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An Expanded Scope of Biodiversity in Urban Agriculture, with Implications for Conservation
Abstract
We performed a systematic literature review to summarize what is known by science about the conservation of biodiversity in urban agroecosystems throughout the world. Our initial search among three literature databases captured 9,066 articles, which we screened and reduced to a final set of 431. Our criteria for retaining studies was that they incorporated each of three clearly defined components: urban, agriculture, and biodiversity. We reviewed the final article set using four methods: we 1) extracted basic article information from the citation databases, 2) used topic model analyses to cluster words extracted from article abstracts into topical clusters, 3) manually categorized articles with a set of eight multiple-answer variables, and 4) summarized and extracted main themes from the articles within general biodiversity type groupings (amphibians, birds, fish, invertebrates, mammals, plants, reptiles, and soil microbes). The most common types of biodiversity studied were plants (67% of articles), invertebrates (39%), and birds (23%), while residential (71%) and community (26%) gardens were the most common types of agriculture in which studies were performed. Ornamental and food plants were the most common agricultural production types (60% and 49%, respectively), but the production type was not identified in 22% of studies. Seventy-one percent of articles did not explicitly apply the research to a conservation question, but the knowledge gained could certainly be applied to taxa-specific conservation efforts. Thirty percent of studies explicitly measured conservation or management effects on biodiversity in an urban agricultural setting. Across taxa, we also highlighted research on two topics important to biodiversity conservation in urban agriculture: 1) landscape characteristics (space, scale, and connectivity), and 2) the role of humans. Finally, our chapter concludes with a summary of information gaps and suggestions for future work.
Supplementary resources (2)
... Urban areas are attracting mounting interest for their potential for biodiversity conservation (Heath et al., 2020), as well as being melting pots of cultural diversity. They are thus interesting places to question the influence of human practices on the genetic diversity of cultivated plants. ...
Crop seed exchange networks, shaped by social dynamics, strongly influence the organization and breadth of plant diversity in human‐managed environments. Integrating an urban and market perspective, this study explores the diversity dynamics of a socio‐economically important Central African fruit tree species, the African plum tree. Tree owners in urban, peri‐urban and rural sites use seeds from different origins as their main propagation material, leading to locational variations in genetic diversity and structure. This analysis contributes toward building a framework to inform the research agenda of cultivated African fruit trees, by highlighting the important role of urban centers in safeguarding crop genetic resources.
Summary
Biocultural factors constrain the dynamics of crop species diversity. Here, we considered different aspects of the social, spatial and temporal dynamics of morphological and genetic diversity in a multi‐purpose perennial crop, the African plum tree ( Dacryodes edulis ). We assessed (i) how seed exchange networks were organized along urbanization gradients, and how they influenced the distribution of species diversity; (ii) the temporal dynamic of seed exchange network by characterizing species genetic diversity through time.
To do so, the study was carried out in Cameroon, where we focused on three urbanization gradients, covering urban, peri‐urban and rural areas, corresponding to three different ethnic groups (Bamileke, Bassa, Beti). We combined interviews with tree owners and nuclear microsatellite‐based genetic analyses.
Tree owners from urban and peri‐urban sites primarily used distant seed sources, acquired in the market or from their village of origin, as propagation material, whereas tree owners in rural sites relied primarily on village‐level seeds. In turn, genetic diversity was not evenly distributed, with rural sites exhibiting their own genetic clusters. On the contrary, the genetic diversity of urban sites was enhanced by extensive human‐mediated seed flows. Looking at trees from different age classes, we found that genetic diversity was stable over time.
Overall, this first attempt to combine different levels of diversity for African plum trees in commercially connected areas expands the scope for in situ intraspecific conservation by highlighting the contribution of urbanized areas.
There is a multi-billion dollar global industry dedicated to feeding wild birds in residential gardens. This extraordinary boost to food resources is almost certainly reshaping entire bird communities, yet the large-scale, long-term impacts on community ecology remain unknown. Here we reveal a 40-year transformation of the bird communities using garden bird feeders in Britain, and provide evidence to suggest how this may have contributed to national-scale population changes. We find that increases in bird diversity at feeders are associated with increasing community evenness, as species previously rarely observed in gardens have increasingly exploited the growing variety of foods on offer over time. Urban areas of Britain are consequently nurturing growing populations of feeder-using bird species, while the populations of species that do not use feeders remain unchanged. Our findings illustrate the on-going, gross impact people can have on bird community structure across large spatial scales.
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.
Green Infrastructure (GI) definition, deriving from the United States green infrastructure for hydro-geological rebalancing through imitating the nature stormwater management, was consolidated in Europe by GI Planning Guide. Nowadays GI can be considered a valid and meaningful approach for ameliorating urban complex ecosystems, and could also be considered as mitigation action of land consumption, according to the guidelines on the soil sealing of the European Commission (2012). The metropolitan area of Naples located in south Italy is characterized by an unauthorized and chaotic urban development. The land-use map reported an average of 30% of urbanization in the metropolitan area, rising up to 50–60% and as high as 98% in the north core area of the city. This high level of urbanization is directly related to the habitat fragmentation. The National Biodiversity Conservation Strategy defines several challenges and targets to counteract the biodiversity loss in Italy, identifying urban areas as places exposed to the greatest pressures on ecosystems. Therefore, the integration of different policies limiting habitat fragmentation, heat island effect and natural soil hydro-geological degradation into spatial planning, especially through green corridors and ecosystem enhancement in urban areas is an urgent need for the society. Spatial planning has to be renewed in metropolitan areas, where threats and weaknesses to biodiversity conservation are stronger than in any other place, according to the Law n. 56/2014, (Gazzetta Ufficiale della Repubblica Italiana, 2014) committing metropolitan cities to the enactment of General Territorial Plan. In the current paper, we aim at designing an ecological network for the metropolitan area of Naples one of the biggest city of southern Italy. The analyses include the adopted methodological procedure, i.e., ecological network analysis and design, and the introductory elements of a spatial analysis on a pilot ecological network of several patches. Finally, the paper illustrates the network analysis conceived as a monitoring system and also in future perspective, as a planning support system.
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.
Urban biotic homogenization is one of the foremost challenges for conservation of biodiversity in urban green areas. Urban gardening is a common practice in many industrialised and developing countries. The ability of urban vegetable gardens to support biodiversity, however, has yet to be studied in depth. To investigate the responses of flora and soil fauna to urbanization, we surveyed the taxonomic and functional composition of plant and collembolan communities, in addition to soil parameters, in 15 urban vegetable gardens across three large French cities. The vegetation was identified in six plots of 1 × 1 m in each urban vegetable garden and collembolan were extracted from one intact soil core sampled in the center of each plot (5 cm depth, 6 cm diameter). We found contrasting effects of urbanization on plants and Collembola biodiversity. The taxonomic and functional composition of the soil fauna was more similar within cities than among cities, which was driven by similarities in soil parameters. In contrast, plant communities were functionally similar among cities. Understanding the effects of urbanization on soil biodiversity could have implications for the management of urban ecosystems, in particular that of urban soils.
It is critical to understand the specific drivers of biodiversity across multiple spatial scales, especially within rapidly urbanizing areas, given the distinct management recommendations that may result at each scale. However, drivers of biodiversity patterns and interactions between drivers are often only measured and modeled at a single scale. In this study, we assessed bee community composition at three time periods in 20 grassland and 20 agriculture sites located across two major metroplexes. We examined how local environmental variables and surrounding landscape composition impact bee abundance, richness, and evenness, including comparisons between groups with different nesting strategies and body sizes. We collected nearly 13,000 specimens and identified 172 species. We found that levels of regional land use differentially impacted bee abundance and diversity depending on local habitat management. Specifically, within agriculture sites, bee richness was greater with increasing landscape‐level seminatural habitat, while in grassland sites, bee richness was similar across landscapes regardless of seminatural habitat cover. Bee evenness at both site types declined with increasing landscape‐level habitat heterogeneity, due to an increase of rare species at the grassland sites, but not in the agricultural sites, further indicating that diversity is driven by the interaction of local habitat quality and landscape‐level habitat composition. We additionally found that agriculture sites supported higher abundances, but not richness, of small‐bodied and below‐ground nesting bees, while grassland sites supported higher abundances of aboveground nesting bees, and higher richness of large‐bodied species. Increased levels of local bare ground were significantly related to multiple metrics of bee diversity, including greater belowground nesting bee abundance and richness. Local floral richness was also significantly related to increases of overall bee abundance, as well as the abundance and richness of small bees. Overall, we suggest that local land managers can support bee abundance and diversity by conserving areas of bare soil and promoting native floral diversity, the latter especially critical in highly urban agricultural spaces. Our results provide the first documentation of significant interactions between local habitat management and landscape composition impacting insect communities in urban systems, indicating that bee conservation practices depend critically on land use interactions across multiple spatial scales.
