Scielo RSS <![CDATA[Bothalia - African Biodiversity & Conservation ]]> http://www.scielo.org.za/rss.php?pid=0006-824120210001&lang=en vol. 51 num. 1 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Knowledge for a different urban future: a reflection</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100001&lng=en&nrm=iso&tlng=en <![CDATA[<b>Hundred years of Botany at the NWU: contributions towards understanding plant and algae function, diversity and restoration in a changing environment</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100002&lng=en&nrm=iso&tlng=en The Department of Botany on the Potchefstroom Campus (formerly Potchefstroom University for Christian Higher Education) of the North-West University (NWU) had its centenary in 2020. In this paper we celebrate this milestone by giving an overview of the history of the Department at this campus, including its recent establishment and expansion on the NWU Mahikeng Campus (formerly the University of North-West). A brief overview is presented of the advances in teaching and research over the years, and the development and relevance of the important plant collections in the botanical garden, two herbaria and the national diatom collection. The main emphasis of this contribution is, however, a reflection on the advancement and significance of research conducted by various disciplines on plant and algae function, diversity and ecological restoration over the years. The different disciplines in Botany at NWU, from the oldest to the more recent, are Plant Taxonomy, Plant Ecophysiology, Terrestrial Plant Ecology, Aquatic Sciences, Urban and Settlement Ecology, Geoecology, and Proteomics. Different aspects contributing to changes occurring in the environment, such as pollution, land degradation, urbanisation, overexploitation of resources and the subsequent effect of these on plant diversity and function are especially addressed in our current research. The results of our research inter alia led to solutions for problems occurring in the landscape and contribute to the well-being of the people using the land and water by restoring important ecosystem services. <![CDATA[<b>The influence of land use-impacted tributaries on water quality and phytoplankton in the Mooi River, North West Province, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100003&lng=en&nrm=iso&tlng=en BACKGROUND: Effluents from agricultural activities, metal and peat mining, urban and industrial areas, informal settlements and wastewater treatment plants all influence tributaries feeding the Mooi River. All these land uses ultimately result in a deterioration of water quality in the Mooi River. OBJECTIVES: The main objective was to relate the effects of inflowing tributaries to water quality and phytoplankton assemblages in the Mooi River. METHOD: Physico-chemical environmental variables were compared with water quality objectives and known limits to assess general water quality in the Mooi River over a one-year period. Water quality and phytoplankton in tributaries were compared to that at sites upstream and downstream from their inflows to determine the extent to which the tributaries affected the Mooi River. Multivari-ate analysis assisted in the interpretation of phytoplankton and physico-chemical data at the different sites. RESULTS: Seven phytoplankton phyla were identified in the Mooi River. Diatoms and green algae were most dense and diverse. Cyanobacteria were responsible for various problems, especially in the Wasgoedspruit where they dominated and reached high densities. Lowest phytoplankton density and diversity were found in the upstream and downstream sections of the river, while maximum density and diversity were found during summer in the middle reaches. The inflow of tributaries, especially the Wasgoedspruit, had a pronounced effect on water quality downstream. Phytoplankton density and diversity were less affected than chemical variables, especially nutrient concentrations. CONCLUSION: Various land use activities surrounding the Mooi River's tributaries contributed to a deterioration of water quality in the main stream of the Mooi River. <![CDATA[<b>Plant diversity and conservation value of wetlands along a rural-urban gradient</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100004&lng=en&nrm=iso&tlng=en BACKGROUND: Wetlands are the most threatened ecosystem in South Africa despite the range of ecosystem goods and services they provide. A significant cause of wetland destruction and degradation is a lack of understanding, by planners, policymakers and developers, of their ecological and socio-economic importance OBJECTIVES: This study assessed the floristic composition and diversity of wetlands in the former Tlokwe Municipal area along a rural-urban gradient METHODS: Fourteen wetland sites were surveyed along an urbanisation gradient. Vegetation surveys were done in quadrats along transects in each wetland recording the cover-abundance of each species. The data were analysed by using ordinations, similarity percentages, and the adjusted Floristic Quality Assessment Index RESULTS: Overall, the proportional species composition of urban and rural wetlands was mainly similar. Trends indicated that the alpha diversity increased with both habitat size and heterogeneity along a rural-urban gradient. In all wetlands, indigenous species were the most abundant, with the highest score in the largest urban wetland. The floristic quality varied widely along the gradient with none of the sites in pristine condition CONCLUSION: The similarity in species composition and floristic quality of the wetlands, as well as the high levels of indigenous species richness, indicated that urban wetlands are worthy of conservation. However, the signs of disturbances and the presence of alien species means that restoration strategies need to be implemented to improve the quality of the wetlands <![CDATA[<b>Diatom responses to river water quality in the