Fate of a climate-driven colonisation: Demography of newly established populations of the limpet Patella rustica Linnaeus, 1758, in northern Portugal

Abstract

Even though a large number of studies linking changes in species distributions to global warming have been published in the last decades, the long-term success of invasions or range shifts has rarely been evaluated. The intertidal limpet Patella rustica Linnaeus, 1758, is a warm-water species whose changes in distribution have been related to the recent warming off northern Portugal. Here we analyse the effects of the severe winter of 2008/2009 on the demographic structure of P. rustica, with the objectives of reassessing its geographical distribution and testing the mechanisms underlying the establishment of range limits. In addition, three decades of sea surface temperature were analysed, providing information on the thermal context contemporaneous to the distributional changes. Despite the cold winter of 2008/2009, the abundance of P. rustica increased in the study area, showing that the previously reported changes on the distribution of this species were not ephemeral. The demographic analyses suggested that even though early life stages are probably affected by extreme low winter temperatures, adults are less sensitive, with important consequences for the resilience of marginal populations and the fluctuations of distributional ranges. These results emphasise the importance of considering the demographic consequences of thermal stress when trying to understand and forecast the effects of climate change on biogeography and biodiversity.