Climate change as it affected Gibraltar in the past and its impact on bird populations

Professor Geraldine Finlayson of the Gibraltar National Museum recently gave a webinar on the subject “The Pleistocene and Holocene conditions for trans-Saharan migrants at the northern edge of the Sahara Desert” which was organized by the prestigious Swiss Ornithological Institute. The webinar was given to an international audience of scientists on Friday 14^th April and was received with great interest. Although the title dealt with past bird migration, the focus of the presentation was also on the work carried out in Gorham’s Cave and in Doñana which examined in detail how climate changed affected the Gibraltar area in the past. This impact was seen dramatically in the form of massive land transformations associated with sea level change; as Prof Finlayson explained, these changes were often erratic and abrupt, transforming the land in short periods.

Climate had its influence on vegetation and Prof Finlayson explained in great detail our current knowledge of that vegetation based on pollen and charcoal studies in Gorham’s Cave and in Doñana. This information included the latest results which have been published in recent years. In spite of the great transformations to the landscape in northern Europe during the glaciations, with much of the British Isles under ice, much of France covered by tundra, sea ice in the Bay of Biscay, and the polar front (currently off Greenland) reaching the latitude of Oporto, olives and other warm-loving Mediterranean plants continued to grow in Gibraltar. These glacial refugial conditions for plants translated into pockets of survival for much of the European fauna, including birds but also people. Remarkably, the re-colonisation of Europe after the glaciations was undertaken by pioneer populations from these climatic refugia. Professor Finlayson concluded with an analysis of the survival of Palaearctic-African migratory birds in these locations, the only ones in Europe, based on the bones of these species retrieved from Gorham’s Cave.

The presentation may be viewed on YouTube at: https://www.youtube.com/watch?v=oikyZHf_LMQ