Strategic water source areas for urban water security: Making the connection between protecting ecosystems and benefiting from their services

Nel, Jeanne; Maitre, David C. Le; Roux, Dirk J.; Colvin, Christine; Smith, Janis; Smith-Adao, Lindie; Maherry, A; Sitas, Nadia

doi:10.1016/j.ecoser.2017.07.013

Cited by 69 publications

(39 citation statements)

References 23 publications

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“…The Cape Fold Ecoregion (CFE) spans 87,900 km 2 across the south‐eastern and south‐western coasts of South Africa. It is a global biodiversity hotspot (Myers et al ., ) and a priority biogeographic unit for freshwater conservation (Abell et al ., ; Nel et al ., ). The CFE is rich in headwater streams that provide the last remaining refuges for many small‐bodied endemic fishes (Ellender & Weyl, ).…”

Section: Introductionmentioning

confidence: 97%

Variation in thermal tolerances of native freshwater fishes in South Africa's Cape Fold Ecoregion: examining the east–west gradient in species' sensitivity to climate warming

Reizenberg

Bloy

Weyl

et al. 2019

Journal of Fish Biology

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The Cape Fold Ecoregion (CFE) is a biodiversity hotspot with high levels of endemism in its freshwater fish fauna. This study examined inter and intra-specific variation in critical thermal maxima (T Cmax ) for eight native species of freshwater fish from the CFE. Cape galaxias Galaxias zebratus, Breede River redfin Pseudobarbus burchelli, Berg River redfin Pseudobarbus burgi, Clanwilliam redfin Pseudobarbus calidus and fiery redfin Pseudobarbus phlegethon were the most thermally sensitive (T Cmax = 29.8-32.8 C). Clanwilliam rock-catfish Austroglanis gilli, Eastern Cape redfin Pseudobarbus afer and Cape kurper Sandelia capensis were moderately sensitive (T Cmax = 33.0-36.8 C). An increase in intra-specific thermal sensitivity of S. capensis was observed from east to west. The results were related to in situ water temperature, which influenced T Cmax for all species, suggesting that thermal history is a major driver of variation in thermal tolerance amongst populations. These thermal tolerance data for freshwater fishes in the CFE demonstrate that resilience to climate warming follows a geographical cline and that the more sensitive western species and regions are conservation priorities.

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Section: Introductionmentioning

confidence: 97%

Variation in thermal tolerances of native freshwater fishes in South Africa's Cape Fold Ecoregion: examining the east–west gradient in species' sensitivity to climate warming

Reizenberg

Bloy

Weyl

et al. 2019

Journal of Fish Biology

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“…Investment in similar efforts is therefore crucial for improving the representation of wetland extent to a moderate confidence level. Further improvements should be done for selected priority areas, at catchment levels, particularly in the strategic water source areas (Nel et al, 2017;Le Maitre et al, 2018), areas of high development pressures, and others identified through the NBA 2018 assessment of threatened ecosystems.…”

Section: Discussionmentioning

confidence: 99%

National Wetland Map 5 – An improved spatial extent and representation of inland aquatic and estuarine ecosystems in South Africa

