Habitat loss and fragmentation are the main drivers of on-going loss of biodiversity. Ilkka Hanski’s and colleagues’ new article shows how to predict the viability of populations living in fragmented landscapes.
The key of the research is the famous Glanville fritillary (Melitaea cinxia) butterfly metapopulation in the Åland archipelago. The study system consists of more than 4000 dry meadows that provide suitable habitat for the butterfly. Hanski’s group has surveyed the presence and absence of the species in these habitats for more than 25 years, which makes the system unique for the use of ecological studies.
Now the combination of metapopulation modelling and the survey data has provided new empirical results. Hanski and colleagues show that Åland Islands can be divided into “cold” and “hot” sections: in “cold” sections the metapopulations are likely to go extinct, while in “hot” sections they are expected to persist. In the Åland system, 74% of the otherwise suitable habitat is below the extinction threshold and therefore prone to go extinct if they do not receive immigration from the more favorable regions.
Vulnerability to extinction is strongly influenced by the fragmentation and quality of habitat as well as genetic factors, rather than habitat area alone.
The research demonstrates how metapopulation modelling together with the knowledge of a species’ habitat and dispersal capacity can be used to classify fragmented landscapes into “hot” and “cold” sections. This knowledge can be used in practical conservation planning.
The study is published in Nature Communications (DOI: 10.1038/NCOMMS14504).