SUNScholar - Browsing by Author "Esler, Karen J."

Browsing by Author "Esler, Karen J."

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Alien tree invasion into a South African montane grassland ecosystem : impact of Acacia species on rangeland condition and livestock carrying capacity
(Taylor & Francis, 2018) Yapi, Thozamile Steve; O'Farrell, Patrick J.; Dziba, Luthando E.; Esler, Karen J.
The degree to which invasive Acacia species affect South Africa’s livestock production has received little attention. We investigated the ecological impacts of Acacia mearnsii invasion on forage quality and quantity and on soil resources, along A. mearnsii invasion gradients, on South African rangelands and the subsequent conditions following clearing. Grazing capacity was reduced by 72% in densely invaded sites, whereas clearing improved grazing capacity by 66% relative to densely invaded sites within 5 years. In densely invaded sites total grass species basal cover was reduced by up to 42%. As a result, A. mearnsii reduced grazing capacity, from 2 to 8 ha required to support one large stock unit (ha/LSU) in uninvaded and densely invaded sites, respectively. Soil moisture content was lower in densely invaded sites compared with lightly invaded and cleared sites. Plant litter increased from 1.3% to 4.2%, carbon content of the soil increased from 2.0% to 4.0% and nitrogen concentrations increased from 0.1% to 0.2% in response to invasion by A. mearnsii. Clearing resulted in improved grazing capacity within 5 years. These results also showed that, if left uncontrolled, wattle species can reduce livestock carrying capacity within montane grasslands in South Africa.
Biocultural diversity : a Mongolian case study
(Resilience Alliance, 2019) Seele, Barbara C.; Esler, Karen J.; Cunningham, Anthony B.
Although conceptual frameworks describing biodiversity and cultural keystone species have been widely accepted over the past 15 years, there remains a need for an overarching framework that covers the various components of biocultural diversity. We present a conceptual framework to enable the better understanding, monitoring, and maintenance of biocultural diversity across a range of spatial scales, from the landscape and ecosystem level to the species and gene/meme level. This is done by combining the concepts of biological diversity and cultural diversity, including cultural values and symbols, ethnoscientific approaches, as well as power relations and institutions, to form a biocultural diversity framework. To illustrate the framework, we use a systems diagram and practical examples from a case study on the ethnoveterinary knowledge and practices of Mongolian pastoralists. Ethnoveterinary knowledge is an example of traditional ecological knowledge and therefore offers valuable insight into biocultural diversity. Using the conceptual framework as a tool, our investigation of biocultural diversity in the Mongolian pastoralist context strongly suggests that an understanding of the historical, political, and cultural contexts, as well as the interrelatedness of cultural processes and ecological systems, is essential for maintaining biocultural diversity. More specifically, our results indicate that retaining a mobile herding way of life as well as the associated balance and communication with nature, is vital for both the continued transmission of ethnoveterinary knowledge and the sustainable use of ecological resources that Mongolian pastoralists rely on. There is a need for national policies that acknowledge, support, and maintain the important and complex processes underlying the Mongolian landscape and the associated worldviews, knowledge, and practices. The development of a coherent framework for biocultural diversity therefore allows for a clearer understanding of the various components and the selection of appropriate indicators for monitoring biocultural diversity.
Challenges in invasive alien plant control in South Africa
(Academy of Science of South Africa, 2012) Van Wilgen, Brian W.; Cowling, Richard M.; Marais, Christo; Esler, Karen J.; McConnachie, Matthew; Sharp, Debbie
Working for Water owes much to the community of fynbos ecologists who were instrumental in putting forward an argument to government for its initiation in 1996.2 The 33rd Annual Fynbos Forum (attended by over 250 delegates at Cape St. Francis on 17–19 July 2012) included a plenary workshop on the effectiveness of Working for Water, and discussions on ways for the scientific community to assist in the identification and implementation of improvements. This brief report outlines the issues discussed, including the problems faced by Working for Water, and possible ways for the scientific community to assist in addressing them.
Determining the relationship between invasive alien species density anda country's socio-economic status
(Academy of Science of South Africa (ASSAf), 2010-04) Sharma, Gyan P.; Esler, Karen J.; Blignaut, James N.