Deventer¹,

Niekerk

Adams

et al. 2019

Preprint

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The improved representation of inland aquatic (freshwater) and estuarine ecosystems and associated data was a key component of the 2018 National Biodiversity Assessment, and is an essential step in enhancing defensible land use planning and decision making. This paper reports on this enhancement of the National Wetland Map version 5 (NWM5) for South Africa and other data layers associated with the South African Inventory of Inland Aquatic Ecosystems. Detail is provided on (i) the extent of wetlands mapped in NWM5, compared to previous versions of the NWMs; (ii) the improved extent of inland wetlands mapped in focus areas in NWM5 relative to NWM4; (iii) the type of cover associated with the wetlands (inundated, vegetated or arid); (iv) the ecotone between rivers or inland wetlands and estuaries mapped as freshwater-estuarine transition zones; and (v) level of confidence for the inland wetlands in terms of how well the extent and hydrogeomorphic units were captured for each sub-quaternary catchment of South Africa. A total of 4 698 824 ha (3.9% of South Africa) of inland aquatic ecosystems and artificial wetlands have now been mapped, with NWM5 delineating 123% more inland wetlands (2 635 809 ha or 2.2% of SA) compared with NWM4. The estuarine functional zone, which encapsulates all estuarine processes, associated habitats and biota, was refined for 292 systems totalling 188 944 ha, with the addition of 42 micro-estuaries totalling 246 ha. Nearly 600 000 ha (0.5% of SA) of artificial wetlands were mapped in SA. Inland wetlands are predominantly palustrine (55%), some arid (34%) and few inundated systems (11%). Transition zones between freshwater ecosystems and estuaries formed a small fraction (<1.5%) of river total extent (164 018 km), indicating an ecotone where biota and processes continuously vary from freshwater to estuarine. The majority of inland wetlands (~70%) had a low confidence ranking for designation of extent and typing. Future improvements of the map should be focussed on catchment-based improvements particularly in strategic water-source areas, areas of high development pressure and those with low confidence designation of wetland type.

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“…2008) -resulting in a mean MAR for the invadable area of 1 001 mm/yr based on the runoff surface generated by Nel et al (2017). The MAR reduction was multiplied by the projected condensed invaded area to give the projected reduction for each of the projected spread rates and tree mean ages.…”

Section: Figurementioning

confidence: 99%

“…The effect of IAPs on evapo-transpiration and runoff has been the subject of much research, originally being based on studies of the hydrological impacts of plantations on pines and eucalypts (Görgens and Le Maitre et al, 1996;Le Maitre et al, 2002) but subsequently extended to wattles (in a plantation), poplars and Prosopis species (see Le Maitre et al, 2015;Dzikiti et al, 2016;Dzikiti et al, 2013a;Dzikiti et al, 2013b;Milton and Dean, 2010;Le Maitre et al, 2009;Everson, et al, 2007). The original flow reduction models were based on volume reductions (e.g.…”

Section: Introductionmentioning

confidence: 99%

Impact of invasive alien plants on water provision in selected catchments

Preston

Maitre

Blignaut

et al. 2018

WSA

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We analyse the impact of failing to control invasive alien plants (IAPs) on the water supply to the Berg River and De Hoop Dams, in other words, the opportunity cost of not clearing IAPs in these two catchments. To do this we used models to assess and compare the impact of current and future invasions on inflows into the dams. Although the clearing of current invasions would only provide a modest increase in the amount of water compared to, for example, the construction of another dam, failure to clear the invasion will have a negative impact on water security in the long term. We estimated that the Berg River Dam could lose up to 51% of its mean annual inflows to IAPs over a 45-year period, and the De Hoop Dam catchment could lose up to 44%. These impacts would continue to increase over time, and the costs of control could become very high as the plants invade rugged terrain. Major infrastructural development requires Ministerial approval, supported by advice from senior officials. We suggest that such advice should substantively take sufficient account of the benefits of clearing existing invasions, or at least of preventing further invasions. Our results suggest that serious consequences arise from insufficient investment in catchment management. An integrated approach to the management of the supply of and demand for water, that ensures long-term sustainability, is essential in informed decision-making and the early control of IAPs is a key component of that approach.Keywords: invasive alien species, water supply, catchment management, long-term water security, investment in restoration of natural capital, economic impact of control

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Strategic water source areas for urban water security: Making the connection between protecting ecosystems and benefiting from their services

Cited by 69 publications

References 23 publications

Variation in thermal tolerances of native freshwater fishes in South Africa's Cape Fold Ecoregion: examining the east–west gradient in species' sensitivity to climate warming

Variation in thermal tolerances of native freshwater fishes in South Africa's Cape Fold Ecoregion: examining the east–west gradient in species' sensitivity to climate warming

National Wetland Map 5 – An improved spatial extent and representation of inland aquatic and estuarine ecosystems in South Africa

Impact of invasive alien plants on water provision in selected catchments

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