dealing with the problem while simultaneously addressing poverty relief. Given competition from other social development projects for future funding, however, there is a need to justify further alien control programmes and to maximize efficiency within the programme. This requires valuing the biodiversity benefits of alien control and improving of the evaluation methods used. The concept of ecological goods and services has been a useful political tool, but the resource-economics concept of the Total Economic Value of biodiversity forms a more useful analytical framework. Studies on the impacts of alien invasive plants in South Africa initially concentrated on water losses, but more recently have included values of direct consumptive and non-consumptive use, option and existence value, and other indirect measures. Secondary effects such as downstream changes in aquatic ecosystem functions have not been assessed. Studies have varied in their scale and scope, as well as in the 'currency' of evaluation (such as financial or economic). Several approaches have been used for valuing water losses, with initial estimates having been the most conservative. Estimates of non-water benefits have frequently involved extrapolation from site-specific investigations within the study area, or been estimated from estimates at the regional level. None of the contingent valuation studies used has been applied following internationally accepted guidelines. In water-yielding catchments, alien control programmes are easy to justify in economic terms. In other areas, this may be more difficult. Cost-benefit analyses to date have tended to include the full financial costs of clearing, whereas, in reality, the opportunity cost of labour is close to zero, and economic costs are therefore much smaller. Benefits, which accrue later, tend to be underestimated from lack of information on biodiversity values and by high discount rates. A revised approach would favour the outlook for control programmes. If this fails to secure funding, what alternatives are there? New regulations are considered suboptimal and likely to fail. Opportunities for creating incentives to clear aliens from private lands are extremely limited, and there are no incentives that can reduce future invasions. Government-funded control programmes are thus the most efficient option. Future studies will need to address the right questions using the appropriate methods, incorporate both ecological and economic dynamics, express values in the right 'currency', and use a discount rate that reflects the rights of future generations. The quality of this research will depend on relevant ecological enquiry.

AbstractThis paper examines the impact of climate change on poor households across South Africa who practise subsistence farming to supplement their household income and dietary requirements. We consider three production systems: specialized crops, livestock and mixed crop-livestock farming. In general, we find specialized crop farmers to be the most vulnerable, while mixed crop-livestock farmers appear to be least vulnerable, suggesting that crop-livestock diversification is a potential coping strategy among poor subsistence farming households. We observe qualitatively similar results when we use self-reported food adequacy as the outcome. Furthermore, predicted impact shows that the climatic changes will be mildly harmful at first but will grow over time and lead to a 151 per cent loss in net revenue by the year 2080. Interestingly, we observe that crop farmers receive higher revenue when land is owned by the household, while on the other hand, livestock farmers earn more revenue when the land is communal.

Predation of livestock in South Africa has been estimated to cost in excess of ZAR1 billion in losses per year1 and has complex social, economic and ecological drivers and consequences. In this context, livestock can be broadly defined as domesticated animals and wildlife (the former excluding poultry and the latter including ostrich, Struthio camelus) managed for commercial purposes or human benefit in free-ranging (or semi-free ranging) circumstances that render them vulnerable to predation. This conflict between livestock producers and predators, and the attempts to manage it, has persisted for over 350 years, with the most notable outcome being the eradication of the majority of the apex predators across much of South Africa.2 In contrast, the mesopredators, black-backed jackal (Canis mesomelas) and caracal (Caracal caracal) are by all accounts thriving, at least as measured by their impact on livestock production. Increasingly, attempts to manage livestock predation give rise to deep polarisations, particularly between animal rightists and livestock producers, which further confounds an already complex situation. This complexity hampers the development of policy and regulations with regard to managing livestock predation. A recent global review of the scientific merit of studies on the efficacy of various predator control interventions highlighted the paucity of adherence to acceptable scientific methods in these studies, and recommends 'suspending lethal control methods' while appropriately designed studies are undertaken.3 Treves et al.3 did not identify any valid (by their criteria) studies undertaken in South Africa. This example highlights the need for a scientifically robust basis for policy and management of livestock predation issues. ; http://www.sajs.co.za/ ; am2017 ; Centre for Wildlife Management

The natural conservation of coastal lagoons is important not only for their ecological importance, but also because of the valuable ecosystem services they provide for human welfare and wellbeing. Coastal lagoons are shallow semi-enclosed systems that support important habitats such as wetlands, mangroves, salt-marshes and seagrass meadows, as well as a rich biodiversity. Coastal lagoons are also complex social-ecological systems with ecosystem services that provide livelihoods, wellbeing and welfare to humans. This study assessed, quantified and valued the ecosystem services of 32 coastal lagoons. The main findings of the study are: (i) the definitions of ecosystem services are still not generally accepted; (ii) the quantification of ecosystem services is made in many different ways, using different units; (iii) the evaluation in monetary terms of some ecosystem service is problematic, often relying on non-monetary evaluation methods; (iv) when ecosystem services are valued in monetary terms, this may represent very different human benefits; and, (v) different aspects of climate change, including increasing temperature, sea-level rise and changes in rainfall patterns threaten the valuable ecosystem services of coastal lagoons. ; DEVOTES project, from the European Union's Seventh Framework Programme for research, technological development and demonstration [308392]; networks and communities of Eurolag; Future Earth Coasts; SCOR; Fundacao para a Ciencia e a Tecnologia (FCT) Investigador Programme [IF/00331/2013]; Fundacao para a Ciencia e a Tecnologia [UID/MAR/04292/2013]; CESAM by FCT/MEC national funds (PIDDAC) [UID/AMB/50017/2013 - POCI-01-0145-FEDER-007638]; FEDER; European Commission, under the 7th Framework Programme through the collaborative research project LAGOONS [283157]; FCT [SFRH/BPD/107823/2015, SFRH/BPD/91494/2012]