We explored the relationships between various socio-economic variables and the prevalence and density of invasive alien species (IAS) on a global scale using country-level data sets. We did this by testing the hypothesis that the abundance and distribution of populations of IAS are correlated with various socio-economic indicators, with the direction of causality being that the state of IAS is determined by socio-economic conditions. We found a positive and statistically significant relationship between the prevalence and density of IAS and the human development index (HDI), the satisfaction with life index and the gross domestic product (GDP) among all the countries tested. Additionally, the density of IAS increased significantly with human-population density, total geographic area, GDP and HDI. We also found a positive relationship between the density of IAS and the top 10 road networks of the world. This provides some insight into the development of renewed policies and management strategies for invasive species across both continents and countries. We do caution, however, that the results are likely to be influenced by the sampling factor, whereby affluent countries have more resources to measure and monitor IAS than poorer countries and hence have better records of such, which then indicates a stronger relationship with the level of development. © 2010. The Authors.
Direct environmental impacts of solar power in two arid biomes : an initial investigation
(Academy of Science of South Africa, 2017) Rudman, Justine; Gauche, Paul; Esler, Karen J.
According to recent national energy plans and policy documents, the number of renewable energy developments is expected to increase in South Africa, thus contributing to the diversification of the country’s energy system. Consequently, numerous solar power developments are being deployed in the sunny arid interior – areas generally represented by the Nama-Karoo and Savanna Biomes. These developments come with a range of novel environmental impacts, providing opportunities for multidimensional exploratory research. Here, a mixed-method approach was used to identify and investigate possible environmental impacts associated with two types of solar power plants: concentrating solar power and photovoltaic. Structured interviews conducted with experts and experienced professionals, together with observations from site visits generated complementary findings. In addition to the risk of cumulative ecological impacts associated with individual solar plant developments, landscape impacts of multiple power plants and the direct impact on avifauna were found to be the most significant environmental impacts. These direct impacts appear to be most significant during the construction stage, which represents an intensive 10% of the total power plant lifespan. This investigation provides an early, broad and informative perspective on the experienced and expected impacts of solar power in South African arid regions as well as insights to possible future research areas.
Down, but not out : recent decline of Berg–Breede River whitefish (Barbus andrewi) in the upper Hex River, South Africa
(AOSIS Publishing, 2017) Shelton, Jeremy M.; Impson, N. Dean; Graham, Shaun; Esler, Karen J.
he Berg–Breede River whitefish, Barbus andrewi, an endangered Cape Floristic Region endemic, was once widespread in both the Berg and Breede River catchments. However, its distribution has been strongly reduced, apparently by human-related activities, over the last century, and the Hex River now contains one of the last recruiting populations within its native range. This population was last surveyed by Christie who found that the species occurred in six pools over a 9-km stretch of the upper Hex River. We re-surveyed fish populations at Christie’s sites in 2015 to evaluate differences in the fish community between 2002 and 2015. Our data indicated that the distribution of B. andrewi in the Hex River has declined from six to four pools and that its density in the study area in 2015 (0.57 fish per 100 m2 ± 0.31 fish per 100 m2 ) was more than fivefold lower than that recorded in 2002 (3.39 fish per 100 m2 ± 1.40 fish per 100 m2 ). Moreover, small size classes of B. andrewi (< 10 cm) were largely absent in 2015, indicating recruitment failure in recent years. Habitat degradation, exacerbated by a severe flood in 2008, and recent invasions by predatory non-native fishes (smallmouth bass, Micropterus dolomieu and sharptooth catfish, Clarias gariepinus) are identified as likely causes of this decline. Cape kurper, Sandelia capensis, another native species, was relatively common in 2002 but not recorded in 2015, whereas the density of native Breede River redfin, Pseudobarbus burchelli, was higher in 2015 than in 2002. Urgent conservation actions including managing non-native fish invasions and mitigating agricultural impacts on aquatic habitat are required to prevent further decline, and possible extirpation, of the Hex River population of B. andrewi. Conservation implications: Urgent conservation actions including preventing further increases in the abundance and distribution of non-native fishes, and improving habitat and water quality through mitigating agricultural impacts, are required to prevent further decline, and possible extirpation, of the Hex River population of B. andrewi.
Ecophysiological traits associated with the competitive ability of invasive Australian acacias
(Wiley-Blackwell, 2011-09) Morris, Taryn L.; Esler, Karen J.; Barger, Nichole N.; Jacobs, Shayne M.; Cramer, Michael D.
