Browsing by Author "Van Deventer, Heidi"
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Item Assessing changes in the hydrological regime of lacustrine wetlands in the Maputaland Coastal Plain, South Africa (2024)(2024-08) Ndlovu, N; Van Deventer, Heidi; Hansen, C; Landman, WAssessing changes in the hydrological regime of lacustrine wetlands in the Maputaland Coastal Plain, South Africa.Item Assessing leaf spectral properties of Phragmites australis impacted by acid mine drainage(AOSIS Open Journals, 2014-07) Van Deventer, Heidi; Cho, Moses AThe decanting of acid mine drainage (AMD) from the Western Basin on the Witwatersrand in late 2010 raised concerns about AMD risks in other gold, coal and copper mining areas of South Africa. Field spectroscopy and the use of vegetation indices could offer an affordable and easy means of monitoring the impact of mine water and/or AMD on vegetation. The impact of raw and treated mine water or contaminated soil on wetland vegetation often manifests in growth inhibition and reduction of foliar pigments and nutrient levels. Surveying the impact on wetland vegetation or underlying soils can be difficult and expensive considering the cost of laboratory analysis of samples. The potential of field spectroscopy for detecting the impact of mine water on wetland vegetation was examined by assessing (1) whether there was a significant difference in leaf spectra between sites receiving mine water and a non-impacted control site and (2) whether there was a gradation of vegetation condition downstream from the decanting site. Two vegetation indices were derived from portable field spectrometer-measured spectra of five green leaves of Phragmites australis – the chlorophyll red edge position (REP) and the normalised difference vegetation index (NDVI) – for two dormant (winter) and peak growth (summer) seasons in 2011–2012. Mean REP and NDVI values were significantly (p<0.05) lower for affected sites compared to the control site for both seasons and years. The range of REP values for young green leaves in winter for affected sites was 695–720 nm compared to the narrower range of 705–721 nm for the control site. The mean REP values for young green leaves in winter was 708 nm for the affected sites compared to 716 nm for the control site. The downstream gradation, however, fluctuated for REP and NDVI over the study period. We conclude that field spectroscopy shows potential to serve as a relatively quick and affordable means to assess the condition and health of vegetation affected by AMD.Item Assessing the effects of subtropical forest fragmentation on leaf nitrogen distribution using remote sensing data(Springer, 2013-10) Cho, Moses A; Ramoelo, Abel; Debba, Pravesh; Mutanga, O; Mathieu, Renaud SA; Van Deventer, Heidi; Ndlovu, NSubtropical forest loss resulting from conversion of forest to other land-cover types such as grassland, secondary forest, subsistence crop farms and small forest patches affects leaf nitrogen (N) stocks in the landscape. This study explores the utility of new remote sensing tools to model the spatial distribution of leaf N concentration in a forested landscape undergoing deforestation in KwaZulu-Natal, South Africa. Leaf N was mapped using models developed from RapidEye imagery; a relatively new space-borne multispectral sensor. RapidEye consists of five spectral bands in the visible to near infra-red (NIR) and has a spatial resolution of 5 m. MERIS terrestrial chlorophyll index derived from the RapidEye explained 50 % of the variance in leaf N across different land-cover types with a model standard error of prediction of 29 % (i.e. of the observed mean leaf N) when assessed on an independent test data. The results showed that indigenous forest fragmentation leads to significant losses in leaf N as most of the land-cover types (e.g. grasslands and subsistence farmlands) resulting from forest degradation showed lower leaf N when compared to the original indigenous forest. Further analysis of the spatial variation of leaf N revealed an autocorrelation distance of about 50 m for leaf N in the fragmented landscape, a scale corresponding to the average dimension of subsistence fields (2,781 m2) in the region. The availability of new multispectral sensors such as RapidEye thus, moves remote sensing closer to widespread monitoring of the effect of tropical forest degradation on leaf N distribution.Item Assessing the extent to which African wetland inventories can report to the global targets on biodiversity, including Goal A of the Global Biodiversity Framework(2024) Sadiki, MM; Van Deventer, Heidi; Hansen, CDWetlands