Understanding the large-scale determinants of species’ geographic distributions is difficult, because many factors shape where a species will occur, including the abiotic environment, evolution, dispersal and species’ interactions. In most systems it is not clear how important each of these forces will be, as a result, it will be difficult to predict range limits with confidence. The New Zealand mud snail (Potamopyrgus antipodarum) offers a rare opportunity to resolve these ambiguities. This species has served both as a model of range expansion and a model system of rapid evolution, making it possible to contrast the effects of the abiotic environment evolution, dispersal and species interactions in a single system.
Results/Conclusions
Here we present a mechanistic model incorporating environmental gradients, rapid evolution and host parasite coevolution. We find that evolution is likely to have a modest effect on the distribution of this species because the effects of evolution are overwhelmed by the strong environmental gradient found in the native range of P. antipodarum. This work clarifies when ecological mechanisms, particularly evolution can be ignored when studying species’ distributions.