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Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.

City street trees are prominent features of urban green infrastructure and can be useful for climate change adaptation. However, street trees may face particularly challenging conditions in urban environments. Challenges include limited soil and space for growth surrounded by sealed surfaces, construction that damages roots, poor pruning and management, and direct vandalism. All of these challenges may reduce the capacity of street trees to provide socialenvironmental benefits, such as attractive landscapes, shading and cooling. Thus, street trees need specific care and resources in urban environments. In this perspective article, we call for a conversation on how to improve the conditions for city street trees. While research has broadly investigated street tree mortality and vulnerabilities, the social perspective may be missing, one that also involves the actions and care by human inhabitants. Here we share perspectives on current management options and discuss from a social-ecological perspective how these can be extended to involve urban residents. [ABSTRACT FROM AUTHOR]

With the boom in urban living has come a boom in urban gardening. In particular, urban community gardening is an increasingly popular form of horticultural production, community involvement and connection to nature. Through the establishment and management of community gardens, biodiversity can flourish, with community gardens as 'hotspots' of flora and fauna within the urban matrix. Gardeners can deeply connect with the natural elements of gardens and thus learn about and gain appreciation for the natural world. Such interactions can combat the loss of nature experiences in cities. Despite their benefits for nature and for people, community gardens are threatened ecosystems as often temporary fixtures in city landscapes due to lack of land tenure and policy protection.In this perspective, we recognize community gardens as an important ecosystem in urban conservation and argue for the defence of urban community gardens by city policy. We formalize this activity and the value of these ecosystems with scientific evidence from ecological and social‐ecological research in 39 community gardens in Berlin and Munich, Germany.Although our data reveal that these gardens support large amounts of biodiversity and catalyse human‐nature connections, a lack of comprehensive documentation of social‐ecological benefits at the city level can make community gardens vulnerable to urban planning threats; we have seen losses of multiple research sites in the last 4 years of biodiversity research.Policy implications: To protect community gardens now and for future urban generations, we call for systematic and comprehensive data collection on community gardening activities and policy support for these urban ecosystems. Some cities are starting to do this and this can be scaled out. We argue for the recognition of urban community gardens as a physical land use and also of the gardeners themselves as important habitat managers and stewards of urban biodiversity. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]