2: Tradeoffs and synergies in biodiversity and ecosystem service provision across rapidly urbanizing landscapes

Ecosystem services are essential for human well-being, especially in urban areas where an estimated 60% of the world’s human population will live by 2030. While local and landscape-level habitat management practices are assumed to drive biodiversity and ecosystem services within urban areas, few studies have quantified the relationships between these metrics or whether habitat management plays a mechanistic role in mediating potential trade-offs or synergies. In this research we leverage 5 years of data (>5,000 site-level observations) across 28 urban gardens in the California central coast to investigate the role of habitat management as a mechanism driving biodiversity, ecosystem service provision, and the potential for landscape-specific trade-offs and synergies. We document a dominance of traditional synergies (significant positive correlations) across a diverse suite of ecosystem services, with very few trade-offs, including few trade-offs between food production and the remaining biodiversity and ecosystem service metrics. We also provide evidence of numerous management-driven mechanism synergies and trade-offs. For example, increasing tree abundance has significant positive effects on pest control and human well-being, but negative effects on food production. In contrast, greater mulch cover results in increased carbon soil storage, water-holding capacity, and gardener reported well-being, but has negative impacts on pest control and pollination. Overall, our results are the first to reveal the importance of landscape-mediation for both biodiversity and ecosystem services and their synergies/trade-offs within cities, highlighting the critical role of local garden management and regional urban planning in maximizing urban ecosystem service synergies.