Coping with change Photo: John Turnbull

Marine ecosystems such as the Great Southern Reef continuously adjust to stresses caused by changes to their environment.

The ability to adapt to a changing environment is called resilience. Kelp forests on the GSR display a high level of natural resilience. For example:

- flexible stipes allow kelp to bend and adjust to changes in wave energy

- high spore production allows for fast propagation and re-establishment

- rapid growth rates under optimal conditions speed recovery from change

- storage of nutrients enables species to survive periods of poorer water quality and low nutrients

- natural predators keep herbivore populations in check eg lobsters that feed on urchins

- high primary productivity supports complex food webs and connections between organisms.

More complex food webs are more resilient.

Kelp forests have a low level of resilience to changes in the atmosphere and hydrosphere such as temperature and water quality.

Kelp forests are extremely vulnerable to natural and human stresses. Kelp is the keystone species and principal primary producer for the Great Southern Reef.

Kelp forests are located along coastlines with high population densities and are expolited for fishing, recreation and waste disposal.

Despite their high biodiversity, the loss of key species such as the kelp or consumers such as abalone and lobsters can impact an entire kelp forest.

Any changes to the environment such as increased storms, wave energy or water temperature and reduced clarity can impact kelp.

The loss or decimation of kelp can have consequences such as kelp forests being replaced by urchin barrens or algal turfs.

The frequency and intensity of extreme weather events is predicted to increase. The events that will increase on the Great Southern Reef include:

• longer, more intense and more frequent heatwaves

• more intense and frequent extreme rainfall events and flooding

• higher sea levels

All of these will change the conditions kelp needs to thrive.

Management is aimed at reducing maintaining or building resilience by:

• protecting vulnerable species and habitats to maintain biodiversity

• conserving and protecting kelp forests and restoring lost forests

• maintaining populations of native species or removing threatening species

• managing stresses at specific locations by controlling human activities such as fishing

Global action on climate change is important for the future of kelp forests.