Mohlamatsane Mokhatla

Amphibians currently represent the most at-risk as well as the least-conserved vertebrate class on earth and factors contributing to these declines are a subject of active research. However, amphibians present a unique challenge to scientists and conservation managers mainly because of their bi-phasic life cycles. Furthermore, it is now generally accepted that each amphibian life history trait is affected differently by anthropogenic threats. In exploring this aspect further, focusing on the amphibians of the southern African sub-continent, frog species were grouped according to their breeding habitats (stream-, permanent aquatic-, temporary aquatic- and terrestrial-breeding groups). First, using a random draw technique focusing specifically on South Africa, at both the national and the biogeographical scales (the latter being defined as sub-regions within the study area identified based on similarities in frog species distributions; see Chapter 2); I evaluate whether areas where di...

Recent studies on conservation and species threat level assessments have advocated the importance of human demographic variables and other associated variables in determining threats to biodiversity. In addition to this, the current study is aimed at determining the extent to which areas representing biologically important frog groups are affected by anthropogenic induced threats. Analyses were conducted at the national scale for South Africa and for predefined biogeographical units, the latter was determined based on discernible anuran assemblages. At the national scale, in order of priority, these areas were characterized by higher levels of alien plants species richness land transformation, human population density and a change in population density than expected. Endemic frog hotspots were the least threatened at both the national and the biogeographical scales. From these analyses, it seems that frogs in South Africa are well-represented in the current conservation network, alt...

In the Grinnellian niche concept, the realized niche and potential distribution is characterized as an interplay among the fundamental niche, biotic interactions and geographic accessibility. Climate is one of the main drivers for this concept and is essential to predict a taxon’s distribution. Mechanistic approaches can be useful tools, which use fitness-related aspects like locomotor performance and critical thermal limits to predict the potential distribution of an organism. These mechanistic approaches allow the inclusion key ecological processes like local adaptation and can account for thermal performance traits of different life-history stages. The African Clawed Frog, Xenopus laevis, is a highly invasive species occurring on five continents. The French population is of special interest due to an ongoing expansion for 40 years and a broad base of knowledge. We hypothesize that (1) the French population exhibits increased activity time in the invasive European range that could...

Abstract Protected areas (PAs) play a critical role in safeguarding Earth's biodiversity and contributing to human wellbeing. Maintenance of ecological intactness, financial viability and social relevance influence PA sustainability. We explore how COVID-19 and associated lockdown regulations influenced the sustainability of South Africa's largest PA management agency. Quantitative and qualitative information, sourced from ongoing monitoring, organizational reports, questionnaires and discussions with agency staff, were used to make sense of the challenges and opportunities. In the short term, lockdown regulations limited people's ability to access benefits from PAs with 50,000 educational visits lost between April and June 2020 and recreational visits in access-controlled national parks decreasing by ~96%. Consequently, tourism revenue dropped by 90% highlighting the fragility and risk of single primary income stream reliance. This resulted in loss of community development revenues and implementation of cost curtailment measures. Increased anxiety regarding health and job security impacted employee morale and complicated operational challenges. Navigating this period required good communication, re-prioritisation and adaptive responses by park managers. Whilst we report on short-term impacts and responses, lagged and longer-term impacts are anticipated. The pandemic highlighted the interconnectedness of people and ecosystems and the complex interdependencies between the sustainability principles which must be considered for increased PA resilience and sustainability.

Temperature and water availability are two of the most important variables affecting all aspects of an anuran’s key physiological processes such as body temperature (Tb), evaporative water loss (EWL) and standard metabolic rate (SMR). Since anurans display pronounced sexual dimorphism, evidence suggests that these processes are further influenced by other factors such as vapour pressure deficit (VPD), sex and body mass (Mb). However, a limited number of studies have tested the generality of these results across a wide range of ecologically relevant ambient temperatures (Ta), while taking habitat use into account. Thus, the aim of this study was to investigate the role of Ta on Tb, whole-animal EWL and whole-animal SMR in three wild caught African anuran species with different ecological specialisations: the principally aquatic African clawed frog (Xenopus laevis), stream-breeding common river frog (Amietia delalandii), and the largely terrestrial raucous toad (Sclerophrys capensis)....

Background: Conservation relies on the strategic use of resources because monies for conservation action are limited, especially in developing countries. South Africa’s Frog Atlas project established a baseline for the country’s amphibian data and threat levels in 2004, and in 2009 a prioritisation exercise developed a strategy for conservation research.Objectives: In this article, we assess this strategy for conservation research.Method: We conducted a quantitative and qualitative assessment of research undertaken since the strategy was developed.Results: The strategy has produced a lasting impact on taxonomy, ecological studies, monitoring and capacity building. Publications in all areas have increased, but particularly in conservation ecology. Other indicators are increases in the numbers of locality records for target taxa, species descriptions and postgraduate degrees with amphibians as the principal topic. We document important milestones for South African amphibian conservati...

The magnitude of impacts some alien species cause to native environments makes them targets for regulation and management. However, which species to target is not always clear, and comparisons of a wide variety of impacts are necessary. Impact scoring systems can aid management prioritization of alien species. For such tools to be objective, they need to be robust to assessor bias. Here, we assess the newly proposed Environmental Impact Classification for Alien Taxa (EICAT) used for amphibians and test how outcomes differ between assessors. Two independent assessments were made by Kraus (Annual Review of Ecology Evolution and Systematics, 46, 2015, 75-97) and Kumschick et al. (Neobiota, 33, 2017, 53-66), including independent literature searches for impact records. Most of the differences between these two classifications can be attributed to different literature search strategies used with only one-third of the combined number of references shared between both studies. For the comm...

Climatic changes have had profound impacts on species distributions throughout time. In response, species have shifted ranges, adapted genetically and behaviourally or become extinct. Using species distribution models, we examined how changes in suitable climatic space could affect the distributions of 37 endemic frog species in the Cape Floristic Region (CFR) – an area proposed to have evolved its megadiversity under a stable climate, which is expected to change substantially in future. Species distributions were projected onto mean climate for a current period (1950 to 2000), hindcasted to palaeoclimate (Last Glacial Maximum; LGM ≈ 21 kya and Holocene Glacial Minimum; HGM ≈ 6 kya) and forecasted for two emissions scenarios (A2a and B2a) for the year 2080. We then determined the changes in area sizes, direction (longitude and latitude), fragmentation index and biotic velocity, and assessed if these were affected by life-history traits and altitude. We found that the biotic velocity...