The Lake Warden System Ramsar site is located adjacent to Esperance on the south coast of Western Australia. The site is a system of saline lakes and marsh areas behind beach-front dunes. It includes Lake Warden, Woody Lake, Wheatfield Lake, Station Lake, Mullet Lake, Ewans Lake, part of Windabout Lake and the reserved land surrounding the lakes. The water entering the lakes comes from the surrounding catchment through groundwater and surface runoff. Coramup Creek drains into Wheatfield Lake, which becomes interconnected to the lakes during winter. Station and Mullet Lakes are occasionally connected to the sea via Bandy Creek. The lakes are a mix of almost permanent to ephemeral wetlands. The site also has a number of small, shallow, brackish wetlands that arise from springs at the eastern end of the site. Mullet Lake and the wetlands to the east of it are located in a large Samphire marsh. Wheatfield Lake and wetlands to the west occur in stabilised sand-dunes which support low woodland on the higher ground between the lakes. Although there is no emergent vegetation in the lakes, Melaleuca trees, rushes and sedges grow on the shorelines. Acacia, Banksia, mallee and scrub are present on higher ground. The lakes provides important habitat for waterbirds, including a significant proportion of the rare Hooded Plover population, which breed regularly at Station Lake and Lake Warden. Other species that use the sites include Australian Shelducks, Black Swans, Grey Teals, Banded Stilts and Chestnut Teal. Twenty-three species listed under international migratory bird conservation agreements have also been recorded at the site. One of the primary purposes of the sites reserves is for conservation. The close location of the site to Esperance has made it a desirable location for human recreation such as sightseeing, bushwalking, picnicking, nature appreciation, horse-riding, waterskiing and bird-watching.
Lake Warden
* About the images
Government evidence of impact of climate change:
Close all
-
Australian Government and WA Government Department of Environment and Conservation, Lake Warden Ramsar Site, Ecological Character Description
Although these are not confirmed climate change events; they have affected hydrological regimes.
The Indian Ocean Climate Initiative (2002) states that the following changes have already occurred to the climate in the south west of Western Australia .
This has altered the perceptions of regional climate even though a similar; albeit less severe; dry sequence was experienced earlier in the century The recent rainfall decrease was only observed in early winter (May July) rainfall late winter (August October) rainfall has actually increased; although by a smaller amount The winter rainfall sharply and suddenly decreased in the mid 1970s by about 15 20 .
The following is a summary of the environmental variances and consequential changes to the ecological character of the Lake Warden System Ramsar Site Climate A 5 to 10 increase in annual rainfall in the Esperance region comparing 1976 1999 to 2000 2007 data (George et al.; 2008) and An increase in unseasonal; episodic rainfall events resulting in floods in 1999; 2000; and 2009. .
Actual or likely Potential and or actual Likelihood Timing of threat threat or threatening impact(s) to wetland activities components; processes; benefits and services Urban industrial Altered hydrological regime Certain high Immediate long development and timing; frequency and extent term agricultural activities of inundation Introduction and Clearing of native establishment of weeds and feral animals vegetation Livestock grazing Increased salinisation General cropping and (secondary salinisation) agricultural activities through changed hydrology (Short et al.; 2000) General infrastructure Pollution nutrient; sediment Urban encroachment and salinity (Comer et al.; 2001) Reduction in waterbird habitat area Reduction in extent and condition of native vegetation Altered fire regimes Changes to water and sediment chemistry Disturbance of potential acid sulfate soils Increased fragmentation; loss of remnants and lack of recruitment . .
High Medium to long term (5 years to decades) Changes in rainfall; temperature and wind regimes Increases in extreme episodic events Altered catchment hydrological regimes timing; magnitude and frequency of flows into the Ramsar site Altered hydrological regime i.e. timing; frequency and extent of inundation Changes to flora and fauna distribution and condition Increased non native flora and fauna species Increases in sedimentation Reduction in the capacity for the site to provide provisioning; regulating; cultural and supporting services Introduction and establishment of weeds Spread of alien and non native species such as weeds Spread of Phytophthora cinnamomi and other plant diseases Destruction of flora and fauna habitat Increased fire risk Direct impacts on flora and fauna (e.g. by vehicles and trampling; impacting vegetation and waterbird; loafing; roosting and breeding sites) Reduction in the capacity for Recreation High Immediate to long term (decades) . .
Ecological Character Description of the Lake Warden System Ramsar Site 4.1.3 ALTERED FIRE REGIMES Fire and fire suppression are a potential threat to the ecological character of the site due to the land use surrounding the Ramsar site.
However; this is also dependant upon other factors such as fire frequency and timing (Morrison; 2002).
Fire can also cause hydrological changes through the removal of vegetation.
Other threats resulting from fire include the attraction of feral animals to an area to feed on new growth that results post fire (Nikki Cowcher; Fire Operations Officer; DEC; pers. comm.; 2008).
For example; after a fire there is often a concentration and abundance of rabbits; which causes erosion and changes vegetation structure rabbits will also attract foxes which may predate on native species (Nikki Cowcher; Fire Operations Officer; DEC; pers. comm.; 2008). .
It is these sorts of balances between intensity and frequency of fire that are difficult to maintain during prescribed burns.
Although; the flood of 2007 was severe and the Esperance region was declared a Natural Disaster Zone; it is anticipated that the impact of flooding events such as these would be more severe if the wetlands within the Ramsar site were not providing this benefit service. 3.2.3 CULTURAL SERVICES Recreation and tourism The Ramsar site offers numerous nature based recreational and tourism values such as bushwalking; bird watching and picnicking.
Limits of acceptable change components and requirements (for optimum waterbird habitat) (new hydrological regime) processes Abiotic components HYDROLOGY The current depth range for Lake Seasonal drying i.e. 0.5 m during Catchment has not reached a Warden is approximately 1.2 m to 2.5 summer autumn period annually. hydrological equilibrium therefore LAC Western m.
Download