We examined the association between spatial synchrony of weather conditions and spatial synchrony of the metapopulation dynamics of the Glanville fritillary butterfly (Melitaea cinxia). We found that the spatial synchronies of weather conditions and metapopulation dynamics increase in parallel and exhibit a relationship after accounting for temporal and distance trends. Alternative explanations for spatial synchrony, that is increased dispersal or trophic interactions with the specialist parasitoid Cotesia melitaearum, do not exhibit concordant patterns and therefore are not supported.
Environment driven synchrony in local population dynamics increases the extinction risk of a metapopulation considerably. With local populations fluctuating in synchrony decreases in abundance at one region are not balanced out by increases in another, and the potential for colonization of unoccupied habitat making up for local extinctions is reduced.
Our results highlight the importance of considering spatial variability in weather conditions when examining the effects of climate change on natural populations. Although our study is probably the first one to document increasing synchrony in a highly dynamic classical metapopulation, similar trends have been recorded in other less dynamic systems in different parts of the world. With synchrony increasing across very different kinds of systems, it is quite possible that that increasing population synchrony is one of the large scale outcomes of global climate change.
Full article here: https://doi.org/10.1111/gcb.14280