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More than 1180 non-native species, mostly of Palaearctic origin, have been recorded from the boreal zone of Canada, with the highest diversity on the island of Newfoundland and in the southern boreal zone of Ontario and Quebec. The non-native biota of the boreal zone (and of Canada in general) is poorly known in terms of species composition and distribution. A large proportion of species are associated with disturbed anthropogenic habitats such as urban areas, agricultural landscapes, transportation and communication corridors, and industrial developments. Natural habitats in the boreal zone have a high degree of resistance to invasion compared with those of other Canadian zones, likely owing to harsh climates, low light levels, poor soil nutrient availability, low soil pH, low productivity, and dense covering of the ground by plants, especially bryophytes. Of the relatively few non-native species that have successfully colonized the boreal zone, many decline greatly in abundance after a few years, suggesting biotic resilience. To date the boreal zone has shown the least resistance and resilience to large vertebrates (moose and white-tailed deer) translocated to islands, diseases of vertebrates, and earthworms. In general, the ecological impacts of non-native species on the boreal zone have been poorly studied, and there are few examples where such impacts are evident. Likewise, there has been little attempt to quantify the economic impacts of non-native species in either the boreal zone or in Canada as a whole. In the few cases where management measures have been implemented for highly destructive non-native species, results have been somewhat successful, especially where classical biological control measures have been implemented against insects on trees. Chemical and mechanical management measures have had only limited success in localized situations. Management resources are most effectively applied to reducing the risk of introduction. The risk to the boreal zone posed by future new non-native species is increasing with the warming climate and the fast and direct transport of goods into the boreal zone from points of origin. Five recommendations are provided to address recognized gaps concerning non-native species. Key words: boreal, non-native species, ecological impacts, risk, biological invasion. On a enregistre plus de 1180 especes non indigenes, surtout d'origine palearctique, dans la zone de la foret boreale du Canada, dont la plus grande diversite se retrouve sur l'ile de Terre-Neuve et dans la zone boreale meridionale de l'Ontario et du Quebec. Le biote non indigene de la zone boreale (et du Canada en general) est mal connu en ce qui concerne sa composition et sa distribution. Une forte proportion des especes est associee a des habitats perturbes par l'homme comme les milieux urbains, les paysages agricoles, les corridors de communication et de transport ainsi que les developpements industriels. Les habitats naturels de la zone boreale montrent un fort degre de resistance a l'invasion, comparativement a ceux d'autres zones du Canada, vraisemblablement a cause des climats rigoureux, des faibles degres d'illumination, de la faible disponibilite des nutriments du sol, du faible pH des sols, de la faible productivite, et de la dense couverture du sol par les plantes, surtout les bryophytes. Parmi les peu nombreuses especes ayant colonise avec succes la zone boreale, plusieurs connaissent un fort declin en abondance apres quelques annees suggerant une resilience biotique. A date, la zone boreale a montre les moindres resistances et resiliences chez les grands vertebres (orignaux et cerf de Virginie) transferes sur ces iles, les maladies des vertebres et les vers de terre. En general, on a peu etudie les impacts ecologiques des especes non indigenes de la zone boreale et il y a peu d'exemples oU ces impacts sont evidents. De meme, il y a eu peu de tentatives pour quantifier les impacts economiques des especes non indigenes, que ce soit en zone boreale ou au Canada en general. Dans les rares cas oU des mesures d'amenagement ont ete mises en place pour les especes non indigenes fortement destructives, les resultats ont eu assez de succes, surtout la oU les mesures de maitrise biologique classique ont ete utilisees contre les insectes et les arbres. Les mesures chimiques et mecaniques n'ont qu'un succes limite dans des situations localisees. Les ressources de l'amenagement sont plus efficaces lorsqu'elles sont appliquees pour reduire le risque d'introduction. Le risque pour la foret boreale pose par de futures especes non indigenes augmente avec le rechauffement climatique et le transport rapide et direct de marchandises dans la zone boreale, a partir de leurs points d'origine. Les auteurs font cinq recommandations pour prendre en compte les lacunes reconnues au sujet des especes non indigenes. [Traduit par la Redaction] Mots-cles: boreal, especes non indigenes, impacts ecologiques, risque, invasion biologique., 1. Introduction Since the Wisconsinan glacial maximum ~21400 years ago, the rate of change of species composition in Canada has been determined by natural processes such as the rate and [...]

More than 1180 non-native species, mostly of Palaearctic origin, have been recorded from the boreal zone of Canada, with the highest diversity on the island of Newfoundland and in the southern boreal zone of Ontario and Quebec. The non-native biota of the boreal zone (and of Canada in general) is poorly known in terms of species composition and distribution. A large proportion of species are associated with disturbed anthropogenic habitats such as urban areas, agricultural landscapes, transportation and communication corridors, and industrial developments. Natural habitats in the boreal zone have a high degree of resistance to invasion compared with those of other Canadian zones, likely owing to harsh climates, low light levels, poor soil nutrient availability, low soil pH, low productivity, and dense covering of the ground by plants, especially bryophytes. Of the relatively few non-native species that have successfully colonized the boreal zone, many decline greatly in abundance after a few years, suggesting biotic resilience. To date the boreal zone has shown the least resistance and resilience to large vertebrates (moose and white-tailed deer) translocated to islands, diseases of vertebrates, and earthworms. In general, the ecological impacts of non-native species on the boreal zone have been poorly studied, and there are few examples where such impacts are evident. Likewise, there has been little attempt to quantify the economic impacts of non-native species in either the boreal zone or in Canada as a whole. In the few cases where management measures have been implemented for highly destructive non-native species, results have been somewhat successful, especially where classical biological control measures have been implemented against insects on trees. Chemical and mechanical management measures have had only limited success in localized situations. Management resources are most effectively applied to reducing the risk of introduction. The risk to the boreal zone posed by future new non-native species is increasing with the warming climate and the fast and direct transport of goods into the boreal zone from points of origin. Five recommendations are provided to address recognized gaps concerning non-native species. [ABSTRACT FROM AUTHOR]

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