Botanical Gardens Can Play an Important Role in the Harmonious Coexistence of Humanity and Nature in Cities

Humans currently face the triple planetary crises, namely, climate change, biodiversity loss, and pollution, which are interlinked and together threaten humanity. They not only damage the global ecosystems but also contribute to a range of mental health challenges. The COVID-19 pandemic highlighted the importance of healthy ecosystems. With a healthier nature, we will become wealthier materially and happier spiritually. Attracted by better employment and lifestyle opportunities, rural populations are migrating to cities, and the rate of urbanization is significantly increasing worldwide. Data show that China's urbanized population has now exceeded 66%, and the proportion of urban populations in developed countries is over 80%. Although cities provide residents with abundant productivity, lifestyle, and other opportunities, there is often a lack of open space and biodiversity compared to rural areas—the diversity of urban green spaces is not high [1], the ecosystems are often stark, and the ecological service benefits are relatively low [2]. At the national and regional levels in China, the “artificiality” of cities and the “wildness” of rural areas form a “yin-yang complementarity,” resulting in a complex system of areas for production, human life, and broader ecological outcomes. In this context, botanical gardens, as the calling card of nature in cities, have increasingly highlighted their ecological value [3]. As ex situ conservation institutions, botanical gardens perform many functions, including plant conservation, scientific research, public education, resource utilization, recreation, and garden display [2]. The annual number of visitors to botanical gardens worldwide is over half a billion [4], including 50 million to Chinese botanical gardens alone. From the perspective of leisure and sightseeing destinations alone, botanical gardens also have an important role. As a green infrastructure in cities, botanical gardens can play a critical function in the harmonious coexistence of humanity and nature. By analyzing the relationships among botanical gardens' functions, human needs, and urban development, we outline the symbiotic relationship between botanical gardens and cities and propose new directions for their development. The modern botanical garden has its origins in the cultivation, research, and study of medicinal plants but has expanded greatly in its scope to include university system gardens, tropical (colonial economy) botanical gardens, European classical botanical gardens, municipal botanical gardens, and special types of botanical gardens (including agricultural botanical gardens, horticultural botanical gardens, germplasm collection gardens, arboreta, thematic botanical gardens, and community Garden, alpine, or mountain botanical gardens). There are perhaps six core functions of a modern botanical garden—conservation, scientific research, public education, resource utilization, recreation, and garden display—all of which must develop and adapt to meet emerging challenges [2, 5]. A good example of this is the response of botanic gardens in recent years to climate change, led by Royal Botanic Gardens Victoria with the release of its “Landscape Succession Strategy” in 2016 and the formation soon after the international Climate Change Alliance [6]. Another is the way botanical gardens have worked together closely as a global network to conserve about 30% of the world's wild plants in ex situ collections, particularly in seedbanks and germplasm banks [7]. A botanical garden can provide a range of ecological services for a city, including greening, beautification, purification (ecologicalization), biodiversification, and addressing local cultural and community needs. The industrialization of economic plants in the development of botanical gardens can also bring economic vitality to cities, and public education in botanical gardens can create a community informed and inspired about the conservation of plants and natural places. The main functions of a city have been described as economic, social, cultural, transportation, and life services [8], and botanical gardens can play a significant role in all except transportation. For example, in the face of challenges, such as the urban heat island effect, air pollution, and water scarcity in the process of urbanization, botanical gardens as a green ecological barrier in cities are a key node in alleviating ecological problems as well as a core conduit for biodiversity conservation, playing an irreplaceable role in maintaining urban ecological balance. The scientific research function of botanical gardens is closely linked to the establishment of innovative cities, and their public education function plays an important role in enhancing residents' scientific literacy [9]. Botanical gardens and their expertise can be a key contributor to sustainable urban development. This may include the building of climate adaptive infrastructure, promoting local drought resistant plants for roof and rainwater gardens, selecting plants for urban “sponge systems,” and improving the ecological resilience of infrastructure to cope with emerging problems such as the urban heat effect and extreme floods. Botanical gardens can also help transform urban spaces into habitats with “low maintenance, high ecological value” while encouraging urban biodiversity by promoting local plants. The value of botanical gardens is not only reflected in the natural environment in and outside cities but also addresses fundamental human needs. As the core space for human settlement, the development of cities should be guided by the principle of being “people-oriented.” Botanical gardens can improve the quality of life