Understanding how habitat forming species recruit is a fundamental first step to understanding how they will be affected by environmental changes. Although highly resilient and reproductive once established in their benthic life stage, habitat forming species such as corals and macroalgae initially rely on propagule (e.g., larvae) survival and settlement during their early life stages. In recent years, it has become clear that benthic microbial films (biofilms), have significant functional roles in the metamorphosis and success of larval settlement of habitat forming species. These benthic biofilms provide important cues for larvae including indicating habitats suitable for settlement. However, their role in larger ecological processes such as species range dynamics along biogeographic transition zones is poorly understood. As both habitat-forming species and biofilms respond to climate change, their interactions are likely to be modified and influence biogeographic range shifts through complex feedback loops. In this talk we explore the functional role of microbial signalling within biofilms, and the roles they may play in species range expansions. Identifying how an understanding the role of microbial signalling in biofilms will facilitate more accurate predictions of species redistributions along tropical-to-temperate transition zones under climate change.