Aim: We explored morphological and ecophysiological traits that enable invasive Australian acacias to compete with native species for resources (light, water and nutrients) necessary to support the substantial growth associated with successful invasions. Location: Global. Results: Invasive Australian acacias grow large and seed prolifically in invaded regions. The greater capacity for vegetative growth is underpinned by their ability to acquire and efficiently use resources in non-native habitats. Key biological traits that enhance acquisition include (1) rapid and substantial allocation to root mass (up to 6-fold more than co-occurring native species) directed towards deep roots (at least 50% longer than those of natives) and to extensive shallow root networks; (2) heteroblasty, in most species, conferring high relative growth rates as bipinnate seedlings but long-lived, nutrient-conserving phyllodes as adults and (3) strong N2-fixation abilities. Main conclusions: The ecophysiological traits that govern the competitive interaction of invasive Australian acacias with native species are an important component of the recognized suite of factors including introduction history, human use and enemy release that combine to produce successful invasions. Traits interact to give Australian acacias competitive advantage over many native species. One such interaction is that of N2 fixation, which when coupled with slow decomposition of sclerophyllous phyllodes results in alteration of soil nutrient cycling. The lasting legacy of soil N-enrichment hinders the competitive ability of native species and further enhances invasions. The importance of edaphic factors and competitive interactions in determining invasive success should be considered in predictive modelling of species distributions. © 2011 Blackwell Publishing Ltd.
Effectiveness of private land conservation areas in maintaining natural land cover and biodiversity intactness
(Elsevier, 2020) Shumba, Tafadzwa; De Vos, Alta; Biggs, Reinette, 1979-; Esler, Karen J.; Ament, Judith M.; Clements, Hayley S.
Private land conservation areas (PLCAs) are increasingly looked to for meeting the deficit left by state-owned protected areas in reaching global conservation targets. However, despite the increasing extent and recognition of PLCAs as a complementary conservation strategy, little research has been done to quantify their effectiveness; a critical consideration if they are to be counted towards international biodiversity conservation targets. The long history of PLCAs in South Africa provides an interesting case study to address this knowledge gap. Here, we quantified the effectiveness of South African PLCAs by comparing losses in natural land cover and biodiversity intactness within PLCAs with different levels of protection to that of unprotected control points. Points within PLCAs were matched with unprotected control points to test the prediction that if PLCAs offer effective protection, losses in natural land cover and biodiversity intactness would be significantly lower within their boundaries in comparison to unprotected controls exposed to similar conditions. Consequences of natural land cover loss on biodiversity intactness were thus assessed, thus advancing standard approaches for quantifying effectiveness. Between 1990 and 2013, PLCAs lost significantly less natural land cover (3%) and biodiversity intactness (2%) than matched unprotected areas (6% and 4%, respectively). Of the natural land cover lost within PLCAs, most was converted to cultivated land. Farms can support more species than other land uses (e.g. mines), a likely explanation for why losses in biodiversity intactness were less than losses in natural land cover. Contrary to the predicted pattern, effectiveness did not increase with level of protection; informal PLCAs with no legal protection had comparable natural land cover and biodiversity intactness retention to strictly protected PLCAs, with most losses recorded among PLCAs with moderate protection. This study provides the first national-scale evidence that PLCAs can be an effective mechanism for conserving natural land cover and biodiversity intactness, which is highly relevant given current discussions around their likely long-term biodiversity conservation capacity.
Effectiveness of private land conservation areas in maintaining natural land cover and biodiversity intactness
(Elsevier, 2020) Shumba, Tafadzwa; De Vos, Alta; Biggs, Reinette, 1979-; Esler, Karen J.; Ament, Judith M.; Clements, Hayley S.
