Notes

Priority actions – Otway Coast Catchment

The Otway Coast Catchment stretches along the region’s coastline from Peterborough to the west to Breamlea to the east and contains the Curdies, Gellibrand, Aire, Otway Coast and Thompsons landscape zones. The zone is on the coastal side of the Otway Ranges. This landscape zone is internationally renowned for its coastline, which has been sculpted over thousands of years to become one of the most impressive natural sites of rock stacks in Australia including sheer limestone cliffs, arches, islands and blowholes that have been carved out of the soft cliffs by the wind and sea. The Twelve Apostles, Loch Ard Gorge, Bay of Islands Coastal Park, Shipwreck Coast and Port Campbell National Park are all in this zone The formation of the Great Otway National Park has meant that conservation and associated tourism are the dominant land use in the catchment with the majority of the area managed by Parks Victoria. The catchment also has some of the largest milk producing regions in Australia. NRM groups include the Heytesbury District Landcare Network, Southern Otways Landcare Network, Surf Coast and Inland Plains Network and various CoastAction groups. A number of environmental non-government groups, such as the Conservation Ecology Centre and ANGAIR, also occur in this area. Public land managers include Parks Victoria, Bellarine Bayside Committee of Management, Wannon Water, Barwon Water and Surf Coast Shire. Local municipalities include Corangamite, Colac Otway, Moyne and Surf Coast shires and the City of Greater Geelong.

Natural values

The Great Otway National Park extends through the area and features rugged coastlines, sandy beaches, rock platforms and windswept heathland in the south. In the north, the park features tall forests, ferny gullies, magnificent waterfalls and tranquil lakes.

The catchment’s main rivers include the Curdies, Gellibrand, and Aire rivers, which enter the Southern Ocean through a series of wetlands. The Aire is the region’s only listed Heritage River. The catchment also has many smaller rivers, such as the Erskine, Kennett and Cumberland, which intersect with the Great Ocean Road before flowing into the sea. Further to the east of the catchment, Thompsons Creek is the dominant waterway, along with the Anglesea River. The latter is fed from tributaries from an increasingly urbanised area between the Otways and Bellarine Peninsula.

The main agricultural practices in this catchment are forestry, grazing and dairy.

Potential impacts of climate change

The main impacts of climate change to natural assets in this catchment include reduced environmental flows, sea level rise, increase in fires – both in number of events and intensity, and vegetation communities to retract, evolve into new vegetation communities or disappear altogether.

Many of the streams and creeks in the Otway Coast catchment are small and rely on the high level of rainfall the Otways provide. A warmer and drier climate will reduce vital runoff, causing many of these rivers and streams to only run intermittingly. This will have ramifications for fauna species that will not be able to adapt before these changes occur. The larger rivers in this catchment will be impacted by reduced runoff in the upper catchments due to agricultural industries and water authorities exploring options for harnessing water on their properties.

Many of the vegetation communities of the Otways will be impacted by climate change. The Cool Temperate Rainforests in the wetter parts of the ranges will most likely disappear or evolve into different vegetation communities; the result of a combination of a warmer and drier climate and the increase in fire events in the surrounding fire-dependent mountain ash forests.

Many of the catchment’s estuaries intermittently open or close depending on the prevailing conditions e.g. freshwater flows, weather changes or tidal movements. Sea level rise will impact on these natural events causing inundation for longer periods of time and over greater areas. This can have adverse impacts to the estuarine environment, including the fauna and flora, which have evolved to the current inundation levels that we see today.

Sea level rise will also cause high levels of inundation on other coastal assets such as inter-tidal zones and rocky shorelines and cause coastal erosion to sandy beaches. More modelling is required to determine when and where these events will occur.

Serrated tussock (Nassella trichotoma) is a weed of national significance within the Thompsons Landscape Zone that may spread in its distribution under a warmer and drier climate. Under a more favourable climate, other environmental weed species may also increase their distribution into areas where they are currently absent.

The catchment has a number of species that climate change may impact.

Examples of flora include the Slender Tree-fern (Cyathea cunninghamii), Swamp Greenhood (Pterostylis tenuissima) and Anglesea Grevillia (Grevillia infecunda). Examples of fauna species include the Grey Goshawk (Accipter novaehollandiae novaehollandiae), Spot-tailed Quoll (Dasyurus maculatus maculatus) and Australian Mudfish (Neochanna cleaveri).

Carbon sequestration opportunities

Carbon sequestration opportunities include riparian protection and the establishment of wildlife corridors. Opportunities for soil carbon may exist, particularly in the wet forests where soil carbon levels are typically highest in the region, but more research is required to determine best methods and locations. Opportunities for blue carbon sequestration occur within the Otway Coast, mainly in the many estuarine habitats.