Cultivation and spread of non-native plant species may result in either phylogenetic homoge-nization (increasing similarity) or differentiation (decreasing similarity) of urban floras. However, it is unknown how non-native species influence homogenization of cultivated versus spontaneously occurring species in cities, and which traits are associated with species that promote homogenization versus differentiation. In this study, we compared homogenization effects of cultivated and spontaneous non-native species in yard floras across and within seven widely distributed U.S. cities. Additionally, we explored which traits explained their particular contribution to homogenization. We recorded plant presence/absence in 178 private yards distributed among seven metropolitan statistical areas in the United States. We compared phylogenetic homogenization effects of non-native species within both the cultivated and spontaneous species pools using phylogenetic dissimilarities and the homogenization index. Then, we expressed contributions of non-native species to the homogenization of each pool as a function of two different sets of plant functional traits using phylogenetic generalized least square (PGLS) models across and within cities. Across cities, spontaneous non-native species homogenized, and cultivated non-native species differentiated, yard floras. Within the spontaneous pool, short, small-seeded non-native plants and non-native grasses significantly homogenized yard floras. Within the cultivated pool, species contribution to homogenization was best predicted by plant height, presence of showy flowers, and growth form, with non-native grasses significantly homogenizing cultivated yard floras. Within cities, non-native species-whether they were cultivated or spontaneous-consistently homogenized yard floras of the three northern cities and differentiated yard floras of three of the four southern cities, suggesting that homogenization processes are context-and scale-dependent. Likewise, traits explaining homogenization differed substantially among cities. The inconsistent patterns among cities in the plant traits that promoted homogenization of both cultivated and spontaneous species suggest that local environmental and anthropogenic conditions of individual cities imposed strong constraints on trait selection. Linking plant functional traits that promote homogenization with residents' preferences for vegetation may further enhance understanding of how yard plant communities assemble at regional and local scales.
The science of urban ecology has increasingly grappled with the long‐term ramifications of a globally urbanized planet and the impacts on biodiversity. Some researchers have suggested that places with high species diversity in cities simply reflect an extinction debt of populations that are doomed to extinction but have not yet disappeared. The longitudinal studies conducted to date have found species composition shifting with urbanization but have not always documented continued species extirpations post‐urbanization. We used long‐term monitoring data on birds from the greater metropolitan area of Phoenix, Arizona, to measure changes in residential bird communities, species–habitat relationships, and human perceptions of bird species diversity over a five‐year period. Bird richness, occupancy, and abundance decreased, as did the percentage of respondents satisfied with bird variety in their neighborhoods. As in previous analyses for this region, we found that desert specialist species were associated with neighborhoods with xeric landscaping consisting of gravel groundcover, and drought‐tolerant, desert‐adapted vegetation. These species were also found in neighborhoods with high per capita income rates and lower percentages of renters and Hispanic/Latinx residents. Non‐native species were positively associated with neighborhoods containing mesic yards with grass and other water‐intensive vegetation. The proportions of yards in our surveyed neighborhoods with these distinct landscaping types likewise remained relatively stable over five‐year period. Although habitat–species relationships remained unchanged, we detected significant loss of species across the sampling period. Declines were not confined to desert specialist species but included generalist and invader species as well. The parallel reduction in residents’ satisfaction suggests that people perceive some aspect of this environmental degradation. Further investigation into the mechanisms underlying these species losses may reveal options for retaining some desert specialist species, and the uniqueness they contribute to urban fauna.
The feeding of wild birds in domestic gardens is one of the most widespread and popular forms of human-wildlife interaction throughout the Western World. The increasing recognition of the benefits to human health and well-being of contact with nature, especially in an increasingly urbanized world, reveals the need for a greater understanding of why we engage in bird feeding. This will undoubtedly result in enhanced benefits of feeding to both people and to the biodiversity it supports. Our study aimed to explore the motivations behind wild bird feeding in south-east England through both qualitative and quantitative approaches. This involved a two-phase process: first, the dimensions of involvement were ascertained through semistructured interviews with 30 people engaged in feeding. Interrogation of their responses was used to construct an online questionnaire. A total of 563 respondents completed this survey. Analysis of their responses discerned a series of themes with the most salient being based on or directed toward: pleasure, bird survival, nurture, education of children, and connection with nature. These findings reveal that bird feeding is underpinned by a complex array of motivations and influences involving both personal and environmental benefits.
Despite growing evidence pointing to the multiple benefits of home gardening, few studies have considered the health and well-being benefits perceived by gardeners who are principally motivated by biodiversity conservation (i.e. home gardening for biodiversity conservation). This study explores the environmental, social and economic co-benefits (and costs) of home gardening for biodiversity conservation in the City of Winnipeg, Canada. A total of 42 semi-structured interviews (30–60 min each) were conducted with 50 home gardeners who were formally certified or locally recognised for undertaking multiple gardening activities that promote biodiversity conservation. Thematic analysis revealed that study participants self-reported a range of environmental, psychological, physiological and social outcomes associated with their home gardening experiences. Despite home gardening often being a solitary activity, most gardeners valued the multiple forms of social interaction that occurred during important social events in their garden, or when connecting with passers-by. Home gardeners also cited benefits related to connection to nature and place attachment; attention restoration; reduced stress and anxiety; improved mood; satisfaction and pride; increased self-esteem and courage to do things differently in life; and, important education or learning opportunities. However, conflicts relating to the nexus between biodiversity and perceived tidiness of gardens emerged, which raise important ethical and social justice issues for sustainability planning. We compare key insights to the benefits (and costs) of community gardening and make some recommendations for future research, including how to engage more disadvantaged groups in gardening for conservation.
Urban and suburban landscapes can be refuges for biodiversity of bees and other pollinators. Public awareness of declining pollinator populations has increased interest in growing plants that provide floral resources for bees. Various publications and websites list “bee-friendly” plants, but such lists are rarely based on empirical data, nor do they emphasize flowering trees and shrubs, which are a major component of urban landscapes. We quantified bee visitation to 72 species of flowering woody landscape plants across 373 urban and suburban sites in Kentucky and southern Ohio, USA, sampling and identifying the bee assemblages associated with 45 of the most bee-attractive species. We found strong plant species effects and variation in seasonal activity of particular bee taxa, but no overall differences in extent of bee visitation or bee genus diversity between native and non–native species, trees and shrubs, or early-, mid-, and late-season blooming plants. Horticulturally-modified varieties of Hydrangea, Prunus, and Rosa with double petals or clusters of showy sterile sepals attracted few bees compared to related plants with more accessible floral rewards. Some of the non-native woody plant species bloomed when floral resources from native plants were scarce and were highly bee-attractive, so their use in landscapes could help extend the flowering season for bees. These data will help city foresters, landscape managers, and the public make informed decisions to create bee–friendly urban and suburban landscapes.
Background
Red foxes (Vulpes vulpes L.) have become successful inhabitants of urban areas in recent years. However, our knowledge about the occurrence, distribution and association with land uses of these urban foxes is poor, partly because many favoured habitats are on private properties and therefore hardly accessible to scientists. We assumed that citizen science, i.e. the involvement of the public, could enable researchers to bridge this information gap. We analysed 1179 fox sightings in the city of Vienna, Austria reported via citizen science projects to examine relationships between foxes and the surrounding land use classes as well as sociodemographic parameters.
