Tree mortality in forests and urban areas of Australia can be connected to one major driver – the introduction of new pests and diseases.
New diseases continually arrive in Australia, with pathogens jumping from host tree to host tree, threatening an increasing number of tree species.
Dr Andrew Gougherty, research landscape ecologist at the US Department of Agriculture Forest Service (USDA Forest Service), said the continued emergence and accumulation of new diseases increases the likelihood of a particularly detrimental one emerging.
Gougherty is author of a project report recently published in NeoBiota.
The project team analysed more than 900 new disease reports relating to 284 tree species in 88 countries globally and quantified how emerging diseases have accumulated geographically and on different hosts.
“The ‘big data’ approach used in this study helps to characterise the growing threat posed by emergent infectious diseases and how this threat is unequally distributed regionally and by host species,” Gougherty said.
The number of emerging diseases has accumulated rapidly over the past two decades globally.
“The accumulation is apparent both where tree species are native and where they are not, with the number of new disease emergences globally found to double about every 11 years,” he said.
Based on the tree species assessed in the study, pines accumulated the highest number of new diseases, followed by oaks and eucalypts.
Gougherty suggested the trend is likely due to the wide distribution of these species throughout the Northern Hemisphere, as well as the planting of pine forests globally.
Europe was found to have the greatest total accumulation of new diseases, with North America and Asia close behind.
Additionally, Gougherty discovered more emerging tree diseases in native rather than introduced species.
“Global trends show little sign of slowing, suggesting the impact of newly emerged diseases is likely to continue to compound and threaten tree populations globally and into the future,” Gougherty said.
“Climate change is likely also playing a role, both by creating more favourable conditions for pathogens and by stressing host plants.”
Source – Phys.org