Private land conservation areas (PLCAs) are increasingly looked to for meeting the deficit left by state-owned protected areas in reaching global conservation targets. However, despite the increasing extent and recognition of PLCAs as a complementary conservation strategy, little research has been done to quantify their effectiveness; a critical consideration if they are to be counted towards international biodiversity conservation targets. The long history of PLCAs in South Africa provides an interesting case study to address this knowledge gap. Here, we quantified the effectiveness of South African PLCAs by comparing losses in natural land cover and biodiversity intactness within PLCAs with different levels of protection to that of unprotected control points. Points within PLCAs were matched with unprotected control points to test the prediction that if PLCAs offer effective protection, losses in natural land cover and biodiversity intactness would be significantly lower within their boundaries in comparison to unprotected controls exposed to similar conditions. Consequences of natural land cover loss on biodiversity intactness were thus assessed, thus advancing standard approaches for quantifying effectiveness. Between 1990 and 2013, PLCAs lost significantly less natural land cover (3%) and biodiversity intactness (2%) than matched unprotected areas (6% and 4%, respectively). Of the natural land cover lost within PLCAs, most was converted to cultivated land. Farms can support more species than other land uses (e.g. mines), a likely explanation for why losses in biodiversity intactness were less than losses in natural land cover. Contrary to the predicted pattern, effectiveness did not increase with level of protection; informal PLCAs with no legal protection had comparable natural land cover and biodiversity intactness retention to strictly protected PLCAs, with most losses recorded among PLCAs with moderate protection. This study provides the first national-scale evidence that PLCAs can be an effective mechanism for conserving natural land cover and biodiversity intactness, which is highly relevant given current discussions around their likely long-term biodiversity conservation capacity.
Exploring integrative research in the context of invasive alien plant management
(Academy of Science of South Africa, 2019-03-27) Abrahams, Brent; Sitas, Nadia; Esler, Karen J.
Addressing complex challenges facing social-ecological systems (SES) requires the integration of knowledge from a diversity of disciplines and stakeholders. This requirement has resulted in the establishment of many integrative research programmes, both globally and locally, aimed at coproducing knowledge relevant to solving SES challenges. However, despite the increase in integrative projects, there has been little research on the nature and extent to which these projects acknowledge and integrate information from diverse disciplines or knowledge types. In this study, we explored the extent to which the integration of different disciplines has occurred, using a case study of the South African invasive species management programme, Working for Water (WfW). Here we provide an overview of the research produced under the auspices of WfW, and how it came to be. Additionally, we assess the extent to which research associated with the programme addressed the research priorities and how these priorities relate to one another. Findings show that WfW-associated research is primarily focused on the ecological processes and impacts associated with invasive alien plants and biological control. Social science and applied research are, however, under-represented, infrequent in nature and inadequately address the research priorities set in the programme. To address these shortcomings, we recommend the development of a detailed research strategy and action plan conducive to integrative research and transdisciplinary collaboration, and relevant to solving complex SES challenges such as those associated with biological invasions.
Fire and life history affect the distribution of plant species in a biodiversity hotspot
(Wiley, 2019) Magadzire, Nyasha; De Klerk, Helen M.; Esler, Karen J.; Slingsby, Jasper A.
Aim: Species distribution models (SDMs) provide valuable insights into species–environment relationships and potential climate change impacts on diversity. Most SDMs do not account for the role of natural disturbance regimes such as fire in determining current and future species distributions, or how species traits mediate their response to these stressors. Here, we investigate the importance of fire in determining the distributions of species in fire‐prone fynbos vegetation, and how this varies in relation to different life history traits (growth form and fire‐response strategy). Location: Cape Floristic Region, South Africa. Methods: We modelled the distribution of 104 plant species with different life history traits, using Maxent. The model included five climatic variables, one edaphic and one fire variable. Post hoc analyses of model output and permutation procedures were conducted to assess variable importance across different life history traits. We accounted for phylogenetic autocorrelation using sister species comparisons. Results: Permutation importance scores identified fire return interval as a major determinant of fynbos species’ distributions. Linear mixed effect analyses revealed that seeder species were significantly more sensitive to fire than resprouters. Coefficients from the (linear) response curves of the different predictors indicated that the occurrence of species across all life histories was negatively associated with longer fire return intervals. Main conclusions: Fire and life history traits governing species’ response to fire are key factors determining species distributions in our study system. SDMs that ignore the role of fire in driving species distributions, and how this varies across different life history types, compromise our ability to understand species–environment relationships in fire‐prone ecosystems. There is great need for better spatial data describing historical, current and future fire regimes and for models that can incorporate different responses based on species life histories, to improve vulnerability assessments for fire‐prone ecosystems.
Foliar nitrogen dynamics of an invasive legume compared to native non-legumes in fynbos riparian zones varying in water availability
(South African Water Research Commission, 2019) Crous, Casparus J.; Drake, Deanne C.; Jacobsen, Anna L.; Pratt, R. Brandon; Jacobs, Shayne M.; Esler, Karen J.