Results
Conditional probabilities of encountering foxes were substantially higher in gardens, areas with a low building density, parks or squares as compared to agricultural areas, industrial areas or forests. Generalized linear model analyses showed that sociodemographic parameters such as education levels, district area, population density and average household income additionally improved the predictability of fox sightings.
Conclusions
Reports of fox sightings by citizen scientists might help to support the establishment of wildlife management in cities. Additionally, these data could be used to address public health issues in relation with red foxes as they can carry zoonoses that are also dangerous to humans.
Context: As urban areas increase in extent globally, domestic yards play an increasingly important role as potential contributors to ecosystem services and wellbeing. These benefits largely depend on the plant species richness and composition of yards.
Objectives: We aim to determine the factors that drive plant species richness and phylogenetic composition of cultivated and spontaneous flora in urban yards at the continental scale, and how these potential drivers interact.
Methods: We analyzed plant species richness and phylogenetic composition of cultivated and spontaneous flora of 117 private yards from six major metropolitan areas in the US. Yard plant species richness and phylogenetic composition were expressed as a function of biophysical and socioeconomic variables and yard characteristics using linear mixed-effects models and spatially explicit structural equation modeling.
Results: Extreme temperatures largely determined yard species richness and phylogenetic composition at the continental scale. Precipitation positively predicted spontaneous richness but negatively predicted cultivated richness. Only the phylogenetic composition of the spontaneous flora was associated with precipitation. The effect of lower temperatures and precipitation on all yard diversity parameters was partly mediated by yard area. Among various socioeconomic variables, only education level showed a significant effect on cultivated phylogenetic composition.
Conclusions: Our results support the hypothesis that irrigation compensates for precipitation in driving cultivated yard plant diversity at the continental scale. Socioeconomic variables among middle and upper class families have no apparent influence on yard diversity. These findings inform the adaptation of US urban vegetation in cities in the face of global change.
Urban landscapes are often florally rich due to extensive management of cultivated plants around the city. High abundance and diversity of these floral resources has been linked to more abundant and diverse pollinator communities, but little is known about how urban pollinators select from the wide variety of available flowers. This study provides unique insight into urban plant-pollinator interactions by examining how many plant taxa, and which taxa, are visited by pollinators. Over a three-year period, we observed foraging of urban pollinators across 63 neighborhoods in Chicago, Illinois (USA). We observed 1815 plant-pollinator interactions between 24 pollinator morpho-types and 106 plant taxa. An additional 57 plant taxa were flowering but not visited by pollinators. On average, each pollinator morpho-type visited 19 plant taxa, and most pollinators showed generalist tendencies. We identified 42 plant taxa that were visited by more pollinator morpho-types than their floral abundance would predict; we call these ‘highly attractive’ plants. In general, perennial and native plants received more pollinator visits than their counterparts, and ornamental plants were visited by more species than unintentional ‘weeds’. However, the two most-visited plant taxa were non-native, perennial weeds. Our results suggest that many flowering plants in cities are not visited by pollinators. Furthermore, the plant-pollinator network could be reduced to only four plant taxa without losing any pollinator morpho-types. To enhance urban pollinator conservation, urban residents can select ornamental plants from our list of ‘highly attractive’ plant taxa, or can allow some of the highly attractive ‘weeds’ to persist in their gardens.
The practice of producing vegetables on green roofs has been gaining momentum in recent years as a method to facilitate agricultural sustainability in urban areas. Rooftop gardens are becoming an important part of the recent rejuvenation of urban agriculture, and offers alternative spaces to grow vegetable products for urban markets. Green roofs create spaces for the production of vegetable crops, which then generate opportunities for integrating agriculture into urban communities. However, vegetable production activities on rooftops are currently minimal due to multiple challenges that must be overcome before widespread implementation will occur, and these are presented and discussed herein in great detail. Although intensive green roof systems (>15 cm medium depths) are thought to be most suited for vegetable production, the greatest potential for sustained productivity is probably through extensive systems (<15 cm depths) due to weight load restrictions for most buildings. Thus, shallow-rooted vegetables that include important salad greens crops are thought to be the most suited for extensive systems as they can have high productivity with minimal inputs. Research presented herein agree that crops such as lettuce, kale and radish can be produced effectively in an extensive green roof medium with sufficient nutrient and moisture inputs. Other research has indicated that deeper-root crops like tomato can be produced but they will require constant monitoring of fertility and moisture levels. Vegetable production is a definite possibility in urban areas on retrofitted green roofs using minimal growing substrate depths with intensive seasonal maintenance. Rooftop agriculture can improve various ecosystem services, enrich urban biodiversity and reduce food insecurity. Food production provided by green roofs can help support and sustain food for urban communities, as well as provide a unique opportunity to effectively grow food in spaces that are typically unused. The utilization of alternative agricultural production systems, such as green roof technologies, will increase in importance as human populations become more urbanized and urban consumers become more interested in local foods for their families. Although cultivation of food on buildings is a key component to making cities more sustainable and habitable, green roofs are not the total solution to provide food security to cities. They should be viewed more as a supplement to other sources of food production in urban areas.
Homegardens are small-scale agroforestry systems consisting of parcels of land on homesteads in which diverse plant species are cultivated in several strata, often integrating herbaceous, tree, vine, crop, and animal components. Among the vines in Mayan homegardens in Yucatán is the pitahaya (Hylocereus undatus), a cactus with edible fruit. We use this species as a model to identify changes in the level of knowledge and management of homegardens due to modernization (increased tourism, paved roads, and urban expansion) in order to propose conservation strategies. Structured interviews were carried out in 100 homegardens; information regarding economics, language, school attendance, and the distance to cities were gathered. Currently, pitahaya is mostly eaten as a sorbet, and women harvest its fruit more often than men do. It is the elderly who teach the next generations about the use and care of pitahayas. The model that best explained the level of knowledge and management about pitahaya included variables such as the location of homegardens; their distance to the nearest city; as well as language, gross domestic product, and school attendance rate of home gardeners. We found that there is less traditional knowledge about pitahayas when home gardeners have higher school attendance and that not only pitahayas but also homegardens near cities are being neglected. We suggest that conservation planning for pitahayas and homegardens should include education programs on their ecological, nutritional, and economic importance. Homegardens, whose owners have the highest level of knowledge about their management and biodiversity, should be interactively conserved, and the knowledge of home gardeners should be acknowledged.
Human-dominated landscapes represent one of the most rapidly expanding and least-understood ecosystems on earth. Yet, we know little about which features in these landscapes promote sustainable wildlife populations. Historically, in urban areas, landowners have converted native plant communities into habitats dominated by nonnative species that are not susceptible to pest damage and require little maintenance. However, nonnative plants are also poor at supporting insects that are critical food resources for higher order consumers. Despite the logical connection, no study has examined the impact of nonnative plants on subsequent population responses of vertebrate consumers. Here, we demonstrate that residential yards dominated by nonnative plants have lower arthropod abundance, forcing resident Carolina chickadees (Poecile carolinensis) to switch diets to less preferred prey and produce fewer young, or forgo reproduction in nonnative sites altogether. This leads to lower reproductive success and unsustainable population growth in these yards compared with those with >70% native plant biomass. Our results reveal that properties landscaped with nonnative plants function as population sinks for insectivorous birds. To promote sustainable food webs, urban planners and private landowners should prioritize native plant species.
In urban and suburban ecosystems, biodiversity can depend on various non-native plant species, including crop plants, garden plants and weeds. Non-native plants may help to maintain biodiversity by providing a source of forage for pollinators in these ecosystems. However, the contribution of plants in urban and agricultural areas to ecosystem services has often been underestimated in biodiversity assessments. In this study, we investigated the pollen sources of native honeybees (Apis cerana) in an arboretum containing native trees and urban and agricultural plants in a suburban landscape. We surveyed the flowering tree species planted inside the arboretum, which were potential pollen sources. The number of potential pollen-source species of native trees peaked in June and July and decreased after August. We collected A. cerana pollen balls every month and identified plant species of pollen in the collected pollen balls using DNA barcoding. In total, we identified 29 plant species from A. cerana pollen balls. The probability of A. cerana using pollen from urban and agricultural plants was higher in July and August than in June. A. cerana collected pollen forages from native tree species (53%), but also gathered pollen from crop plants (13%), garden trees (19%) and native and non-native weeds (14%); the predominant pollen sources in September and October were the garden tree Ulmus parvifolia and the non-native weed Solidago altissima. We found that native honeybees used plants from a variety of habitats including non-native plants to compensate for apparent seasonal shortages of native tree sources in suburban ecosystems. Our results highlight the importance of assessments of both positive and negative roles of non-native plants in urbanized ecosystems to improve biodiversity conservation.
