Traditional agricultural landscapes in mountain communities are critical for conserving biodiversity, biocultural diversity, and agroecological resources. Despite their significance, traditional farming systems are overlooked in modern agriculture and conservation, leading to genetic erosion and reduced cultivation of local crop landraces. Our research focuses on the fragile ecosystems of northwest Himalaya in India, and examines the ecological and genetic resilience of black pea (lesser known and understudied traditional crop) and barley (Hordeum vulgare) and compares them to the introduced cash crop of green pea (Pisum sativum L.). We conducted field experiments across elevation gradients to assess survival and reproductive traits for the three crops. We performed whole-genome sequencing to investigate the genetic diversity of black pea in relation to other Pisum species. Additionally, we analyzed the nutritional profile of black pea in comparison with green pea. Our findings indicate that traditional crops are better adapted to local climatic conditions in terms of their growth performance, and hold considerable genetic diversity and nutritional potential. Our results support the importance of integrating traditional knowledge with modern agroecological research and policy to promote climate-resilient, sustainable food systems. The results also argue for a reevaluation of traditional and often underutilized crops to support small-holding farmers and promote socio-ecological stability in vulnerable mountain regions.