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Urban gardens, or spaces that include vegetables, fruit trees, and ornamental plants, can support bird species and communities by providing food and nesting habitat within urban landscapes. Yet, variation in management of gardens (e.g., garden size, number of tree and shrub species, ground cover) and the landscape (e.g., urban cover, landscape diversity) that surrounds them may alter communities within gardens. We examined how garden management and landscape features influence bird abundance, richness, species composition, and traits in 19 urban community gardens in the central coast of California. We found that bird abundance was higher in larger gardens and in gardens with more grass, and species richness was higher in larger gardens. Bird abundance also differed with garden ecoregion. Urban cover influenced bird species composition while bird trait distributions were influenced by urban cover, ecoregion, and grass cover. Gardens with more urban cover supported fewer insectivores, ground-nesters, and forest-associated birds, higher nesting height and more urban-associated bird species. Gardens in the ecoregion closer to the coast had more cliff nesters and more marsh-associated birds. Although urban cover and ecoregion were important for the composition and trait distribution of birds, manipulation of garden management and size may promote bird species richness, or abundance of functionally important birds in gardens.

Urban community gardens are important social–ecological systems from which urban citizens receive many benefits. In this study of 18 urban community gardens in the Central Coast of California, USA, we use a combination of gardener surveys and field-based measurements to evaluate the amount of fresh fruit and vegetables produced by gardeners. We then investigate how food production differed between segments of the gardening population, specifically as a function of gardening experience, time spent in gardens, and food security status. Lastly, we ask gardeners to describe their motivations for gardening to better understand how motivations may relate to individual levels of food production. Thirty-eight percent of gardeners estimate harvesting one to five pounds of food per week, with another 26% estimating six to ten pounds. These estimates were corroborated by field measurements of tomato, squash, and pepper cultivation, where gardeners produced, at the height of the harvest season, an average of four pounds of food per week—an estimated savings of ~ $16USD per week (compared to the cost of local organic fruits and vegetables, June 2023 prices). Regarding the ability of community gardens to reduce food insecurity, gardeners who spent more time in the garden and with higher incomes reported higher food security, while those with larger families or lower incomes were more food insecure. These results show that gardeners in most need of food support were not necessarily the ones cultivating the most fruits and vegetables. While 48% of gardeners reported food cultivation as a primary motivator for gardening, many other motivations (e.g., hobby, being outdoors, relaxation, social interaction, and exercise) were identified as reasons to spend time in the garden, indicating that food production is not the only factor motivating gardeners. Overall, we document that community gardens can be highly productive and provide valuable produce that substantially offsets high fresh food costs; however, gardeners with the greatest food needs are currently not the largest producers, but could benefit from additional resources and support.

Studies have documented biodiversity losses due to intensification of coffee management (reduction in canopy richness and complexity). Nevertheless, questions remain regarding relative sensitivity of different taxa, habitat specialists, and functional groups, and whether implications for biodiversity conservation vary across regions. We quantitatively reviewed data from ant, bird, and tree biodiversity studies in coffee agroecosystems to address the following questions: Does species richness decline with intensification or with individual vegetation characteristics? Are there significant losses of species richness in coffee-management systems compared with forests? Is species loss greater for forest species or for particular functional groups? and Are ants or birds more strongly affected by intensification? Across studies, ant and bird richness declined with management intensification and with changes in vegetation. Species richness of all ants and birds and of forest ant and bird species was lower in most coffee agroecosystems than in forests, but rustic coffee (grown under native forest canopies) had equal or greater ant and bird richness than nearby forests. Sun coffee (grown without canopy trees) sustained the highest species losses, and species loss of forest ant, bird, and tree species increased with management intensity. Losses of ant and bird species were similar, although losses of forest ants were more drastic in rustic coffee. Richness of migratory birds and of birds that forage across vegetation strata was less affected by intensification than richness of resident, canopy, and understory bird species. Rustic farms protected more species than other coffee systems, and loss of species depended greatly on habitat specialization and functional traits. We recommend that forest be protected, rustic coffee be promoted, and intensive coffee farms be restored by augmenting native tree density and richness and allowing growth of epiphytes. We also recommend that future research focus on potential trade-offs between biodiversity conservation and farmer livelihoods stemming from coffee production.