Urban gardens are a prominent part of agricultural systems, providing food security and access within cities; however, we still lack sufficient knowledge and general principles about how to manage pests in urban agroecosystems in distinct regions. We surveyed natural enemies (ladybeetles and parasitoids) and conducted sentinel pest removal experiments to explore local management factors and landscape characteristics that influence the provisioning of pest control services in California, USA, and Chiapas, Mexico. We worked in 29 gardens across the two locations. In each location, we collected data on garden vegetation, floral availability, ground cover management, and the percentage of natural, urban, and agricultural land cover in the surrounding landscape. We sampled ladybeetles, Chalcidoidea, and Ichneumonoidea parasitoids with sticky traps, and monitored the removal of three different pest species. Ladybeetle abundance did not differ between locations; abundance decreased with garden size and with tree cover and increased with herbaceous richness, floral abundance, and barren land cover. Chalcicoidea and Ichneumonoidea parasitoids were more abundant in Chiapas. Chalcicoidea abundance decreased with herbaceous richness and with urban cover. Ichneumonoidea abundance increased with mulch and bare ground cover, garden size, garden age, and with agriculture land cover but decreased with tree richness and urban cover. Predators removed between 15-100% of sentinel prey within 24 h but prey removal was greater in California. Generally, prey removal increased with vegetation diversity, floral abundance, mulch cover, and urban land cover, but declined with vegetation cover and bare ground. Although some factors had consistent effects on natural enemies and pest control in the two locations, many did not; thus, we still need more comparative work to further develop our understanding of general principles governing conservation biological control in urban settings.
African woolly-necked storks (Ciconia microscelis) depend on wetland habitats for foraging and nesting in natural environments. Recently, they have started colonising urban environments in KwaZulu-Natal, South Africa, and are now a common sight in suburban areas in particular. There have been some anecdotal reports on supplementary feeding of this species by households in some urban areas where they are common. However, these reports have never been confirmed and therefore the extent of feeding and lack thereof is unknown. Using a questionnaire survey, we therefore investigated the extent (if any) to which householders in urban and suburban areas of KwaZulu-Natal provide supplementary food to African woolly-necked storks. We also determined the feeders’ provisioning habits, and identified the motivation behind and attitudes toward feeding. We found that a significant number of householders fed African woolly-necked storks on a daily basis throughout the year. The majority of respondents provided meat while others provided inappropriate food such as bread. Respondents were most often motivated to feed for personal pleasure. Our results showed that this species is successfully utilising and exploiting anthropogenic food – a novel behaviour. The observations and narratives from respondents strongly suggest that the African woolly-necked stork is present throughout the year, contrary to the perception that this species is migratory during winter. Based on the results obtained in this study, supplementary feeding of African woolly-necked stork by householders is relatively common, widespread and established in suburban areas of KwaZulu-Natal, South Africa. However, reported inappropriate feeding may create concerns regarding the health status of African woolly-necked storks in urban population. Therefore, to prevent further detrimental effects and potential human-wildlife conflicts we recommend that suitable feeding guidelines be formulated.
Urbanization and achieving sustainable agriculture are both major societal challenges. By reducing food miles and connecting people with nature, food cultivation in cities has several major advantages. However, due to further urban development (peri-) urban agriculture (UPA) is under threat. To strengthen UPA, we argue for considering UPA as a nature-based solution (NbS) supporting systemic approaches for societal challenges. However, academic knowledge on UPA's contribution to various societal challenges of urbanization is still fragmented. This study addresses the gap by conducting a systemic literature review, incorporating 166 academic articles focusing on the global north. The results of the review show that UPA contributes to ten key societal challenges of urbanization: climate change, food security, biodiversity and ecosystem services, agricultural intensification, resource efficiency, urban renewal and regeneration, land management, public health, social cohesion, and economic growth. The value of UPA is its multifunctionality in providing social, economic and environmental co-benefits and ecosystem services. When implementing UPA, social, institutional, economic, technical, geographical, and ecological drivers and constraints need to be considered. To upscale UPA successfully, the study develops an integrative assessment framework for evaluating the implementation and impact efficiency of UPA. This framework should be tested based on the example of edible cities.
Urban agroecosystems offer an opportunity to investigate the diversity and distribution of organisms that are conserved in city landscapes. This information is not only important for conservation efforts, but also has important implications for sustainable agricultural practices. Associated biodiversity can provide ecosystem services like pollination and pest control, but because organisms may respond differently to the unique environmental filters of specific urban landscapes, it is valuable to compare regions that have different abiotic conditions and urbanization histories. In this study, we compared the abundance and diversity of ladybird beetles within urban gardens in California and Michigan, USA. We asked what species are shared, and what species are unique to urban regions. Moreover, we asked how beetle diversity is influenced by the amount and rate of urbanization surrounding sampled urban gardens. We found that the abundance and diversity of beetles, particularly of unique species, respond in opposite directions to urbanization: ladybirds increased with urbanization in California, but decreased with urbanization in Michigan. We propose that in California water availability in gardens and the urbanization history of the landscape could explain the divergent pattern. Thus, urban context is likely a key contributor to biodiversity within habitats and an important consideration for sustainable agricultural practices in urban agroecosystems.
1. Habitat loss and modification are hallmarks of anthropogenic ecosystems, but the consequences for ecosystem functions and services often remain unclear. Understanding these links in cities is complicated by strong but fine‐scale differences in habitat structure among green space patches, and a high variance in habitat amount across urban landscapes.
2. We used airborne laser scanning (ALS) data to disentangle the effects of 3D woody habitat heterogeneity of urban home gardens, and woody habitat amount at four landscape spatial scales (50, 100, 250, 500 m), on the predation risk of artificial sentinel prey by birds and arthropods.
3. In both predator groups, and at all the investigated spatial scales, cross‐scale interactive effects between garden habitat heterogeneity and habitat amount in the urban landscape were the main drivers of predation. Risk of predation by birds was highest in heterogeneous garden habitats, but only in densely built urban landscapes where habitat amount was low to intermediate (10‐20%) at large spatial scales (250‐500 m). It dropped independently of garden habitat heterogeneity when habitat amount became too low (<10%) at small (50‐100 m) spatial scales. In contrast, risk of predation by arthropods mostly peaked in homogenous garden habitats when habitat amount was intermediate (20%) at large spatial scales.
4. Our findings show that the ability of urban green space patches to sustain ecosystem functions in cities mainly depends on cross‐scale interactive effects with larger‐scale habitat amount. In birds, predation risk can increase when high patch‐scale habitat heterogeneity contrasts with reduced larger‐scale habitat amount, suggesting concentration effects. Yet thresholds exist under which ecosystem functioning drops independently of habitat structure.
5. Synthesis and applications: The potential of small‐scale interventions to enhance habitat heterogeneity (e.g. by planting native trees with understory shrubs) for restoring ecosystem functions such as bird predation in urban areas is dependent on wider landscape habitat structure. Urban planning should therefore adopt a multi‐scale approach to sustain and restore ecosystem functions and services; a simple but still not broadly recognized finding. Airborne laser scanning is a useful tool to infer habitat structure across a hierarchy of scales in spatially heterogeneous anthropogenic ecosystems.
