I was fortunate to attend a workshop hosted by the National Climate Change Adaptation Research Facility last year that focused on riparian ecosystems under climate change. Among the various discussions at the workshop, some colleagues and I started discussing how riparian ecosystems might be affected by climate change and ways in which their abiotic and biotic characteristics are likely to change. It soon became clear that envisioning future ecosystems is no easy task, so we set about trying to come up with an approach by which to do so.
We present our approach in a paper that has recently been published in the journal Ecosystems. Based around four recommendations, we present the approach in the first part of the paper. We then use four case studies from contrasting environments to illustrate the approach and to determine:
- Whether certain characteristics make some ecosystems more susceptible to climate-induced shifts in community structure than others; and
- Which aspect of climate change seems to have the greatest effect on community structure and therefore should be a research priority.
Focusing on changes in community structure, we use qualitative process models to predict likely abiotic and biotic changes in four case study systems: tropical coastal floodplains, temperate streams, high mountain streams and urban riparian zones. We concentrate on functional groups rather than individual species and consider dispersal constraints and the capacity for genetic adaptation. Our scenarios suggest that climatic changes will reduce indigenous diversity, facilitate non-indigenous invasion (especially C4 graminoids), increase fragmentation and result in simplified and less distinctive riparian ecosystems.
Compared to models based on biota-environment correlations, process models built on mechanistic understanding (like Bayesian belief networks) are more likely to remain valid under novel climatic conditions. We posit that predictions based on species’ functional traits will facilitate regional comparisons and can highlight effects of climate change on ecosystem structure and function. Ecosystems that have experienced similar modification to that expected under climate change (e.g. altered flow regimes of regulated rivers) can be used to help inform and evaluate predictions.
While the paper centres on Australian riparian zones experiencing climate change, the approach can be applied to ecosystems in other biomes that are subject to environmental change.
The paper is now online early; you can find the abstract and link here.
Please drop me a line if you’d like a copy.