Effects of spring temperature and volcanic eruptions on wader productivity

Key demographic parameters often show substantial annual variation that can have important consequences for rates of population growth. Since 2011 we have conducted annual estimates of the productivity of Icelandic Black-tailed Godwits Limosa limosa islandica over a large part of their breeding range. During this period, a volcanic eruption resulted in extensive dust deposition across the region. We show that Godwit productivity varies with spring temperatures but in the year of the volcanic eruption, productivity was reduced to almost zero. This rare but extreme event is likely to have had only a short-term influence, whereas ongoing warming of sub-Arctic regions is potentially a more substantial driver of the continued growth of this population.