Riparian restoration mitigates impacts of climate change

Chrystal Mantyka-Pringle (CSIRO postdoc in the team) worked in collaboration with the University of Queensland, Griffith University and the Queensland Government, to better understand the combined effects of climate change and land-use change on freshwater biodiversity. 

Freshwater habitats occupy less than one percent of the Earth’s surface, yet they contribute disproportionately to global biodiversity, supporting approximately ten percent of all known species, and one third of all vertebrates. Despite their importance, freshwaters are experiencing declines in biodiversity far greater than those in the most affected terrestrial and marine ecosystems due to widespread habitat degradation, overexploitation, exotic invasions, water extraction and flow regulation. The combined and interacting influences of multiple stressors in freshwater ecosystems have resulted in population declines and range reductions of freshwater species worldwide. Yet, our understanding of the combined effects of climate change and land-use change on freshwater biodiversity is limited. For example, large uncertainties remain regarding which processes (e.g. biophysical processes such as water temperature or nitrogen enrichment) will have the greatest impact on biodiversity in freshwater ecosystems and whether the sum of the individual stressor effects are greater than either stressor alone (i.e. a synergistic interaction).

Working with UQ, Griffith University and the Queensland Government, CSIRO researchers modelled the independent and combined effects of climate change and land-use change on freshwater macroinvertebrates and fish using South East Queensland and the Ecosystem Health Monitoring Program (http://www.healthywaterways.org/ehmphome.aspx ) as a case study. The team built a Bayesian Belief Network parameterized under current land-use and climatic conditions to predict the effect of future land-use and climate change on the richness of macroinvertebrates and fish. They discovered little change in richness averaged across catchments, but identified important impacts and effects at the finer scale. High nutrients and high runoff as a result of urbanization interacted with high nutrients and high water temperature as a result of climate change, and was the leading driver of potential declines in macroinvertebrates and fish at fine scales. This is the first study to separate out the constituent drivers of impacts on biodiversity that result from climate change and land-use change.

By identifying the mechanisms behind predicted biodiversity loss, Mantyka-Pringle et al. (2014) were able to identify management strategies that can simultaneously tackle both climate change and land-use change. The good news story that came out of this study was that they identified riparian vegetation restoration as an important adaptation tool that can mitigate the negative effects of climate change and land-use change on freshwater biota. In Australia and elsewhere, riparian restoration management has been transformed over the last few decades from engineer-based to ecosystem-based approaches. As a result, planting of native riparian buffers has become a priority for restoration projects as it improves ecological conditions within streams without negatively impacting riparian soils.

Reference: Mantyka-Pringle, C.S., T.G. Martin, D.B. Moffatt, S. Linke, and J.R. Rhodes. (2014) Understanding and Predicting the Combined Effects of Climate Change and Land-Use Change on Freshwater Macroinvertebrates and Fish. Journal of Applied Ecology doi: 10.1111/1365-2664.12236