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Although urban gardens are often celebrated for supporting bee abundance and diversity within cities, little is known about how garden management and urbanization levels influence bee foraging behavior and ability to utilize resources within these landscapes. Specifically, the preferences and diet breadth of bees may depend critically on local and landscape conditions in human-managed, urban environments. To understand how foraging patterns and pollen preferences are influenced by urban landscape composition, we first examined if bees visit plants grown within urban gardens and second assessed the relationships between local floral resources, urban land cover, and pollen collection patterns, focusing on 20 community gardens across 125 km of the California central coast. We targeted a well-studied, essential native pollinator in this ecoregion, Bombus vosnesenskii, and analyzed pollen on the bodies of individuals collected in our study gardens to compare their contents to local and landscape garden composition factors. We found that greater landscape-level urban cover and greater plant species richness in the garden both drove higher within-garden pollen collection. We also found that B. vosnesenskii preferred ornamental plant species over highly available crop species in the gardens. Our study indicates that landscapes that support plant diversity, including both ornamental plants and sustenance-oriented food crops, promote greater within-garden pollen collection patterns, with likely benefits for urban garden food production. [ABSTRACT FROM AUTHOR]

It is often argued that biodiversity and ecosystem functioning are linked by both habitat and species composition, and that this relationship is particularly critical for mobile ecosystem service providers. This may be especially true for pollinators, which are essential for the reproduction of the majority of flowering plant species, are highly mobile, and can exhibit dramatically different foraging behaviors across ecosystems. Understanding how habitat and community composition impact pollination is especially relevant in urban environments where pollinators can promote food security. We examined the relationships between local resource density, landscape composition, pollinator abundance and richness, and pollination services in an urban agricultural system spanning >125 km of the California central coast. We used a replicated, experimental approach to evaluate the reproductive success of jalapeño peppers across urban gardens and conducted a greenhouse experiment to evaluate the benefits of insect-mediated pollination to pepper reproduction. In the greenhouse, we found that jalapeño fruit weight and seed number was significantly greater with insect-mediated pollination than without. In the field, we found that jalapeño seed number increased significantly with herbaceous (weed, crop, and ornamental) plant richness and the number of perennial trees and shrubs at the site level, but decreased with the amount of natural landscape cover. We also found that higher pollinator richness enhanced seed number in floral-dense gardens, likely due to the greater functional complementarity of a more diverse pollinator community. Furthermore, there was a positive relationship between pollinator abundance and seed number, but it weakened in gardens with more flowers, likely through lower per-plant pollinator visitation in the presence of competing floral resources. As in past studies, we found that mulch had a negative impact on pollinator abundance, highlighting that abiotic factors commonly managed by gardeners can directly impact ecosystem service providers. This study demonstrates that local conditions can significantly influence ecosystem service provision and that urban gardeners need to optimize for both pollinator richness and floral resource availability to achieve optimal pollination. [ABSTRACT FROM AUTHOR]

Urban gardens in Central California are highly vulnerable to the effects of climate change, experiencing both extended high heat periods as well as water restrictions because of severe drought conditions. This puts these critical community-based food production systems at risk as California is expected to experience increasing weather extremes. In agricultural systems, increased vegetation complexity, such as greater structure or biodiversity, can increase the resilience of food production systems from climate fluctuations. We test this theory in 15 urban gardens across California's Central Coast. Local- and landscape-scale measures of ground, vegetation, and land cover were collected in and around each garden, while climate loggers recorded temperatures in each garden in 30 min increments. Multivariate analyses, using county as a random factor, show that both local- and landscape-scale factors were important. All factors were significant predictors of mean temperature. Tallest vegetation, tree/shrub species richness, grass cover, mulch cover, and landscape level agricultural cover were cooling factors; in contrast, garden size, garden age, rock cover, herbaceous species richness, and landscape level urban cover were warming factors. Results were similar for the maximum temperature analysis except that agriculture land cover and herbaceous species richness were not significant predictors of maximum temperature. Analysis of gardener watering behavior to observed temperatures shows that garden microclimate was significantly related to the number of minutes watered as well as the number of liters of water used per watering event. Thus gardeners seem to respond to garden microclimate in their watering behavior even though this behavior is most probably motivated by a range of other factors such as water regulations and time availability. This research shows that local management of ground cover and vegetation can reduce mean and maximum temperatures in gardens, and the reduced temperatures may influence watering behavior of gardeners. [ABSTRACT FROM AUTHOR]

