Protecting coastal wetlands in a changing climate: reinvigorating integrated coastal zone governance

Wetlands are a critical part of the coastal environment. Encompassing estuaries, saltmarsh, mangroves, coastal swamps, lakes and lagoons, saline wetlands occupy the biophysical interface between terrestrial and marine, and between marine and freshwater environments (Australian State of the Environment Committee (ASEC), 2011, p. 849). They have values oflocal, regional, state, national and, occasionally, international significance. Coastal wetlands perfonn ecosystem functions important for commercially valuable industries such as fisheries and tourism, including nutrient and pollutant filtering, erosion control to protect coastal infrastructure and aid the adaptation of coastal communities and carbon sequestration (Millennium Ecosystem Assessment (MEA), 2005; Australian State of the Environment Committee (ASEC), 2011, p. 858; McLeod et al., 2011). They also have cultural significance for indigenous people, as well as scenic, research, conservation and recreational values (Rogers et al., 2014, pp. 67-8). Their protection affects both public and private property rights. Accordingly, decisions over their use, protection, destruction and management potentially span multiple tiers of government, public and private actors and a wide range of sector-specific agencies and managers. The need for integrated governance approaches is clear.

Despite the importance of coastal wetlands, like many estuaries around the world the heavy concentration of Australia's population around the estuaries of major river systems has transformed our coasts (Millennium Ecosystem Assessment (MEA), 2005, pp. 41-2). The combined pressures of urban development, catchment land and water use and flood mitigation measures have radically altered and, in many places, destroyed, these coastal ecosystems (Lee et al., 2006; Australian State of the Environment Committee (ASEC), 2011, pp. 858-61; Rogers et al., 2014, p. 68). Climate change will further threaten coastal ecosystems and the land on which they are located (Nicholls et al., 2007, pp. 507, 540; Australian State of the Environment Committee (ASEC), 2011, pp. 878-81; Burley et al., 2012; Wong et al., 2014, p. 18). Sea level rise and more intense storm activity will exacerbate coastal erosion and shoreline recession in many areas (Gilman et al., 2008). The changed frequency and extent of coastal flooding from both stom1 surge and catchment rainfall will affect the health and composition of these ecosystems. Saltwater intrusion into groundwater will have impacts on both water supply and ecosystem dynamics in some places (ASEC, 2011 , p. 854). Warmer conditions will also affect the diversity of wetland ecosystems, and increase the risks of pests and disease.

Under appropriate conditions, many coastal wetlands have some capacity to adapt to higher sea levels in situ, by increasing their root mass and hence their elevation. Critical factors in this process include overall sea level rise and sedimentation, which is affected by flood barriers and other structures that alter natural flows (Rogers et al., 2014). Wetlands that are unable to adapt in situ could potentially move landward (ASEC, 2011, p. 880), but in countries like Australia, extensive development in the coastal zone restricts the potential for this natural migration (Blankespoor et al., 2012; Rogers et al., 2014). Australia's population is already highly concentrated in coastal areas. Projected population increases are expected to follow this trend and further restrict adaptation space for coastal wetlands. Furthermore, as sea levels rise and coastal hazards worsen, there is likely to be considerable pressure to protect existing settlements and infrastructure with hard coastal and flood defences, such as sea walls, groynes and levies which fundamentally disrupt natural coastal processes (Department of Climate Change (DCC), 2009; ASEC, 2011).

In many situations, planned retreat policies (involving the avoidance or removal of hard coastal defences) will be critical to maintaining coastal ecosystems and providing room for them to migrate inland as sea levels rise. Indeed, 'living shorelines' (the deliberate construction or rehabilitation of coastal wetlands, such as mangroves, as an alternative to traditional engineering structures such as seawalls) are increasingly promoted as an adaptation approach to increase the resilience of shorelines to erosion and inundation (Siders, 2013). Planning for such measures raises difficult trade-offs between the shortteml socio-economic costs associated with limiting land use and development, and losing buildings and infrastructure before the end of their economic life; and longer-term goals of public interest nature conservation (Abel et al., 2011). Trans-jurisdictional tensions therefore arise between tiers of government, between public and private legal interests and actors, and across regulatory regimes for different land uses or policy domains. The uncertainties and long timeframes that pervade projected climate change impacts raise new issues of 'temporal trans-jurisdictionality', which compound existing governance challenges.

In light of these current and future pressures, this chapter explores contemporary approaches to the management of coastal wetlands in Australia and argues for urgent reinvigoration of Integrated Coastal Zone Management (ICZM). We begin in Part Two by briefly reviewing the history and current status of ICZM in Australia as a strategic framework for improved coastal management in a climate change context. Part Three then maps and critiques the current regulatory framework, focusing specifically on legal and policy regin1es for coastal land use planning, coastal protection works, catchment water to ICZM, our analysis reveals a complex, fragmented regulatory landscape that has hitherto failed to protect coastal wetlands and which is likely to be vastly insufficient to support their adaptation to climate change. Our research also suggests that current approaches reinforce static patterns of land use and environmental protection that are ill-equipped to respond to the impacts of climate change and directly threaten many coastal aquatic ecosystems over the long term. These deficiencies point to the need for a fresh approach to coastal governance, which gives greater prominence to the protection of coastal ecosystems in a changing climate. To this end, in Part Four we suggest some priority reforms for refreshing and reinvigorating the ICZM agenda in Australia.