Urban green spaces, such as forest fragments, vacant lots, and community gardens, are increasingly highlighted as biodiversity refuges and are of growing interest to conservation. At the same time, the burgeoning urban garden movement partially seeks to ameliorate problems of food security. Arthropods link these two issues (conservation and food security) given their abundance, diversity, and role as providers of ecosystem services like pollination and pest control. Many previous studies of urban arthropods focused on a single taxon (e.g. order or family), and examined either local habitat drivers or effects of landscape characteristics. In contrast, we examined both local and landscape drivers of community patterns, and examined differences in abundance, richness, and trophic structure of arthropod communities in urban forest fragments, vacant lots, and community gardens. We sampled ground-foraging arthropods, collected data on 24 local habitat features (e.g., vegetation, ground cover, concrete), and examined land-cover types within 2 km of 12 study sites in Toledo, Ohio. We found that abundance and richness of urban arthropods differed by habitat type and that richness of ants and spiders, in particular, varied among lots, gardens, and forests. Several local and landscape factors correlated with changes in abundance, richness, and trophic composition of arthropods, and different factors were important for specific arthropod groups. Overwhelmingly, local factors were the predominant (80 % of interactions) driver of arthropods in this urban environment. These results indicate that park managers and gardeners alike may be able to manage forests and gardens to promote biodiversity of desired organisms and potentially improve ecosystem services within the urban landscape.

Biological pest control relies on interactions between herbivores and their natural enemies. Maintaining this ecosystem service requires considering herbivore and natural enemy interactions and their response to anthropogenic change at multiple scales. In this study, we used ecological networks to quantify the network structure of interactions between herbivorous insects and their parasitoids. We examined how herbivore host abundance, parasitism rates, and shifts in network structure relate to changes in local habitat management and landscape context. We sampled herbivores and parasitoids in Brassica oleracea plants at 22 urban gardens in the Central Coast of California. At each site, we measured local management characteristics (e.g., vegetation, ground cover, canopy cover) and quantified surrounding landscape composition (e.g., urban, natural, open, and agricultural cover). For the eight sites with large enough networks, we calculated three network structure metrics (interaction richness, vulnerability, and functional complementarity). We then used generalized linear and mixed models to examine relationships between herbivore host abundance, parasitism rates, garden management and landscape characteristics, and network metrics. We found that both local management and landscape composition influenced parasitism, while only local factors affected host abundance and network structure. Higher network interaction richness was marginally associated with enhanced parasitism rates for two host species and lower parasitism rates for one host species. Our results suggest that local garden management decisions may shift the structure of host–parasitoid networks, which may subsequently affect host parasitism rates, but outcomes for biological pest control will likely vary across host species.

(1) Urbanization threatens biodiversity, yet urban native plants support native biodiversity, contributing to conservation and ecosystem services. Within urban agroecosystems, where non-native plants are abundant, native plants may boost the abundance and richness of beneficial arthropods. Nevertheless, current information focuses on pollinators, with little attention being paid to other beneficials, like natural enemies. (2) We examined how the species richness of native plants, garden management, and landscape composition influence the abundance and species richness of all, native, and non-native bees, ladybeetles, ants, and ground-foraging spiders in urban agroecosystems (i.e., urban community gardens) in California. (3) We found that native plants (~10% of species, but only ~2.5% of plant cover) had little influence on arthropods, with negative effects only on non-native spider richness, likely due to the low plant cover provided by native plants. Garden size boosted native and non-native bee abundance and richness and non-native spider richness; floral abundance boosted non-native spider abundance and native and non-native spider richness; and mulch cover and tree and shrub abundance boosted non-native spider richness. Natural habitat cover promoted non-native bee and native ant abundance, but fewer native ladybeetle species were observed. (4) While native plant richness may not strongly influence the abundance and richness of beneficial arthropods, other garden management features could be manipulated to promote the conservation of native organisms or ecosystem services provided by native and non-native organisms within urban agroecosystems.

