Conservation biogeography of ecologically interacting species: the case of the Iberian lynx and the European rabbit

Abstract

Aim: To assess overlooked conservation problems of the Iberian lynx by exploring biogeographic relationships with its staple prey, the European rabbit. Location: The Iberian Peninsula. Methods: We modeled environmental favorability for the lynx based on its distribution before 1989, and for the rabbit using distribution data collected primarily after its population crash of 1989. We used the latter as a current trophic favorability model for the lynx. We validated that both models reflect abundance using independent data. We then combined these models in a lynx occurrence forecast and compared it with the recent lynx records. As Iberian rabbits evolved in two geographically separated lineages, being the recent lynx range practically restricted to the southwestern lineage, we correlated the prevalence of this lineage with environmental favorability for the rabbit. Results: The environmental lynx model correlated with past lynx abundance data, but did not reflect its recent strong range contraction. The rabbit model correlated with recent rabbit abundance, but was negatively correlated with the environmental model for the lynx. The combination of both models forecasted lynx occurrence in a few separated nuclei, which encompass all recent lynx records. The prevalence of rabbit’s southwestern lineage correlated negatively with favorability for the rabbit. Main conclusions: The region to which the lynx became confined before 1989 is currently less favorable for its staple prey, whereas more favorable areas remain outside lynx reach. This differential favorability correlates with rabbit phylogeographic structure, suggesting that the southwestern lineage is facing more unfavorable conditions or is less resilient to recent diseases. The loss of concordance between lynx distribution and rabbit phylogeographic structure has prevented lynx persistence in northeastern rabbit lineage areas, which should be considered in lynx reintroduction planning. Similar conservation problems could affect other ecologically and evolutionarily related species whose distributions’ overlapping has sharply diminished.