Evolutionary Conservation

Integrating evolution into practical conservation

The Socotra Archipelago has been referred to as ‘the Galapagos of the Indian Ocean’: its’ charismatic flora sits at the crossroads of three biogeographical regions and includes such intriguing endemic life forms as the dragon’s blood tree Dracaena cinnabari. The island is topographically, geologically and climatically diverse, with endemic taxa concentrated in high altitude ‘wet refugia’ which experience increased precipitation. Endemic taxa are also found on dry upland limestone plateaus and coastal plains. Several genera appear to have radiated within and among these refugia, while others appear to have radiated on an island-by-island basis throughout the archipelago.

Socotra harbours some 835 vascular plant species: 308 of these (37%) and 14 genera are found nowhere else. This is complemented by high levels of animal endemism, resulting in its’ designation as a UNESCO World Heritage Site, UNESCO Man & Biosphere Reserve, WWF Global 200 Ecoregion and Plantlife International Centre of Plant Diversity. Despite this, it does not qualify as a biodiversity hotspot in its own right as it falls short of the criterion of 0.5% of the world’s plant species as endemics, although its’ 37% plant species endemism exceeds that of 11 out of 34 officially designated hotspots. When ranked by number of endemic species per km2 it is exceeded by a single oceanic archipelago (Hawai’i) and isolated continental islands that are much larger (eg. New Caledonia, Jamaica).

Socotra is a continental fragment whose extant biota may reflect vicariant or dispersed elements, in contrast to oceanic islands where taxa have dispersed, adapted and diversified in situ on a clean slate of environmental opportunity. While the flora and its traditional uses have been comprehensively described, the evolutionary drivers of this diversity and endemism are poorly understood. Conservation assessments have been carried out for most of its vascular plant species and areas designated for protection: however these designations do not take into account the evolutionary uniqueness of the flora or identify and conserve the processes by which it has evolved.

Objective One:

Are protected areas on Socotra best defined by patterns of plant phylogenetic diversity?

Objective Two:

What is the origin of the Socotran flora, and what processes have driven the evolution of the island’s endemic species?

Objective Three:

How can evolution be integrated into practical conservation strategies?