Climatic resilience of coastal dune vegetation

Dr Teresa Konlechner1, A/Prof David Kennedy1

1National Centre for Coasts and Climate, School of Geography, University Of Melbourne, Parkville, Australia

Abstract

This paper reviews the potential impact of climate change on dune vegetation and associated resilience of coastal foredunes in Victoria. Foredunes are the shore parallel ridges formed at the back of beaches by aeolian sand deposition within vegetation. They are critical in mitigating coastline erosion and flooding, and as a result have been encouraged to form naturally, or be artificially created, for coastal defence. Vegetation is fundamental both to building and stabilizing foredunes. The flora of coastal dunes is, however, highly sensitive to changes in temperature, precipitation, and wave erosion especially under conditions predicted to occur as the result of climate change. In Victoria there is an added complexity in that foredunes are dominated by exotic species capable of altering foredune morphology. Vegetation on the Victorian coast occurs in distinct zonational patterns determined in part by microclimates and beach erosional state. The indigenous dune-building grass, Spinifex sericeus, is limited at its seaward margin by wave swash processes and on its landward margin by competition with other species, for example. The complexity in predicting future shoreline dynamics of spinifex dominated dunes is that the grass is being displaced by invasive species; seawheat grass (Thinopyrum junceiforme) closest to the wave swash zone and by marram grass (Ammophila arenaria) above the limit of waves. As dune morphology, and subsequently storm response, is a direct function of species composition, effective coastal management therefore requires consideration of both species occurrence and ecological shift driven by invasive species colonisation.

Biography

I am a coastal geomorphologist with connections to ecology and conservation management. My research interests lie at the interface of physical geography and ecology with a focus on the response of coastal biogeomorphic systems to disturbance. Recent projects have involved measurements of sand transport on vegetated foredunes, the impact of invasive plants on dune morphology and ecology, and evaluating dune restorations. Current research examines the sensitivity of sandy coasts to erosion.

About the Association

The Australian Coastal Society (ACS) was initiated at the Coast to Coast Conference in Tasmania in 2004. The idea was floated as a means for those interested in coastal matters to communicate between conferences and where possible take resolutions of the conference to appropriate levels of government.

The idea was discussed further at the Coast to Coast Conference in Melbourne in 2006 and it was agreed that Bruce Thom develop a constitution of a company limited by guarantee that would operate on a national basis.

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