Evaluating the cost-effectiveness of ecosystem-based adaptation: Kamiesberg wetlands case study

Ecosystem-based adaptation (EbA) is increasingly being promoted as a cost-effective means of adaptation to climate change. However, in spite of considerable international press, there is still little evidence to substantiate this claim. This study proposes a method through which the cost-effectiveness of EbA strategies can be evaluated against alternative adaptation options, and contributes to South African literature on the subject. The potential cost-effectiveness of wetland restoration is assessed as a means of securing the carrying capacity of land for pastoralist communities of the Kamiesberg communal area in South Africa under projected future climate conditions. The conventional alternatives would be to respond to increasingly dry conditions by drilling boreholes and using supplemental feed for livestock. It was assumed that the EbA interventions would occur upfront, whereas the alternatives are more likely to be implemented in reaction to droughts over a longer time period. The study found the implementation of conventional alternatives to be more cost-effective than EbA as a means to sustaining livestock stocking rates, with EbA being twice as costly. However, this is framed from the perspective of those directly affected (the landowners), and does not include the benefits to broader society

Viability of investing in ecological infrastructure in South Africa’s water supply areas

Ecological infrastructure (natural ecosystems that provide important services and save on built infrastructure costs) can have an important role in securing water supply, particularly in water-scarce areas, but this importance is not reflected in investment decisions, partly due to a lack of evidence. In South Africa, one of the main threats to water supply is the proliferation of woody invasive alien plants which significantly reduce stream flow and water yields. We used existing spatial data and estimates of the impact of woody invasive plants on flows and water yields and on restoration costs to analyse the viability of investing in ecological infrastructure at the scale of major water supply areas. The analysis involved comparison of the costs and effects on water yields of catchment restoration with those of planned built infrastructure interventions designed to meet increasing water demands in the medium to long term. The cost-effectiveness analysis used the unit reference value as a measure of comparison, which is based on the discounted flows of costs and water supplied over a defined time. Restoration could supply 24% of the combined yield of planned built infrastructure interventions by 2050, and is not only cost-effective but has the added advantage of a range of co-benefits delivered by improving ecosystem health. This finding suggests that investing in ecological infrastructure should be considered ahead of new built-infrastructure projects. Significance: • Clearing invasive alien plants from South Africa’s main water catchment areas could increase water yields by 997 million m3 by 2050 relative to a business-as-usual approach, equivalent to a quarter of the yield gains through implementation of built infrastructure interventions planned over the same period. • Invasive alien plant clearing would be more cost-effective than built infrastructure interventions in all water supply systems, except one, the Orange River System. • These findings add to the growing body of literature that advocates for ecological infrastructure investments to secure hydrological ecosystem services

A synthesis of three decades of socio-ecological change in False Bay, South Africa: setting the scene for multidisciplinary research and management

Over the past three decades, marine resource management has shifted conceptually from top-down sectoral approaches towards the more systems-oriented multi-stakeholder frameworks of integrated coastal management and ecosystem-based conservation. However, the successful implementation of such frameworks is commonly hindered by a lack of cross-disciplinary knowledge transfer, especially between natural and social sciences. This review represents a holistic synthesis of three decades of change in the oceanography, biology and human dimension of False Bay, South Africa. The productivity of marine life in this bay and its close vicinity to the steadily growing metropolis of Cape Town have led to its socio-economic significance throughout history. Considerable research has highlighted shifts driven by climate change, human population growth, serial overfishing, and coastal development. Upwelling-inducing winds have increased in the region, leading to cooling and likely to nutrient enrichment of the bay. Subsequently the distributions of key components of the marine ecosystem have shifted eastward, including kelp, rock lobsters, seabirds, pelagic fish, and several alien invasive species. Increasing sea level and exposure to storm surges contribute to coastal erosion of the sandy shorelines in the bay, causing losses in coastal infrastructure and posing risk to coastal developments. Since the 1980s, the human population of Cape Town has doubled, and with it pollution has amplified. Overfishing has led to drastic declines in the catches of numerous commercially and recreationally targeted fish, and illegal fishing is widespread. The tourism value of the bay contributes substantially to the country’s economy, and whale watching, shark-cage diving and water sports have become important sources of revenue. Compliance with fisheries and environmental regulations would benefit from a systems-oriented approach whereby coastal systems are managed holistically, embracing both social and ecological goals. In this context, we synthesize knowledge and provide recommendations for multidisciplinary research and monitoring to achieve a better balance between developmental and environmental agendas.https://www.elementascience.orgam2020Mammal Research Institut

Valuing the Provisioning Services of Wetlands: Contrasting a Rural Wetland in Lesotho with a Peri-Urban Wetland in South Africa

