MIGRATION AND SURVIVAL OF PARNASSIUS SMINTHEUS: DETECTING EFFECTS OF HABITAT FOR INDIVIDUAL BUTTERFLIES

Abstract

We examined the migration and survival of the butterflyParnassius smintheusin a heterogeneous landscape consisting of 21 habitat patches imbedded in a matrix of meadow and forest habitat. We modified an existing mark–release–recapture model to account for multiple habitat types and fit the model to data for 839 and 873 individuals in two separate years. Migration was infrequent with only 24 and 27 observed movements between patches in each year. Daily within‐patch survival was moderate (>0.90) and did not vary greatly with patch isolation. Estimated mortality during migration was low, but increased markedly for isolated populations. Despite the limited data, the model showed that forest matrix habitat reduced migration distance to a greater degree than did meadow habitat, indicating that the effective isolation of populations depends on both the habitat type and the distance between populations. This result concurs with previous investigations of these data, demonstrating the utility of the model even when movement is infrequent. Studies of migration are often hampered by few observable events. Our model provides reasonable estimates given few migration events. The ecological results of this study illustrate the need for spatial population studies to account for the effects of different habitat types on the migration of individuals among habitat patches. Our results also suggest management options for the conservation of endangeredParnassiusspecies in other parts of the world.