Hans Cornelissen, Rien Aerts and colleagues
Systems Ecology, Dept. of Ecological Sciences, FALW, VU University Amsterdam
Office: De Boelelaan 1085: A162, A154
E-mail: j.h.c.cornelissen@vu.nl, +31 (0)20 – 59 86962 and, m.a.p.a.aerts@vu.nl, +31 (0)20 – 59 87211


Climate warming is progressing particularly strongly above the Arctic Circle. Predicting how this warming will affect northern ecosystem functions, and how changes in these functions feed back to climate (e.g. via changes in CO2 uptake or release), is a hot topic internationally. While we know quite a lot about direct effects of climate warming and other climatic changes on biological processes, we know little about indirect effects. However, we do expect major changes in ecosystem functions from climate-induced shifts in vegetation composition. This is because different plant species have different functional traits to help them to make a living in different habitats. For instance, certain leaf traits (e.g. high nitrogen concentration or specific leaf area) help plants to grow fast, while other traits (e.g. high lignin concentration) protect leaves to help them live longer. But the same traits will determine whether, after death, these leaves are decomposed fast or slowly. Also, certain moss species will be better at holding water than other species, which makes that the moss species composition will have consequences for soil water regimes in northern tundra areas. These, and many more links between climate, plant traits and ecosystem functions, are being studied in Swedish Lapland, just north of the Arctic Circle. We do field and lab work there at the Abisko Research Station, which has good facilities, accommodation and a diversity of northern ecosystems on its doorstep. There are various opportunities to do MSc internships which include a research stay there.


Since 2000 we have been mimicking climate warming by exposing a Sphagnum peatland near Abisko to experimental warming, using transparent, open-top chambers (kind of tents without a roof). The experimental factorial design is unique in that it includes winter warming (snow accumulation), spring warming and summer warming treatments, as well as control treatments. So we can really study how the warming effects differ between seasons. Various internships are possible here, which for instance study the responses to treatments for (1) vegetation development and plant trait composition; (2) various ecosystem functions (e.g. decomposition, emission of greenhouse gases); (3) links between vegetation, soil and invertebrate animal traits (collaboration with Matty Berg, Animal Ecology); (4) microbial communities and biogeochemical transformations.

Other internships include comparisons of different functional groups of plant species for their traits, especially those traits that tell us something about the effects that the species have on their environment. Both higher plants and cryptogams (mosses, lichens) are important in this research, which in practice often involves measuring traits of multiple species in standardised tests.

Please contact Hans, Rien or colleagues for an MSc internship! (But please be aware that expenses can not be covered by our department and that physically and mentally tough fieldwork conditions may be involved).