The western Palaearctic tundra is a breeding habitat for large populations of
European geese. After their arrival in spring, pink-footed geese (Anser
brachyrhynchus) forage extensively on below-ground plant parts, using a
feeding technique called grubbing that has substantial impact on the tundra
vegetation. Previous studies have shown a high frequency of grubbing in
lowland fen vegetation. In the present study, we examined the occurrence of
grubbing in other habitat types on Spitsbergen, in the Arctic archipelago of
Svalbard. Goose grubbing was surveyed along 19 altitudinal transects, going
from the valley bottom to altitudes dominated by scree. Grubbing was more
frequent in the wet habitat type at low altitudes compared to the drier habitat
type at higher altitudes. For the dry habitat type, a higher frequency of
grubbing was found in study plots with a south-east facing exposure where
snowmelt is expected to be early. This suggests that pink-footed geese primarily
use dry vegetation types for grubbing when they are snow-free in early spring
and the availability of snow-free patches of the preferred wet vegetation types
in the lowlands is limited. Dry vegetation types have poorer recovery rates
from disturbance than wet ones. Sites with early snowmelt and dry vegetation
types may therefore be at greater risk of long-term habitat degradation. We
conclude that the high growth rate of the Svalbard-breeding pink-footed goose
population suggests that increasing impacts of grubbing can be expected and
argue that a responsible monitoring of the effects on the tundra ecosystem is
crucial.
anser brachyrhynchus, grubbing, habitat, pink-footed goose, Svalbard, tundra