The legume Acacia mearnsii invades South Africa’s fynbos riparian zones and may alter the nitrogen (N) dynamics and supply in these areas that typically support few native N fixers. Nitrogen uptake by A. mearnsii may also be influenced by water availability, potentially affecting riparian-specific performance and impact estimations. We expected to find functional differences between the invasive legume and the two co-occurring but non-leguminous native species Brabejum stellatifolium and Metrosideros angustifolia. We also wanted to examine whether in-situ water availability affected N source or uptake in the invasive species. We found A. mearnsii was indeed functioning differently from non-N-fixing native species, and had considerably higher foliar %N. Interestingly, 15N abundance and uptake were associated with site hydrology, meaning water availability should be scrutinised when assuming N-fixing in A. mearnsii using δ15N. Nonetheless, higher water availability to A. mearnsii in fynbos riparian ecosystems did increase foliar N uptake. This has implications for prioritizing clearing of sites with increased nutrient deposition, such as dense stands in relatively moist riparian zones.
Functional traits explain the Hutchinsonian niches of plant species
(Wiley, 2019-11-22) Martina, Treurnicht; Pagel, Jorn; Tonnabel, Jeanne; Esler, Karen J.; Slingsby, Jasper A.; Schurr, Frank M.
Aim: The Hutchinsonian niche is a foundational concept in ecology and evolutionary biology that describes fundamental characteristics of any species: the global maximum population growth rate (rmax); the niche optimum (the environment for which rmax is reached); and the niche width (the environmental range for which intrinsic population growth rates are positive). We examine whether these characteristics are related to inter- and intraspecific variation in functional traits. Location: Cape Floristic Region, South Africa. Time period: Present day. Major taxa studied: Twenty-six plant species (Proteaceae). Methods: We measured leaf, plant-architectural and seed traits across species geographical ranges. We then examined how species-mean traits are related to demographically derived niche characteristics of rmax, in addition to niche optima and widths in five environmental dimensions, and how intraspecific trait variation is related to niche widths. Results: Interspecific trait variation generally exceeded range-wide intraspecific trait variation. Species-mean trait values were associated with variation in rmax (R2 = 0.27) but were more strongly related to niche optima (mean R2 = 0.56). These relationships generally matched trait–environment associations described in the literature. Both species-mean traits and intraspecific trait variability were strongly related to niche widths (R2 = 0.66 and 0.59, respectively). Moreover, niche widths increased with intraspecific trait variability. Overall, the different niche characteristics were associated with few, largely non-overlapping sets of traits. Main conclusions: Our study relating functional traits to Hutchinsonian niches demonstrates that key demographic properties of species relate to few traits with relatively strong effects. Our results further support the hypothesis that intraspecific trait variation increases species niche widths. Given that niche characteristics were related to distinct sets of traits, different aspects of environmental change might affect axes of trait variation independently. Trait-based studies of Hutchinsonian niches thus yield important insights into the mechanisms shaping functional biodiversity, which should reinforce the role of traits in functional biogeography.
Fynbos Proteaceae as model organisms for biodiversity research and conservation
(Academy of Science of South Africa, 2012) Schurr, Frank M.; Esler, Karen J.; Slingsby, Jasper A.; Allsopp, Nicky
Woody plants of the Proteaceae family are a symbol of fynbos. Of the approximately 360 southern African species, over 330 are restricted to the Fynbos biome1 and form an important part of this biome’s exceptional plant diversity.2 Proteaceae dominate the overstorey of fynbos vegetation, play a key role for water, carbon and nutrient cycling, and provide resources for many species of pollinators and herbivores.1,3 Moreover, Proteaceae are responsible for the bulk of the economic value generated by the fynbos wildflower industry4 and serve as flagship species for conservation.
Guidelines for restoring Lowland Sand Fynbos ecosystems
(2022-02) Holmes, Patricia M.; Esler, Karen J.; Geerts, Sjirk; Ngwenya, Duduzile K.; Rebelo, Anthony G.; Dorse, Clifford; van der Merwe, Jacques; Retief, Jacobus; Hall, Stuart A.; Grey, Penelope; Nsikani, Mlungele N.; Faculty of AgriSciences, Department of Conservation Ecology and Entomology.
