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Restoring riparian ecosystems in human-dominated landscapes requires attention to complexity, and consideration of diverse drivers, social actors, and contexts. Addressing a Global North bias, this case study uses a mixed-method approach, integrating historical data, remote sensing techniques and stakeholder perceptions to guide restoration of a river in the Western Cape, South Africa. An analysis of aerial photographs of the riparian zone from 1953 to 2016 revealed that although anthropogenic land conversion happened primarily before the 1950s, several land use and land cover classes showed marked increases in area, including: waterbodies (+ 1074%), urban areas (+ 316%), alien weeds (+ 311%) and terrestrial alien trees (+ 79%). These changes have likely been driven by land fragmentation, disturbance, and agricultural intensification. Stakeholder interviews revealed that despite the clear need for restoration, several barriers exist to successful implementation; these stem from inadequate financial resources, inappropriate funding models, institutional challenges, and a lack of techno-scientific knowledge. We give several recommendations to overcome these barriers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Healthy wetlands had higher C uptake, N&P uptake efficiency & flood attenuation. • Their value coupled with marginal agriculture advocates more strategic use of wetlands. • High downstream demand for ES suggests potential for payments for ES scheme. • The rapid tool didn't adequately assess degraded wetland ecosystem services (ES). • Healthy wetlands were accurately scored for ecosystem service provision by the tool. Abstract Wetlands globally are highly threatened by agriculture, and damage associated with it, such as invasion by alien species and the impacts of fertilizers and pesticides. South African palmiet wetlands make an interesting case study to investigate this, as they are valuable valley-bottom, peat-forming systems, highly threatened by agricultural development. Currently most agriculture in these palmiet wetlands is marginal (low agricultural productivity) due to the challenges of farming a system that experiences severe floods and erodes rapidly, forming gullies, when wetland vegetation is disturbed. The current situation seems to be a lose-lose situation for nature and society. We aimed to assess this conflict between water-related services and agriculture objectively by comparing provision of fifteen ecosystem services by degraded and pristine sections of three palmiet wetlands using a rapid ecosystem service assessment tool (WET-Ecoservices). To validate this technique, we compared results to those obtained from examining three key ecosystem service complexes in slightly more detail. We found that pristine palmiet wetlands provide valuable ecosystem services to society, which are currently being compromised for private, marginal agricultural gain. These pristine wetlands sequester between 21 and 41 g.m−2 of carbon per year, have nitrogen and phosphorus uptake efficiencies of 62–85% and 16–89% respectively, and provide about 16 times more flood attenuation relative to degraded ones. The full impact of degradation on wetland ecosystem services was not entirely captured by the rapid ecosystem service assessment tool: WET-Ecoservices. We suggest some adaptations to this tool for the valley-bottom wetland hydro-geomorphic unit. Overall, these wetlands have high potential for incorporation into a Payments for Ecosystem Services scheme, due to the ecosystem services provided and their position above important municipal dams. We recommend collaboration between private landowners struggling with marginal agriculture, and decision makers in cities dealing with water shortages and debt to ensure the most efficient and judicious use of these palmiet wetland ecosystem services. [ABSTRACT FROM AUTHOR]

Commercial plantations and alien tree invasions often have substantial negative impacts on local biodiversity. The effect of plantations on faunal communities in the fire‐adapted fynbos vegetation of the Cape Floristic Region biodiversity hotspot is not yet well quantified. We studied small mammal community structure in alien Pinus radiata plantations and adjacent fynbos regenerating after clear‐felling of plantations on the Cape Peninsula, South Africa. Small mammal sampling over 1,800 trap‐nights resulted in 480 captures of 345 individuals (excluding recaptures) representing six species. Significantly more species, individuals (12 X) and biomasses (29 X) of small mammals occurred on recovering fynbos sites compared to plantations. This was commensurate with a higher diversity of plant growth forms, vegetation densities and live vegetation biomass. Only one small mammal species, the pygmy mouse (Mus minutoides), was consistently trapped within plantations. Fynbos sites were dominated by three small mammal species that are ecological generalists and early successional pioneer species, rendering the recovering fynbos slightly depauperate in terms of species richness and evenness relative to other studies done in pristine fynbos. We make three recommendations for forestry that would facilitate the restoration of more diverse natural plant communities and progressively more diverse and dynamic small mammal assemblages in a key biodiversity hotspot. [ABSTRACT FROM AUTHOR]

