LIFE HISTORY DOES MATTER IN ASSESSING POTENTIAL ECOLOGICAL IMPACTS OF THERMAL CHANGES ON AQUATIC MACROINVERTEBRATES

Thermal alteration is associated with ecological change in freshwater systems. Global climate change is likely to amplify thermal stresses on aquatic systems. We used cumulative daily heat units to examine potential impacts of temperature changes on selected aquatic organisms using scenario analyses. We selected two species of aquatic macroinvertebrates to test our hypotheses of thermal effects on life history pattern, viz. a univoltine stenothermic ephemeropteran species of conservation importance, and a multivoltine dipteran pest species. A combination of spreadsheet probability and logistic regression models was used to model probabilities of hatching and breeding success, plus population sizes and generation numbers per month, under current and projected 2 degrees C warmer water temperature scenarios. We propose that cold-adapted Gondwanaland relic species are likely to become increasingly vulnerable and range limited, whereas multivoltine pest species are likely to become more abundant under scenarios of increased water temperatures. We propose management options that include maintaining river connectivity and dam re-operation as potential mitigation measures. Copyright (c) 2012 John Wiley & Sons, Ltd.