%0 Articles
%T Invasive insects in Europe - the role of climate change and global trade
%A Vanhanen, Henri
%D 2008
%J Dissertationes Forestales
%V 2008
%N 57
%R doi:10.14214/df.57
%U http://dissertationesforestales.fi/article/1839
%X Human induced inadvertent introductions of invasive forest insects have become a serious threat to both biodiversity and the economy, causing disturbance and direct damage to natural forests and commercial stands. The rates of forest pest invasions have increased with increased trade and travel between and within continents. There are 109 exotic phytophagous species known to have successfully invaded and established themselves on Europe’s woody plants from both North America and Asia, and more will invade as international trade continues and its volume increases (I).

Risk analysis of potential invaders is a way to prevent or suppress the number of potential invasive species. Recognition of potential invaders and their major pathways helps to prevent or reduce introductions, since not all of the imported exotic insects are invasive, nor do they manage to establish themselves in novel environments. Successful colonization is governed by several factors independent of or dependent on the invading species. The most prominent factors governing successful establishment are the ecological opportunities on arrival and the competitiveness of the invader (I, II). Suitable climate and available host species are the most prominent factors, but species abilities or life history traits, e.g. wide tolerance of hosts, asexuality and tolerance of population gaps enhance the possibility for establishment (I, II). Also the number of invading individuals, i.e. the propagule pressure may be important in increasing the probability of establishing a viable population (II).

The risk of establishment is most severe where the main host species for the potential invader occurs naturally or is widely cultivated. Climatic comparisons and simulations of climatically or biogeographically suitable areas for targeted high risk species have become increasingly important in targeting preventive or eradicative efforts where they are most needed (III, IV). Climate-based modeling tools are also helpful in determining the potential risks posed by climate change induced range shifts of native and exotic insect species (III, IV, V). Range shifts and potential population fluctuation of forest pests to outbreak levels pose a potential threat to silviculture that should be considered when planning forest management practices.