Despite the importance of water purification to society, it is one of the more difficult wetland ecosystem services to quantify. It remains an issue in ecosystem service assessments where rapid estimates are needed, and poor-quality indicators are overused. We attempted to quantify the water purification service of South African palmiet wetlands (valley-bottom peatlands highly threatened by agriculture). First, we used an instantaneous catchment-scale mass balance sampling approach, which compared the fate of various water quality parameters over degraded and pristine sections of palmiet wetlands. We found that pristine palmiet wetlands acted as a sink for water, major cations, anions, dissolved silicon and nutrients, though there was relatively high variation in these trends. There are important limitations to this catchment-scale approach, including the fact that at this large scale there are multiple mechanisms (internal wetland processes as well as external inputs) at work that are impossible to untangle with limited data. Therefore, secondly, we performed a small field-scale field survey of a wetland fragment to corroborate the catchment-scale results. There was a reasonable level of agreement between the results of the two techniques. We conclude that it appears possible to estimate the water purification function of these valley-bottom wetlands using this catchment-scale approach. [ABSTRACT FROM AUTHOR]

Plant functional traits (PFTs) underpin ecosystem processes and therefore ecosystem service provision. If PFTs are possible to detect and discriminate spectrally, then it may be possible to use remote sensing applications to map ecosystem processes or services within and across landscapes. As a first step towards this application, we explored whether functional groups of 22 dominant South African wetland species were spectrally separable based on their PFTs. We measured 23 biochemical and morphological PFTs in combination with spectra from 350 to 2349 nm using a handheld radiometer. First, we evaluated the possibility of accurately predicting morphological and biochemical PFTs from reflectance spectra using three approaches: spectrum averaging, redundancy analysis (RDA), and partial least squares regression (PLSR). Second, we established whether functional groups and species were spectrally distinguishable. We found seven PFTs to be important in at least two of the three approaches: four morphological and three biochemicals. Morphological traits that were important were leaf area (PLSR: r 2  = 0.40, regression: r 2  = 0.41), specific leaf area (r 2  = 0.67), leaf mass (r 2  = 0.43, r 2  = 0.38), and leaf length/width ratio (r 2  = 0.62). Biochemical traits that play a role in the structural composition of vegetation, like lignin content (r 2  = 0.98, r 2  = 0.54), concentration (r 2  = 0.45) and cellulose content (r 2  = 0.57, r 2  = 0.49), were found to be important by at least two of the analyses. Three other traits were important in at least one of the analyses: total biomass (r 2  = 0.56), leaf C/N ratio (r 2  = 0.99), and cellulose concentration (r 2  = 0.76). Redundancy analysis suggests that there is a large percentage (52%) of the spectrum not explained by the PFTs measured in this study. However, spectral discrimination of functional groups, and even species, appears promising, mostly in the ultraviolet A part of the spectrum. This has interesting applications for mapping PFTs using remote sensing techniques, and therefore for estimating related ecosystem processes and services. [ABSTRACT FROM AUTHOR]

Quantification of ecosystem services ( ES) is an important step in operationalizing the concept for management and decision-making. With the exponential increase in ES research, ES have become a 'catch-all phrase', which some suggest has led to a poorly defined, impractical and ambiguous concept. An overview of the methods used in ES quantification is needed to examine their scientific rigour and provide guidelines for selecting appropriate measures., We present a systematic review of 405 peer-reviewed ES research papers to address the question: 'Is the biophysical and socio-economic reality of ES adequately quantified? First, we considered whether ES measures are scientifically rigorous enough by considering four predefined criteria (the type of data used, quantification of uncertainty, validation done and data reported). Secondly, using a novel approach, we determined which part of the ES cascade was measured: the ecosystem property, function, service, benefit or value., Our results showed that each of the 21 ES analysed had on average 24 different measures, which may indicate the complex reality of ES and/or suggest a potential lack of consensus on what constitutes an ES. We found that uncertainty is often not included and validation mostly missing., When analysing which part(s) of the ES cascade each measure corresponded to, we found that for regulating ES, ecosystem properties and functions (ecological aspects) are more commonly quantified (67% of measures). Conversely for provisioning ES, benefits and values (socio-economic aspects) are more commonly quantified (68%). Cultural ES are predominantly quantified using scores (35%)., In conclusion, ES appear to be poorly quantified in many cases, as often only one side of the cascade is considered (either the ecological or socio-economic side) and oversimplified and variable indicators are often used., Policy implications. This review provides a detailed overview of ecosystem services ( ES) quantification (ranging from simple scores to advanced methods) with the aim to support future ES quantification and ultimately the successful application of the ES concept. [ABSTRACT FROM AUTHOR]

