Climate change impact on Balearic shearwater through a trophic cascade

Area of Science:

• Marine Ecology
• Climate Change Biology
• Avian Conservation

Background:

• The Balearic shearwater (Puffinus mauretanicus), a critically endangered species, has shown northward expansion in the Northeast Atlantic.
• A correlation exists between seabird abundance and sea temperature around the British Isles.
• The link between temperature and the seabird's biogeographic shift was hypothesized to be mediated by the food web.

Purpose of the Study:

• To test the hypothesis that climate change affects the Balearic shearwater's distribution through its food web.
• To investigate concomitant changes across sea temperature, plankton, fish prey, and seabird populations.

Main Methods:

• Analysis of long-term data (1980-2003) for sea temperature, plankton (calanoid copepod), fish prey (anchovy, sardine), and Balearic shearwater abundance.
• Statistical examination of correlations and shifts across trophic levels.

Main Results:

• Significant shifts were detected across all three trophic levels (sea temperature, plankton, fish prey) and the Balearic shearwater population between 1994 and 1996.
• These findings indicate a synchronized response to environmental changes.

Conclusions:

• Climate change directly and indirectly influences the spatial distribution of the post-breeding Balearic shearwater.
• A trophic cascade driven by climate change is a key factor in the observed biogeographic shift.