The Indian Ocean dipole and European avifauna. Why NAO and ENSO are not enough and why we need something more?

Friday seminar by Piotr Tryjanowski.



Variation in climatic conditions can have wide-ranging effects on local weather patterns and ecological processes. For example, is well known that a positive shift in the North Atlantic Oscillation during the last two decades has coincided with warmer, wetter winters over Northern Europe, advances in plant phenology, and an earlier spring emergence of some species of insects. Studies also show that the North Atlantic Oscillation can influence the timing of breeding of European and North American birds. However not in all places on Northern Hemisphere an effect of NAO is evident, and the same is linked to ENSO and their influence on survival of northern birds wintering mainly in Africa. Recently, a growing body of evidence suggests that an independent ocean circulation system in the Indian Ocean, the Indian Ocean dipole (IOD), is partly responsible for driving climate variability of the surrounding landmasses. The IOD had traditionally been viewed as an artefact of the El Niño–Southern Oscillation (ENSO) system although increasingly the evidence is amassing that it is separate and distinct phenomenon. I present some results that the causes of the IOD, how it develops within the Indian Ocean, the relationships with ENSO, and the consequences for East African climate dynamics and associated impacts on ecosystems, in particular along the Eastern Arc Mountains of Kenya and Tanzania. I evaluate current research initiatives focussed on characterizing and constraining the IOD and examine how effective these will be in determining climate change impacts on East African ecosystems, mainly different aspects of birdlife.

Piotr Tryjanowski
Institute of Zoology, Poznań University of Life Sciences, Poland


Published Feb. 6, 2012 2:50 PM