face global threats with estimates suggesting a loss ranging from 21% to 85% of their original extent. Africa’s wetlands, covering about 4.4% of the continent, provide crucial services to millions of people and harbour significant biodiversity. This study assesses African countries’ readiness for the Kunming−Montreal Global Biodiversity Framework (GBF) through wetland inventories. It examines the progress made under the Aichi Targets for 2020, revealing 39% of reporting African countries indicating being on track for Aichi Target 11. Subsequently, the study explores wetland inventorying trends from national reports made to the Ramsar Convention from COP07 (1999) to COP14 (2022), showcasing increased membership and progress in African countries. Notable patterns emerge, revealing challenges in maintaining accurate inventories. Despite varying responses, 67% of African countries reported having a comprehensive wetland inventory at one point in the past 23 years. However, the wetland inventories are out of date, and critical information is not easily accessible, hampering accurate reporting on the current state of wetlands, and hindering informed decision-making for conservation and protection initiatives. Global datasets have contributed to reporting on wetland ecosystems; however, biodiversity-focused wetland typology systems like the IUCN Global Ecosystem Typology are crucial for a comprehensive understanding of wetland ecosystems.Item Assessing the feasibility of mapping changes of ecosystem functional groups in South African estuaries using Landsat and Sentinel images of 1990, 2014, 2018 and 2020(2024-12) Van Deventer, Heidi; Apleni, P; Adams, JB; Riddin, T; Whitfield, E; Machite, A; Van Niekerk, LaraThis study evaluates the feasibility of using medium-resolution satellite sensors to monitor changes in the extent of ecosystem functional groups (EFGs) in South African estuaries, for reporting on the 2030 targets of the Global Biodiversity Framework (GBF). Landsat and Sentinel-1 and -2 image collections in Google Earth Engine (GEE) were used to generate output layers for each of the national land cover years—1990, 2014, 2018 and 2020. Image composites of each year’s two growth seasons and one dry season, vegetation indices and topographic data were generated. Changes in the extent and accuracies of three estuarine (mangroves, salt marshes and submerged macrophytes) and three freshwater (forested wetlands, freshwater marshes and large macrophytes) EFGs were calculated and compared to a manually mapped through image interpretation, high-confidence layer. Overall, estuarine EFGs comprised between 10 and 18% of the extent of the EFGs, while freshwater EFGs made up 15% of the extent of estuaries. The overall accuracies of detection of EFGs for 1990 were < 64% compared to the > 71% attained for 2014, 2018 and 2020. In comparison to manual delineations of some of these habitats, the outputs generated from these medium-resolution sensors resulted in overestimation of extent for all EFGs; for mangroves by 115% and for salt marshes and submerged macrophytes by 150–230%. Finer spatial resolution images, and time-series mapping would be critical for improved delineation and monitoring of South Africa’s estuarine habitats.Item Assessment of the inland wetland ecosystem types in South Africa: threats and protection(2025-04) Van Deventer, Heidi; Nel, JLEcosystem threat status (ETS) and ecosystem protection levels (EPLs) are headline indicators that can assess freshwater ecosystems at a country-wide scale. A spatial layer of freshwater, inland wetland ecosystem types of South Africa was combined with a range of spatial data sets to model their ecological condition. The ETS and EPL of each ecosystem type were determined using the area of that type in good ecological condition relative to a biodiversity target, which represented 20% of the total area of that ecosystem type. Thresholds were applied to distinguish four ETS categories ranging from Least Concern to Critically Endangered, and four EPL categories ranging from Not Protected to Well Protected. A total of 79% of the 135 of South African inland wetland ecosystem types were found to be threatened, of which 83 (62% of the number of types) are Critically Endangered, 12 (9%) are Endangered, 12 (9%) are Vulnerable and 28 (21%) of Least Concern. Of the 135 inland wetland types, 61% were Not Protected, with 6% being Well Protected, 3% Moderately Protected, and 30% Poorly Protected. Protected and Ramsar sites hosted only 7% of the total area of inland wetlands, which means that the Aichi Biodiversity