Network structure and composition shape resilience of migratory species to habitat loss and degradation

Migratory species rely on multiple sites to complete their lifecycles, and connectivity between sites is crucial for population viability. However, little is known about how specific connectivity patterns influence vulnerability to habitat loss and degradation. Here, we classify migratory networks into eight broad connectivity types, ranging from more directed to more diffuse, and with varying degrees of adaptive potential. Using a graph-theoretic approach, we quantify their vulnerability to habitat loss and degradation. We find that networks are often more sensitive to incremental habitat degradation than to the loss of entire sites. We also find that networks differ in their tolerance to site loss, with more diffuse networks withstanding up to 80% site loss before collapse, but more directed networks collapsing after the loss of a single site. Identifying key connectivity patterns across network types enables more effective conservation planning by targeting actions at sites where they will have the greatest impact.