Overwintering of Vaccinium vitis-idaea in two sub-Arctic microhabitats: a reciprocal transplantation experiment

Northern plants have to cope with a wide range of overwintering conditions, as the depth and physical properties of snow show high spatial variation in the Arctic. The overwintering of lingonberry (Vaccinium vitis-idaea) was studied in a reciprocal transplantation experiment between two sub-Arctic microhabitats in northern Finland. The experiment was set up in the autumn, and physiological traits related to overwintering were measured at the time of snowmelt in the following spring. The origin of the plants was not a significant source of variation for most of the traits measured, whereas major differences were observed between the two sites. Plants that overwintered at an exposed site above the treeline showed high relative winter damage, assessed by the electrolyte leakage of the leaves. No severe winter damage was observed in the plants that overwintered under a moderate snowpack at a sheltered birch forest site. These plants were able to maintain their photosynthetic capacity through the winter. A low capacity of photosystem II and a very low capacity of CO2 uptake were characteristic of the exposed site, where low temperatures and high irradiation predominate during late winter. However, photosynthetic capacity was recovered within a few days when the plants were kept under favourable conditions after the field experiment. The content of nonstructural carbohydrates was low, probably because of high respiratory losses under the snow. This short-term study suggests that lingonberry, which occupies a wide range of microhabitats in the present climate, may thrive even if the overwintering conditions change as a result of climatic warming.