Target 11 for 2020 (17%) was not met.Item Blue Carbon at the southern tip of Africa: Current knowledge and future perspectives for dynamic estuarine environments(2025-09) Adams, JB; Buttner, D; Hawkes, S; Human, LRD; Machite, A; Mfikili, AN; Ndhlovu, A; Smit, L-A; Van Deventer, Heidi; Van Niekerk, LaraBlue Carbon Ecosystems (BCEs), specifically salt marsh, seagrass, mangroves, occur in South Africa's relatively small, sheltered estuaries that are often disconnected from the ocean. These are dynamic environments where shifts between BCEs and other habitats along ecotones occur in response to mouth changes, floods and droughts, as well as anthropogenic pressures. Although Blue Carbon is becoming well established in South Africa, critical knowledge gaps remain; these are summarised under seven themes and future research and management actions identified. A holistic approach is recommended for Blue Carbon studies in estuaries to measure across elevation gradients (rather than focusing on individual vegetation types) and to include reeds, sedges and forested wetlands. Additionally, quantifying data deficient carbon stocks and processes, modelling future climate change impacts, instilling a sustainable long-term monitoring program, incorporating relevant emerging blue carbon stocks, realizing nationally inclusive restoration and protection co-management plans, and aligning local approaches with global frameworks of reporting are advocated as future recommendations with respect to South African BCEs. South Africa has high biodiversity and unique pressures influencing BCEs and is well positioned to inform the global research agenda. While the limited spatial extent of BCEs restricts the feasibility of carbon credit opportunities, high biodiversity values of these ecosystems hold potential under emerging ‘nature credit’ frameworks.Item Charting a course for freshwater biomonitoring: The grand challenges identified by the global scientific community(2025-07) Yates, AG; Brua, RB; Culp, JM; Aguiar, FC; Ajayan, AP , AG Brua; Aspin, T; Bundschuh, M; Calderón, MR; Van Deventer, Heidi; Van Niekerk, LaraThe past 50 years have seen biomonitoring emerge as an essential means of generating the knowledge needed to inform protection and restoration of freshwater ecosystems. Despite the successes of biomonitoring, most freshwater ecosystems remain unmonitored. Moreover, degradation of freshwaters continues at a rapid rate with new threats and novel stressors emerging that are difficult to assess using existing techniques. New technologies and techniques have been developed to improve biomonitoring, but application has been slow and integration with existing approaches is often problematic. Clearly, freshwater biomonitoring faces many important challenges that must be addressed to meet management needs of the coming decades. We identify Grand Challenges facing freshwater biomonitoring with the aim of encouraging research and practice to address these challenges. We asked 256 biomonitoring scientists from around the globe to identify what they considered the most important challenges. From their submissions we established five Grand Challenges and 18 associated subchallenges. For each Grand Challenge, we outline the current state of biomonitoring practice and suggest promising pathways and approaches to address them. By identifying and describing these challenges, we strive to position freshwater biomonitoring to take advantage of emerging opportunities and enhance its capacity to meet current and future management needs.Item Collating data for freshwater biodiversity planning in South Africa(2010-03) Petersen, C; Nel, JL; Smith-Adao, Lindie B; Maherry, A; Van Deventer, Heidi; Van Niekerk, Lara; Amis, M; Bhengu, S; Hardwick, D; Mack, S; Mbona, N; Swartz, E; Wistebaar, NThe National Freshwater Ecosystem Priority Areas (NFEPA) project builds on the river component of the National Spatial Biodiversity Assessment (NSBA) 2004, and will feed directly into the National Biodiversity Assessment (NBA) 2010. This multi-partner project between CSIR, WRC, SANBI, DWEA, WWF, SAIAB and SAN Parks aims to identify a national network of freshwater conservation areas and to explore institutional mechanisms for their implementation. A range of input data layers were used in the NFEPA project. These data layers include for example river networks, sub-quaternary catchments, river types, mosaiced land cover and transformed water bodies, river condition, free-flowing rivers, wetland delineations, significant wetland clusters, estuary delineations, high groundwater recharge areas, high water