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Our research involves of how Paraguayan migrants who are living in Misiones, Argentina, manage medicinal plants in home gardens, and how this practice can be related to the landscape. We examine the relationship between the richness of home garden medicinal plants and landscape variables (e.g., distance to the forest) by applying PLS analysis, which combines principal component analysis with linear regression. We surveyed 60 home gardens localized in a rural area, and we characterized the surrounding landscape with geospatial tools. Paraguayans’ home gardens are extremely diverse sites (total of 136 medicinal species), where both native (82) and introduced species (50) are managed. People who live close to the native forest or mixed use areas (e.g., farms, secondary vegetation) tend to possess less native plants in their gardens because they are available nearby. While gardeners, who live in proximity to tree crops (e.g., pine plantations), have reduced access to wild medicinal resources; therefore, their effort is concentrated on maintaining native plants. These results reflect a relationship between accessibility to medicinal plants in the landscape and the management practices in the home gardens, a neglected driver in explaining the richness and composition of the medicinal plants in home gardens so far. Thus, we contributed evidence in support of the environmental scarcity compensation hypothesis. Finally, our study supports the idea that home gardens appear to function as a springboard for plant domestication.
Electronic supplementary material
The online version of this article (10.1007/s12231-018-9417-3) contains supplementary material, which is available to authorized users.
Background: Intentional winter bird feeding in gardens is one of the most common interactions between birds and humans. Because feeding may have both desired effects (provisioning of nutritious food for under-nourished birds) and undesired effects (favouritism of competitively superior species, transmission of disease), management of supple-mentary sites should be optimized from an ecological and conservation perspective. Therefore, the main aim of this study was to experimentally test winter food preferences of birds, with underlying potential influence of habitat (rural vs. urban) on realised food preferences pattern.
Methods: We conducted an experimental analysis of food preferences of wintering birds by provided bird-feeders in urban and rural environments across Poland. Data were collected twice during winter 2013–2014 across Poland, in total with 80 experimental trials.
Results: Sunflower seeds were the most preferred food supplement both in urban and rural habitats, significantly more exploited than any other food simultaneously available in feeders (animal fat, millet seed and dry fruits of row-anberry). However, no significant differences were recorded between urban and rural habitats in use of food.
Conclusions: The degree of use of a particular type of food at bird-feeders depended on the overall use of food in a bird-feeder consumption of each of the four types of food was significantly positively correlated with that of the others, and it was positively correlated with the number of birds observed at the feeders.
Gardens are hot spots for urban biodiversity and provide habitats for many plant and animal species, both above- and below-ground. Furthermore, gardens provide a wide range of ecosystem services, including carbon (C) storage and nutrient cycling. Although the soil is the foundation of sustainable gardens providing those ecosystem services, very little is known about the consequences of garden management on soil quality. Here we present a comprehensive assessment of urban garden soil quality, including biotic and abiotic site characteristics combined with land-use history and garden management information in a multivariate evaluation. A set of 44 soil quality indicators was measured at 170 sites of 85 gardens in the city of Zurich, Switzerland, comprising contrastingly managed garden habitats along a gradient of urban density. Taken together, our results show that garden management was the driving factor that influenced soil quality and soil functions. Eco-physiological soil quality indices were useful to identify differences in disturbance and intensity of soil use, showing highest microbial [microbial biomass (Cmic)/soil organic carbon (SOC)] and lowest metabolic (qCO2) quotients in perennial grass sites compared to annual vegetable sites. Despite the intensity of soil disturbance in annual vegetable and flower beds, the highest endogeic earthworm biomass and diversity were found in those habitats. Whereas decomposition of green tea bags was higher in grass sites. Soil heavy metal contents varied considerably and could not be linked with garden management practices, but with spatial patterns of industry and traffic. We conclude that understanding soil quality in urban ecosystems needs multi-indicator frameworks to capture the complexity of soil characteristics and the influencing factors in space and time. This study contributes to a better understanding of urban gardens and enhances the development of sustainable soil management strategies aimed at long-term improvement of soil quality and related ecosystem services in cities.
Polish allotment gardeners, who cultivate publicly owned urban space, constitute the largest group of city land managers in the country. Although research on allotment gardens in Poland exists, detailed studies about the uses of cultivated plants are absent. The aims of this study are to document plant richness and diversity of allotment-garden use and to explore the (changing) purpose of such gardens. Interviews, guided walks, and plant inventories were done, conducted among 46 urban allotment gardeners in three Polish cities in 2009. We documented 257 botanical taxa; the great majority were used as ornamentals (191 taxa), followed by food (66) and medicinal plants (5). However, names of edible varieties were rarely reported. In addition, very few protected and invasive species were registered in our study. Polish urban gardeners are attached to traditional food and ornamental plants (core repertoire), but they also show a moderate interest in novel plants (peripheral fashion). We observed an important shift in urban allotment garden management in Poland. Until the collapse of Communism, in the late 1980s, they had a chiefly productive character and today they are becoming more akin to pleasure gardens.
British Culex pipiens complex [Culex pipiens sensu lato) mosquito distribution, abundance, and potential for disease transmission are intimately linked to their environment. Pond and lake dyes that block light to restrict algal photosynthesis are a relatively new product assumed to be an environmentally friendly since they are based on food dyes. Their use in urban garden ponds raises questions linked to mosquito oviposition, since coloured water can be an attractant. Culex (mostly pipiens) is commonly found in UK gardens and is a potential vector of viruses including the West Nile Virus (WNV). Any factors that significantly change the distribution and population of Cx pipiens could impact future risks of disease transmission. A gravid trap was used to catch female Cx pipiens mosquitoes for use in oviposition choice tests in laboratory and semi-field conditions. Two types of pond dye, blue and shadow (which looks slightly red), were tested for their impact on oviposition and survival of wild caught Cx pipiens. There were no significant differences in the number of egg batches laid when gravid mosquitoes were given a choice between either blue dye and clear water or shadow dye and clear water indicating that these dyes are not attractants. Larvae hatched from egg batches laid by wild-caught gravid females were used to measure survival to adulthood with or without dye, in a habitat controlled to prevent further colonisation. The experiment was run twice, once in the summer and again in the autumn, whereas the dyes had no impact on emergence in the summer, there were highly significant reductions in emergence of adults in both dye treated habitats in the autumn. Containers with or without shadow dye were placed outside to colonise naturally and were sampled weekly for larvae and pupae over a 6 month period through summer and autumn. There was a significant negative effect of shadow dye on pupal abundance in a three week period over the summer, but otherwise there was no effect. It is likely that population abundance and food was a more powerful factor for mosquito survival than the dye.
Urban agriculture is a unique form of agriculture that can provide fresh, local produce for urban residents, and may benefit biodiversity by decreasing the need to expand agriculture into natural areas as well as enhancing biodiversity in urban areas. However, although urban agriculture is also often cited as promoting biodiversity in urban areas, the extent of empirical evidence for such claims has not been studied. Here we systematically review the relationship between urban agriculture and biodiversity in the scientific literature. We strictly define urban agriculture as areas in cities that grow produce specifically for human consumption. We examined 148 papers from 2000 to 2017, of which only 24 studies fit our definition of urban agriculture, and of those, only 18 both involved urban agriculture and measured biodiversity. Of the studies that did measure biodiversity, some showed increases in diversity compared to urban vacant lots, but other showed no difference. Moreover, these studies were mostly focused on plants and invertebrates and were conducted almost exclusively in North America. In order to use the generalization that urban agriculture will have a positive influence on urban biodiversity, more studies will need to be conducted across a wider geographic range worldwide (particularly in developing countries in the tropics) and on a greater diversity of species and taxa (e.g., herpetiles, birds and small mammals). Such studies will likely increase in conservation importance as urban expansion and agricultural demands increase globally.
