The spring range of barnacle geese Branta leucopsis in relation to changes in land management and climate

摘要: This study examines recent changes in the distribution of spring staging barnacle geese Branta leucopsis Norway. From early 1980s onwards, two major have taken place. First, increasing numbers moved from traditional islands with a semi-natural vegetation towards agricultural fields on larger close to mainland. Secondly, expanded their range by exploring more northerly located islands. Data food exploitation were collected interpret these changes. The density shoots edible grasses explained spatial variation grazing pressure over pattern was caused intensive available habitat, where apparently lower threshold intake rate set limit amount cropped. It is concluded that carrying capacity had been reached. On many islands, declined, however, as type highest and most preferred disappeared. negative development seems started when people abandoned summer sheep stopped. declining number can find sufficient within range, conjunction rapidly growing size total population, are main causes for observed expansion population. Increasing temperatures change agriculture may allowed move north, invade areas. To lessen conflicts between farmers large lines management available: restoration enhancing attractiveness saltmarshes