Valley-bottom wetlands are valuable assets as they provide many ecosystem services to mankind. Despite their value, valley-bottom wetlands are often exploited and land-use/land-cover ( LULC) change results in trade-offs in ecosystem services. We coupled physically based hydrological modeling and spatial analysis to examine the effects of LULC change on water-related ecosystem services in the Kromme catchment: an important water-providing catchment for the city of Port Elizabeth. LULC scenarios were constructed to match 5 different decades in the last 50 years to explore the potential effects of restoring the catchment to different historic benchmarks. In the Kromme catchment, valley-bottom wetlands have declined by 84%, driven by key LULC changes: an increase in irrigated land (307 ha) and invasion by alien trees (336 ha). If the wetlands were restored to the relatively pristine extent and condition of the 1950s, riverflow could increase by approximately 1.13 million m3/a, about 6% of the current supply to Port Elizabeth. Wetland restoration would also significantly improve the catchment's ability to absorb extreme rainfall events, decreasing flood damage. We conclude that in the face of the water scarcity in this region, all ecosystem services, particularly those related to water flow regulation, should be taken into account by decision makers in charge of land zonation. Zonation decisions should not continue to be made on the basis of provisioning ecosystem services alone (i.e. food provision or dam yield). We recommend prioritization of the preservation and restoration of valley-bottom wetlands providing water-related ecosystem services to settlements downstream. [ABSTRACT FROM AUTHOR]

[Display omitted] • Alien tree clearing is predicted to increase mean streamflow by 15.1–29.5%. • Clearing trees in riparian areas had a 1.7x greater impact than terrestrial areas. • Greatest impacts were in the mid to low flows, and in dry relative to wet years. • Caused by decreasing transpiration and increasing overland flow and interflow. • Clearing exotic trees from treeless ecosystems may improve water security. Ecological restoration efforts at scale have been shown to play an important role in reducing human impact on the environment, improving climate change adaptation and halting extinctions globally. Upscaling restoration efforts requires funding, and therefore evidence of the benefits of restoration is needed. This study aims to contribute towards addressing these gaps by: (1) bolstering the evidence base of the water-related impacts of investment into ecological restoration by improving the methods of predicting the streamflow impacts of alien tree clearing; and (2) exploring the potential size of the variability in catchment responses at a fine-scale (60x60 m) in one particular region by comparing four different neighbouring catchments. We model the impacts on streamflow in four strategic water providing catchments using the fully-distributed MIKE-SHE modelling tool. We find that the benefits of clearing mature infestations of alien trees, such as pines, from naturally tree-less ecosystems can increase available surface water resources by 15.1 to 29.5%. Clearing riparian invasions is predicted to have a 1.7 times greater impact compared to terrestrial (non-riparian) invasions. The largest modelled impact of restoration on streamflow is on the mid to low flows, and this impact is greater in dry years relative to wet years. The findings are novel in that they shed light on the types of spatial uncertainties that can be expected in modelled gains, with implications for generalisation. These findings are important for leveraging investment to upscale restoration efforts in water scarce regions, as they suggest improved water security during the dry season and droughts. Upscaling efforts is essential if the degradation of ecosystems globally is to be prevented, halted and reversed, as proposed by the United Nations Decade on Ecosystem Restoration. [ABSTRACT FROM AUTHOR]

Scaled up planning and implementation of nature-based solutions requires better understanding of broad characteristics (typologies) of the current governance and financing landscape, collaborative approaches amidst local complexities, and factors of scalability. An inventory was compiled of water-related ecological infrastructure intervention projects in two river systems in South Africa, incorporating actor, environmental, social, and financial dimensions and benefits. Qualitative participatory analysis revealed eight typologies. Post-hoc classification analysis determined similarities and/or unique characteristics of seven quantitative typologies. Key characterising factors included the complexity/size of financial flows, complexity of partnership/governance arrangements, mandates/goals of actors, type of ecological infrastructure, trade-offs in investment in ecological/built infrastructure, and the model used for social benefits. Identified scalable typologies offer structures suited to increased investment, with other typologies offering specialised local value. A range of ecological infrastructure intervention typologies with differing biophysical and socioeconomic outcomes provide choices for investors with specific goals, and benefits to landscape actors. [ABSTRACT FROM AUTHOR]