A Pragmatic Approach to the Management of Plant Invasions in Galapagos

This chapter presents an overview of the process undertaken to understand alien plant invasions and work towards their effective management in the Galapagos Islands. Galapagos is a unique case study for the management of alien plants in protected areas because much the archipelago has few alien plants and the original ecosystems are relatively intact. We discuss a pragmatic approach developed over 15 years to help prioritise management of 871 plant species introduced to the islands. This approach includes understanding invasion pathways; identifying which species are present and their distribution; determining invasive species impact on biodiversity, ecosystem function and mutualisms; prioritising management using weed risk assessment; guidelines to prevent further introduction through quarantine and early intervention; and developing methods to control or eradicate priority species. Principal barriers to application of the approach are limited capacity and coordination among managers and inherent difficulties arising from invasive species traits such as seed banks and dispersal and their interactions with ecosystems. We also discuss the approach of managing invasive species individually and suggest it may be more appropriate, when feasible, for the relatively intact uninhabited islands and dry regions of Galapagos. The more degraded highlands of the inhabited islands need a more complex approach that balances costs with prioritised outcomes for biodiversity and ecosystem functionality.