Lowland Sand Fynbos ecosystems are among the most threatened terrestrial systems in South Africa. Of the ten Sand Fynbos veld types, seven are Critically Endangered or Endangered according to the IUCN Red List of Ecosystems. They are all either poorly protected, or not protected at all in the conservation network. Sand Fynbos ecosystems harbour unique biodiversity, but owing to their lowland locations experience extensive losses to other land uses. Some natural pockets remain scattered within agricultural or urban developments. They are, however degraded due to invasive alien plants, inappropriate fire regimes or pollution and are an urgent priority to restore. National biodiversity targets aim for a minimum proportion of an ecosystem type to be retained in a natural or near-natural state. The minimum target for Sand Fynbos ecosystems is mostly 30% of the original extent – a target no longer attainable for several of these ecosystems, such as Cape Flats Sand Fynbos. For many of these precious systems, this means a necessary focus on their restoration. The purpose of these guidelines is to assist managers and landowners of degraded Sand Fynbos vegetation to restore biodiversity and contribute to the conservation of these threatened ecosystems. The guidelines outline appropriate methods to restore degraded Sand Fynbos ecosystems, based on the latest research and field trial outcomes.
Heat and smoke pre-treatment of seeds to improve restoration of an endangered Mediterranean climate vegetation type
(John Wiley & Sons Australia Ltd, 2017) Hall, Stuart A.; Newton, Rosemary J.; Holmes, Patricia M.; Gaertner, Mirijam; Esler, Karen J.
Invasive alien plants impact ecosystems, which often necessitates their removal. Where indigenous species recovery fails following removal alone, an active intervention involving reintroduction of seed of native species may be needed. This study investigated the potential for a combination of the fire cues of smoke and heat as a pre-treatment of seeds in breaking dormancy and facilitating increased germination. Species were selected to represent different functional types within Cape Flats Sand Fynbos; a fire-prone, critically endangered vegetation type in South Africa. Seeds were exposed to either a heat pulse (temperatures between 60 and 300°C for durations of between 30 s and 20 min) or dry after-ripening (1 or 2 months at milder temperatures of 45°C or less). Thereafter, seeds were soaked in smoke solution for 18 h and subsequently placed on agar at 10/20°C for germination. Most species fell into one of two main groups: Seed germination in the first group was greatest following a lower temperature (60°C) heat pulse, an extended period of mild temperature (20/40°C or 45°C) exposure, or no pre-treatment with heat. Seed germination in the second group was promoted after brief exposure to higher (100°C) temperatures. No germination occurred in any species following heat treatments of 150°C or higher. Species which responded better to higher temperatures were mainly those possessing physical dormancy, but seed morphology did not correlate with germination success. This study showed that heat stimulation of seeds is more widespread in fynbos plant families than previously known and will enable the development of better seed pre-treatment protocols before large-scale sowing as an active restoration treatment after alien plant clearing.
Identifying and categorizing stakeholders for protected area expansion around a national park in Namibia
(Resilience Alliance, 2019) Mannetti, Lelani M.; Göttert, Thomas; Zeller, Ulrich; Esler, Karen J.
Protected areas and adjacent landscapes are increasingly being viewed as integrated. A more general awareness is emerging of the relevance of collectively managed landscapes for conservation and human well-being. In Namibia, areas dedicated to conservation are increasing because of the proliferation of conservancies and game reserves. Management toward integrated conservation in these landscapes involves land use practices variably dedicated to wildlife management and the inclusion of land owners and resource users in the decision-making process. We use stakeholder analysis to identify participants integral to an expanded protected area network around the Etosha National Park in Namibia. We identified and categorized important stakeholder groups, and quantitatively and qualitatively assessed their relative importance to the protected area decision-making process. Twelve stakeholder groups were identified, and categorized according to proximity to the national park, land tenure, and land use type. Primary stakeholders, those who both affect and are affected by decision making, comprised livestock farmers, communal conservancy members, resettlement farmers, and tourism/hunting enterprises. For each group the cumulative values of position (level of support for, or opposition to the concept), interest (perceived disadvantages and advantages thereof), and power (resources stakeholders can mobilize to express their position) were calculated. These attributes provide an indication of stakeholder salience, i.e., how likely stakeholders are to affect or be affected by an integrated conservation landscape. We find that livestock farmers, although interested in the concept, mostly oppose protected area expansion. The conflict in opinion is linked to the benefits derived from being part of the conservation landscape and the losses endured due to the porous park fence, including human-wildlife conflict and regulations involving a veterinary cordon fence. A consideration of stakeholder salience, taking into account the different perceptions surrounding the benefits of living adjacent to a protected area, can potentially lead to the better implementation of integrated conservation areas.
