Integrating a phylogenetic framework for mapping biodiversity patterns to set conservation priorities for an oceanic island flora

Abstract

Effective biodiversity conservation requires accurate assessments to inform management decisions, particularly in biodiversity-rich regions. The Gran Canaria Biosphere Reserve (GCBR) is located in one of the Canary Islands, an oceanic archipelago that belongs to the Mediterranean biodiversity hotspot and lies <100 km from NW Africa. We aim to help improve conservation in this territory by complementing traditional biodiversity metrics with phylogenetic analyses, using the two official plant DNA barcode sequences (matK and rbcL), and distribution data for 202 endemic angiosperm taxa within the GCBR, which encompasses about 42% of Gran Canaria's territory. We compare the geographical patterns of Phylogenetic Diversity (PD) and Phylogenetic Endemism (PE) with traditional diversity metrics such as Species Richness (SR) and Weighted Endemism (WE), and we use categorical analyses of neo-and paleo-endemism. Our results highlight significant centres of PD and PE that do not entirely overlap with those detected for SR and WE. Notably, the northern region of the GCBR includes important conservation areas, representing either accumulations of ancestral diversity or spots of incipient speciation. Moreover, evolutionarily significant areas displaying high values of neo- and paleo-phylogenetic endemism were identified in the east and southeast of the GCBR beyond the current core zones and protected areas. These results highlight the enhanced resolution provided by PD and related metrics, and offer a more nuanced understanding of plant biodiversity compared to SR alone. This study underscores the need to establish a new core zone to preserve all key plant evolutionary sites within the GCBR and to ensure comprehensive protection of the endemic flora, which will require coordination among conservation biologists and decision-makers. The methodology used showcases the value of integrating taxonomic and phylogenetic diversity metrics for guiding the design of protected areas and improving territorial management in the Canaries and other oceanic archipelagos.