Kruger National Park, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100005&lng=en&nrm=iso&tlng=en BACKGROUND: Although the Kruger National Park (KNP) is a protected area, it is not exempted from anthropogenically induced impacts, which often compromise river water flow and quality. Measures of river water quality in South Africa have conventionally been based on water chemistry as well as different ecological indicator groups such as fish and macroinvertebrates. Diatoms have been shown to be useful indicators of changes in water quality resulting from pollution and land-use impacts. OBJECTIVES: To determine the applicability of diatoms for hind-casting water quality in the KNP and to compare recent diatom community composition with those from the 1980s. METHODS: In this study, pH and electrical conductivity (EC) were used to evaluate temporal changes in water quality of three rivers within the KNP Additionally, we made use of historic diatom samples from three of the five perennial rivers to evaluate if diatom communities reflected changes in water conditions between 1983 and 2015. RESULTS: Diatom community structure was significantly different between 1983 and 2015. Diatom-based index scores (SPI) indicated an improvement in water quality for the Letaba and Olifants rivers. CONCLUSION: Diatoms were shown to be useful indicators of current water quality and are also useful for determining temporal changes. <![CDATA[<b>Impact of land-use and floaw conditions on the phytoplankton of the Sabie River, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100006&lng=en&nrm=iso&tlng=en BACKGROUND: The understanding of the impact of land-use on the dynamics of phytoplankton assemblages during varying climate conditions on rivers is limited. OBJECTIVE: To determine the impact of land-use types and flow on phytoplank-ton assemblages in the Sabie River. METHODS: The relationships between land-use patterns, water quality and phy-toplankton assemblages were analysed using canonical correspondence analyses (CCA). RESULTS: Six main land-use types could be distinguished in the eight identified sub-catchments of the river. The CCA results showed that the land-use had a stronger correlation with phytoplankton classes during the higher flow conditions than during low flow conditions. The forestry land-use type had the strongest correlation with nitrate-nitrite concentrations in the Sabie River. Chlorophyll-a concentrations were higher during 2016, and a slightly lower number of genera were observed for the class Chlorophyceae. During 2017 the number of genera of the class Cyanophyceae decreased together with chlorophyll-a and total cell concentrations. CONCLUSION: Low flow conditions favoured filamentous genera that are common to mesotrophic conditions while higher flow conditions favoured single-celled small genera more common to oligotrophic waters with higher disturbance. This study showed that flow has the potential to enhance the impact of land-use on phytoplankton community dynamics in a river system and thereby may have further impacts on the health and activities of surrounding communities. <![CDATA[<b>Restoration after bush control in selected range-land areas of semi-arid savannas in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100007&lng=en&nrm=iso&tlng=en BACKGROUND: One of the main causes of land degradation in South Africa is bush thickening (BT) of mainly Senegalia or Vachellia species. Restoration methods are required to control BT, and to improve grass biomass production and soil conditions in South Africa. OBJECTIVES: The objectives of this study were to determine the effect of brush packing (BP) as a restoration method to increase grass biomass production, assess soil moisture after BP on different soil types, and document the perceptions of the local communities towards BP METHOD: Methods included cutting the stems of woodies with a diameter of at least 10 cm at knee height by chainsaw and manual clipping after which an arborocide was applied to the stumps. A neutron probe was used to measure volumetric moisture content at two different soil depths. The grass biomass was analysed using ANOVA at a confidence level of 95%. Quantitative and qualitative approaches were used to gather information about the perceptions of local communities towards restoration in group discussions RESULTS: The short-term data showed that the implementation of BP as restoration method increased grass biomass production. The soil texture influenced the volumetric soil moisture. Higher soil moisture content was found in the deeper clayey soils. The local participants' interpretation towards the restoration project was positive. CONCLUSION: The project increased the grazing potential and contributed to job creation to improve the well-being of the people in the community. <![CDATA[<b>Effects of land-use change on herbaceous vegetation in a semi-arid Mopaneveld savanna</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100008&lng=en&nrm=iso&tlng=en BACKGROUND: Low altitude Mopaneveld savanna in the northeastern parts of South Africa is generally well conserved. However, extensive copper mining, agricultural practices and urbanisation in the Phalaborwa region prompted research on the possible effects of land-use change on plant community diversity and function. Species diversity measures are usually considered adequate to assess disturbance effects to inform conservation efforts and management practices. However, diversity measures based on species level accounts often limit the outcomes of these studies as this approach fails to quantify how disturbances affect ecosystem functioning when community assembly, and not species diversity alone, is altered by land-use change. OBJECTIVES: The aim of this study was to apply both species and functional diversity measures to a data set derived from various land-use types (i.e. areas exposed to strip mining activities, communal farming practices and