Offsetting has become an important part of the government tool box for minimising environmental impacts and EDG researchers have been at the forefront of developing offsetting tools and concepts for the Federal Department of the Environment (see a Guide to the EPBC Act).
When this work was being done, the things being primarily focussed on were largely on terra firma, and concerned matters like black cockatoos or listed terrestrial habitats. Of course, developments that impact on biodiversity aren’t restricted to the land as recent proposals for port developments demonstrate. So the question is – does the government’s offsetting policy work in the sea?
When we examined the environmental legislation underpinning the offsets policy under a legal lens we found that it may not adequately protect vulnerable marine ecosystems (Bell et al., 2014). Without amendments to the offsets policy, iconic habitats such as coral reefs, seagrass and mangroves, could all pay a heavy toll.
Biodiversity losses at sea
The new Environmental Offsets Policy, a component of the Environment Protection and Biodiversity Conservation (EPBC) Act, was released in October 2012. The policy allows ‘unavoidable’ losses of biodiversity attributed to development to be ‘offset’ by protecting or rehabilitating an equal or greater quantity of that same biodiversity elsewhere.
The policy was developed specifically for terrestrial ecosystems, but applies equally to marine ecosystems. For instance, it was recently used to guide the environmental permission for the expansion of the Abbot Point coal terminal in the Great Barrier Reef World Heritage Area (see ‘Abbot Point coal port’).
“Without amendments to the offsets policy, iconic habitats such as coral reefs, seagrass and mangroves, could all pay a heavy toll.”
Marine ecosystems, however, are fundamentally different to terrestrial ecosystems in a number of key areas. This could significantly affect the success of offsetting strategies and could gravely threaten the marine habitats the policy is designed to protect. In comparison to terrestrial ecosystems, marine ecosystems:
- Exhibit faster rates of response and higher sensitivity to environmental variability•
- Have significantly larger spatial scales of ecological connectivity•
- Demonstrate ‘alternate stable states’: The effort it takes to rehabilitate a habitat may be significantly greater than the effort it took to destroy it.•
- Are subject to ‘diffuse impacts’: Actions occurring far away can have deleterious impacts.
Our research focusses specifically on seagrass meadows, the ‘ugly ducklings’ of shallow seas. While not offering the spectacular diversity and colour of coral reefs, seagrass meadows provide nursery areas for commercially important fish species; grazing areas for iconic species like sea turtles and dugongs; and a range of vital ecosystem services such as the stabilization of ocean sediments and water filtration. They are also one of the most intensive carbon sinks on Earth – burial rates of organic carbon in seagrass meadows (and salt marshes and mangroves) are exceptionally high, exceeding those in the soils of terrestrial forests by 30–50 fold.
So, seagrass meadows are important for a range of reasons. They are also one of the most threatened ecosystems on Earth, with staggering rates of decline around the globe in recent years. Dredging associated with coastal development is one of the major causes of this decline. The process of dredging directly damages seagrass plants and releases sediments into the water column which obscures the light the plants require to grow.
Acknowledging the difference In that it provides a transparent and quantitative framework for mitigating losses, the EPBC Act Offsets Policy does make a sound contribution to protecting biodiversity. However, acknowledging the differences with terrestrial habitats (as we have outlined here), we recommend that a separate policy related to marine habitats be formulated. In the case of seagrass, this policy should include:
Marine ecosystems, like seagrass meadows are quite different to terrestrial ecosystems like forests. Among other things, marine ecosystems tend to be more sensitive to
- Clear guidelines for selecting offset environmental variability, have larger spatial scales of connectivity and are subject to diffuse impacts. project sites;
- Consideration of diffuse impacts as threats to seagrass, as many threats to seagrass come from offsite (eg, agricultural run-off );
- Allowing proponents to remedy diffuse impacts as an offset activity, as traditional replanting or protection strategies used to offset terrestrial habitats are not always appropriate;
- An adaptive management approach to allow governments to assess a small number of projects before allowing offsets to be widely used; and
- Coordination between Federal and state policies.
As we’ve already said, seagrass meadows are a very special place. They hold important economic and environmental values in terms of serving as fishery nurseries and wildlife habitat. Once they were largely overlooked but these values are now widely acknowledged meaning the meadows of the sea now have high social value – loved by fishermen, greenies and dugongs alike. The coastal fringe is also a development zone that will see these values contested as other claims are made of these areas. A capacity to create appropriate offsets will be essential if we are going to effectively protect our biodiversity. This is going to be an exciting space to watch as issues of coastal development heat up.
More info: Justine Bell firstname.lastname@example.org
References: Bell J, MI Saunders, CE Lovelock & HP Possingham (2014). Legal frameworks for unique ecosystems – how can the EPBC Act Offsets Policy address the impact of development on seagrass? Environmental and Planning Law Journal, 31: 34-46.
This paper was an output of an interdisciplinary research project conducted at the University of Queensland, TE Beirne School of Law, Global Change Institute, School of Biological Sciences, and the ARC Centre of Excellence in Environmental Decisions. The research was funded in part by the Australian Research Council.