Diversity and distribution of Phytophthora species in association with water quality and the health of trees in fragmented riparian ecosystems
Burgess, T., Klunzinger, M., White, D., Lymbery, A. and Hardy, G. (2012) Diversity and distribution of Phytophthora species in association with water quality and the health of trees in fragmented riparian ecosystems. In: 6th International Union of Forest Research Organisations,IUFRO Working Party 7-02-09, 9 - 16 September, Córdoba, Spain.
The riparian zone in Western Australia is dominated by Eucalyptus rudis in a similar manner to Alnus spp. in Europe. For the last 20 years the health of these trees have been declining. This is attributed to an endemic leaf sucking Psyllid, however contributing factors could be an increase in the salinity of the waterways or the presence of a root pathogen, both of which would reduce the health of the trees. We sampled 25 sites along different rivers and streams in the southwest of Western Australia. At each site we recorded tree health, determined water quality and filtered water for the isolation of pythiaceous oomycetes. There was considerable variation in water quality (pH and salinity) and the health of the adjacent E. rudus, however the poor health w as not related to low water quality. There was also considerable variation in the number of colony forming units (from 1.33 to 90 L‐1), the proportion of Phytophthora compared to Pythium isolates (from 0‐100%) and the species biodiversity. In general, far more isolates were obtained from low quality water, except for when the pH was greater than 8.5. Water quality did not effect the proportion of Phytophthora isolates. Phytophthora species isolated included P. thermophila, P. fluvialis, P. amnicola and hybrids between these species. Additionally, numerous isolates of P. taxon salixsoil were obtained. Remnant sites closer to the urban area contained predominantly P. thermophila while P. taxon salixsoil predominated on the more southerly sites from remnants within agricultural zones. The link between tree health, water quality and associated pythiaceous populations was not established in this study.
|Publication Type:||Conference Item|
|Murdoch Affiliation:||Centre for Phytophthora Science and Management
School of Biological Sciences and Biotechnology
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