Climate variability and growth competition in an arctic-alpine ecosystem: retrospective growth analyses of one deciduous and one evergreen dwarf shrub in the Norwegian Scandes
Ecology and Biodiversity of Plants and Ecosystems
Final Report Abstract
Alpine ecosystems are regarded as vulnerable to climate change. Species evolved under specific harsh conditions might lose their competitive ability under warming conditions, resulting in range shifts in the species’ distribution, structural alterations of alpine ecosystems, and in certain areas, ultimately, a replacement of species currently growing in the high alpine belt with those from the middle and lower alpine belts. Retrospective growth analyses support predictions of the faith of alpine ecosystems under future global warming. In the high alpine belt woody dwarf shrubs species form the backbone of the ecosystem. As trees, such shrubs form annual growth rings, and in recent years dendroecology of (dwarf) shrubs has emerged as a new and promising scientific field. Here, we aim to analyze the timing of growth of, climate-growth interactions in, and competition between two species, one deciduous and one evergreen, from a single site in the Norwegian Scandes Mountains. This will be done through the construction of ring-width chronologies (one for each species) and the statistical comparison of these growth time-series with both a unique, long-term, site specific, microclimatic record and the regional climate record. By studying the species response to past and ongoing climate change through retrospective growth analyses, the susceptibility of the species to climate change and the influence of climate change on their competition will be revealed. This way, their future response to climate change can be quantified and our understanding of the vulnerability of subarctic alpine ecosystems to climate change will increase. Currently we are developing two growth chronologies from the two most dominant dwarf-shrub species (the evergreen Empetrum nigrum ssp. hermaphroditum and the deciduous Betula nana) growing on a ridge, 1100 m above sea level, in the Central Norwegian Scandes. For this purpose we are applying serial sectioning on plant samples of both species.
Publications
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(2014) Growth responses of one evergreen and one deciduous dwarf shrub to the alpine micro-climate in the Norwegian mountains. Abstracts of the 9th International Conference on Dendrochronology, 13-17 January 2014, Melbourne, Australia. pp. 125-126
Weijers, S. & Löffler, J.
