Horizon scanning for invasive alien species with the potential to threaten biodiversity in Great Britain

Abstract

Invasive alien species (IAS) are considered one of the greatest threats to biodiversity, particularly through their interactions with other drivers of change. Horizon scanning, the systematic examination of future potential threats and opportunities, leading to prioritization of IAS threats is seen as an essential component of IAS management. Our aim was to consider IAS that were likely to impact on native biodiversity but were not yet established in the wild in Great Britain. To achieve this, we developed an approach which coupled consensus methods (which have previously been used for collaboratively identifying priorities in other contexts) with rapid risk assessment. The process involved two distinct phases: Preliminary consultation with experts within five groups (plants, terrestrial invertebrates, freshwater invertebrates, vertebrates and marine species) to derive ranked lists of potential IAS.Consensus-building across expert groups to compile and rank the entire list of potential IAS.Five hundred and ninety-one species not native to Great Britain were considered. Ninety-three of these species were agreed to constitute at least a medium risk (based on score and consensus) with respect to them arriving, establishing and posing a threat to native biodiversity. The quagga mussel, Dreissena rostriformis bugensis, received maximum scores for risk of arrival, establishment and impact; following discussions the unanimous consensus was to rank it in the top position. A further 29 species were considered to constitute a high risk and were grouped according to their ranked risk. The remaining 63 species were considered as medium risk, and included in an unranked long list. The information collated through this novel extension of the consensus method for horizon scanning provides evidence for underpinning and prioritizing management both for the species and, perhaps more importantly, their pathways of arrival. Although our study focused on Great Britain, we suggest that the methods adopted are applicable globally.

Risk management to prioritise the eradication of new and emerging invasive non-native species

“…Twenty species were already established in GB at the time of assessment, but with limited distributions; a further 21 were horizon species, defined as species not established in GB at the time of assessment but considered likely to invade in the near future. The list of horizon species was based on the top 30 threats identified by Roy et al (2014c), less nine species that were excluded. Species were excluded if they were primarily crop, forestry or fish pests and dealt with by established plant or fish health regimes in GB; or were species that had already established in GB by the time of assessment, in which case they were included as established species.…”

“…We applied the scheme to a group of new and emerging INNS that pose a threat to GB, as these were considered most likely to be potential candidates for eradication (Roy et al 2014c). We demonstrate how the scheme can be used, in combination with existing risk assessment scores, to indicate priorities for eradication and contingency planning; and examine the importance of risk management for prioritisation.…”

Harmonia + and Pandora +: risk screening tools for potentially invasive plants, animals and their pathogens

“…Outside of Belgium, the ISEIA protocol has, among others, been used to inform risk analyses of particular species in the Netherlands (e.g. Gyimesi andLensink 2010, van de Koppel et al 2012), black lists of vascular plants in Luxembourg (Ries et al 2013), and a horizon scan of potentially invasive species in Great Britain (Roy et al 2014a). Although the field of risk analysis of invasive alien species has seen much progress in recent years, a considerable scope for improvement is still left (see reviews by Leung et al 2012;Kumschick and Richardson 2013).…”

Robust cropping systems to tackle pests under climate change. A review

“…Interactions between the changing environment, crops, cropping systems, and pests demand a new multi-disciplinary and integrative knowledge base for the development of viable adaptive strategies. The capacity to adapt is needed to reduce the impact of both invasive alien species as well as rapidly evolving resident pest populations (Chakraborty 2013;Roy et al 2014). Here, we contend that anticipatory strategies, enhanced adaptation capacity, and the development of more resilient cropping systems require new insights and innovative organizational change.…”