A classical metapopulation is a set of local populations confined to discrete habitat patches, spread out in a nonsuitable matrix. All local populations have a probability of extinction but patches can be recolonized. Metapopulation persistence depends on a balance between colonization and extinction rates, that result in an equilibrium proportion of occupied patches. Interest in the application of the metapopulation framework to wildlife conservation has grown during the last two decades, and the metapopulation concept has been adjusted to apply to real field situations, but maintaining two key characteristics: a spatially discrete distribution and a nontrivial probability of local extinctions. Thus, under a metapopulation framework extinctions are expected to occur and conservation interventions should focus on the colonization-extinction balance in the whole network. We reviewed the literature to assess geographic and taxonomic biases and the practicality of the metapopulation framework, in terms of the research effort required and the conservation and management recommendations derived from its application.
Results/Conclusions
Metapopulation studies were geographically biased towards the north-temperate zone (North America and Europe, 69 of 77 papers) and taxonomically biased towards butterflies (26/77) and mammals and birds (34/77). Median number of patches was 17 (range 1-4000, N=106), and 34% of cases had <10 patches. Median study duration was 4 years (range 1-21, N=60). One third of 103 cases measured dispersal and estimated metapopulation dynamics from colonization and extinction rates derived from occupancy patterns. Another third focused on demographic aspects of local populations. Only 25 of 77 studies made specific conservation recommendations, mostly focusing on improving patch habitat and augmenting local populations, and managing the matrix to increase connectivity. Metapopulation is a term that loosely refers to any fragmented population. In principle, metapopulations can be characterized by patch occupancy patterns but these studies require a large effort in terms of duration and number of patches, and many studies are small-scale and short-term. Most papers do not make specific conservation recommendations. Those that do, emphasize interventions aimed at maximizing local population persistence and functionally defragmenting the populations by increasing dispersal rates, i. e., steering the system away from a metapopulation structure and converting it into a single spatially structured population.