Publication Details

Category Text Publication
Reference Category Journals
DOI 10.3354/meps09126
Title (Primary) Exploiting the closest productive area: geographical segregation of foraging grounds in a critically endangered seabird
Author Louzao, M.; Navarro, J.; Forero, M.G.; Igual, J.M.; Genovart, M.; Hobson, K.A.; Oro, D.
Journal Marine Ecology-Progress Series
Year 2011
Department OESA
Volume 429
Page From 291
Page To 301
Language englisch
Keywords Balearic shearwater; Geographical foraging ground segregation; Habitat modelling; Mediterranean Sea; Oceanography; Puffinus mauretanicus; Stable isotopes
Abstract While breeding, seabirds are limited to exploiting resources within a restricted area around their breeding site and should exploit the closest productive marine areas within their distribution range. We investigated this hypothesis in one of the most endangered European seabirds, the Balearic shearwater Puffinus mauretanicus (ca. 3200 breeding pairs), restricted to the Balearic Islands. Our aims were (1) to assess whether isotopic evidence (i.e. stable isotopes of d13C and d15N) of foraging habitat partitioning occurs among northern, central and southern populations, (2) to geographically locate population-specific potential foraging grounds along the Iberian continental shelf, and (3) to assess whether oceanographic conditions could explain observed patterns of stable isotopes (SI). SI values showed a latitudinal gradient, with birds from the northern population having lower d15N and d13C values than central and southern populations. Potential foraging grounds of northern, central and southern populations were centred in Cape Creus, Ebro Delta and Cape La Nao, respectively, results which were supported by habitat models. Oceanographic conditions in each potential foraging ground were different; the northern population used richer, colder and deeper waters compared to the central and southern populations. Chlorophyll a was the main oceanographic variable that explained variation in SI values. We hypothesised that SI differences among Balearic shearwater populations might be a consequence of differences in baseline isotopic values among potential foraging grounds rather than real differences in diet. Our comprehensive study also provides important information for management strategies to conserve this critically endangered shearwater.
Persistent UFZ Identifier
Louzao, M., Navarro, J., Forero, M.G., Igual, J.M., Genovart, M., Hobson, K.A., Oro, D. (2011):
Exploiting the closest productive area: geographical segregation of foraging grounds in a critically endangered seabird
Mar. Ecol.-Prog. Ser. 429 , 291 - 301