Wetlands are important biodiversity assets distributed across agricultural landscapes throughout much of temperate Australia. The contribution to landscape biodiversity of such systems is recognised through the listing of over a dozen different wetland ecosystems as Threatened Ecological Communities (TEC) under the Environment Protection and Biodiversity Conservation Act (1999). These wetland ecosystems have biodiversity values at both local (wetland) and landscape scales that benefit terrestrial and aquatic species by increasing native population sizes and helping to connect remnant native habitats in the landscape, including reserve networks.
However, wetlands only persist in these heavily human-dominated landscapes because they are ‘too wet’ for other uses. Climate change could impact this delicate balance but how might any changes manifest across these diverse ecosystems? What magnitude of impacts should we expect, when will they happen, and how should we prepare? Here a basis is presented to start sorting through this problem at a national scale.
Wetland TEC are first grouped into two categories: seasonal and permanent. This temporal habitat variability helps define both the contributions to landscape biodiversity made by these systems and the risks they face from global change. Thus grouping wetlands on this basis allows us to generalise predictions. To then move to a more explicit predictive framework, I propose a focus on wetland plant communities at the water plant functional group level of organisation.
Hydrological niche conditions preferred by different water plant groups provides the high-level filter necessary to predict the nature of changes to wetland vegetation for a given scenarios for changes in water availability, whether due to climatic shifts or changes in water resource usage. Understanding the taxonomic and structural complexity within functional groups, allows exploration of likely impacts of different climatic extremes of wetting and drying and to potentially detect broad tipping points within a resist-accept-direct planning framework.