of residents through seven key mechanisms: (1) Satisfying human curiosity for experiencing new and interesting plant life; (2) quality of life improvements—with a beautiful natural environment and leisure facilities helping a city to meet the aspirations of residents for a better life; (3) increased wealth—by researching and utilizing economic plants and medicinal plants collected from botanical gardens for economic development (while also increasing personal wealth); (4) cultivation of scientific literacy—through popular science exhibitions, lectures, and practical activities to strengthen public awareness of environmental protection; (5) promoting mindfulness, stress reduction, and emotional wellbeing through interaction with nature in botanical gardens through their educational programs; (6) recognizing and understanding ecoanxiety as a response to environmental challenges; and (7) examining the role of therapeutic horticulture programs in botanical gardens for mental health. The health benefits of visiting a botanic garden are many [10], supported by research showing that the greater the biodiversity, the greater the psychological benefit [11]. Exposure to botanical gardens and green spaces is a low-cost, high-yield health intervention. The relationship between botanical gardens and cities has gone through three stages: from the early independent existence of “botanical gardens in cities,” to the systematic integration of “cities in botanical gardens,” and finally to the harmonious coexistence of “cities in nature.” Often described as “Garden Cities,” this final stage bridges cities and nature, creating an urban environment that meets the physical and mental needs of its human inhabitants. Strengthen conservation capabilities: deepening research on plant ex situ conservation and ecological restoration technologies; Promote collaborative innovation: strengthening cooperation with urban planning and research institutions to integrate botanical gardens into the urban ecological network; setting up collaborative networks between botanical gardens and universities, museums, as well as zoos etc., for enhancing educational programming and addressing common conservation and climate challenges in the cities; Enhance service efficiency: building a national biodiversity conservation network through public education and public engagement. To achieve the global target to conserve 30% of the world's terrestrial and marine areas as protected zones by 2030, botanical gardens play a critical role in building a broader societal understanding of biodiversity issues and in fostering collective responsibility for conservation; Urban Actions and Sustainable Development Goals (SDGs): The UN SDGs consist of 17 goals, and Goal 11- Sustainable Cities and Communities—is crucial for achieving urban sustainability. Botanic gardens empower people to take action for a greener and more sustainable future; Leaving no one in the cities behind: Promoting equity and inclusion in botanical gardens. For those people with mental health issues, botanical gardens could collaborate with clinics to prescribe garden visits for their recovery. Botanical gardens can promote equity and inclusivity, especially by playing a key role in supporting psychological health and social integration. There is a growing need to increase accessibility by removing or reducing physical and economic barriers. Botanical gardens can collaborate with the community directly and with medical institutions to develop therapeutic gardening courses for patients with depression and post-traumatic stress disorder, and alleviate anxiety and rebuild a sense of life control through immersive experiences of planting and caring for plants. Many botanical gardens run activities, such as “Plant Adoption” and “Horticultural Mutual Aid Groups”, for left-behind children, elderly people living alone, and other groups with a high incidence of loneliness, using plants as a medium to build social bridges and reduce social isolation [10]. Other examples of botanical gardens contributing to improved community health include the “Green Prescription” system, collaborating with hospitals to issue “Horticultural Healing Prescriptions” to patients with mental illnesses and chronic illnesses. In some countries, immigrant and low-income groups are involved in the planning of botanical gardens and the introduction of plants based on their cultural backgrounds. This not only celebrates local cultural diversity but also allows marginalized groups to gain a sense of “spatial belonging,” ultimately transforming botanical gardens from “public spaces” to “fair and inclusive carriers” [12]. The essence of the relationship between botanical gardens and cities is a combination of symbiosis and prosperity—the former is the ecological cornerstone and cultural symbol of the city, whereas the latter provides development space and resource support for the former. In the dual context of accelerating global urbanization and upgrading biodiversity conservation, it is necessary to further strengthen the position of botanical gardens from the perspective of human needs, promote their deep integration with cities at the ecological, economic, and social levels, and ultimately seek the sustainable development vision of an “integrated city and garden, natural symbiosis.” Ultimately, good and effective botanical gardens enhance human life. Xiangying Wen: writing – original draft, methodology. Timothy John Entwisle: writing – review and editing, formal analysis. Hai Ren: conceptualization, methodology, writing – original draft, writing – review and editing, funding acquisition. This work was supported by the Guangdong Province Basic and Applied Basic Research Project (2023B0303050001). Thanks also to the anonymous reviewers for their constructive comments.