Routledge Handbook of Biosecurity and Invasive Species Chapter 7: Forest ecosystems

There are few better study ecosystems than forests to reveal global insights into the patterns and processes associated with biological invasions. Forests range from single species stands to some of the most biodiverse terrestrial ecosystems and are managed for a wide variety of environmental, social and economic values in myriad ways with equally contrasting intensity of effort. There are no forests left on the planet that are untouched by global environmental change. The impacts of non-native species invasions and anthropogenic climate change act individually and synergistically to drive considerable change in the direct and indirect interactions between species in these ecosystems. If we are to improve our management of non-native species, as well as conserve forest habitats worldwide, there is merit in bringing together contrasting examples to improve our understanding. Here we provide an overview of non-native species invasions in forest ecosystems using broad to fine scale examples to illustrate key patterns and highlight priority areas for future research. Our aim is to represent complex human interactions with the invasion phenomenon through the use of emblematic species groups (plants, pathogens and insects) and forest ecosystems (temperate and tropical). Specific attention is also given to the active management of the tree component because such management could be either the major factor of disturbance favouring non-native species spread or, conversely, the only way to prevent further invasions, which could happen without proactive mitigation.