yield areas per primary catchment, fish sanctuaries, etc. The data layers were refined and finalized following regional expert review from May to July 2009 for the NFEPA planning process. These data layers will be incorporated into a series of maps per Water Management Area, showing the freshwater ecosystem areas identified. The input GIS layers used are briefly described, together with methods that were used to collate the data. Furthermore, data dissemination through for example SANBI's BGIS website (http://bgis.sanbi.org) will be discussed as well as the development of an atlas of freshwater conservation planning in South Africa.Item Conserving cross-realm coastal biodiversity when real-world planning and implementation processes split the land and sea(2025-04) Harris, LR; Van Niekerk, Lara; Holness, SD; Sink, KJ; Skowno, AL; Dayaram , A; Van Deventer, Heidi; Job, N; Lamberth , SJ; Adams, JB; Raw, JL; Riddin, T; MacKay , CF; Perschke, MJConservation planning and implementation are typically applied in land and sea areas separately, placing already impacted coastal biodiversity – which spans the divide – at risk of being inadequately managed and conserved. In South Africa, we tested how well existing land-based and marine biodiversity priority areas cover coastal priorities that we identified cross-realm using Marxan with >1000 biodiversity features. Existing priorities covered 83% of coastal priorities, indicating good but incomplete coverage. Proportionately, the seashore (foredunes, shores) and estuaries had greatest selection as coastal priorities, confirming their important biodiversity value. Finally, we developed a map of Critical Biodiversity Areas for the South African seashore and estuaries, with management recommendations. To include coastal biodiversity in real-world planning, we propose: co-developing data and targets for cross-realm features; identifying broad coastal priorities that can be used in land-based and marine plans; and developing dedicated seashore and estuary priorities to seamlessly align land-based and marine prioritisation maps.Item Determining the wetland-dryland boundary of depressions using littoral gradient analysis of soil edaphic factors(2021-08) Nondlazi, Basanda X; Cho, Moses A; Van Deventer, Heidi; Sieben, EJDepressional wetlands are highly vulnerable to changes in land surface temperature and rainfall but little is known about their responses to future climate change. This study assessed the variation in edaphic factors between wetlands and along their littoral gradients to detect the boundary between the endorheic wetlands and upland zones. A sample of 202 paired measurements of three edaphic factors were collected (Soil Moisture Content – SMC-g/g, Bulk Density – BD-g/cm 3 and Salinity as Electrical Conductivity – EC-dS/m) in 10 m plots along 14 belt transects in eight representative wetlands in the Mpumalanga Lake District, South Africa. In general, there were significant differences between the eight wetlands for SMC and BD but not for EC.SMC and BD generally showed negative trends along the littoral gradients. The trends occurred over short distances, ranging from 30 to 70 m, reflecting the extent of the wetlands. Understanding of the spatial variation of edaphic factors helps in the management and monitoring of depressional wetlands under a changing climate. In addition, the study showed that the current wetland buffer zone stipulated in local legislation was too narrow and recommended that this be extended to 100 m.Item Do seasonal profiles of foliar pigments improve species discrimination of evergreen coastal tree species in KwaZulu- Natal, South Africa?(2013-04) Van Deventer, Heidi; Cho, Moses A; Mutanga, OStudies in the Northern hemisphere have shown the potential of foliar pigment seasonal profiles as a means of improving species discrimination. Remote sensing vegetation indices have been used to optimise absorption features presented by foliar pigments, as well as improve species discrimination. This study investigated the potential of seasonal pigment profiles (for foliar carotenoid and total chlorophyll) in improving species discrimination for trees using leaf spectral data. Our aims were to (i) determine whether species have unique seasonal profiles of carotenoids and chlorophyll; and (ii) whether these seasonal profiles can be used to improve species discrimination, compared to single season pigment concentrations. We sampled sunlit leaves of seven evergreen tree species in a sub-tropical region of South Africa, over four seasons during 2011-12. Parametric ANOVA classification was compared to