Document ID: chunk:federal_register_of_legislation:F2019L00157:body:0:p6
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infection have similarities, at least initially, to those of water stress. In susceptible species, apparently healthy plants (in groups or individually) can suddenly die. Less susceptible species can show crown decline symptoms, including leaf yellowing and death of primary leaf-bearing branches. Epicormic2 branches with smaller leaves can develop and, over time, epicormic branches will decline, with an overall thinning of the crown. Trees with such symptoms can take a number of years     to decline and die. The removal of bark at the base of trees just above or below the soil line can reveal areas of necrosis. These necrotic areas effectively girdle the trees and cause death.

         It is important to note the intractable nature of Phytophthora dieback, but also that actions which ameliorate its effects—particularly on endangered species and communities—are vital to the conservation of Australia's biodiversity. The background document (DoEE, 2018a) contains further details on the pathogen.

              2.                         Growth from previously dormant buds on the trunk or limb of a tree—very common in Eucalyptus species

               1.3             Impacts of Phytophthora dieback

           Healthy natural environments provide a range of direct and indirect benefits that are threatened by Phytophthora dieback. This disease is often difficult to detect and can cause significant and permanent damage to ecosystems and landscapes before detection.

           Potential consequences of infection include:
•   inability of infected plants to develop new shoots, flowers, fruit and seed
•   extinction of populations of some flora species
•   a dramatic modification of the native plant community's structure and composition
•   a significant reduction in primary productivity and functionality
•   habitat loss and degradation of dependent flora and fauna; to date, these have been irreversible
•   local extirpation and a significant loss of genetic diversity
•   major declines in some animal species due to the loss of shelter and nesting sites or food sources. Further details on the impact of Phytophthora dieback are in the background document (DoEE, 2018a).

           Wildflowers on Mondurup Peak, Stirling Range WA before the introduction of Phytophthora cinnamomi © Rob Olver

 Mondurup Peak, Stirling Range WA after the introduction of Phytophthora cinnamomi © Department of Biodiversity, Conservation and Attractions, Western Australia

           1.3.1 Impacts on matters of national environmental significance

           Phytophthora dieback is a key threatening process under the EPBC Act due to its actual and potential impacts on threatened species and ecological communities, which are matters of national environmental significance under the Act. It also has the potential to cause unlisted species or ecological communities to become eligible for listing. An estimated 49 per cent of the rare, poorly known or data-deficient flora of south-west Western Australia are susceptible to P. cinnamomi (Shearer et al., 2004), and their conservation status is likely to change significantly over time.

           Appendices A,