Showing papers by "Jane Turpie published in 2022"

Accounting for ecosystem services and asset value: pilot accounts for KwaZulu-Natal, South Africa

Abstract: Pilot monetary ecosystem accounts were compiled for KwaZulu-Natal Province, South Africa, in order to highlight any data, methodological or process issues in their compilation and to contribute towards charting a strategy for ecosystem accounting. The Province is highly diverse, with eight biomes, large proportions under communal, private and state tenure, globally important biodiversity, variable landscape condition and encompassing catchment areas of nine river systems. We accounted for the supply and use of wild biomass, reared animal production, cultivation (including silviculture), nature-based tourism, property value, carbon storage and sequestration, pollination, flow regulation (maintenance of base flows), sediment retention, water quality amelioration and flood attenuation. For each ecosystem service, we devised conceptually valid methods that were suitable for the existing data to produce values consistent with the System of National Accounts. These were then summed to estimate total annual flows from each 100 x 100 m spatial unit and its asset value. Challenges encountered included lack of data on small-scale and subsistence production, mismatches in the classification of landcover and government production statistics, unreliable measures of ecosystem condition, the large scale of hydrological modelling and lack of centralised data organisation relating to hydrological services. There was heavy reliance on past empirical research and on global datasets. The combined value of the annual flow of the ecosystem services valued was R52.5 billion in 2011, equivalent to 12% of the provincial GDP. However, the values of many of the services have decreased over the accounting period, due to a combination of changes in demand and ecosystem condition. Asset value was undermined to some extent by unsustainable use of provisioning services. Some areas will require careful messaging, particularly in regard to the contentious issue of valuing carbon retention and the use of exchange values rather than welfare values that are used in economic analysis.

The effect of forest land use on the cost of drinking water supply: machine learning evidence from South African data

Abstract: ABSTRACT Water quality amelioration is one of the key ecosystem services provided by forests in the catchment areas of water supply systems. In this study, we applied random effect models and the least absolute shrinkage and selection regression method of machine learning to South African panel data to estimate the causal effect of natural forest cover on municipalities' water treatment cost. We controlled for a range of confounding covariates including other land cover variables including wetlands, plantation forests, grassland, woodland etc. The Lasso based instrumental variable (IV) method allowed us to simultaneously account for model uncertainty surrounding variable selection and endogeneity bias. We found significant and robust evidence that natural forestland cover reduces water treatment costs at the intensive margin. Estimates from our preferred models indicated that the marginal benefit of increasing forest cover is R310.63 /ha/year. We also found that the elasticity response of water treatment cost to natural forest area is 0.02%. Our estimate of the marginal value of the water purification service is small compared to the producer's surplus from alternative land uses. However, protection of natural forest land use might be defended if other ecosystem goods and services provided by natural forests are taken into account.

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

Abstract: 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 (NO x ) reaching the estuary from the catchment have increased dramatically (6–7 fold) over the past five decades, dissolved reactive phosphate (PO 4 ) slightly less so (2–3 fold), but ammonia (NH 4 ) 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.

Assessing protected area vulnerability to climate change in a case study of South African national parks

Abstract: Climate change is challenging the ability of protected areas (PAs) to meet their objectives. To improve PA planning, we developed a framework for assessing PA vulnerability to climate change based on consideration of potential climate change impacts on species and their habitats and resource use. Furthermore, the capacity of PAs to adapt to these climate threats was determined through assessment of PA management effectiveness, adjacent land use, and financial resilience. Users reach a PA‐specific vulnerability score and rank based on scoring of these categories. We applied the framework to South Africa's 19 national parks. Because the 19 parks are managed as a national network, we explored how resources might be best allocated to address climate change. Each park's importance to the network's biodiversity conservation and revenue generation was estimated and used to weight overall vulnerability scores and ranks. Park vulnerability profiles showed distinct combinations of potential impacts of climate change and adaptive capacities; the former had a greater influence on vulnerability. Mapungubwe National Park emerged as the most vulnerable to climate change, despite its relatively high adaptive capacity, largely owing to large projected changes in species and resource use. Table Mountain National Park scored the lowest in overall vulnerability. Climate change vulnerability rankings differed markedly once importance weightings were applied; Kruger National Park was the most vulnerable under both importance scenarios. Climate change vulnerability assessment is fundamental to effective adaptation planning. Our PA assessment tool is the only tool that quantifies PA vulnerability to climate change in a comparative index. It may be used in data‐rich and data‐poor contexts to prioritize resource allocation across PA networks and can be applied from local to global scales.