Recovery from change

2016

Recovery from change can be observed in systems that have been heavily degraded, and then either actively restored or allowed to recover by natural processes. Challenges in restoration ecology are the setting of appropriate goals, and the ability to detect when goals are reached. The problem of shifting baselines complicates restoration, since some habitats have been so heavily degraded since European colonisation that restoring them to a recent state (e.g. to a 1950s baseline) is insufficient to recover their predisturbed biodiversity or function.

The most common method of achieving recovery is through protection from human use. Approximately 22 million hectares of major vegetation types in the coastal zone of Australia (from the shore to 50 kilometres inland) receive some level of protection, and 14 million hectares receive the higher levels of protection (IUCN levels 1 to 4, which include strict nature reserves or wilderness areas, national parks, natural monuments or features, and habitat/species management areas). The trend in extent of area receiving protection is positive—from 2010 to 2014, an additional 3.7 million hectares received protection, almost 800,000 hectares of which were at protection levels 1 to 4.

Active restoration is when humans actively intervene to restore an ecosystem to its former state, rather than simply managing or protecting it from negative impacts of human use. Examples of this in the coastal zone are the restoration of seagrasses in the Coorong (the Ruppia Translocation Project), and restoration of shellfish reefs that were once far more abundant than they are at present (see Box COA13).

Box COA13 Shellfish reef restoration - recovering a lost marine habitat for environmental, social and economic benefit

What are shellfish reefs and where have they gone?

Shellfish reefs are complex, 3D living structures, made up of high densities of oysters, mussels and other shellfish. They play a similar ecological role to coral reefs, providing food, shelter and protection for a range of invertebrate and fish species, as well as helping to reduce coastal erosion and improve water clarity. Shellfish reefs occur in enclosed and nearshore coastal waters in both tropical and temperate regions across every state in Australia. Before the 20th century, shellfish reefs were common features of coastal systems and were an important food source for Indigenous Australians. Early maritime explorers, such as Cook, Flinders, Eyre and Vancouver, regularly referred to extensive shellfish reefs in voyage reports and journals. From early European settlement of Australia, vast quantities of oysters and mussels were harvested for food to support the growing colonies and as a source of lime for the construction of early roads and buildings. It is estimated that shellfish reefs were commercially harvested during the 1800s and early 1900s in more than 150 locations across Australia, but are now considered functionally extinct habitats, with only a handful of reefs remaining (Gillies et al. 2015).

Towards the recovery of shellfish reef habitats

The loss of shellfish reef habitat, in addition to the loss and degradation of other important marine habitats, greatly inhibits our ability to manage the health of coastal environments and to ensure they remain environmentally, economically and socially productive. Healthy habitats enable the processing of nutrients and sediments into cleaner waters and abundant fish, while also sequestering carbon and helping to mitigate coastal risks such as sea level rise. Rebuilding native shellfish reefs and other marine habitats is considered a job-intensive industry, with more than 17 full-time and part-time jobs created per $1 million spent (Edwards et al. 2013). Types of jobs generated from restoration include marine engineering, construction, science, recreational fishing, tourism and ecotourism. Shellfish reefs are also considered ‘fish factories’, supporting the growth and augmentation of recreationally and commercially important fish species, such as snapper (Pagrus auratus), yellowfin bream (Acanthopagrus australis) and King George whiting (Sillaginodes punctatus).

In 2014, Australia’s first shellfish reef restoration project was initiated in Port Phillip Bay, Victoria. Since then, several new shellfish reef restoration projects have been established across Australia, demonstrating the momentum and interest in recovering shellfish reef habitat. These include Oyster Harbour in Western Australia, Pumicestone Passage and Noosa River in Queensland, Georges River in New South Wales, and Gulf St Vincent in South Australia. Much of this early work has leveraged the success of large-scale, long-term shellfish reef restoration projects in the United States, such as in Chesapeake Bay. Efforts to recover shellfish reefs can be strengthened by forming partnerships and collaborations with groups that have complementary knowledge and experiences that can support restoration efforts and long-term community stewardship. Partnerships among the shellfish aquaculture industry, recreational fishers, Indigenous groups, government and not-for-profit groups are particularly well suited to providing the resources, knowledge and community ownership required to sustain large-scale restoration efforts.

Native flat oyster (Ostrea angasi) reef, Georges Bay, Tasmania

Native flat oyster (Ostrea angasi) reef, Georges Bay, Tasmania

Native flat oyster (Ostrea angasi) reef, Georges Bay, Tasmania

Photo by Chris Gillies

Sydney rock oyster (Saccostrea glomerata) reef, Richmond River, New South Wales

Sydney rock oyster (Saccostrea glomerata) reef, Richmond River, New South Wales

Sydney rock oyster (Saccostrea glomerata) reef, Richmond River, New South Wales

Photo by Patrick Dwyer

Hundreds of volunteers repairing oyster reef for shoreline protection work in the United States. Similar large-scale projects are possible in Australia

Hundreds of volunteers repairing oyster reef for shoreline protection work in the United States. Similar large-scale projects are possible in Australia

Hundreds of volunteers repairing oyster reef for shoreline protection work in the United States. Similar large-scale projects are possible in Australia

Photo by  Erika Nortemann © The Nature Conservancy,

Source: Dr Chris Gillies, The Nature Conservancy

Clark GF, Johnston EL (2016). Coasts: Recovery from change. In: Australia state of the environment 2016, Australian Government Department of the Environment and Energy, Canberra, https://soe.environment.gov.au/theme/coasts/topic/2016/recovery-change, DOI 10.4226/94/58b659bdc758b