Drivers of plant biodiversity and ecosystem service production in home gardens across the Beijing Municipality of China

Home gardens have been recognized as repositories of agricultural biodiversity across the world. The influence of socioeconomics and location-specific factors on urban gardening patterns merits continued study. Using Beijing Municipal Province in China, a rapidly urbanizing region, as a case study, we address two questions: 1) How do biodiversity patterns change between different urbanized regions in Beijing? 2) How do ecosystem services provided by Beijing home gardens change with socioeconomic status and location-based preferences of gardeners? We surveyed 104 home gardens in Beijing Municipal Province for plant biodiversity, abundance, and species ecosystem services (ES) (provisioning or cultural uses). The gardens were distributed across three urbanized regions (suburban, peri-urban, and exurban). We found that species biodiversity and abundance shift according to a hierarchy of need from ornamentals (cultural ES) to edibles (provisioning ES) with increasing distance from Beijing. These trends are related to reduced income, lowered food security, and lack of urban markets in exurban regions. Rarefaction curves indicate ornamental species drive β diversity. Ordination also showed a shift in species composition with increasing isolation from the city; Suburban and exurban gardens were the most different, while peri-urban gardens were similar to both others. Only exurban gardens had a positive relationship between species and area. High edible cover and high species density indicates that demand for edibles in exurban regions may be higher than space constraints allows. Our study better quantifies species biodiversity patterns in Beijing, and can inform urban planners about the value and usefulness of home garden space.