Threatened exotic species of botanical gardens: Application of trait-based naturalized species risk scoring assessment

Invasive alien / exotic species (IAS) are one of the major global threat that contributing to plant extinctions. Interestingly, there are also many exotic species that are threatened with extinction that are housed in Botanical Gardes throughout the world. We defined threatened species as plant species with Red List IUCN category of VU (vulnerable), EN (endangered), CR (critically endangered). We excluded other Red List categories such as NT (near threatened), LC (least concern), DD (data deficient), and NE (not evaluated). We used Tropical Weed Risk Assessment Procedure (TWRAP) to estimate the risk of invasion of selected threatened exotic plant species in Indonesian Botanical Gardens. The climate suitability and seed traits were considered as the main source of scoring variability between assessors in this study that directly contribute to the TWRAP score results uncertainty. This study showed that rapid scoring risk assessment can be conducted practically and feasibly to support invasion risk management of threatened botanical garden species. Invasive species risk assessment is crucial to be conducted for botanical garden exotic species with important conservation status, to allow botanical garden management to properly managed the risk of invasion while also conserve these threatened species as botanical garden species.