Living at the limit in the Pyrenees: Peripheral and endemic plants are rare but underrepresented in protection lists

© 2022 The Authors. Diversity and Distributions published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

[Aim] Mountains shelter high biological diversity and constitute both important barriers and confluence areas for species. They often contain species whose populations occur at their range limit (peripheral species), which according to the “Centre-Periphery” hypothesis (CPH) are expected to occur in marginal environments, exhibit low abundance and consequently high vulnerability. Our study investigates this hypothesis for the flora of the Pyrenees, a biogeographical crossroads containing a large proportion of the total European plant diversity.

[Location] Pyrenees.

[Methods] We determined whether more than 2600 native plant species were endemic to the Pyrenees or found at the centre or periphery of their whole distribution range within the mountain chain. We then compared the ecological preferences, local and regional abundance, and conservation status among central, peripheral and endemic species.

[Results] A quarter of the flora was found at its geographic range limit within the Pyrenees. Endemic and peripheral species were more likely to be soil specialists in alpine grasslands and rocks, and exhibited smaller regional ranges than central species, but their local abundance did not tend to differ. Peripheral species at their southern range edge were more widespread regionally than at their northern range edge. Peripheral taxa were more prevalent in the Pyrenean red list of threatened species (55%) compared to national and regional protection lists (40% and 31%, respectively).

[Main conclusions] Peripheral species contribute substantially to the diversity of the Pyrenean flora. They follow the predictions of the CPH given their occurrence in scarce habitats, their low regional abundance and their high vulnerability according to the Pyrenean red list, although they tend to show similar local abundances as other species and are infrequent in protection lists. Integrative and cross-border assessments of the ecology and rarity of mountain floras provide better estimates of their vulnerability and ensure more efficient prioritization of their conservation.

Species records were compiled through the European projects FLORAPYR and FLORAPYR AVANCE, funded by the Pyrenean Work Community, a cross-border cooperation consortium. The authors thank all regional project leaders and multiple Pyrenean collaborators involved in the project, for gathering and putting together much information used here (http://www.atlasflorapyrenaea.eu/src/home/index.php?idma=0), and the OPCC-POCTEFA (EFA322/19 EFA 235/11). SP and MBG received funding by the Spanish Ministry of Science and Technology through a doctoral grant (FPI, BES-2011-045169), the project CAMBIO (CGL2010-21642) and VULBIMON (CGL2017-90040-R).

Peer reviewed