Impact of erect shrubs on the cover and fruit productivity of berry species in subarctic Canada

Berry species are an important source of food in late summer for resident and migrant animals, and an integral part of the diet and culture of Indigenous Peoples. This study investigated how the presence of erect shrub patches (cover > 25%) affected the occurrence, cover, and fruit productivity of Vaccinium uliginosum L., Vaccinium vitis-idaea L., and Empetrum nigrum L. in the vicinity of Umiujaq, a subarctic community that has experienced a rapid increase in erect shrub cover since the 1990s. Our results indicated that berry species are ubiquitous in the area although the likelihood of occurrence is nearly three times lower under shrub patches. The cover and fruit productivity of V. uliginosum and E. nigrum diminished under erect shrub patches and this effect was more pronounced at the center of patches. In contrast, the cover and fruit productivity of V. vitis-idaea was not influenced by the presence of erect shrub patches. Finally, erect shrub patches delayed fruit ripening for V. uliginosum and V. vitis-idaea but differences could not be measured for E. nigrum. This study suggests that observed and forecasted increases in erect shrub cover in the Arctic may have widespread negative impacts on berry species.