Many people look forward to spring flowers, only to discover that mule deer (Odocoileus hemionus) have eaten the sprouting plants and flower buds. One potential method to prevent this problem is to grow unpalatable flowering plants in gardens where deer herbivory is expected, but this requires knowledge about the relative palatability of plant species. We examined spring-flowering plants in gardens located in Cache County, Utah, USA (2010 through 2017), and recorded the proportion of leaves and flower buds browsed by mule deer. Mule deer browsing was greatest on tulips (Tulipa spp.), grape hyacinths (Muscari spp.), and crocuses (Crocus spp.) and lowest on iris (Iris spp.) and daffodils (Narcissus spp.) We hypothesized that the first plants to sprout in the spring experienced greater levels of deer herbivory because of the lack of alternate plants that deer can browse during that time of year. To test this hypothesis, we started plants in greenhouses so that they sprouted at the same time. We then placed these plants in locations throughout Cache Valley where there were deer trails and deer feces. Among these plants, tulip, liatris (Liatris spp.), and grape hyacinth were browsed heavily, suggesting that deer found these plants palatable. In contrast, crocus were rarely eaten, suggesting that deer damage on this plant results more from its early sprouting rather than its palatability. Planting unpalatable plants may be a viable approach to reducing homeowners’ angst from finding that their spring-flowering plants have been browsed. Wildlife biologists and Cooperative Extension agents should find our results useful when guiding homeowners in selecting which spring-flowering plants to grow in areas where deer herbivory can be expected. © 2018 The Wildlife Society.
Pests of urban vegetation cause substantial aesthetic, economic and biodiversity damages, by weakening
or completely destroying the plants. The recent climate changes, such as the excessive droughts alternating
with heavy rain falls, and the significant imports of ornamental plants for urban landscape, as small parks,
private gardens, and vertical walls, drastically increase the number of urban pests. These species are either
newly introduced in the area, either they enlarge their host plant spectrum or increase their aggressiveness.
We present the results of over a five-year period of monitoring of pests in the main city parks and private
ornamental gardens in Bucharest. We detected 52 species of pests of urban vegetation. Each species
locations and host plants are given. Eighteen of these species are alien to Romania: Cameraria ohridella
on Aesculus hippocastanum, Cydalima perspectalis on Buxus spp., Unaspis euonymi on Euonymus sp.,
Corythucha ciliata and Phyllonorycter platani on Platanus sp., Corythucha arcuata on Quercus sp.,
Pseudaulacaspis pentagona on Syringa vulgaris and Morus alba, Adelges piceae on Picea sp., Adelges
abietis on Abies sp., Adelges laricis on Larix sp., Macrosiphoniella sanborni on Chrysanthemum sp., Aphis
spiraephaga on Spiraea × vanhouttei, Halyomorpha halys, Nezara viridula, Hyphantria cunea, Metcalfa
pruinosa, Tetranychus urticae, and Trialeurodes vaporariorum on numerous ornamental species. Twelve
of the alien species are considered invasive. More detailed information is presented for six of the most
destructive species and a single case of interception for a mite not present in Europe.
Urbanization is a leading cause of species extinction; however, interest in urban greenspaces as sites for conservation has grown considerably in recent decades, raising questions about the ability of these habitats to support desired wildlife. Our goal was to determine how distinct forms of urban greenspace and their landscape context influenced the species composition of ground-dwelling beetle communities. We examined the taxonomic and functional composition of Carabidae and Staphylinidae in urban vacant lots, urban farms, and planted urban prairies within the City of Cleveland, Ohio. Beetles were collected using pitfall traps across 23 sites. We found that the three habitats examined varied significantly in beetle composition, with several unique species found within each type of greenspace. Carabidae abundance and richness were greater in urban prairies and urban farms relative to vacant lots. The abundance and taxonomic richness of Staphylinidae were highest within urban farms. Canonical correspondence analysis (CCA) and partial CCA revealed that both local features and landscape variables influenced beetle community assembly. Most beetle taxa were negatively associated with buildings within the surrounding 1-km landscape, whereas grass was the most important local habitat feature. Additionally, we found variation in the distribution of species traits among habitats; ecological traits such as moisture tolerance and dispersal capacity differed significantly among urban greenspaces. Most interesting from a conservation perspective was a greater abundance of brachypterous carabids found in urban prairies, which suggests that these habitats provide overwintering and breeding habitat for some beetle species. Our findings demonstrate that urban greenspaces play important roles in shaping arthropod diversity in cities, and maintaining habitats that vary in design and management is important for their conservation.
The field of evidence synthesis is growing rapidly, with a corresponding increase in the number of software tools and workflows to support the construction of systematic reviews, systematic maps, and meta‐analyses. Despite much progress, however, a number of problems remain including slow integration of new statistical or methodological approaches into user‐friendly software, low prevalence of open‐source software, and poor integration among distinct software tools. These issues hinder the utility and transparency of new methods to the research community. Here I present revtools, an R package to support article screening during evidence synthesis projects. It provides tools for the import and de‐duplication of bibliographic data, screening of articles by title or abstract, and visualization of article content using topic models. The software is entirely open‐source and combines command‐line scripting for experienced programmers with custom‐built user interfaces for casual users, with further methods to support article screening to be added over time. Revtools provides free access to novel methods in an open‐source environment, and represents a valuable step in expanding the capacity of R to support evidence synthesis projects.
The terrestrial lizard Podarcis siculus is the most abundant reptile in Italy, where is considered a ubiquitous species. This lizard is widely distributed from the islands to the Apennines, from cultivated fields to anthropized areas such as gardens and city parks. For this reason, these animals are exposed to extensive physical and chemical stresses, as well as to the possibility of coming into contact with industrial pollutants and substances used in agricultural practices. Here, we review the health status of lizard specimens inhabiting natural non-anthropized areas and fields devoted to organic farming, considering the condition of (1) liver, representing the main detoxifying organ, directly influenced by feeding, and (2) gonads, essential for reproduction and, therefore, for the survival of the species. The morphological and biomolecular condition of these organs was then compared with those obtained from lizard specimens experimentally treated with nonylphenol, a co-formulant of many insecticides and plant protection products widely used in conventional farming, known to have harmful estrogenic effects. Taken together, data demonstrate that lizards inhabiting manured soil are in good health status and show a regular morphology of liver, testis, and ovary. Animals are found to be less exposed to the toxic heavy metals cadmium and lead if compared with specimens collected in areas not devoted to agriculture, but probably more exposed to vehicular traffic. However, manure, as well as nonylphenol, exerts a xeno-estrogenic effect, particularly evident in male specimens, more sensitive to estrogenic contamination.
Residential yards comprise most land and green space across cities. Despite yards being ubiquitous, little comprehensive information exists on how vegetation varies between front and backyards. This hinders our ability to optimize greening interventions on private urban land. We devised an accurate GIS algorithm to locate and classify front and backyards within residential landscapes. By applying this method to the greater Boston area, we measured vegetation structure (i.e., canopy cover, height and volume) of front and backyards with LiDAR and multispectral imagery. We further investigated relationships between urban form, architectural style, socio-economics, and the structure of front and backyard vegetation across Boston's residential landscapes. Among the 85,732 residential parcels that were not corner lots and had cadastral and architectural data available, backyards were twice as large as front yards on average and had significantly greater canopy cover, vegetation volume and taller trees. Parcel-level characteristics, including vegetation in the corresponding front or backyard, as well as morphological characteristics of parcels, were the best predictors of vegetation structure. House architectural style was related to vegetation structure. The neighborhood socioeconomic characteristics were the least important factors in predicting yard vegetation structure. Our study highlights that urban greening in yards depends on urban form and morphology at the parcel scale, and as such, it could be enhanced through urban to provide opportunities for additional vegetation. Architectural style might represent a further filter by which residents manage vegetation in their home environment, making it possible to devise strategies to green our cities-in style.
