Study Design

Our study is located on the slopes of Mt Saana, in northwest Finland. In two spatially-interspersed habitats, we manipulated nutrient levels for six years of nutrient addition followed by eight years of recovery. We collected trait data to examine the role of “resource-acquisitive” plant traits in the persistence of nutrient addition effects.

Map of study sites on Mt Saana showing the interspersed locations of the two habitat types. Photos show examples of the 25 x 25 cm community survey plots in each habitat.

Persistent effects

Eight years after the end of the nutrient treatment, we found persistent differences in species composition, forb abundance, and litter depth. Communities on originally fertile habitats were more strongly impacted than those on infertile habitats.

Traits as predictors

We found that plants with fast-growing traits, including higher specific leaf area and height and lower foliar C:N, were more likely to show persistent increase in fertilized plots than control plots. These patterns were consistent across both habitat types.

Seeds and disturbance

As an extension of this project, we also surveyed plots that were treated with seed addition, biomass removal, or both at the start of the experiment. We’ll be using this data to look at the interactions between nutrients, disturbance, and recruitment in tundra communities.