Consistency of impact assessment protocols for non-native species

Abstract

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.

This article is based upon work from the COST Action TD1209: Alien Challenge. COST (European Cooperation in Science and Technology) is a pan-European intergovernmental framework. The mission of COST is to enable scientific and technological developments leading to new concepts and products and thereby contribute to strengthening Europe’s research and innovation capacities. PGM was supported by the CABI Development Fund (with contributions from ACIAR (Australia) and Dfid (UK) and by Darwin plus, DPLUS074 ‘Improving biosecurity in the SAUKOTs through Pest Risk Assessments’. MV by Belmont Forum-Biodiversa project InvasiBES (PCI2018-092939). CP by Sciex-NMSch 12.108. JMJ and WCS by BiodivERsA (FFII project; DFG grant JE 288/7-1). JMJ by DFG project JE 288/9-1,9-2. CR and MB by Fundação para a Ciência e a Tecnologia grants SFRH/BPD/91357/2012 and SFRH/ BPD/86215/2012, respectively. PS by MESTD of Serbia, grant #173025. JP by RVO 67985939 and 17-19025S. JCC was supported by a starting grant in the framework of the 2014 FCT Investigator Programme (IF/01606/2014/CP1230/CT0001).