Whilst much of the coastline is formed from mobile sand dunes shifting gradually eastward, in the far east the coastline is punctuated by rocky headlands and outcrops (EGCMA, 2013). Estuaries and coastal wetlands within this zone range from the largest and most modified, in the west of the region (the Gippsland Lakes), to a series of smaller systems that are in exceptional condition, in the east (EGCMA, 2013). Many of the region’s estuaries provide important waterbird habitat, especially during drought. The mid-sized estuaries such as Snowy River and Sydenham Inlet are of national importance, and the Gippsland Lakes are internationally significant (EGCMA, 2013).

Asset vulnerability

In East Gippsland shallow freshwater coastal wetlands[1] and estuaries were assessed as being the most vulnerable natural assets (Spatial Vision & Natural Decisions, 2014). These results are due to both the sensitivity of these systems to changing climate and their adaptive capacity. For those coastal wetlands in the Gippsland Lakes and Hinterlands Landscape Area a low adaptive capacity was due to impacts from adjoining land uses and quality and amount of adjacent native vegetation.

These results are consistent with a vulnerability assessment, completed in 2013 for all Victorian wetlands, which indicated that coastal wetlands were highly vulnerable (SKM, 2013).

The impact of climate change on existing threats to natural assets in East Gippsland was assessed through a simple framework (see section 2.1 ‘Threat assessment’). For coasts, estuaries and coastal wetlands climate change was assessed as having the highest impact on invasive plants and animals (through increased populations and range of invasive species), and loss of native vegetation (including impacts from sea level rise and storm surge).  

Potential adaptation options

Potential adaptation options for coasts, coastal wetlands and estuaries in response to key climate change variables are set out in Table 1 below and have formed the basis of analysis for development of this Plan.

Table 1. Potential adaptation options for coasts, estuaries and coastal wetlands in East Gippsland.

Climate Change Variables Reduced and more variable rainfall	Increased temperatures and extreme heat	Increased intensity and frequency of rainfall events (including flooding)	Increased frequency of fire	Storm surge and sea level rise
Supporting a planned migration; start including pioneering species into the next EVCs where there is potentially saltwater ingress   Investigate potential solutions where coastal habitats become trapped between landward boundaries and rising sea level		Geomorphic recovery through works (vegetation and structural)	Focus fuel reduction burning to protect vulnerable areas.   Increase effort in recovery programs to assist with rehabilitation of burnt habitats.	Map where new areas will be and plan appropriately for migration of habitats

Mitigation Options

Vegetated aquatic habitats, including coastal environments (saltmarsh, mangroves, and seagrass meadows) and freshwater ecosystems, collectively known as ‘blue carbon’ environments, together sequester nearly equivalent quantities of organic carbon (Corg) as their terrestrial counterparts, in spite of their comparatively limited biomass (0.05% of terrestrial plant biomass).

East Gippsland contains significant areas suitable for the conservation and sequestration of ‘blue carbon’. In many cases these areas are in good condition and therefore the protection of these ecosystems, and their carbon stores, should be a high priority. As noted by Carnell et al. (2014), these features make vegetated estuarine environments particularly ideal candidates for carbon offset programs and nature-based climate mitigation initiatives. Waterways and wetlands (which include alpine peatland, freshwater wetland and coastal wetlands) are also thought to be significant carbon sinks (Carnell et al., 2014).

A preliminary assessment of the potential of ‘blue carbon’ for estuaries in the East Gippsland region was completed in 2014 (Carnell et al., 2014), with the following recommendations to maximize carbon stocks within vegetated coastal environments in East Gippsland:

• Prioritise ‘blue carbon’ hotspots for conservation
• Produce updated seagrass distribution maps
• Focus revegetation projects on saltmarsh ecosystems and/or estuarine environments closer to fluvial inputs
• Restore natural hydrology to enhance carbon sequestration in vegetated coastal habitats
• Research the distribution and carbon storage potential of wetland ecosystems in East Gippsland.

It is not clear how ‘blue carbon’ would be assessed under the current ERF approved methods. The current literature also has a focus on marine and estuarine vegetation communities as opposed to other aquatic and water dependent vegetation communities such as riparian and in-stream vegetation. The carbon potential of riparian vegetation can be assessed using the method described above and therefore it may be more appropriate to assess these vegetation communities within the methods described for environmental plantings and human induced natural regeneration.

For more information on climate change pressures on coasts, estuaries and coastlines, please see East Gippsland Regional Catchment Strategy: Climate Change Adaptation and Mitigation Plan.

 

[1] Coastal wetlands were defined by Spatial Vision & Natural Decisions, 2014 as being those wetlands with a tidal water source or within an area that had potential to be inundated by sea level rise by 2100.