For more information click here http://www.swclimatechange.com.au/cb_pages/regional_planning.php

Natural asset	Vulnerability rating*	Climate change threat (direct &/or indirect)	Guiding adaptation responses	Stakeholders
Waterways – Ford River, Aire River, Parker River, Elliot River, Carlisle River and Barham River (West Branch)	Very High	Higher temperatures and longer periods without rainfall will lead to less environmental flows and reduced areas of refugia for aquatic species. More intense rainfall events may lead to more areas being susceptible to bank erosion.	Prioritise areas within reaches for targeted revegetation to improve shading and habitat as well as alleviate impacts of potential bank erosion. Protect riparian vegetation through fencing. Revegetate priority areas and provide instream habitat. Investigate options for removing artificial fish barriers e.g. weirs. Investigate feasibility of relocating isolated fish populations (Yarra Pygmy Perch). Collaboratively review and optimise water management to increase waterway resilience.	CCMA, NRM groups, DELWP (ARI), VEWH, Water Authorities, Private landholders
Waterways – Curdies River, Barham River (East Branch), Wye River, Kennett River, Cumberland River, Erskine River, St George River and Painkalac Creek	High
Waterways – Scotts Creek, Cooriemungle Creek, Port Campbell Creek, Anglesea River and Thompson Creek	Moderate
Waterways – Kennedys Creek and Gellibrand River	Low
Estuaries – Curdies River, Gellibrand River, Aire River and Anglesea River	Very High	A sea level rise of between 0.8-1.1 metres by 2100, hotter temperatures, a reduction in rainfall and an increase in extreme natural events e.g. flooding, are all expected to impact the ecology and dynamics of estuaries. Existing threats, such as changes to natural estuary openings and increases in nutrient levels may also be exacerbated by the indirect impacts of climate change, in particular through sea level rise and increases in storm surges.	Assess natural freshwater flow regimes estuaries and determine options for improved flows. Investigate opportunities to upgrade infrastructure that becomes inundated with high estuary water levels, with ‘green infrastructure’. Use LiDAR to identify latitudinal and elevational gradients, areas of refugia and opportunities to enhance connectivity. Establish management agreements with private landholders adjacent to estuaries to improve resilience of estuarine vegetation to climate change Protect riparian vegetation through fencing Restore riparian zone using appropriate revegetation. Explore opportunities for an EstuaryWatch group for Curdies River estuary and maintain existing groups to help monitor changes associated with climate change.	PV, LGAs, CCMA, NRM Groups, Private landholders
Coastal Wetlands – Lake Horden, Lake Costin, Lake Craven and Gellibrand Wetlands	Very High	Coastal wetlands are very vulnerable to climate change. Increased drought frequency and intensity, decreases in freshwater inputs, rising sea levels and increases in coastal storm surges may all impact these important ecosystems. These conditions may also change the character of coastal wetlands through a reduction in size, conversion to dryland or a shift from one wetland type to another (e.g. brackish to saline). Under hotter and drier conditions and reduced inflows, acid sulphate soils in coastal wetlands will face an increased risk of being exposed. The retention of coastal wetlands will require planning approaches which allow for the migration of wetland communities in order to avoid significant loss in both extent and character.	Assess the likely impacts of climate change on coastal wetland processes (i.e. tidal exchange, berm position and shoreline recession, entrance openings, water balance, geomorphology, water quality and biodiversity). Monitor sea level rise and associated impacts. Plan areas for marginal terrestrial vegetation (e.g. Coastal Saltmarsh) migration due to sea level rise. Prioritise blue carbon habitats and investigate blue carbon opportunities. Investigate opportunities to upgrade infrastructure that becomes inundated with high sea water levels, with ‘green infrastructure’. Develop an Adaptation Plan for the Wetlands including adjacent habitats. Establish the baseline condition and extent of all EVCS to monitor impacts of sea level rise.	PV, NRM groups, Private landholders
Native Vegetation – Rainforests, Wet or Damp Forests and Herb-rich Woodlands	Very High	A hotter and drier climate may cause existing vegetation communities to change in their composition and structure, with some species being replaced by others. Fire regimes will be modified, most likely with more frequent and intense events. Vegetation communities may be vulnerable to environmental weeds. Some vegetation communities will be more vulnerable than others to the direct impacts of climate change e.g. Riparian Woodland.	Management could focus on maximising the resilience of communities and maintaining ecosystem function. In many cases this will mean managing native vegetation as we do today. Improving the current condition is likely to be important for the long-term viability of a community, with those in better condition more resilient to change in the short term, and more adaptable in the long term, due to their greater genetic, floristic and structural diversity.	PV, Trust, CCMA, NRM groups, Private landholders
