As global urbanization intensifies, high-density cities increasingly embrace vertical development to accommodate population growth while limiting urban sprawl. Yet verticalization often comes at the expense of direct access to natural environments, leading to reduced opportunities for human-nature interaction and declining urban biodiversity. Biophilic design frames architecture as an interface for integrating natural elements, processes, and experiences into the built environment, with a primary concern for human health and well-being (Kellert, 2008;Zhong et al., 2022). It differs from green architecture, which is often evaluated through energy, material, and life-cycle environmental performance (Ragheb et al., 2016). Nature-inclusive cities focus more broadly on incorporating biodiversity goals into urban development, district planning, green-blue infrastructure, and real estate projects (Mattijssen et al., 2023;Monti, 2019). Since urban residents spend nearly 90% of their time indoors (Ma et al., 2024), buildings become critical spaces for reconfiguring human-nature relationships. Building-integrated green spaces can also serve as vertically distributed ecological nodes, supplementing limited ground-level greenery and providing habitats for urban flora and fauna. This article therefore explores nature-inclusive architecture, which integrates living organisms, habitat conditions, and ecological processes into buildings to promote human health and urban biodiversity.In dense cities, nature-inclusive architecture is often materialized through three-dimensional green spaces (e.g., sky terraces, green balconies, and vertical gardens), representing a shift from horizontal greening to volumetric and vertically distributed ecological systems (Zhong et al., 2026). However, optimistic narratives of nature-inclusive architecture often mask the uneven performance in practice; despite the potential for mutual benefits between human well-being and non-human habitat needs, this is by no means guaranteed. Integrating nature into architecture necessitates profound trade-offs, such as human demands for comfort, safety, and ease of maintenance, which sometimes clash with the "messy" nature of functional ecosystems. This article critically examines the synergies and trade-offs of nature-inclusive architecture in dense cities, emphasizing the delicate considerations for multi-species symbiosis. It argues that not all types of green spaces yield the same effects. By categorizing three-dimensional green spaces according to the spatial verticality (sky, elevated, and ground) and openness (open, semi-enclosed, and enclosed), the discussion highlights the differentiated strengths and limitations of varied types in supporting human health and urban biodiversity. This typological perspective underscores the need to move beyond generic applications of vertical greening and towards more context-sensitive and performanceoriented design approaches that acknowledge both the potentials and constraints of nature-inclusive architecture.Synergies: co-benefits between health and biodiversityNature-inclusive architecture can create urban microhabitats by providing nesting, feeding, or resting spaces for birds, arthropods, and other organisms (Wooster et al., 2022). A ten-year assessment of an intensive green roof with a bioreceptive façade at a French school recorded 345 species (including 207 plants, 100 invertebrates, 20 birds, and a few reptiles and bats), showcasing biodiversity levels comparable to nearby parks (Lewandowski et al., 2026). Distributed among buildings, various green spaces can form ecological networks for wildlife while bringing urban dwellers into closer contact with other species (Fuller et al., 2007). People who regularly watched and fed garden birds reported feeling more relaxed and connected to nature (Cox & Gaston, 2016). Observing pollinators, seasonal changes of plants or bird activities in rooftop gardens, balconies, or other spaces can strengthen residents' nature connectedness and emotional attachment. A study also found that two weeks of nature intervention during the winter can enhance positive affect, hope, and nature connectedness (Passmore et al., 2022).In this way, ecological habitat provision and human psychological connection to nature can become mutually reinforcing rather than isolated.Nature-inclusive architecture links biodiversity and environmental comfort because plant traits influence habitat provision, shading, evapotranspiration, air filtration, and sound attenuation. A survey of vertical greenery systems in Singapore shows that vegetated walls support greater animal diversity than bare walls, cooling building surfaces during the day and providing insulation at night (Hecht et al., 2025). On an extensive green roof in Rome, native Mediterranean perennials outperformed better than Sedum album in terms of plant health, coverage, and flowering; meanwhile, the temperature in the planted area was 2.9-4.4 °C lower than in the adjacent concrete area (Bellini et al., 2025). A comparative roof study also identified vegetation cover, plant assemblage, season, and urban location as determinants of thermal performance (Robbiati et al., 2024). Vegetation can remove airborne pollutants, although dense planting may restrict airflow in poorly ventilated settings and affect airquality outcomes (Chen et al., 2025). On extensive green roofs, vegetation and substrate together reduced noise by 1-4 dBA, with performance influenced by plant cover, substrate, moisture, and gaps in the planting (Lu et al., 2025). Hence, biodiversity and environmental comfort can be jointly enhanced when plant traits and system configurations are matched to local climate, water availability, substrate conditions, target species, and ecological goals.The synergy arises when nature-inclusive architecture offers not only vegetation covering but also nurtures a richer diversity of species. Research...