San Clemente Island’s native ecosystems were significantly affected by domestic animal grazing and introduced herbivores. While feral goats (Capra hircus) and pigs (Sus scrofa) were extirpated by the late 1990s, their historic impacts on habitats had lasting negative consequences for imperiled native species such as the endangered San Clemente loggerhead shrike (Lanius ludovicianus mearnsi). Invasive mesopredators – black rats (Rattus rattus) and feral cats (Felis catus) – are present on the island alongside naturalized island foxes (Urocyon littoralis), all of which have been observed preying upon shrike nests. In addition to past and present threats to shrike populations, we must now consider how climate change may challenge shrike conservation on the island. To better understand potential trajectories of the San Clemente loggerhead shrike population under different climate change scenarios, we first quantified the effects of weather on shrike breeding and survival. We then conducted population viability analyses incorporating predictions from our initial modelling effort for current climate conditions, and both moderate and severe climate change projections. We also examined the effects of increased predator management and captive juvenile shrike releases throughout climate change scenarios. The results of this work provide a foundation for adaptive management practices as climate change progresses.

Hunter Cole is an ecological analyst and project manager for the Institute for Wildlife Studies, with the majority of his work involving native wildlife conservation on Naval Auxiliary Landing Field San Clemente Island. After studying bird, bat and arthropod sensory ecology in the Rocky Mountains, Hunter started as a predator biologist on San Clemente Island in 2020. Since then, he has been involved in field work, analyses and conservation planning for non-native nest predators, San Clemente loggerhead shrikes and island foxes.