similarity measures of shape (spectral angle mapper; SAM) and magnitude (sum of Euclidean Distance; ED). For both pigments, the parametric analysis of combined seasonal content improved species discrimination when compared to single season content and the similarity measures. ED outperformed SAM in species discrimination for both pigments. Multi-seasonal carotenoid and chlorophyll content information improved species discrimination of evergreen coastal tree species in KwaZulu-Natal, South Africa.Item Earth Observation for Biodiversity Assessment (EO-BA)(2012-10) Cho, Moses A; Debba, Pravesh; Mathieu, Renaud SA; Ramoelo, Abel; Naidoo, Laven; Van Deventer, Heidi; Malahlela, O; Mathieu, Renaud SAThe Earth Observation for Biodiversity Assessment (EO-BA) programme is designed to enhance biodiversity assessment and conservation through the application of earth observation data, with particular focus on the African continent.Item Estimating above ground biomass as an indicator of carbon storage in vegetated wetlands of the grassland biome of South Africa(Elsevier, 2019-06) Naidoo, Laven; Van Deventer, Heidi; Ramoelo, Abel; Mathieu, Renaud; Nondlazi, Basanda; Gangat, RWetlands store higher carbon content relative to other terrestrial ecosystems, despite the small extent they occupy. The increase in temperature and changes in rainfall pattern may negatively affect their extent and condition, and thus the process of carbon accumulation in wetlands. The introduction of the Sentinel series (S1 and S2) and WorldView space-borne sensors (WV3) have enabled monitoring of herbaceous above ground biomass (AGB) in small and narrow wetlands in semi-arid areas. The objective of this study was to assess (i) the capabilities of the high to moderate resolution sensors such as WV3, S1A and S2A in estimating herbaceous AGB of vegetated wetlands using SAR backscatter, optical reflectance bands, vegetation spectral indices (including Leaf Area Index or LAI measurements) and band ratio datasets and (ii) whether significant differences exists between the AGB ranges of wetland and surrounding dryland vegetation. A bootstrapped Random Forest modelling approach, with variable importance selection, was utilised which incorporated ground collected grass AGB for model calibration and validation. WorldView-3 (WV3) yielded the highest AGB prediction accuracies (R2=0.63 and RMSE=169.28g/m2) regardless of the incorporation of bands only, indices only or the combination of bands and indices. In general, the optical sensors yielded higher modelling accuracies (improvement in R2 of 0.04-0.07 and RMSE of 11.48–17.28g/m2) than the single Synthetic Aperture Radar (SAR) sensor but this was marginal depending on the scenario. Incorporating Sentinel 1A (S1) dual polarisation channels and Sentinel 2A (S2) reflectance bands, in particular, yielded higher accuracies (improvement in R2 of 0.03–0.04 and RMSE of 5.4–16.88g/m2) than the use of individual sensors alone and was also equivalent to the performance of the high resolution WV3 sensor results. Wetlands had significantly higher AGB compared to the surrounding terrestrial grassland (with a mean of about 80g/m2 more). Monitoring herbaceous AGB at the scale of the wetland extent in semi-arid to arid grasslands enables improved understanding of their carbon sequestration potential, the contributions to global carbon accounting policies and also serving as a proxy for functional intactness.Item Estimating Green and Teal carbon stocks across the Gauteng Province of South Africa using a multi-source remote sensing approach(2024-09) Naidoo, L; Main, R; Van Deventer, HeidiEstimating Green and Teal carbon stocks across the Gauteng Province of South Africa using a multi-source remote sensing approach.Item Forty years of remote sensing mapping and monitoring of freshwater ecosystems in South Africa(2021-10) Van Deventer, HeidiThe first space-borne satellite was launched nearly fifty years ago in 1972, initiating global monitoring of freshwater ecosystems. Space-borne images have contributed to forty years of mapping and monitoring of wetlands in South Africa, and are important tools in our monitoring toolboxes. Changes in the areal extent and water quality of the lacustrine wetland biome have advanced much faster compared to studies on the palustrine wetland biome. Studies related to the palustrine wetland biome, making up 89% of the known wetland extent of South Africa, are rare and predominantly done at a fine scale. Most studies used land cover data to map and monitor changes in both the lacustrine and palustrine wetland biomes, however, a significant