IntroductionThe current consensus is that the world is rapidly warming,and that the anthropogenic production of greenhouse gasesis a major contributing factor. There are, of course, otherways in which environments change, sometimes anthro-pogenic (especially habitat loss and fragmentation), andsometimes not, but climate change in particular has ourattention at the moment. In the context of climate change,mobile species that are not prevented from moving byphysical barriers may simply move to where the climate ismore suitable (e.g. Root et al. 2003; Gregory et al. 2009).There are a number of studies that model the projectedpattern of re-distribution, and a recent paper describes theimplications for designing and maintaining wildlifereserves (Hole et al. 2009). In general, a strategy forreserve design would need to emphasize the importance ofcorridors and stepping stone habitat to provide the capacityfor redistribution in future as climate changes. Of coursethere will be practical and logistical problems associatedwith this. For example, since multiple species will beaffected, likely including those that are interdependent (e.g.predator and prey), the outcome will be hard to predict. It’salso not trivial to predict where populations may move,which is typically based on current species distributionsand projected changes in ‘climate envelope’ (Pearson andDawson 2003).Another possible response to changing environments islocal adaptation to the new conditions. There are manyexamples, perhaps the most famous of which is therapid evolution of the Galapagos medium ground finch(Geospiza fortis) in response to dryer conditions during anEl Nin˜o event (Boag and Grant 1981). Beak thicknessincreased, as birds with thicker beaks were better able tobreak into the harder, desiccated seeds, and consequentlyhad higher fitness. The effect was later shown to be pri-marily due to a single locus (Abzhanov et al. 2004). At thesame time, a 30 year study of the impact of selection on themedium ground finch and the cactus finch (Geospizascandens) showed that the response was dynamic over thatperiod, and that the end result after 30 years was unpre-dictable (Grant and Grant 2002). If the relevant trait canquickly evolve when environments change, as in thisexample, the population may not move, but may showsigns of local contraction due to selective load. Trackingthe evolution of functional genes under selection as envi-ronments change will be an important objective for thefuture as genomic data becomes more widely available. Sofar examples of this incorporating ancient DNA havemostly investigated disease resistance in human popula-tions (e.g. Zawicki and Witas 2008).A further possible response to changing environments isphenotypic plasticity, whereby behaviour or some plasticaspect of morphology or physiology changes to adapt to thenew conditions (see Pigliucci 2001). Of course the capacityfor a single genotype to have multiple phenotypic respon-ses to environmental change will also have a genetic basis,and could evolve in response to a dynamic habitat. If therelevant traits are plastic when habitats change, populationsize and connectivity may not be affected, though this willalso depend on the impact on other relevant species (e.g.prey, predator, competitor, etc.). Finally, a population willgo extinct if it cannot move or adapt quickly enough, orsurvive the change as it is.