Water Research Commission Project K5/2182: Adaptability and vulnerability of aquatic biota to climate change - developing tools for assessing biological effects

Project leader: Dr Helen Dallas (

Project Duration: April 2012 to March 2015 -  Completed

Project team: Dr Nick Rivers-Moore (FRC), Mr Vere Ross-Gillespie (PhD student, UCT), Mr Pfananani Ramulifho (MSc student, UKZN), Ms Jody-Lee Reizenberg (FRC Intern) 

Spillage from the Stettynskloof Dam into the Holsloot River

This project built on a previous WRC project (K5/1799), focusing on the refinement of upper thermal limits and the formulation of biological temperature thresholds for incorporation into the water temperature component of the ecological Reserve.  Existing stress on aquatic resources, including both water quantity and quality, is likely to increase in response to demand for water. There will also likely be an increase in impacts on water temperature as a result of climate change, hydrological changes (e.g. water abstraction, low flows, river regulation, dams, interbasin water transfers), changes in rainfall patterns, etc. Thermal stress is also likely to exacerbate water quality issues such as increased outbursts of algal blooms and spread of disease vectors. Such water quality effects have obvious health and economic impacts for society. Understanding of the biological consequences of thermal stress, and incorporation of this stress in the form of biological temperature thresholds, applied within the context of the ecological Reserve, will provide a valuable tool for managing aquatic resources. This knowledge will provide insight into the adaptability and vulnerability of biota to climate change and allow for the generation of recommendations linking biota and climate change. 

Thermal experiments underway at UCT

Thermal experiments were undertaken in the Western, Southern and Eastern Cape, Mpumalanga and Kwazulu-Natal Eastern Cape. The extent to which upper limits vary amongst regions will increase our understanding of biotic responses to water temperature and guide the development of thermal guidelines.

This research has been written up in a final WRC report and several scientific publications are being prepared.

Dallas HF, Rivers-Moore NA, Ross-Gillespie V, Ramulifho P and Reizenberg J. 2015. Adaptability and vulnerability of Riverine Biota to Climate Change – Developing Tools for Assessing Biological Effects. WRC Report No 2182/1/15. Water Research Commission, Pretoria, South Africa. 

Dallas HF and Rivers-Moore N. 2014 Ecological consequences of global climate change for freshwater ecosystems in South Africa. S Afr J Sci. 110(5/6): 48-58.

Dallas HF and Ross-Gillespie V. 2015. Sublethal effects of temperature on freshwater organisms, with special reference to aquatic insects. Water SA 41(5): 712-726

Dallas HF. 2016. The influence of thermal history on upper thermal limits of two species of riverine insects: the stonefly, Aphanicerca capensis, and the mayfly, Lestagella penicillata. Hydrobiologia. DOI: 10.1007/s10750-016-2826-3.31. 

Rivers-Moore NA, Mantel S, Ramulifo P and Dallas HF. 2016. A disconnectivity index for improving choices in managing protected areas for rivers. Aquatic conservation: marine and freshwater ecosystems 26: 29-38. DOI: 10.1002/aqc.2661


Vere and Jody collecting bugs for thermal experiments