Traditional Ecological Knowledge as Biocultural Insurance: Quantifying Homegarden-Based Agrobiodiversity and Climate Resilience in Ethiopia

Traditional Ecological Knowledge (TEK) underpins smallholder resilience, yet its functional contribution to climate adaptation remains poorly quantified. This study investigates TEK-driven homegardens as biocultural insurance systems that maintain biodiversity, productivity, and livelihood stability under climate stress in the Hadiya and Kambata-Tembaro Zones, Central Ethiopia. Using a mixed-methods design integrating ecological inventories (n = 180 plots), ethnobotanical and socio-cultural assessments, and household surveys (n = 384), the Homegarden Insurance Hypothesis was tested through structural equation modeling. A total of 77 plant species across 38 families were identified, with Lamiaceae, Fabaceae, and Asteraceae most represented. Species diversity was high (Shannon H′ = 1.95–3.45), and 60% of taxa served multiple roles food, medicinal, and agroecological. TEK-guided co-cultivation practices, such as Cajanus cajan with Ficus sur, enhanced soil fertility, shading, and pest regulation. Culturally significant species received stronger conservation attention (r = 0.84, p < 0.001), while intergenerational knowledge transfer correlated with adaptive species richness (r = 0.67, p < 0.001). Following droughts, TEK-managed homegardens retained 86% of productive species and 92% of dietary diversity, compared with 42% and 50% in monocultures. Structural equation modeling indicated that TEK intensity significantly improved homegarden diversity (β = 0.68, p < 0.001), yield stability (β = 0.42, p = 0.003), and income resilience (β = −0.55, p < 0.001). Overall, these results provide robust quantitative evidence that TEK functions as a biocultural insurance mechanism, linking indigenous knowledge intensity to ecological stability and livelihood security offering practical insights for climate-resilient agroecosystem design and biodiversity policy integration.