• We synthesize three years of research in urban community gardens in Central Coast, California. • Global social and environmental change factors impact management and delivery of ecosystem services. • Garden regulations and management decisions by gardeners determine the ecological complexity of gardens. • Ecological complexity can affect the ecosystem service, such as food provision, coming from gardens. • Active management can increase social-ecological outcomes that feedback to the larger system. Urban community gardens are vital green spaces threatened by global social and environmental change factors. Population growth has reduced the amount of space available in cities, and climate change challenges plant growth thresholds. Urban community gardens provide dynamic socio-ecological systems to study how such social and environmental change factors affect the management and delivery of ecosystem services. They provide spaces where urban citizens purposefully interact with nature and receive multiple benefits. In this paper, we synthesize the results of three years of research in a case study of urban community gardens across the Central Coast of California and present a framework showing how both social and environmental change factors at the regional scale affect the ecological make-up of urban community gardens, which in turn affect the ecosystem services coming from such systems. Our study reveals that global environmental change felt at the regional level (e.g., increased built environment, climate change) interact with social change and policy (e.g., population growth, urbanization, water use policy), thus affecting regulations over garden resources (e.g., water availability) and management decisions by gardeners (e.g., soil management, crop planting decisions). These management decisions at the plot-scale, determine the ecological complexity and quality of the gardens and affect the resulting ecosystem services that come from these systems, such as food provision for both humans and urban animals. A greater understanding of how environmental and social change factors drive the management processes of urban community gardens is necessary to design policy support systems that encourage the continued use and benefits arising from such green spaces. Policies that can support urban community gardens to maintain ecological complexity and increase biodiversity through active management of soil quality and plant diversity have the potential to increase social and environmental outcomes that feedback to the larger environmental and social system. [ABSTRACT FROM AUTHOR]

Climatically similar regions may experience different temperature extremes and weather patterns that warrant global comparisons of local microclimates. Urban agroecosystems are interesting sites to examine the multidimensional impacts of climate changes because they rely heavily on human intervention to maintain crop production under different and changing climate conditions. Here, we used urban community gardens across the California Central Coast metropolitan region, USA, and the Melbourne metropolitan region, Australia, to investigate how habitat-scale temperatures differ across climatically similar regions, and how people may be adapting their gardening behaviors to not only regional temperatures, but also to the local weather patterns around them. We show that, while annual means are very similar, there are strong interregional differences in temperature variability likely due to differences in the scale and scope of the temperature measurements, and regional topography. However, the plants growing within these systems are largely the same. The similarities may be due to gardeners' capacities to adapt their gardening behaviors to reduce the adverse effects of local temperature variability on the productivity of their plot. Thus, gardens can serve as sites where people build their knowledge of local weather patterns and adaptive capacity to climate change and urban heat. Climate-focused studies in urban landscapes should consider how habitat-scale temperature variability is a background for interesting and meaningful social-ecological interactions. [ABSTRACT FROM AUTHOR]

• Ants were the most abundant predator observed in urban gardens. • Egg removal was higher under vegetation compared to bare and mulched open areas. • Prey removal increased with floral abundance, but declined with tree abundance. • Plant richness and urban cover influenced predators, but not predation. Agroecosystem management at microhabitat, habitat, and landscape scales shapes natural enemy communities, with critical implications for ecosystem services. Yet few studies examine the impacts of small to large scale habitat management features on predator communities, abundance of predator species, or removal of prey items from urban agroecosystems. In this study, we used observations and a sentinel prey removal experiment to examine the impact of substrate (prey placed on the ground vs. on kale plants), microhabitat (prey placed under vegetation, on bare soil in open areas, or on mulch in open areas), local garden management features, and landscape features on predator species composition and removal of two prey species in urban gardens in the California central coast. We found that both microhabitat characteristics and substrate type shaped prey removal rates within urban gardens, and microhabitat, but not substrate, impacted predator species composition. In addition, both garden management (floral abundance, herbaceous plant richness, and tree and shrub abundance) and landscape features (urban land cover within 2 km) influenced prey removal and predator composition. Nearly all prey removal of eggs was accomplished by ants; larvae predators were more diverse and included ants, birds, lizards, wasps, and spiders. Although predator composition was mediated by many habitat features, prey removal was greater under vegetation, from the ground, when floral abundance in gardens was high, and in gardens with fewer trees and shrubs. Considering how these different management features affect predator foraging behavior and interactions will be a promising next step in this field. [ABSTRACT FROM AUTHOR]