Consistency of impact assessment protocols for non-native species

Pablo González-Moreno, Lorenzo Lazzaro, Montserrat Vilà, Cristina Preda, Tim Adriaens, Sven Bacher, Giuseppe Brundu, Gordon H. Copp, Franz Essl, Emili García-Berthou, Stelios Katsanevakis, Toril Loennechen Moen, Frances E. Lucy, Wolfgang Nentwig, Greta Srebaliene, Helen E. Roy, Venche Talgø, Sonia Vanderhoeven, Ana Andjelkovic, Kestutis ArbaciauskasMarie Anne Auger-Rozenberg, Mi Jung Bae, Michel Bariche, Pieter Boets, Mário Boieiro, Paulo A.V. Borges, João Canning-Clode, Frederico Cardigos, Niki Chartosia, Elizabeth Joanne Cottier-Cook, Fabio Crocetta, Bram D'hondt, Bruno Foggi, Swen Follak, Belinda Gallardo, Øivind Gammelmo, Sylvaine Giakoumi, Claudia Giuliani, Fried Guillaume, Lucija Šeric Jelaska, Jonathan M. Jeschke, Miquel Jover, Alejandro Juárez-Escario, Stefanos Kalogirou, Aleksandra Kocic, Eleni Kytinou, Ciaran Laverty, Vanessa Lozano, Alberto Maceda-Veiga, Elizabete Marchante

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)
48 Downloads (Pure)


Standardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.
Original languageEnglish
Pages (from-to)1-25
Number of pages25
Publication statusPublished - 1 Apr 2019


  • Environmental impact
  • Expert judgement
  • Invasive alien species policy
  • Management prioritization
  • Risk assessment
  • Socio-economic impact


Dive into the research topics of 'Consistency of impact assessment protocols for non-native species'. Together they form a unique fingerprint.

Cite this