The Impact of the Urban Matrix on Arthropod Biodiversity and Ecosystem Services in Community Gardens

Abstract As the number of humans living in cities increases, there is a growing interest in the value of community gardens to provide agricultural products to city dwellers in their own neighborhoods. However, neighborhoods with different land cover and socioeconomic characteristics often differ in their ecological attributes, leading to potential differences in biodiversity-mediated ecosystem services (i.e., pollination and pest control). The "luxury effect" is a documented phenomenon in urban ecology, showing that higher-income neighborhoods have greater biodiversity. Here we ask, how do the landscape and socioecological features of the urban matrix around community gardens impact arthropod biodiversity and the ecosystem services it provides as measured through crop yield? We collected arthropods across community garden sites in Boulder Co., CO, and used experimental jalapeno pepper plants as a sentinel crop to measure herbivory damage and pollination services. Through structural equation modeling, we found that fruit size increased as a function of pollinator biodiversity, and, unexpectedly, pollinator biodiversity was negatively related to neighborhood wealth. Investing in interventions that maximize bee biodiversity in cities may increase equitable food access from community gardens.