Coffee agroecosystems are critical to the success of conservation efforts in Latin America because of their ecological and economic importance. Coffee certification programs may offer one way to protect biodiversity and maintain farmer livelihoods. Established coffee certification programs fall into three distinct, but not mutually exclusive categories: organic, fair trade, and shade. The results of previous studies demonstrate that shade certification can benefit biodiversity, but it remains unclear whether a farmer's participation in any certification program can provide both ecological and economic benefits. To assess the value of coffee certification for conservation efforts in the region, we examined economic and ecological aspects of coffee production for eight coffee cooperatives in Chiapas, Mexico, that were certified organic, certified organic and fair trade, or uncertified. We compared vegetation and ant and bird diversity in coffee farms and forests, and interviewed farmers to determine coffee yield, gross revenue from coffee production, and area in coffee production. Although there are no shade-certified farms in the study region, we used vegetation data to determine whether cooperatives would qualify for shade certification. We found no differences in vegetation characteristics, ant or bird species richness, or fraction of forest fauna in farms based on certification. Farmers with organic and organic and fair-trade certification had more land under cultivation and in some cases higher revenue than uncertified farmers. Coffee production area did not vary among farm types. No cooperative passed shade-coffee certification standards because the plantations lacked vertical stratification, yet vegetation variables for shade certification significantly correlated with ant and bird diversity. Although farmers in the Chiapas highlands with organic and/or fair-trade certification may reap some economic benefits from their certification status, their farms may not protect as much biodiversity as shade-certified farms. Working toward triple certification (organic, fair trade, and shade) at the farm level may enhance biodiversity protection, increase benefits to farmers, and lead to more successful conservation strategies in coffee-growing regions.

Increasing human populations are challenging cities to grow sustainably while maintaining green spaces that deliver ecosystem services and well-being benefits. Community gardens are green spaces that provide food, community, and health benefits, but gardens often are non-permanent due to development and green space loss. Thus, investigating their significance and benefit across urban regions is critical for research and policy alike. This study investigated the role of community gardens in providing human well-being benefits across three counties in the California Central Coast—a region undergoing massive urban transformation in the last century. We measured how multiple aspects of self-reported gardener well-being varied in relation to the social opportunities of surrounding neighborhoods and the biophysical features of the landscapes in which the gardens were embedded. The results document improvements in gardener well-being through gardening across social and biophysical gradients. Gardeners are motivated by diverse reasons, varying from gardening in order to connect to nature, to gardening for improved food access, or to enhance time spent with family. Community gardens are therefore important for supporting many well-being benefits. Policies to maintain and protect gardens should prioritize neighborhoods with needs for connecting to nature and enhancing social interaction within the community.

Urban ecosystems, as mosaics of residential, industrial, commercial, and agricultural land, present challenges for species survival due to impervious surface, degradation, fragmentation, and modification of natural habitat, pollution, and introduced species. Some urban habitats, such as community gardens, support biodiversity and promote ecosystem services. In gardens, local factors (e.g., vegetation, groundcover) and landscape surroundings (e.g., agriculture, built or impervious cover) may influence species abundance, richness, and functional traits that are present. We examined which local and landscape factors within 19 community gardens in the California central coast influence ground beetle (Carabidae) activity density, species richness, functional group richness, and functional traits—body size, wing morphology, and dispersal ability. Gardens with higher crop richness and that are surrounded by agricultural land had greater carabid activity density, while species and functional group richness did not respond to any local or landscape factor. Gardens with more leaf litter had lower carabid activity, and gardens with more leaf litter tended to have more larger carabids. Changes in local (floral abundance, ground cover) and landscape (urban land cover) factors also influenced the distribution of individuals with certain wing morphology and body size traits. Thus, both local and landscape factors influence the taxonomic and functional traits of carabid communities, with potential implications for pest control services that are provided by carabids.

It is commonly thought that diverse agroecosystems are less prone to pest outbreaks because they support a high diversity of natural enemies. The idea that diversity stabilizes functional properties of communities to environmental perturbation is formalized in the ecological literature as the \"insurance hypothesis.\" Recently this hypothesis has been examined theoretically and in microcosm experiments. However it has not been tested empirically in an agroecosystem. Here we provide a test of the insurance hypothesis by examining insect predation by birds in coffee farms with different levels of plant diversity. Lepidopteran larvae were placed in coffee plants, and larval disappearance rates were measured within and outside bird exclosures in two farms with distinct levels of shade. Significant differences were found associated with the exclosure treatment, indicating that birds can potentially prevent pest outbreaks. Furthermore, the effect was significant only for the farm with a high floristic diversity, providing partial evidence in support of the insurance hypothesis.