Contribution to the knowledge of Portuguese serpentine flora: ecological characteristics, endemic plants, and implications for biodiversity conservation

Serpentine areas are scarce in the world, but contain a large number of endemic taxa. These areas have, in many cases, been little or not at all surveyed from a vegetation and biodiversity conservation point of view. The most important Portuguese serpentine outcrops are found in northeastern Portugal, particularly in the Braganca-Vinhais and Morais massifs. Here, we present a complete ecological-floristic check-list of serpentinophites that are found in these areas since this knowledge is essential for their evaluation, management and conservation. A total of 25 taxa, classified into three categories with different grades of serpentinophily, were included in the list: (1) obligate serpentinophytes (exclusively on serpentine), (2) endemic or widespread taxa that in Portugal occur exclusively in ultramafic outcrops, and (3) preferential serpentinophytes (most of the distribution range, at least 90% of populations, are found on serpentine). Genera common to other Iberian serpentine areas (Andalusian serpentine flora) are Odontarrhena, Arenaria, Armeria, Asplenium, Paragymnopteris, Saxifraga and Silene. The majority of the studied serpentinophytes (72%) occurred in endemic and highly specialized plant communities. About half of the studied serpentinophytes (48%) are assigned in some IUCN threat category. Consequently, it is necessary to implement conservation measures to guarantee the protection of these habitats. Supplemental data for this article is available online at https://doi.org/10.1080/11263504.2021.2013337 .