amount of work is required to improve our knowledge on the palustrine wetland biome in our country. Examples of how remote sensing was used to quantify Essential Biodiversity Variables of palustrine wetlands will be showcased, including the mapping of above-ground biomass, phenology, soil moisture, fire disturbances in peatlands, the hydrological regime and other health indices. The value of South Africa's land cover maps, derived from satellite remote sensed images, is also explored for use in the red listing of freshwater ecosystems. Four epochs of KZN's land cover data sets (2005, 2008, 2011 and 2017), derived from SPOT and Sentinel2 images, were used to quantify changes in the extent and fragmentation of subtropical-temperate forested wetlands on the Maputaland Coastal Plain. The limitations of these provincial data sets were compared to a finer-scale study, showing the challenges in using the coarser-scale data in estimating rates of decline. For example, the total extent lost over 11 years appeared to be underestimated using the provincial scale data.Item Generating alternative alignments in terrain suitability studies for environmental impact assessments of linear developments(2010-08) Van Deventer, HeidiThe construction of linear developments, such as roads, railways, pipelines and power lines, in South Africa requires a number of alternatives to be considered prior to the submission of a proposed development for an Environmental Impact Assessment (EIA). Though legislation requires a screening or scoping of alternative options prior to the EIA, the use of Geographical Information Systems (GIS) is seldom used in generating alternatives through a Terrain Suitability Study (TSS). The inclusion of a wide variety of specialist in a TSS could ensure a well informed choice of alternatives for the EIA and a choice of optimum corridors, could result in cost savings. This may in turn avoid delays during the EIA process if routes were rejected completely by the public and have to be rerouted and new specialist studies done. This study investigates the benefits of generating alternative corridors in a TSS as part of the preplanning phase of an EIA. The inclusion of a number of specialists and environmental aspects are discussed to ensure a democratic and participative process. Methods for generating alternatives using GIS, are also described. The results are shown to demonstrate how the alternatives were voted for by the specialists and recommendations made on improvement and proceeding into the EIA.Item Global biodiversity framework for freshwater wetlands of South Africa: Preliminary calculation of progress towards achieving the restoration target of goal 2(2025-03) Van Deventer, Heidi; Durand, F; Grundling, PLThe National Biodiversity Assessment of 2018 listed wetlands (estuaries and freshwater ecosystems) as the most threatened ecosystem of South Africa. By 2030, South Africa must report to the United Nations’ Global Biodiversity Framework (GBF) to which degree we have reached Target 2 that aims to have 30% of the extent of degraded ecosystems under restoration. This study aimed to calculate the preliminary extent as a percentage of wetlands that have been under ecological restoration interventions, relative to the total extent of degraded freshwater wetlands of South Africa. We also assessed the percentage of extent relative to ownership of the degraded wetlands and those that are under ecological restoration. Data released by the Working for Wetlands and Working for Water programmes were combined with the National Wetland Map version 6 as well as information on land ownership and protection level status of the country. The majority of the freshwater wetlands (51%) were modelled as degraded, with > 2 million ha of the 4 million ha of wetlands showed impacts resulting from various pressures, including changes to the hydrological cycle, water quality, fragmentation and degradation of habitats, climate change, or a combination of these pressures. The 30% GBF Target 2 requires that almost 613 136 ha of freshwater wetlands should be under restoration by 2030. The government’s two restoration programmes have reached only 203 283 ha (10%) of the desired target. The majority (82,8%) of freshwater wetlands is located on private land, of which the majority is degraded. Many of the impacts and none of the restoration interventions undertaken by the private sector or individuals are refl ected. Monitoring and quantifi cation of all freshwater habitats are therefore needed to attain the 30% extent target of the GBF.Item Identifying the best season for mapping