conservation) in the Phalaborwa region to examine the effects of land-use change on the community ecology of the herbaceous layer. RESULTS: Land-use change, particularly severe top-soil disturbances through strip mining activities, had a significant filtering effect on all measures of species diversity, though functional evenness was maintained across land-use types. CONCLUSION: These results suggest that, despite initial species loss, this particular savanna ecosystem is buffered against anthropogenic disturbances through functional stability. Indicator species analyses, as well as relationships between plant functional types and land-use change, revealed that forb species are largely responsible for ecosystem stability in areas exposed to anthropogenic disturbances. <![CDATA[<b>Open Ecosystems: Ecology and Evolution Beyond the Forest Edge</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100009&lng=en&nrm=iso&tlng=en BACKGROUND: Low altitude Mopaneveld savanna in the northeastern parts of South Africa is generally well conserved. However, extensive copper mining, agricultural practices and urbanisation in the Phalaborwa region prompted research on the possible effects of land-use change on plant community diversity and function. Species diversity measures are usually considered adequate to assess disturbance effects to inform conservation efforts and management practices. However, diversity measures based on species level accounts often limit the outcomes of these studies as this approach fails to quantify how disturbances affect ecosystem functioning when community assembly, and not species diversity alone, is altered by land-use change. OBJECTIVES: The aim of this study was to apply both species and functional diversity measures to a data set derived from various land-use types (i.e. areas exposed to strip mining activities, communal farming practices and conservation) in the Phalaborwa region to examine the effects of land-use change on the community ecology of the herbaceous layer. RESULTS: Land-use change, particularly severe top-soil disturbances through strip mining activities, had a significant filtering effect on all measures of species diversity, though functional evenness was maintained across land-use types. CONCLUSION: These results suggest that, despite initial species loss, this particular savanna ecosystem is buffered against anthropogenic disturbances through functional stability. Indicator species analyses, as well as relationships between plant functional types and land-use change, revealed that forb species are largely responsible for ecosystem stability in areas exposed to anthropogenic disturbances. <![CDATA[<b>A baseline assessment of the photosynthetic potential of <i>Welwitschia mirabilis </i>using the JIP-test for monitoring and conservation purposes</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100010&lng=en&nrm=iso&tlng=en BACKGROUND: Welwitschia mirabilis is highly specialised to survive the harsh climate of the Namib Desert. Changes in land use, such as the expansion of mining activities, may endanger their survival. OBJECTIVES: The purpose of this study was to understand the photosynthetic potential of W. mirabilis plants to provide a baseline for future long-term monitoring, and for future comparison to determine plant health status after the onset of mining operations METHODS: The study was conducted in a population of W. mirabilis on the Welwits-chia Plains. Chlorophyll a fluorescence data were used to measure plant photochemical potential and analysed using the JIP-test. RESULTS: Significant differences in the photosynthetic potential was observed for W. mirabilis plants located in different catchments. The partial parameters of the PI ABS values were also significantly lower, which indicated that all aspects of photosynthesis were influenced CONCLUSION: PI ABS values can serve as a baseline for future long-term monitoring studies to detect any changes in the health status of W. mirabilis that might result from land use change. <![CDATA[<b>Drought tolerant forb flora of a semi-arid protected savanna in the Lowveld of South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100011&lng=en&nrm=iso&tlng=en BACKGROUND: Increased frequency and intensity of droughts related to climate change are predicted to induce pressure on herbaceous communities. Considering that forbs contribute significantly to savanna ecosystem resilience, we investigated forb communities of a protected semi-arid savanna during an extensive drought. OBJECTIVE: We identified drought-tolerant species with their related functional traits. RESULTS: Drought-tolerant forb flora comprised of several plant families and species with overlapping traits, of which the ability to resprout was related to perennials, whereas succulence and prostrate growth form were typical annual forb dominance traits. CONCLUSION: Results highlight the functional importance of forbs and their resilience to drought events in protected areas. <![CDATA[<b>A floristic assessment of grassland diversity loss in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0006-82412021000100012&lng=en&nrm=iso&tlng=en BACKGROUND: Land-use effects on grassland flora are difficult to predict due to poor understanding of species losses caused by transformation. OBJECTIVES: To determine changes in species diversity and composition by comparing transformed with untransformed grassland. METHODS: Floristics of paired plots were sampled within 18 transformed sites (representing agricultural and urban land-uses) and neighbouring untransformed grassland. RESULTS: Endemic and threatened species were negatively affected by transformation, particularly species with belowground bud-banks and storage organs. Species composition, with clear shifts in dominant families, was changed by over 90% on average by transformation CONCLUSION: Land-use transformation lead to the loss of native species and increased alien invasive species.