Species • SPECIES OF THE MONTH

Alien species are a species, subspecies, or lower taxon introduced outside its normal past or present distribution; includes any part, gametes, seeds, eggs, or propagules of such species that might survive and subsequently reproduce. Invasive alien species are widely recognized as a threat to the sustainability of natural resources and agricultural production. Recent establishments of invasive insect pests such as the brown spruce longhorn beetle (Tetropium fuscum), Asian longhorned beetle (Anoplophora glabripennis), and emerald ash borer (Agrilus planipennis) highlight the risk of alien species to natural and urban forests of Canada. Invasive insects may introduce and vector alien fungal pests or may serve as vectors for native fungi. The impacts of alien species on native biodiversity are many and varied, including displacement of indigenous species through competition or predation, structural damage to aquatic habitats, and loss of genetic integrity. Climate change is also likely to have an impact on alien species, e.g. by extensions or retractions of the range of both native and alien species as temperatures change. The effect of climate change is likely to be complex and the response of both native and non-native species is difficult to predict. A new semi-quantitative method that enables researchers and others to assess the environmental impacts posed by alien species is now used in Norway. This method is tailored to the Norwegian environment; and can easily be adapted to other countries, an