Relation between extinction and assisted colonization of plants in the arctic-alpine and boreal regions

Taxonomy of Thelidium auruntii and T. incavatum complexes (lichenized Ascomycota, Verrucariales) in Finland

The taxonomy of lichen species morphologically similar to Thelidium auruntii and T. incavatum in Finland is being revised. Based on ITS and morphology, ten species occur in Finland. All species are restricted to calcareous rocks. The Thelidium auruntii morphocomplex includes six species: T. auruntii, T. huuskoneniisp. nov., T. pseudoauruntiisp. nov., T. sallaense sp. nov, T. toskalharjiensesp. nov. and T. sp. 1. In the ITS phylogeny, T. auruntii, T. pseudoauruntii and T. sallaense group together, but the remaining species are placed outside of this clade. All the species have northern distribution in Finland, occurring on fells in NW Finland and/or in gorges in the Oulanka area in NE Finland. The Thelidium incavatum morphocomplex includes four species: T. declivumsp. nov., T. incavatum, T. mendaxsp. nov. and T. sp. 2. This morphogroup is not resolved as monophyletic in the ITS phylogeny, with only T. declivum and T. mendax forming a strongly supported group. Thelidium incavatum is rather common in SW Finland, with one separate locality in eastern Finland. Thelidium declivum occurs only in the Oulanka area. Thelidium mendax occurs in the Oulanka area, but one locality is known from eastern central Finland. Thelidium sp. 2 is known from one locality in SW Lapland.

Assisted species migration and hybridization to conserve cold-adapted plants under climate change

Temperature rise due to climate change is putting many arctic and alpine plants at risk of extinction because their ability to react is outpaced by the speed of climate change. We considered assisted species migration (ASM) and hybridization as methods to conserve cold-adapted species (or the genes thereof) and to minimize the potential perturbation of ecosystems due to climate change. Assisted species migration is the deliberate movement of individuals from their current location to where the species' ecological requirements will be matched under climate projections. Hybridization refers to crossbreeding of closely related species, where for arctic and alpine plants, 1 parent is the threatened cold-adapted and the other its reproductively compatible, warm-adapted sibling. Traditionally, hybridization is viewed as negative and leading to a loss of biodiversity, even though hybridization has increased biodiversity over geological times. Furthermore, the incorporation of warm-adapted genes into a hybrid may be the only means for the persistence of increasingly more maladapted, cold-adapted species. If approached with thorough consideration of fitness-related parameters of the source population and acknowledgement of the important role hybridization has played in shaping current biodiversity, ASM and hybridization could help save partial or whole genomes of key cold-adapted species at risk due to climate change with minimal negative effects on ecosystem functioning.