Among-year and within-population variation in foraging distribution of European shags Phalacrocorax aristotelis over two decades: Implications for marine spatial planning

• Published in: Biological conservation Vol. 170; pp. 292 - 299
• Main Authors: Bogdanova, Maria I., Wanless, Sarah, Harris, Michael P., Lindström, Jan, Butler, Adam, Newell, Mark A., Sato, Katsufumi, Watanuki, Yutaka, Parsons, Matt, Daunt, Francis
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-02-2014; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Aves; Balancing; Biological; Biological and medical sciences; Breeding season; Coastal; Conservation; Conservation, protection and management of environment and wildlife; Forages; Fundamental and applied biological sciences. Psychology; General aspects; Heterogeneity; Long-term; Marine; Marine Protected Area; Marine renewables; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Phalacrocorax aristotelis; Sampling; Sea water ecosystems; Seabird; Segregations; Synecology; Telemetry; Tracking; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Breeding season; Marine Protected Area; Long-term; Coastal; Marine renewables; Seabird; Telemetry; Marine animal; Range finding; Phalacrocorax aristotelis; Protected area; Long term; Foraging behavior; Marine environment; Vertebrata; Space planning; Aves; Environmental protection
• ISSN: 0006-3207; 1873-2917
• DOI: 10.1016/j.biocon.2013.12.025

•We identified key foraging areas of breeding European shags over a 23-year period.•8years’ data captured over 90% of the foraging area used during the study period.•Over 60% of this area was captured with just 2years’ data.•Foraging range varied with sex, environmental conditions and population density.•Foraging locations of birds from different sub-colonies were spatially segregated.
Marine spatial planning aims to deliver sustainable use of marine resources by minimizing environmental impacts of human activities and designating Marine Protected Areas. This poses a challenge where species’ distributions show spatio-temporal heterogeneity. However, due to logistic constraints and challenging timescales many studies of distribution are undertaken over few years or on a restricted subset of the population. Long-term studies can help identify the degree of uncertainty in those less comprehensive in space and time. We quantify inter-annual and sub-colony variation in the summer foraging distribution of a population of European shags Phalacrocorax aristotelis, using a tracking data set comprising 320 individuals and 1106 foraging trips in 15years from 1987 to 2010. Foraging distribution over the study period was concentrated in three areas. Data from one and two years captured an average of 54% and 64% of this distribution, respectively, but it required 8years’ data to capture over 90% of the distribution. Foraging range increased with population size when breeding success was low, suggesting interplay between extrinsic and intrinsic effects. Furthermore, females had foraging ranges on average 36% greater than males. Finally, sub-colony segregation occurred in foraging areas up to 4km from the colony and in the most distant locations (>10km), whilst there was considerable overlap at intermediate distances (6–10km). Our study highlights important considerations for marine spatial planning in particular, and species conservation in general, notably the proportion of the population distribution identified, the prevailing conditions experienced and the need for balanced sampling across the population.