Can sacrificial feeding areas protect aquatic plants from herbivore grazing? Using behavioural ecology to inform wildlife management

Effective wildlife management is needed for conservation, economic and human well-being objectives. However, traditional population control methods are frequently ineffective, unpopular with stakeholders, may affect non-target species, and can be both expensive and impractical to implement. New methods which address these issues and offer effective wildlife management are required. We used an individual-based model to predict the efficacy of a sacrificial feeding area in preventing grazing damage by mute swans (Cygnus olor) to adjacent river vegetation of high conservation and economic value. The accuracy of model predictions was assessed by a comparison with observed field data, whilst prediction robustness was evaluated using a sensitivity analysis. We used repeated simulations to evaluate how the efficacy of the sacrificial feeding area was regulated by (i) food quantity, (ii) food quality, and (iii) the functional response of the forager. Our model gave accurate predictions of aquatic plant biomass, carrying capacity, swan mortality, swan foraging effort, and river use. Our model predicted that increased sacrificial feeding area food quantity and quality would prevent the depletion of aquatic plant biomass by swans. When the functional response for vegetation in the sacrificial feeding area was increased, the food quantity and quality in the sacrificial feeding area required to protect adjacent aquatic plants were reduced. Our study demonstrates how the insights of behavioural ecology can be used to inform wildlife management. The principles that underpin our model predictions are likely to be valid across a range of different resource-consumer interactions, emphasising the generality of our approach to the evaluation of strategies for resolving wildlife management problems

Sexual segregation in timing of foraging by imperial shags (Phalacrocorax atriceps): is it always ladies first?

The time seabirds have to forage is restricted while breeding, as time at sea must be balanced against the need to take turns with the partner protecting the nest site or offspring, and timing constraints change once the breeding season is over. Combined geolocator-immersion devices were deployed on eleven Imperial Shags (four males and seven females) in Argentina (43°04′S; 64°2′W) in November 2006 and recovered in November 2007. During the breeding season, females foraged throughout the morning, males exclusively in the afternoon, and variability between individuals was low. Outside the breeding season, both sexes foraged throughout the day, and variability between individuals was high. Timing differences may be explained by higher constraints on foraging or greater demands of parental duties experienced by the smaller sex, females in this case. Sexual differences in reproductive role, feeding habits or proficiency can also lead to segregation in timing of foraging, particularly while breeding