Native Vegetation – Lowland Forests and Coastal Scrub Grasslands/ Woodlands	Moderate
Native Vegetation – Heathy Woodlands, Riparian Scrubs or Swampy Scrubs/Woodlands and Heathlands	Low
Wetlands – Brown Swamp	High	Wetlands that are highly vulnerable to a climate that is hotter and drier will reduce in both extent and quality. A reduction in rainfall and runoff could cause some temporary wetlands to dry up permanently. A reduction in water inflow may also cause an increase in the salinity of some wetlands, and changes in the types of vegetation communities that they can support. Wetlands that are reliant on groundwater/spring fed may also be impacted.	Management should focus on maximising the resilience of communities and maintaining ecosystem function. In many cases this will mean managing wetlands as we do today. Improving the current condition is likely to be important for the long-term viability of a wetland, with those in better condition more resilient to change in the short term, and more adaptable in the long term, due to their greater genetic, floristic and structural diversity. Develop climate adaptation plans for Lake Modewarre and Lake Purrembete. Research ‘blue carbon’ opportunities of the catchment’s wetlands. Research potential groundwater sources (both quality and quantity) for selected wetlands. Research flora and fauna requirements of the littoral zone of major lakes in light of predicted changes caused by climate change.	PV, CCMA, NRM groups, Private landholders
Wetlands – Lake Modewarre	Moderate
Wetlands – Lake Purrumbete	Low
Agricultural Land	Low – Moderate	Climate change will have a direct impact on soil health and the ability of soil to support specific uses. Prolonged periods of higher temperatures and reduced moisture may lead to more areas being more susceptible to wind erosion. More intense rainfall events may also lead to areas of sheet, rill and gully erosion. Reduced vegetation cover due to climate change will also exacerbate these impacts. An increase in dryness and lack of moisture will also impact organic carbon in soil. Agricultural productivity may increase or decrease under a changing climate, depending on where it is located e.g. from grazing to cropping.	Addressing the impacts on soil will need to be assessed, planned and implemented at a site level due to a) the level of impact (often site-specific) and b) the adaptation response of the land manager of that site. A changing climate may mean that a current agricultural enterprise may need to also change to make better use of the climatic conditions, as well as changes to the soil properties that are expected. Research opportunities for soil carbon sequestration within this catchment should also be a priority.	Ag groups, NRM groups, CCMA, private landholders
Native Flora	Very High	The rate of climate change is likely to overtake the ability of most flora species to adapt and as a result, changes to the distribution of flora species are expected to occur. Changes in life cycle events e.g. flowering times, are also expected to greatly impact flora populations. There is also potential for greater tree mortality under climate change due to drought and temperature increases.	Management should focus on maximising the resilience of communities and maintaining ecosystem function. In many cases this will mean managing flora populations as we do today. Improving the current condition is likely to be important for the long-term viability of a community, with those in better condition more resilient to change in the short term, and more adaptable in the long term, due to their greater genetic, floristic and structural diversity. Protection and promoting the regeneration of large old paddock trees should be seen as a landscape priority due to their genetic capacity to survive through a significant range of climatic conditions and therefore provide a future seed source.	NRM groups, LGAs, CCMA, PV, ANGAIR, CEC, DELWP (regional)
Native Fauna	Very High	The rate of climate change is likely to overtake the ability of most species to adapt and as a result, changes to the distribution of fauna are expected to be a major response to climate change. More mobile species may find refuge from increasing temperatures by shifting to higher, cooler elevations or cooler, south-facing slopes. Species already restricted to high altitudes without the option of upslope migration are expected to become extinct unless they are able to adapt. Some species will be more vulnerable than others to extinction. Species may not be able to shift to areas with suitable climatic conditions where they are located in fragmented habitats, or because of their limited dispersal ability. Species with small, isolated or fragmented ranges, or those with low genetic variation and specific climatic requirements, will be more vulnerable and local extinctions are likely.	Protect and enhance existing natural populations. Maintain and improve diversity. Accept and accommodate unavoidable loss and facilitate transformation, when possible. Reduce impacts from other impacts of climate change (i.e. invasive species & changes to flooding and fire regimes). Allow and create space for species shifts and movement throughout the landscape. Increase connectivity (i.e. buffers, corridors, stepping stones) and areas of refugia. Monitor species, communities and ecological processes.	NRM groups, LGAs, CCMA, PV, ANGAIR, CEC, DELWP (regional)