A large-scale multi-species spatial depletion model for overwintering waterfowl

摘要: In this paper, we develop a model to evaluate the capacity of accommodation areas for overwintering waterfowl, at large spatial scale. Each day geese are distributed over roosting sites. Based on energy minimization principle, birds daily decide which surrounding fields exploit within reserve boundaries. Energy expenditure depends distance roost and weather conditions. Food intake rate is determined by functional responses, declines with consumption. A shortage occurs when cannot fulfil their requirement. Most foraging takes place pasture, complementary feeding some species cereals harvest remains. We applied five waterfowl in Netherlands. From comparison field data, appears produce realistic grazing pressures especially geese, decline sward height, but use arable less agreement observations. For current goose wigeon numbers, hardly any shortages expected, extrapolating population increase observed during last decade, considerable expected near future (2015). However, find that several uncertainties may contribute more severe shortages: probabilistic (and therefore optimal) choice location, shorter maximum roost, lower effective availability resources due disturbances other edge effects. Between both competition facilitation. Both type interactions, as well pattern resource exploitation, explained from responses energetic costs species.