In the face of growing urban densification, green spaces in cities, such as gardens, are increasingly important for biodiversity and ecosystem services. However, the influences of urban green space management on biodiversity and ecosystem functioning (BEF) relationships is poorly understood. We investigated the relationship between soil fauna and litter decomposition in 170 urban garden sites along a gradient of urbanisation intensity in the city of Zurich, CH. We used litter bags of 1 and 4 mm mesh size to evaluate the contribution of soil meso- and macrofauna on litter decomposition. By using multilevel structural equation models (SEM), we investigated direct and indirect environmental effects and management practices on litter decomposition and litter residue quality. We evaluated the role of taxonomic, functional and phylogenetic diversity of soil fauna species on litter decomposition, based on a sample of 120 species (81,007 individuals; 39 collembola, 18 earthworm, 16 isopod, 47 gastropod species). We found highest litter decomposition rates using 4 mm mesh size litter bags, highlighting the importance of soil macrofauna. Urban warming, a proxy for urbanisation intensity, covaried positively, whereas soil disturbances, such as intensive soil and crop management, were negatively correlated with decomposition rates. Interestingly, soil fauna species richness decreased, with the exception of gastropods, and soil fauna abundance increased with urban warming. Our data also show that plant species richness positively affected litter decomposition by increasing soil fauna species richness and microbial activity. A multivariate analysis of organic compounds in litter residues confirmed the importance of soil fauna species richness and garden management on litter decomposition processes. Overall, we showed, that also in intensively managed urban green spaces, such as gardens, biodiversity of plants and soil fauna drives key ecosystem processes. Urban planning strategies that integrate soil protecting management practices may help to maintain important ecosystem services in this heavily used urban environment.
Horticulture has long been an important source of exotic plant species that may naturalize and become invasive. To analyze the extent of exotic plant species and their possible preference in modern landscaping in Rochester, New York, USA, we inventoried 101 randomly chosen suburban (peri-urban) house gardens. On average, 72% of plants per property were not native to the Eastern United States. Of the exotic species present in gardens, 44% have naturalized in New York State. Additionally, invasive plants were often intentionally planted, such as Japanese barberry (Berberis thunbergii), which was found in nearly half of the gardens. We also sought to ascertain if garden diversity could be correlated with the age, size, or cost of properties. Although our findings were not as distinct as previous garden inventories, property size and mortgage value correlated positively with species richness. Overall, landscape trends across all property types favored exotic over native garden plants.
This study examines individual commitment to biodiversity during adulthood. We studied the interrelations between everyday experiences of nature, knowledge about biodiversity, connectedness with nature, and implementation of specific pro-biodiversity practices, through a survey covering 473 adults in Paris surroundings (France). More specifically, we showed that people involved in experiences of nature in which attentiveness to biodiversity is explicit (citizen science, nature watch association, environmental association) have more knowledge about biodiversity and conservation than both people involved in experiences of nature in which attention to biodiversity remains implicit (community garden, allotment, community-supported agriculture), and people without such kinds of experience of nature. However, we found that people experiencing nature as part of a daily routine, whatever the type of experience, were more connected to nature and more likely to implement active pro-biodiversity practices. With this interdisciplinary study that links conservation biology and conservation psychology, we help understand more precisely the levels of commitment of urban and sub-urban adults toward biodiversity conservation.
During the last years Urban Green Infrastructure (UGI) has evolved as a research focus across Europe. UGI can be understood as a multifunctional network of different urban green spaces and elements contributing to urban benefits. Urban agriculture has gained increasing research interest in this context. While a strong focus has been made on functions and benefits of small scale activities, the question is still open, whether these findings can be up-scaled and transferred to the farmland scale. Furthermore, multifunctionality of urban and peri-urban agriculture is rarely being considered in the landscape context. This research aims to address these gaps and harnesses the question if agricultural landscapes – which in many European metropolitan regions provide significant spatial potential – can contribute to UGI as multifunctional green spaces. This work considers multifunctionality qualitatively based on stakeholder opinion, using a participatory research approach. This study provides new insights in peri-urban farmland potentials for UGI development, resulting into a strategy framework. Furthermore, it reflects on the role of the stakeholder involvement for `multifunctionality planning´. It suggests that it helps to define meaningful bundles of intertwined functions that interact on different scales, helping to deal with non-linearity of multiple functions and to better manage them simultaneously.
Urban environments are being subject to increasing temperatures due to the combined effects of global climate change and urban heat. These increased temperatures, coupled with human planting preferences and green space management practices, influence how urban plants grow and survive. Urban community gardens are an increasingly popular land use, and a green space type that is influenced by unique climate-human behavior interactions. Despite ongoing rapid temperature changes in cities, it is unknown how gardeners are adapting to these changes, and to what extent changes influence planting decisions and patterns of urban plant diversity. In this study, we monitored the variation in daily air temperatures and measured plant species richness at the garden and garden plot scale in 11 community gardens in Melbourne, Australia. We surveyed >180 gardeners to better understand the relationships between temperature variation, garden plant species diversity, and gardener management practices. We found that garden scale temperature variability is driven by regional context, and temperatures are more stable in landscapes with higher impervious surface cover. Gardeners agreed that climatic/temperature changes are influencing their watering behavior, but not their plant selection. Instead plant selection is being driven by desired food production. Yet, when comparing two bioregions, temperature did have a measurable relationship with garden plant composition in the region with more temperature variation. Temperature variability negatively related to plant species richness within garden plots, providing evidence that plant survival is related to climate at this scale in such regions. Although gardeners may be able to water more in response to regional climate changes, gardeners are unlikely to be able to completely control the effects of temperature on plant survival in more variable conditions. This suggests the inner city with more stable temperatures (albeit potentially hotter for longer due to heat island) may accommodate more species diverse gardens.
The conservation of pineapple in urban backyards is an innovative strategy that aims to involve city residents. A program of this nature requires careful planning and monitoring because of the involvement of people who do not have technical knowledge. This paper reports the implementation and evaluation of 30 gardens in urban backyards in Cabaceiras do Paraguaçú, Bahia, Brazil, to establish the parameters to allow creating a model for pineapple germplasm conservation cells with the collaboration of urban residents. A questionnaire was applied in two steps to people interested in participating, from which it was possible to choose and evaluate a general profile of the participants. Thirty pineapple accessions from the Active Germplasm Bank (AGB) of the Embrapa were selected for testing in the gardens. Two production cycles were considered, during which quantitative and qualitative traits of the plants and fruits were evaluated. The data were compared with the characteristics of the same accessions in the Pineapple AGB and were analysed by mixed principal component analysis. With respect to adequate maintenance, 20 gardens were well cared for until the end of the assessments, five were reasonably well tended and five were lost, due to home remodelling or lack of care by the guardians. Despite the loss of the five gardens, no accession was totally lost, thanks to the experimental design with three plants of each accession in three different gardens. The plants preserved in the gardens did not differ from those maintained by the AGB, demonstrating the effectiveness of this conservation strategy.
Edited by T Kraaij 1. The invasion of alien plants into natural ecosystems in South Africa is a substantial conservation concern. The primary reason for the introduction of alien plants has been ornamental horticulture, and urban centres are the main sources of invasions. Small towns have high edge: area ratios which favour the launching of invasions into surrounding areas. There is, however, a shortage of information at the global and local scale on the occurrence, distribution, and status of alien plants in an urban context. 2. We surveyed all alien plants in the small town of Riebeek Kasteel in the Western Cape, South Africa, to gain insights on where to find alien plant species, and to assist with future studies and the management of alien floras in small towns. 3. We surveyed publically accessible land, recording the abundance of all alien plant species every 10 m of road. A species accumulation curve was compiled to show the rate at which new species were encountered. This approach was used to test the efficacy of different sampling strategies. 4. Two hundred and ninety eight alien plant taxa were recorded in five land-use types. Half of the alien plant species recorded were naturalised within the town, while a third were invasive in the region (the Berg River catchment). 95% of the taxa, including many invasive species, occurred in gardens or adjoining roadsides , highlighting the invasion risk posed by ornamental horticulture. The most efficient way of collecting data on alien plant distribution for this town would have been to survey roads in the town centre first, rather than urban-edge roads and industrial areas. 5. Synthesis and applications: The gardens of small towns in South Africa harbour a high diversity of alien plants, many of which are already invasive or are potentially invasive. As the alien flora differs markedly between gardens, it is difficult to extrapolate generalised rules of thumb on where to survey. This means that compiling accurate inventories of alien plants in urban areas requires substantial search effort and taxonomic expertise.
