Biocultural conservation approaches recognise the relationships between nature and humans, and are built on local cultural perspectives. Hawai‘i has been described as a model for biocultural conservation, and a biocultural approach can be applied in endangered ecosystems such as tropical dry forests that are often found in human settlement areas. The extent of native tropical dry forest cover remaining in Hawai‘i is as low as 1% on some islands, with 45% of the tropical dry forest plant species at risk of extinction. Despite the long-running relationship of tropical dry forests with ‘Indigenous people and local communities’, there has been little assessment of the potential social–ecological outcomes of a biocultural approach to tropical dry forest restoration. Two Hawai‘i forest restoration projects, located within Ka‘ūpūlehu and Auwahi, have been excluding ungulates and removing alien plant species for >20 years, and have applied biocultural approaches. Drawing on these two sites as case-studies, we explore the motivations for, and components of, a biocultural approach, and highlight four categories (ecological, social, cultural, and spiritual) of biocultural measures of success. We show that a biocultural approach to restoration can provide purpose and meaning to a person’s relationship to place, and can transform conservation biology through Indigenous perspectives. We also address challenges and provide recommendations to those interested in engaging in a biocultural approach.

Tropical dry forests (TDFs) are among the most at-risk ecosystems globally. In Hawai‘i, more than 45% of TDF species are threatened or endangered. Despite decades of active TDF restoration, there remains limited information on the potential for long-term success, since there are few studies of natural regeneration. We assess natural regeneration of endangered plants at Ka‘ūpūlehu dryland forest, a Hawaiian biocultural restoration initiative. Drawing on 6 annual censuses we (1) assess rates and patterns of natural regeneration across species and as a function of rainfall and (2) identify bottlenecks. Our surveys document natural recruits of 11 of the 12 endangered species first outplanted 15–20 years ago. Higher annual rainfall increased the number of new recruits per year and growth, but decreased survival of larger recruits. The total number of natural recruits increased three-fold over the study period and varied across species. For nearly half of the species, we documented a second generation of recruits. Successes appear to be a function of time, including a changing microclimate and adaptive management practices. Remaining bottlenecks include lack of seed dispersal, and seed predation and herbivory by introduced species. The success at Ka‘ūpūlehu highlights the potential for TDF restoration and the value of a biocultural approach.