Will Collared Lemmings and Their Predators be the First Vertebrates to "Fall Over the Cliff" in Greenland Due to Global Climate Changes?

the world’s simplest terrestrial vertebrate predator-prey community, with the Collared Lemming (Dicrostonyx groenlandicus) being the single main prey of four predators, the Snowy Owl (Bubo scandiacus), Arctic Fox (Vulpes lagopus), Long-tailed Skua (Stercorarius longicaudus), and Stoat (Mustela erminea). Using a 20-year time series (Figure 1) and a model that has been previously parameterized with data from northeast Greenland (Gilg et al. 2003), we analysed the population and community level consequences of the ongoing and predicted climate change. Species’ responses are complex, because in addition to the direct effects of climate change, which vary depending on species’ life histories, species are affected indirectly through interactions with their prey and predator species. The lemmingpredator community exemplifies these complications, yet a robust conclusion emerges: in practically all scenarios and for the ranges of parameter values examined, climate change increases the length of the lemming population cycle and decreases the maximum densities reached during the fluctuations (Gilg et al. 2009). The latter change, in particular, is detrimental to populations of their predators, which are adapted to make use of the years of prey abundance (Gilg et al. 2006). Indeed, in northeast Greenland, even the Gyrfalcon is strongly dependent on lemmings, for the densities of larger prey, such as Arctic Hare (Lepus arcticus) and ptarmigan are too low in most years.