Citation: Jauni, M.; Huusela, E.; Urho, L.; Hyvönen, T. Prioritizing Management of Invasive Alien Species of EU Concern—A Northern Perspective. Diversity 2023, 15, 585. https://doi.org/10.3390/d15050585 Academic Editors: Mario A. Pagnotta, Tiiu Kull and Jonne Kotta Received: 15 March 2023 Revised: 17 April 2023 Accepted: 19 April 2023 Published: 22 April 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). diversity Article Prioritizing Management of Invasive Alien Species of EU Concern—A Northern Perspective Miia Jauni 1, * , Erja Huusela 2 , Lauri Urho 1 and Terho Hyvönen 2 1 Natural Resources Institute of Finland (Luke), Latokartanonkaari 9, 00790 Helsinki, Finland 2 Natural Resources Institute of Finland (Luke), Tietotie 4, 31600 Jokioinen, Finland * Correspondence: miia.jauni@luke.fi Abstract: Invasive alien species (IAS) represent one of the major threats to biodiversity globally. Each member state in the EU is required to compile a management plan for IAS of Union concern. This requires risk assessments to prioritize management measures consistent with the requirements of each EU member state. Here, we review the management priorities for the 88 IAS of Union concern based on the risk assessment scheme developed for Finland. Of 88 species, 52 had not been detected in Finland and 51 species were categorized as species that fail to succeed in Finland. Climatic conditions can be regarded as a major factor limiting the success of those species. Five primary management categories were recognized. Monitoring was deemed the primary management option for 30 species, prevention of entry into Finland for 30 species, prevention of escape into nature for 17 species, prevention of further spread and/or the management of areas with high biodiversity value for 4 species and eradication for 7 species. It is concluded that national management plans should consider local environmental conditions and adjust management options according to national risk assessments. Keywords: biodiversity; biological invasions; non-native species; risk assessment 1. Introduction Invasion of alien species represent one of the major threats to biodiversity globally. In Europe, the number of alien species is high for many taxonomic groups (e.g., [1]). While the invasion histories of alien species and their impacts are recognized in Europe, the legislation for preventing species invasions has only been enacted recently [2]. Each EU member state is required to implement measures for the species included in the list of invasive alien species of Union concern, with special focus on pathways, early detection and rapid eradication, as well as management of widely spread species. Compiling management plans requires risk assessments to prioritize management measures adjusted for the requirements of each EU member state. Risk assessments of invasive alien species (IAS) included in the list of Union concern are conducted by following EPPO standard 5/5 (1) with a slight modification (see [3,4]). Fundamentally, the risk assessment can be based on any protocol if the detailed elements of the risk assessments are fulfilled [5]. The national-scale risk assessments utilize the information on IAS obtained from EU-scale risk assessments, which is complemented with more detailed information on the species distribution, invasion pathways and impacts (e.g., [6–9]). As a result, each country compiles adjusted management plans for IAS with prioritized management measures. Finland is the most northern country in the EU (located between latitudes 60 ◦ and 70 ◦ north) and belongs mostly to the Dfc climate class with the southern coast in the Dfb climate class according to the Köppen–Geiger classification (e.g., [10]). Finland’s location and climate affect the introduction, spread and impacts of IAS and should be considered in the risk assessments. Natural pathways of the introduction of IAS are limited due to Diversity 2023, 15, 585. https://doi.org/10.3390/d15050585 https://www.mdpi.com/journal/diversity