Projectdetails

Cold northern biomes, particularly peatlands dominated by bryophytes, have been accumulating of carbon in plant litter and older soil organic matter. Changes in the turnover (decomposition) of this organic material and in the release of carbon through soil respiration as a consequence of global warming, will have profound repercussions for regional carbon budgets and will feed back to climate. Climate change will affect carbon turnover both through the species composition of the vegetation, via its effects on organic matter production and quality, and through the changing composition and activity of the decomposer (including invertebrate detritivore) communities. Understanding high-latitude climate change effects on carbon cycling therefore requires knowledge on changes in the species composition of the constituent plants and decomposer organisms. The most exciting innovation of the proposed project is its focus, not on the species and their diversity per se, but rather on the functional traits that they have evolved in relation to the actual processes of carbon turnover. We will for the first time link functional trait spectra of plants, with particular emphasis on bryophytes (e.g. litter water retention capacity or pH), with functional trait spectra of animals, particularly soil invertebrates (e.g. morphology of mouth parts), to help us understand and predict their interactive effects on carbon turnover. The main objectives of our project are (1) to study how functional trait compositions of bryophyte, vascular plant and soil invertebrate communities interact to control belowground carbon turnover in wet and drier arctic tundra, and (2) how the functionally based associations among these groups of organisms are affected by climate warming.

We will address this objective through a combination of four approaches addressing specific research questions, all to be carried out near the arctic Abisko Research Station (ANS), North Sweden, which is also the coordination site of the IPY umbrella project ENVISNAR:

1. Trait-based databases will be constructed that will contain the predominant species of bryophytes, vascular plants and soil invertebrates and their measured trait values, to be screened for using tailor-made standardized assays. The focus will be on traits underlying carbon dynamics. This work will be the key to interpreting the interactive effects of biota on carbon turnover in the studies under point 2, 3 and 4 below.

2. We shall sample vegetation, litter and soil fauna biomass and functional trait composition in a range of wet and dry ecosystems in the Abisko-Torneträsk region, in order to detect and quantify general patterns of association among functional trait spectra of bryophytes, vascular plants and soil invertebrates.

3. To assess the impact of simulated climate change scenarios on associated trait compositions of bryophytes, vascular plants and invertebrates, we shall sample these biota in two in situ global change manipulation experiments, in which both realistic summer and winter warming scenarios are mimicked.

4. To investigate the mechanisms by which plant composition (relative abundance of bryophytes versus vascular plants) and invertebrate functional trait spectra (specifically community functional dissimilarity) affect soil carbon turnover and soil respiration, we shall create a microcosm experiment with artificial ecosystems representing wet and drier peatlands. 13C labelled litter will be introduced and the label tracked through different ecosystem compartments, biota and soil respiration CO2. Comparison with delta-13C signatures of different soil invertebrate species in different plant and fauna composition treatments will reveal the contributions of soil fauna to carbon turnover.

Artikelen

• (2008). Amino acid uptake among wide-ranging moss species may contribute to their strong position in higher-latitude ecosystems. Plant and Soil. pp. 199-208