evergreen swamp and mangrove species using leaf-level spectra in an estuarine system in KwaZulu-Natal, South Africa(AARSE2014, 2014-10) Van Deventer, Heidi; Cho, Moses A; Mutanga, O; Naidoo, Laven; Dudeni-Tlhone, NSwamp and mangrove forests are some of the most threatened forest types in the world. In Africa, these forests are essential in providing food, construction material and medicine to people. These forest types have not sufficiently been mapped and changes in the extent or quality of these habitats can therefore not be effectively monitored. Compared to traditional surveying methods, remote sensing can be used to map these inaccessible areas over regional extents. This study investigated which season would provide the best discrimination of six evergreen tree species, associated with swamp (Ficus Trichopoda), mangrove (Avicennia marina, Bruguiera gymnorrhiza, Hibiscus tiliaceus), wetlands in adjacent woodlands (Syzygium cordatum) and coastal floodplain systems (Ficus sycomorus), using leaf-level hyperspectral data. Leaf spectra were collected from 113 trees for the winter, spring, summer and autumn months between the years of 2011-2012 in the subtropical estuarine system of the uMfolozi, uMsunduzi and St Lucia Rivers, on the east coast of KwaZulu-Natal, South Africa. The classification accuracy for each season was evaluated in the WEKA software using the Random Forest classification algorithm. When the data was upscaled to canopy-level, the results showed that all four seasons produced overall accuracies of > 90%. Spring, summer and autumn produced the highest overall accuracy of 94.7%, whereas the overall accuracy for winter was 89.5%. The results of the leaf-level analysis showed a decrease in accuracy of between 4 – 11% for the four seasons. Similar to other studies, our results showed that the simulated object-oriented approach showed a higher level in accuracy compared to the pixel-level approach. The results of this study showed that evergreen tree species around the uMfolozi, uMsunduzi and St Lucia Rivers in KwaZulu-Natal, South Africa, is highly separable over all four seasons. Further analysis will be done to assess whether the accuracies can be improved for certain species, for example Ficus trichopoda. Similar tests should be done on other tropical and subtropical regions of Africa, to assess whether these trends prevail for other species and regions.Item Incorporating free-flowing rivers into global biodiversity targets: Prioritization and targeted interventions to maintain ecological integrity(2022-12) Petersen, CR; Van Deventer, Heidi; Smith-Adao, Lindie B; Nel, JLFree-flowing rivers (FFRs) are important surrogates for freshwater biodiversity as there are increasingly fewer rivers that reflect intact habitat and species diversity from source to sea. The status and changes in the ecological condition or protection of FFRs is not explicitly reported on in global biodiversity targets. Indices are proposed for reporting such changes to the Sustainable Development Goals (SDGs) 6 and 15, Aichi Target 11, and the post-2020 global biodiversity framework. FFRs were identified at a countrywide scale in South Africa for protection, planning, monitoring, and assessing changes in their ecological condition and protection status. They were selected and prioritized using criteria co-produced with national, provincial, and local river managers and policy makers. Given the high competition for water resources and the unlikely possibility for strictly protecting all FFRs, a subset of FFRs, termed ‘flagship FFRs’, was identified. Methods for reporting changes in the protection levels of prioritized FFRs at a countrywide scale were developed, which included indices of FFRs related to global targets: the loss of the extent of FFRs in a natural and largely natural ecological condition for SDG 6; changes in the connectivity of FFRs included in the post-2020 global biodiversity framework targets; and changes in protection levels of FFRs for Aichi Target 11 and SDG 15.1.2. Flagship FFRs attracted targeted management initiatives and thus maintained their connectivity and ecological condition. This was not true when all FFRs were considered; in the broader set of FFRs, longitudinal fragmentation increased and ecological condition declined from 2011 to 2018.Considering the increasing pressures rivers are likely to experience from human and climate change impacts, particularly in semi-arid to temperate environments, urgent prioritization and monitoring of FFRs is called for so that a targeted set of protection and management strategies can be applied.