Maintaining food production while sustaining productive ecosystems is among the central challenges of our time, yet, it has been for millennia. Ancient clam gardens, intertidal rock-walled terraces constructed by humans during the late Holocene, are thought to have improved the growing conditions for clams. We tested this hypothesis by comparing the beach slope, intertidal height, and biomass and density of bivalves at replicate clam garden and non-walled clam beaches in British Columbia, Canada. We also quantified the variation in growth and survival rates of littleneck clams (Leukoma staminea) we experimentally transplanted across these two beach types. We found that clam gardens had significantly shallower slopes than non-walled beaches and greater densities of L. staminea and Saxidomus giganteus, particularly at smaller size classes. Overall, clam gardens contained 4 times as many butter clams and over twice as many littleneck clams relative to non-walled beaches. As predicted, this relationship varied as a function of intertidal height, whereby clam density and biomass tended to be greater in clam gardens compared to non-walled beaches at relatively higher intertidal heights. Transplanted juvenile L. staminea grew 1.7 times faster and smaller size classes were more likely to survive in clam gardens than non-walled beaches, specifically at the top and bottom of beaches. Consequently, we provide strong evidence that ancient clam gardens likely increased clam productivity by altering the slope of soft-sediment beaches, expanding optimal intertidal clam habitat, thereby enhancing growing conditions for clams. These results reveal how ancient shellfish aquaculture practices may have supported food security strategies in the past and provide insight into tools for the conservation, management, and governance of intertidal seascapes today.

The need to diversify science includes increasing both the diversity of science practitioners and the voices included in decision-making processes. Indigenous communities have been sought out to provide Indigenous knowledge to mainstream science research programs. As working across the mainstream science and community boundary is increasingly codified into the future of natural sciences, models for equitable collaboration and roles within project structures are needed. The goal of this project is to present a framework for collaboration between mainstream science and Indigenous communities. Specifically, we are addressing an underrecognized role central to partnership, a boundary spanner, who acts as the fulcrum facilitating collaboration. To better understand the role of boundary spanners in collaborative projects, we engaged six boundary spanners who participated in semi-structured interviews and workshops. Emergent common experiences and perspectives of how boundary spanners can be supported and their role in collaborative projects were defined and articulated. The boundary spanners identified 10 characteristics that contribute to equitable partnership between mainstream science and Indigenous communities. From the perspective of the boundary spanners, they detailed how collaborative projects can be structured to increase long-term partnerships and community support of research projects. Equitable collaboration between Indigenous communities and mainstream science is frequently only achieved when individuals at the interface of the mainstream science and Indigenous community have a high level of cultural competency. Equally important is the support provided to the boundary spanners and early engagement of partner Indigenous communities. Through the use of story and metaphor, we highlight the voices of boundary spanners and how their contributions can best be used.