Rare to be warm in Svalbard: An ecological and genetic snapshot of four red listed plant species

Abstract

Climate change is emerging as the most far reaching and significant stressor on Arctic biodiversity and it is predicted that it will lead to large changes in distributions, geographical ranges and abundances of species. Many species might soon be at extinction risk, and subsequently will good management of flora and fauna be of outermost importance. In high Arctic Svalbard, a third of the vascular flora is found in the regional red list, but management is difficult due to limited knowledge. For four of Svalbard’s most threatened vascular plant species, Botrychium lunaria, Sibbaldia procumbens, Kobresia simpliciuscula ssp. subholarctica and Ranunculus wilanderi will the following subjects therefore be investigated: 1) Localities, population sizes and possible threats to the populations 2) characteristics of the habitat and dispersal potential within localities 3) levels of genetic diversity and distinctness of the Svalbard populations and 4) implications for conservation in Svalbard. Evaluation of population sizes and immediate threats was carried out in the field and the data was reported to the Norwegian red list. For the habitat description, a selection of ecological parameters and vegetation data was recorded in 1-2 localities for each of the four focus species. Furthermore, in order to investigate possibilities for population expansion, ecological data was collected both from where the focus species was growing and from sites that the species do not yet occupy in its immediate surroundings. The suitability of this unoccupied habitat was then statistically tested and described through ordinations. Amplified Fragment Length Polymorphism (AFLP) was used to determine levels of genetic diversity, gene flow and genetic distinctiveness of the Svalbard populations compared to selected populations from other parts of the species distribution area. A thorough mapping of occurrences and population sizes was achieved. New data led to a downgrading of S. procumbens and R. wilanderi from Critically Endangered to Endangered in the regional red list for Svalbard, while the remaining species were kept in their categories. All populations were restricted to the warmer parts of Svalbard, and although some had local dispersal potential, dispersal potential outside these warm localities is probably low. The level of genetic diversity was extremely low, or nonexistent. Compared to populations from other parts of their distribution range, the Svalbard populations all had the lowest level of genetic diversity observed. Ranunculus wilanderi, an endemic for Svalbard, was the only species that seemed to represent an evolutionary divergent line, although data was lacking for K. simpliciuscula ssp. subholarctica. The focus species all shared an affinity for warmer temperatures, but still climatic induced changes to their habitat can threaten their presence in Svalbard.