Towards SDG 15.3: The biome context as the appropriate degradation monitoring dimension
- Xoxo, Sinetemba, Mantel, Sukhmani K, de Vos, Alta, Mahlaba, Bawinile, le Maître, David, Tanner, Jane
- Authors: Xoxo, Sinetemba , Mantel, Sukhmani K , de Vos, Alta , Mahlaba, Bawinile , le Maître, David , Tanner, Jane
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415961 , vital:71304 , xlink:href="https://doi.org/10.1016/j.envsci.2022.07.008"
- Description: Accurate and reliable estimation of terrestrial ecosystem degradation is critical to meeting the challenge of reversing land degradation. Remote sensing data (especially land productivity dynamics) is commonly used to estimate land degradation, and this study uses the TRENDS.EARTH toolbox for the period covering 2000–2018, demonstrating the benefit of tracking the degradation process (SDG 15.3.1) at a biophysical unit. Contributing to the country’s SDG 15.3.1 monitoring, anthropogenic degradation was estimated based on RESTREND land productivity, biome-specific land cover trends, and soil organic carbon (SOC) stocks. Underlying degradation was evaluated by reclassifying a 28-year national land cover change dataset to match the UNCCD land cover legend. Analysis results indicate that land productivity changes (especially in stable grasslands, afforested, and cropland areas) mainly influenced the degradation status of the biome (19.9% degraded and 25.6% improvement). Global datasets also suggest that land cover and SOC had a minimal contribution (more than 2%) to anthropogenic degradation dynamics in the biome between 2000 and 2018. The GIS analysis showed that long-term, the major contributors to the biome’s underlying 9% anthropogenic degradation were woody proliferation into the Grassland Biome, urban expansion, and wetland drainage.
- Full Text:
- Date Issued: 2022
- Authors: Xoxo, Sinetemba , Mantel, Sukhmani K , de Vos, Alta , Mahlaba, Bawinile , le Maître, David , Tanner, Jane
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/415961 , vital:71304 , xlink:href="https://doi.org/10.1016/j.envsci.2022.07.008"
- Description: Accurate and reliable estimation of terrestrial ecosystem degradation is critical to meeting the challenge of reversing land degradation. Remote sensing data (especially land productivity dynamics) is commonly used to estimate land degradation, and this study uses the TRENDS.EARTH toolbox for the period covering 2000–2018, demonstrating the benefit of tracking the degradation process (SDG 15.3.1) at a biophysical unit. Contributing to the country’s SDG 15.3.1 monitoring, anthropogenic degradation was estimated based on RESTREND land productivity, biome-specific land cover trends, and soil organic carbon (SOC) stocks. Underlying degradation was evaluated by reclassifying a 28-year national land cover change dataset to match the UNCCD land cover legend. Analysis results indicate that land productivity changes (especially in stable grasslands, afforested, and cropland areas) mainly influenced the degradation status of the biome (19.9% degraded and 25.6% improvement). Global datasets also suggest that land cover and SOC had a minimal contribution (more than 2%) to anthropogenic degradation dynamics in the biome between 2000 and 2018. The GIS analysis showed that long-term, the major contributors to the biome’s underlying 9% anthropogenic degradation were woody proliferation into the Grassland Biome, urban expansion, and wetland drainage.
- Full Text:
- Date Issued: 2022
Ecological impacts of small dams on South African rivers Part 2: Biotic response – abundance and composition of macroinvertebrate communities
- Mantel, Sukhmani K, Muller, N W J, Hughes, Denis A
- Authors: Mantel, Sukhmani K , Muller, N W J , Hughes, Denis A
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:7095 , http://hdl.handle.net/10962/d1012437
- Description: This paper investigates the cumulative impacts of small dams on invertebrate communities in 2 regions of South Africa – the Western Cape and Mpumalanga. Previous research found reduced discharge, increased total dissolved salts, and a decrease in average score per taxon (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigated using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catchment in foothill-gravel streams (in both Western Cape and Mpumalanga) and in foothill-cobble streams (in Western Cape only). Opportunistic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and seasons) and detailed (at species level) collection of data to verify the results of cumulative effects of small dams. This can further the development of a framework for small-dam construction and management that will limit their impact on river catchments.
