Protected areas act as establishment centres for species colonizing the UK

Protected area (PA) networks will remain valuable for conservation, as the global environment changes, if they facilitate the colonization of new regions by species that are shifting their geographical ranges. We tested the extent to which wetland bird species colonizing the UK since 1960 have exploited PAs. Colonization commenced in a PA for all six species that established permanent (greater than 10 years) breeding populations in the UK during this period. Subsequently, birds started to breed outside as well as inside PAs: the colonizing species showing declining fractions of breeding within PAs over time, a trend not seen in already-resident species. PAs were valuable as 'landing pads' for range-shifting species first arriving in a new region, and then as 'establishment centres' from which viable populations spread. Given future projections of range change across a broad range of taxonomic groups, this role for PAs can be expected to become increasingly important.