If we want Australia’s beaches to persist as living ecosystems, we need to develop a way of checking beach health.
We all know that beaches are beautiful playgrounds whose values go far beyond mere dollars. Monitoring beach health is vital to ensure we have healthy beaches into the future, but the ways in which we measure their health are likely to vary in accuracy, practicability and cost. We put the measurements under scrutiny and selected those that perform best.
Beaches are the most extensive coastal landform comprising about 70% of open-ocean coasts. Australia is blessed with about 8,000 ocean beaches and, in Sydney, Manly and Bondi Beaches are international icons. Beaches provide important ecological services that include recreation and coastal protection.
Three broad facts have influenced my research direction. Firstly, sandy beaches are not the biological deserts of common belief but are home to hundreds of plant and animal species most of which evade our attention by being small and buried. Secondly, beaches have received little biological attention compared with other coastal landforms. Beach biologists are a lonely band.
And thirdly, beaches are under the gun. They are squeezed between burgeoning human coastal developments on the terrestrial side and pressures resulting from climate change on the marine side (sea levels and erosion pressures will rise and pH will fall). Erosion, in particular, is threatening both societal assets (buildings, roads, parks etc) and the very existence of beaches. Already most of the world’s beaches are eroding. Management responses include building seawalls and the large-scale nourishment of beaches using sand from deep water offshore. Will these factors cause ecological change? How can we tell? There are numerous potential indicators of beach health but which are best?
Since nobody has addressed this question before, I collaborated with several international colleagues to suss out the best indicators of change. We chose six categories of management-relevant issues: erosion, habitat loss, recreation, fishing, pollution and wildlife conservation. Numerous possible indicators were scored in terms of their ability to reflect environmental change, and against criteria such as sensitivity, practicability, costs, and public appeal.
The indicators of change that performed best included traits of bird populations and assemblages (eg, abundance, diversity, distributions and habitat use), the reproductive performance of several taxa (eg, birds, turtles, invertebrates and plants), population parameters and distributions of vertebrates associated primarily with dunes and the supralittoral beach zone, and the abundance/cover/biomass of plants and animals. The choice of indicators will depend on the issue of concern and the local beach context. For example, urban beaches are more likely to suffer pollution but less likely to have dunes than non-urban beaches.
If we want the manifold values of beaches to persist, we need to develop effective toolboxes to diagnose beach health. We really don’t want people to say “life used to be a beach”.
Dr Alan Jones