- Full Text:
- Date Issued: 2010
- Authors: Mantel, Sukhmani K , Muller, N W J , Hughes, Denis A
- Date: 2010
- Language: English
- Type: text , Article
- Identifier: vital:7095 , http://hdl.handle.net/10962/d1012437
- Description: This paper investigates the cumulative impacts of small dams on invertebrate communities in 2 regions of South Africa – the Western Cape and Mpumalanga. Previous research found reduced discharge, increased total dissolved salts, and a decrease in average score per taxon (ASPT; collected using SASS4 methods) at sites with high density of small dams in their catchment. These changes in ASPT are investigated using the invertebrate abundance data available in the River Health Programme. Multivariate analyses found differences in invertebrate communities in rivers with high densities of small dams in their catchment in foothill-gravel streams (in both Western Cape and Mpumalanga) and in foothill-cobble streams (in Western Cape only). Opportunistic taxa that are tolerant of pollution, and capable of exploiting various habitats, and those that prefer slower currents increased in numbers, while other taxa that are sensitive to pollution and disturbance declined in numbers. Some regional differences were noted possibly reflecting climatic differences between the regions. Since the results of this study are correlative, it highlights the need for a systematic (by sites and seasons) and detailed (at species level) collection of data to verify the results of cumulative effects of small dams. This can further the development of a framework for small-dam construction and management that will limit their impact on river catchments.
- Full Text:
- Date Issued: 2010
First steps in the development of a water temperature model framework for refining the ecological Reserve in South African rivers
- Rivers-Moore, N A, Hughes, Denis A, Mantel, Sukhmani K, Hill, Trevor R
- Authors: Rivers-Moore, N A , Hughes, Denis A , Mantel, Sukhmani K , Hill, Trevor R
- Date: 2008-10-05
- Language: English
- Type: text , Article
- Identifier: vital:7092 , http://hdl.handle.net/10962/d1012425
- Description: Ecological Reserve determination for rivers in South Africa presently does not include a water temperature component, in spite of its importance in determining species distribution patterns. To achieve this requires an understanding of how lotic thermographs from South African rivers differ from northern hemisphere rivers, to avoid mismanaging rivers based on incorrect regional assumptions. Hourly water temperatures from 20 sites in four river systems, representing a range of latitudes, altitudes and stream orders, were assessed using a range of metrics. These data were analysed using principal component analyses and multiple linear regressions to understand what variables a water temperature model for use in ecoregions within South Africa should include. While temperature data are generally lacking in low- and higher-order South African rivers, data suggest that South African rivers are warmer than northern hemisphere rivers. Water temperatures could be grouped into cool, warm and intermediate types. Based on temperature time series analyses, this paper argues that a suitable water-temperature model for use in ecological Reserve determinations should be dynamic, include flow and air temperature variables, and be adaptive through a heat exchange coefficient term. The inclusion of water temperature in the determination and management of river ecological Reserves would allow for more holistic application of the National Water Act's ecological management provisions. Water temperature guidelines added to the ecological Reserve could be integrated into heuristic aquatic monitoring programmes within priority areas identified in regional conservation plans.
- Full Text:
- Date Issued: 2008-10-05
- Authors: Rivers-Moore, N A , Hughes, Denis A , Mantel, Sukhmani K , Hill, Trevor R
- Date: 2008-10-05
- Language: English
- Type: text , Article
- Identifier: vital:7092 , http://hdl.handle.net/10962/d1012425
- Description: Ecological Reserve determination for rivers in South Africa presently does not include a water temperature component, in spite of its importance in determining species distribution patterns. To achieve this requires an understanding of how lotic thermographs from South African rivers differ from northern hemisphere rivers, to avoid mismanaging rivers based on incorrect regional assumptions. Hourly water temperatures from 20 sites in four river systems, representing a range of latitudes, altitudes and stream orders, were assessed using a range of metrics. These data were analysed using principal component analyses and multiple linear regressions to understand what variables a water temperature model for use in ecoregions within South Africa should include. While temperature data are generally lacking in low- and higher-order South African rivers, data suggest that South African rivers are warmer than northern hemisphere rivers. Water temperatures could be grouped into cool, warm and intermediate types. Based on temperature time series analyses, this paper argues that a suitable water-temperature model for use in ecological Reserve determinations should be dynamic, include flow and air temperature variables, and be adaptive through a heat exchange coefficient term. The inclusion of water temperature in the determination and management of river ecological Reserves would allow for more holistic application of the National Water Act's ecological management provisions. Water temperature guidelines added to the ecological Reserve could be integrated into heuristic aquatic monitoring programmes within priority areas identified in regional conservation plans.
- Full Text:
- Date Issued: 2008-10-05
- «
- ‹
- 1
- ›
- »