Identifying challenges to building an evidence base for restoration practice
(MDPI, 2015-11-30) Ntshotsho, Phumza; Esler, Karen J.; Reyers, Belinda
Global acknowledgement of ecological restoration, as an important tool to complement conservation efforts, requires an effort to increase the effectiveness of restoration interventions. Evidence-based practice is purported to promote effectiveness. A central tenet of this approach is decision making that is based on evidence, not intuition. Evidence can be generated experimentally and in practice but needs to be linked to baseline information collection, clear goals and monitoring of impact. In this paper, we report on a survey conducted to assess practitioners’ perceptions of the evidence generated in restoration practice in South Africa, as well as challenges encountered in building this evidence base. Contrary to a recent assessment of this evidence base which found weaknesses, respondents viewed it as adequate and cited few obstacles to its development. Obstacles cited were mostly associated with planning and resource availability. We suggest that the disparity between practitioners’ perceptions and observed weaknesses in the evidence base could be a challenge in advancing evidence-based restoration. We explore opportunities to overcome this disparity as well as the obstacles listed by practitioners. These opportunities involve a shift from practitioners as users of scientific knowledge and evidence, to practitioners involved in the co-production of evidence needed to increase the effectiveness of restoration interventions.
Identifying research questions for the conservation of the Cape Floristic Region
(Academy of Science of South Africa, 2019-09-26) Allsopp, Nicky; Slingsby, Jasper A.; Esler, Karen J.
We conducted a survey among people working in the nature conservation community in an implementation, research or policy capacity to identify research questions that they felt were important for ensuring the conservation of the Cape Floristic Region. Following an inductive process, 361 submitted questions were narrowed to 34 questions in seven themes: (1) effective conservation management; (2) detecting and understanding change: monitoring, indicators and thresholds; (3) improving governance and action for effective conservation; (4) making the case that biodiversity supports critical ecosystem services; (5) making biodiversity a shared concern; (6) securing sustainable funding for biodiversity conservation; and (7) prioritising research. The final questions were evaluated against the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services Conceptual Framework to test whether the questions addressed elements identified by this Framework as those essential to ensure that conservation contributes to a positive future for the Cape Floristic Region. We found that all elements in this Framework received attention from the collective group of questions. This finding suggests that the conservation community we approached recognises implicitly that research in multiple disciplines as well as interdisciplinary approaches are required to address societal, governance and biological issues in a changing environment in order to secure the conservation of the Cape Floristic Region. Because the majority of people responding to this survey had a background in the natural sciences, a challenge to tackling some of the questions lies in developing integrative approaches that will accommodate different disciplines and their epistemologies.
The influence of biophysical and socio-economic factors on the effectiveness of private land conservation areas in preventing natural land cover loss across South Africa
(Elsevier B.V., 2021-06-09) Shumba, Tafadzwa; De Vos, Alta; Biggs, Reinette, 1979-; Esler, Karen J.; Clements, Hayley S.
There is increasing interest in the potential of private land conservation areas (PLCAs) as a complementary biodiversity conservation strategy to state-owned protected areas. However, there is limited understanding of how the diverse social-ecological contexts of PLCAs influence their effectiveness in conserving biodiversity. Here, we investigated how the effectiveness of South African PLCAs in conserving biodiversity varied across social-ecological contexts, using natural land cover as a proxy. Social-ecological contexts were represented by biophysical and legal factors (distance to towns and roads, elevation, slope, terrain ruggedness, rainfall, PLCA size, distance to state-owned national parks, and presence of legal protection) and, for a subset of commercially-operated PLCAs, management factors (adopted business model, and profitability). Biophysical and legal contextual factors had low explanatory power in the best model for the nationwide analysis (n = 5121 PLCAs). For a subset of PLCAs (n = 72) we found that effectiveness depended on the strategy they adopted to generate an income, as opposed to the amount of income itself. PLCAs that attracted high volumes of visitors to small properties to view charismatic “Big 5” wildlife were less effective in conserving natural land cover than larger, more exclusive “Big 5” PLCAs and those focused on hunting. Overall, site-specific management factors were better at explaining the effectiveness of PLCAs than biophysical factors. Our findings indicate that conservation practitioners and policy makers need to recognise the diverse goals, motivations and management models of PLCAs when considering how to support them in conserving biodiversity. Future studies could explore whether these trends hold for other proxies of biodiversity conservation, beyond land cover change.

Browsing by Author "Esler, Karen J."

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