Process-Based Species Action Plans: an approach to conserve contemporary evolutionary processes that sustain diversity in taxonomically complex groups

Abstract

Many endemic plant species belong to taxonomically complex groups. These endemics have often arisen as a consequence of recent and rapid evolutionary divergence facilitated by processes such as hybridization, polyploidy and/or breeding system transitions. The rapid and dynamic nature of divergence in taxonomically complex groups leads to problems in the implementation of traditional species-based approaches for the conservation of the biodiversity that they contain. Firstly, the taxa of interest can be difficult to define and identify, leading to practical difficulties in implementing conservation measures. Secondly, a species-based approach often fails to capture the complexity of diversity present in the taxonomically complex group. To accommodate these challenges, we have developed a Process-Based Species Action Plan approach. This is designed to conserve the processes leading to the generation of biodiversity, rather than focusing on the preservation of individual named taxa. We illustrate the approach using a group of endemic tree species (Sorbus) on the Scottish island of Arran that have originated via a combination of multiple recent hybridization events and apomixis. The plan focuses on the optimization of habitat management to ensure the reproduction and regeneration of Sorbus in the zone in which these evolutionary processes operate, and to facilitate hybridization that will ensure the continued generation of diversity in this group.