Transboundary priorities for protection of frigatebird non-breeding habitat in a heavily impacted region

Abstract

**Abstract:** Species that inhabit spatially-distinct regions at different stages of their lifecycle pose challenges to conservation managers, particularly when distributions span international or jurisdictional boundaries. Despite the importance of non-breeding habitat to the persistence of individuals and species, there remains limited information on the habitat requirements of many species during the non-breeding period. We used global positioning system tracking devices to determine the non-breeding movements of Great Frigatebirds, Fregata minor, and Lesser Frigatebirds, F. ariel, across much of Southeast Asia. These data were analysed with MaxEnt modelling to identify important habitat features for non-breeding frigatebirds and inform priorities for addition to the marine protected area (MPA) network. Models with the greatest predictive performance were influenced strongly by bathymetry. Predicted habitat suitability was greatest in shallow waters. Similarly, warmer waters had greater predicted suitability during the wet season. The existing protected area network contains only a small proportion of habitat identified as suitable or optimum for non-breeding frigatebirds. This is of particular concern given that some parts of the region's marine environment are among the most heavily human-impacted in the world. Currently proposed additions to the MPA network will likely provide negligible benefits to non-breeding frigatebirds due to their small extent relative to suitable habitat and their limited or complete lack of overlap with areas predicted to represent optimum habitat. Our findings can be used to make targeted additions to the MPA network to efficiently increase the representation of suitable and optimum habitat for non-breeding frigatebirds in the MPA network. Such an approach will likely provide benefits to frigatebird populations tracked in the present study as well as those dispersing to the study region from other ocean basins. **Authors:** Rowan Mott¹, Ashley Herrod², Rohan Clarke¹ ¹School of Biological Sciences, Monash University, ²Moonlit Sanctuary