Collection C
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Browsing Collection C by Subject "Amphibians"
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- ItemAssessing water conditions for Heleophryne rosei tadpoles and the conservation relevance(AOSIS, 2020) Ebrahim, Zishan; De Villiers, Atherton; Measey, JohnThe Table Mountain Ghost Frog (Heleophryne rosei) is endemic to the Table Mountain massif and is Critically Endangered. Other than clear, clean perennial stream flow, the optimal aquatic conditions required by their larvae are unknown. Dissolved oxygen, temperature, pH, electro-conductivity, aspect and permanence of flow are the independent variables measured seasonally at two sampling altitudes at 12 rivers of the massif. Using a logistic regression model we found that a permanence of water flow and lower water temperature were significant predictors of tadpole presence. Streams with mean summer temperature above 17.2 °C, at 300 m – 400 m above sea level, do not have tadpoles. Summer and autumn abstraction should be avoided, while a summer water temperature above an average of 17.2 °C is a threshold of potential concern for management authorities responsible for biodiversity conservation, threat mitigation efforts, and bulk-water supply and abstraction. Conservation implications: The Environmental Water Reserve has not been determined for streams of Table Mountain. The requirements of the Critically Endangered Table Mountain Ghost Frog (Heleophryne rosei) can be adopted as the minimum conditions to support this species and associated communities. Perennial flow, an average January water temperature of 17.2 °C or lower.
- ItemThe cost and complexity of assessing impact(Pensoft, 2020) Measey, John; Wagener, Carla; Mohanty, Nitya Prakash; Baxter-Gilbert, James; Pienaar, Elizabeth F.The environmental and socio-economic impacts of invasive species have long been recognised to be unequal, with some species being benign while others are disastrous. Until recently there was no recognised standard impact scoring framework with which to compare impacts of species from very different taxa. The advent of the Environmental Impact Classification for Alien Taxa (EICAT) and Socio‐Economic Impact Classification of Alien Taxa (SEICAT) schemes allows for the possibility of assessing impact through a standard approach. However, both these schemes are still in their infancy and the associated costs of the research that informs them is unknown. We aimed to determine the study costs and complexity associated with assessing invasive species’ socio-economic and environmental impacts. We used amphibians as a model group to investigate papers from which EICAT and SEICAT scores could be drawn up to 2019. Our analysis shows that studies that resulted in higher impact scores were more costly. Furthermore, the costs of studies were best predicted by their complexity and the time taken to complete them. If impact scores from EICAT and SEICAT are allowed to inform policy, then we need to carefully consider whether species with low scores represent true impact, or require more research investment and time. Policy makers needing accurate assessments will need to finance larger, more complex, and rigorous studies. Assessing impacts in low and middle income countries may need investment using international research collaborations and capacity building with scientists from high income areas.