Well are they dead or are they alive? There have certainly been considerable changes in the microbial communities in the thrombolites in the last 10 years. Yesterday the Lake Clifton thrombolites were listed as critically endangered under the Federal EPBC Act under the following criteria
- Criterion 2 as critically endangered because its geographic distribution is very restricted and the nature of its distribution makes it likely that the action of a threatening process could cause it to be lost in the immediate future;
- Criterion 3 as critically endangered because the loss or decline of functionally important species is very severe;
- Criterion 4 as critically endangered because the reduction in integrity of critical ecological processes is very severe; and
- Criterion 5 as endangered because the rate of continuing detrimental change is severe and is projected to continue in the immediate future.
“The Lake Clifton thrombolite community is subject to numerous threats, most of which originate outside the ecological community itself. Scientific research suggests that there has been significant environmental degradation at Lake Clifton since at least the early 1990s (Moore, 1990; WA CALM, 2004a). This is despite the Peel-Yalgorup System being recognised as a wetland of international importance, and Lake Clifton being situated within the Yalgorup National Park (Moore, 1990).
…the thrombolite community occupies much of the eastern edge of Lake Clifton, which in turn forms the eastern boundary of the Yalgorup National Park. This means that the thrombolites are adjoined by private rural and rural-residential land holdings, which contributes significantly to the level of threat they face (Moore, 1990). The vegetation buffer zone between these properties and the foreshore of Lake Clifton is considered inadequate (Davies and Lane, 1996). The greatest current threat to the ongoing growth and survival of the Lake Clifton thrombolite community appears to be increased salinity due to increased groundwater extraction and altered groundwater flows, followed by increased nutrient levels coming from adjacent agricultural and rural-residential properties. If Lake Clifton becomes permanently hypersaline, it is likely that the patterns of thrombolite growth, faunal diversity and waterbird useage will also be affected. It is possible that the international scientific significance of the Lake will also be lost as a direct result (Knott et al., 2003). Current studies suggest that the change to a permanent state of hypersalinity may have already occurred (Alexander and John, 2008a).
Pollution, changes to surrounding vegetation, sedimentation and the introduction of fauna not native to the area also negatively impact on the ecological community (WA CALM, 2004a). People visiting Lake Clifton also directly impact by crushing or trampling the thrombolite structures, which are very fragile. Finally, possible impacts of climate change must also be considered.”