Increasing global habitat fragmentation is expected to impact arboreal wildlife even more than terrestrial wildlife. While terrestrial wildlife must face the challenge of moving between fragments, arboreal wildlife must do so after descending to the ground, an unfamiliar activity. Species with the behavioral plasticity to cross between fragments over linear infrastructure face the threat of terrestrial predators and collisions with vehicles, while the species that do not cross face the threats of inbreeding depression and resource loss. Given these threats along with the danger of electrocutions when crossing on power lines, it is more important than ever to develop canopy bridge solutions, with both natural and artificial bridges, that provide continued habitat connectivity for arboreal species. The number of canopy bridge projects around the world has grown in recent years. However, results of few projects have been shared in the peer-reviewed literature. For this reason, researchers have had little opportunity to learn from each other to understand such fundamental questions as which bridge designs work for which species with which body sizes and locomotor strategies and which bridge materials work best under different contexts. An up-coming Special Issue of Folia Primatologica will feature 25 peer-reviewed papers on canopy bridge studies, effectively doubling the number of studies on this topic and dramatically expanding their geographic scope. We will provide a summary of the review paper that we contributed to the Special Issue on all canopy bridge studies published to date, demonstrating where they have been performed, which species have used bridges, and, most importantly, which bridge designs seem to be most effective. We will also evaluate gaps in the field of canopy bridge research, including species that seem not to use them, with suggestions on possible solutions. With this review of the expanding literature on an important conservation topic, we hope to provide information to guide future studies to scale up the practice of canopy bridges across fragmented habitats globally.
Conservation solutions, fragmentation, connectivity, linear infrastructure, arboreal wildlife