The loss of biodiversity represents one of the defining challenges of our time. Urbanization bears significant responsibility for this crisis, driving land-use changes, fragmentation, and the eradication of natural habitats. As urban expansion continues, the traditional sustainability model has proven inadequate to face this crisis. Rather than relying on technical remedies aimed merely at impact mitigation and energy efficiency, a transformative change is required. A new paradigm centered on justice, equity, and responsibility, where architecture distances itself from extractivist practices and serves as an opportunity to shape a different relationship with nature, actively contributing to its regeneration. Though often dismissed as biological deserts, cities conceal an exceptional conservation potential for more-than-human actors.