Given that few studies have valued the provisioning services of temperate southern African wetlands, research on this topic was undertaken in a remote rural wetland, Letseng-la-Letsie, in Lesotho and a peri-urban wetland in Mfuleni, Cape Town. The objectives were to quantify incomes from wetland resources, assess the relative dependency of communities on wetland provisioning services, and estimate the total provisioning value of the wetlands. Data were collected from informal interviews and structured household surveys. Despite the different settings, both wetlands were used mainly for grazing livestock. The estimated total value added during 2007 from grazing was U.S. $180,078 for Letseng-la-Letsie and U.S.$540,286 for Mfuleni. Letseng-la-Letsie and Mfuleni were also used for hunting, and Mfuleni was partially cultivated. Even though the local wetlands were easier to access from Mfuleni, only 13% of households used them, compared with 65% in Letseng-la-Letsie. However, the households around Letseng-la-Letsie derived less of their income (6%) from the wetlands, compared with 82% in Mfuleni. This reflects the more specialized livelihood strategies in the urban compared with the rural setting, in which risk-spreading household production strategies were more prevalent. The loss of the wetland in Letseng-la-Letsie would therefore potentially affect more people but have less of an effect on the finances of individual households than in Mfuleni. It is estimated that U.S. $220/ha and U.S.$1765/ha is derived annually from wetland provisioning services in Letseng-la-Letsie and Mfuleni, respectively. A standard protocol is needed for valuing wetlands in southern Africa

The impacts of long-term flow reductions and an extreme drought on a large, permanently open estuary, and implications for setting the ecological reserve

Environmental water requirements (EWRs) are set for South Africa’s estuaries to ensure that they are maintained in a state that is both achievable and commensurate with their level of conservation and economic importance.  However, these EWRs are typically determined on the basis of models and scenario analyses that require extrapolation beyond existing data and experience, especially if climate change is considered.  In the case of the Berg Estuary, South Africa, available data on changes in freshwater flow and water quality span a period of at least five decades (1970s–present) during which significant reduction in flows has been observed.  Monitoring data also cover an extreme 3-year drought, from 2015−2017, which provided a unique opportunity to study the effects of severe freshwater starvation (zero-flow for an extended period) on this large, permanently open system.  Our analyses show that mean annual runoff (MAR) under present-day conditions has been reduced to around 50% of that under reference (natural) conditions and that reduction in runoff during the low-flow season (summer) has been more severe (80–86% reduction) than for the high-flow season (39–42% reduction).  The salinity gradient now extends much further upstream than under reference conditions.  Hypersaline conditions along with a reverse salinity gradient were recorded in the estuary for the first time ever during the drought of 2015/17.  Levels of dissolved inorganic nitrogen (NOx) reaching the estuary from the catchment have increased dramatically (6–7 fold) over the past five decades, dissolved reactive phosphate (PO4) slightly less so (2–3 fold), but ammonia (NH4) hardly at all.  Increases in nutrient input from the catchment in the high-flow season are also much more dramatic than in the low-flow season.  The estuary is no longer compliant with gazetted EWRs and requires urgent interventions to restore the quantity and quality of freshwater it receives. &nbsp

A synthesis of three decades of socio-ecological change in False Bay, South Africa: setting the scene for multidisciplinary research and management

CITATION: Pfaff, M. C., et al. 2019. A synthesis of three decades of socio-ecological change in False Bay, South Africa: setting the scene for multidisciplinary research and management. Elementa: Science of the Anthropocene, 7(32). doi:10.1525/elementa.367The original publication is available at https://online.ucpress.edu/elementaOver the past three decades, marine resource management has shifted conceptually from top-down sectoral approaches towards the more systems-oriented multi-stakeholder frameworks of integrated coastal management and ecosystem-based conservation. However, the successful implementation of such frameworks is commonly hindered by a lack of cross-disciplinary knowledge transfer, especially between natural and social sciences. This review represents a holistic synthesis of three decades of change in the oceanography, biology and human dimension of False Bay, South Africa. The productivity of marine life in this bay and its close vicinity to the steadily growing metropolis of Cape Town have led to its socio-economic significance throughout history. Considerable research has highlighted shifts driven by climate change, human population growth, serial overfishing, and coastal development. Upwelling-inducing winds have increased in the region, leading to cooling and likely to nutrient enrichment of the bay. Subsequently the distributions of key components of the marine ecosystem have shifted eastward, including kelp, rock lobsters, seabirds, pelagic fish, and several alien invasive species. Increasing sea level and exposure to storm surges contribute to coastal erosion of the sandy shorelines in the bay, causing losses in coastal infrastructure and posing risk to coastal developments. Since the 1980s, the human population of Cape Town has doubled, and with it pollution has amplified. Overfishing has led to drastic declines in the catches of numerous commercially and recreationally targeted fish, and illegal fishing is widespread. The tourism value of the bay contributes substantially to the country’s economy, and whale watching, shark-cage diving and water sports have become important sources of revenue. Compliance with fisheries and environmental regulations would benefit from a systems-oriented approach whereby coastal systems are managed holistically, embracing both social and ecological goals. In this context, we synthesize knowledge and provide recommendations for multidisciplinary research and monitoring to achieve a better balance between developmental and environmental agendas.https://online.ucpress.edu/elementa/article/doi/10.1525/elementa.367/112511/A-synthesis-of-three-decades-of-socio-ecologicalPublisher’s versio