Although bees have been demonstrated to be abundant and species-rich in cities, several studies pointed out that oligolectic species are scarce in those urban landscapes. Oligolectic species are those whose females collect pollen from a few closely related plant species or from some species belonging to the same or related plant families. We studied three nest aggregations of the oligolectic bee Centris collaris (Apidae) in an urban area. Nest aggregations were found underneath building ramps at a university campus within the city of Uberlândia, southeastern Brazil. Females were observed in nesting activity from April to May 2016. The analysis of satellite images of a 2.57‑km2 area revealed that only 0.15% was suitable for nesting sites, i.e. areas of exposed soils. Seventeen plant species were identified as floral sources of C. collaris through the pollen analysis of 43 females’ scopae. The interaction analysis produced a highly specialized network (C = 0.314, H2´ = 0.744). The numbers of interactions of the plant species Senna pendula (Fabaceae), Malpighia emarginata (Malpighiaceae) and Dioclea violacea (Fabaceae) with C. collaris females were the highest, and those plants were classified as the main sources of pollen, oil, and nectar, respectively. Our results showed that in spite of the negative effects of urbanization, a small population of the oligolectic C. collaris could find places that met its biological requirements (floral resources, nesting sites) allowing for a long-term establishment in an urban area. Preservation of exposed soil areas as well as the use of native plants in urban forestry and gardening, especially those species visited by oligolectic bees, would be important measures to be adopted for bee conservation in cities.
Urban green areas, due to their high plant diversity, can be supportive as floral resources (nectar and/or pollen) to wild and managed pollinating insects. This research aims towards understanding the contribution of ornamental ground cover perennials as a food source for urban pollinators. We compare floral phenology and abundance, nectar and pollen production, and insect visitation to flowers of Geranium macrorrhizum, G. platypetalum and G. sanguineum, planted in the botanical garden of Lublin, SE Poland. The investigation revealed that the studied hardy geraniums exhibit many features valuable for pollinators, including large floral display (G. macrorrhizum and G. platypetalum), extended flowering period (G. sanguineum) and ample nectar and pollen reward (G. macrorrhizum). They can supply urban pollinators with a high quality food during spring and early summer time, i.e. the period of high food demand by many bee species. Moreover, hardy geraniums might be valuable plants for urban beekeeping as they are eagerly visited by honeybees. The investigated ground cover plants could therefore be considered in future city plantings.
Policies to move us towards livable, sustainable cities need involvement and support from urban societies. For children in particular, as future players in urban development, experiences in nature provide a basis for further interactions with nature and increase awareness of environmental issues. However, children are spending less and less time in nature, which threatens the development of environmentally aware behavior and can have negative health impacts.
Schools are critical for environmental education, and there is a long tradition of schools serving as sites of
food production and consumption, although consideration of biodiversity is often absent. We argue here for a
concept of “biodiverse edible schools” that link food production and consumption with local biodiversity. This
increases opportunities for children to better understand both urban nature and healthy food. We highlight the
role of edible wild plants as a promising vector for coupling the usually distinct fields of food and biodiversity in the daily life of students.
Using a case study from Berlin, Germany, we illustrate how stakeholders from different spheres can work
together to bring critical components of biodiverse edible schools to reality. The components of our project include (1) a school kitchen supplied with food from regional producers; (2) a garden on the school’s grounds for producing food; (3) a neighboring vacant wild site as a habitat for wild edible plants, and, most importantly, (4) collaborative activities in planning, managing, and using the garden and the wild site.
This case study demonstrates opportunities and challenges for policies aimed at strengthening the bonds between children and nature, helping them better understand food production, and improving their diet. The concept of biodiverse edible schools highlights promising functions of wild urban land as an informal component of urban green infrastructure that can jointly support cultural and provisioning ecosystem services in cities.
The contemporary renaissance of urban agriculture is crucially linking ecological and social systems in modern cityscapes. Community gardens contribute ecological (biodiversity conservation) and social (food security) benefits to urban residents and enhance landscape multifunctionality. Cities have been recently labeled "novel ecosystems" because of the multiscalar interaction of sociocultural and biophysical elements. We conceptualize community garden soils within the novel ecosystem framework, arguing that gardeners are cultivating novel agroecosystems starting from their garden beds' soil. Although urban soil characteristics are linked to land-use legacies in most urban ecosystems, we find that in our system, the California central coast, community-garden soils may live outside the influence of legacies associated with geographic location. Instead, the intensive (re)working of soils by gardeners may washout legacy signals and decadal chronological trends, leading to soil homogenization that reduces the biophysical ties to the meters of earth below. Thus, socioecological novelty can be created in multiple forms in cities.
Globally with increased urban development, understanding spatial habitat requirements of urban-dwelling wildlife is increasingly important for conservation management. Consequently, we determined the factors that influence the presence of vervet monkeys (Chlorocebus pygerythrus) in urban landscapes. Firstly, we hypothesized that troop size is influenced by seasonality, residence type, proximity to water sources and food provisioning. Secondly, we hypothesized that the resting behaviour of vervet troops is influenced by natural factors, including the presence/absence of raptor nest(s)) and man-made structures including the distance to the nearest main road. Thirdly, we hypothesized that resting by vervet monkey troops would be influenced by the seasons, the distance to the nearest main road (due to the relative openness) and the residence type. Fourthly, we hypothesized that foraging by vervet monkey troops is influenced by food provisioning and bird feeders. Finally, we hypothesized that playing by vervet monkey troops are influenced by the presence/absence of a raptor nest(s), a dog(s) and the residency type. From June 2013 through May 2014 observations were conducted on vervet monkey troops in 20 suburban gardens in the Ethekwini and Msunduzi municipalities of KwaZulu-Natal, South Africa, following a standardized group scan sample method. The observation data were analyzed to determine population-level patterns of landscape use and key suburban landscape features influencing seasonal behaviour, troop size and sex ratios of vervet monkey troops. Mean troop size (29 ± 3.4 (SE) individuals) was influenced by female and juvenile numbers and sex ratio varied across study sites. Behavioural observations (foraging, grooming, playing) were more frequent during winter in gardens with high tree density, and a preference for visitation was found in gardens closer to roads, and where food was provisioned. Probability of foraging, grooming and playing was higher in gardens with greater canopy cover, however this decreased with increasing troop size. Probability of resting decreased with increasing distance from indigenous forest patches and roads. Gardens experienced high levels of raiding. Understanding vervet monkey spatial ecology within a transformed landscape contributes to determining sustainable ways to mitigate conflict and manage their populations in suburbia.
Community-driven vertical greenery provides a previously under-appreciated resource that could be an important component of tropical urban ecology. While the corridors of buildings have been designed to facilitate the circulation of residents between spaces, this study shows that such corridors incidentally served as an informal space for community-driven vertical greenery. Across 1.86 ha of surveyed corridors, a total of 265 plant species and cultivars were present, with an average richness of 124 species per hectare. This is beneficial to urban ecology through its high species diversity, occurrence of endangered and vulnerable native species. Based on a classification of specific plant attributes referenced from literature, provision of food and medicinal resources (77.5%), and aesthetic benefits (72.3%) were the key ecosystem services provided by the species present. Community-driven vertical greenery could function as refugia for native species of conservation interest through providing an additional buffer against further losses in the wild. It also provides immediate opportunities for interactions between humans and nature. This study finds that corridors with larger areas and simpler geometries typically hold a higher abundance of plant pots. Future efforts to increase the abundance and diversity of vertical greenery, and its concomitant increase in the provision of ecosystem services, could be driven by local communities, rather than be formally planned by landscape architects, engineers and urban planners.
Fast-growing cities in tropical countries are characterized by rapid and unplanned urbanization, food crop farming and gardening in urban and peri-urban areas, and woodfuel gathering in surrounding forested areas. While urban forestry and agriculture has drawn the attention of science, decision makers, and practitioners as a valuable strategic components of the cities and of their green infrastructure, little effort has been made to understand and facilitate the introduction of high value multipurpose trees into farmlands and garden plots within or on the fringe of cities, i.e. to develop tailored agroforestry practices. To fill this gap, an ex-ante analysis of factors influencing the adoption of agroforestry systems by farmers and gardeners of urban and peri-urban areas of Kinshasa was conducted. Up to 17% of households were sampled in five communities of farmers and 3 communities of gardeners in Kinshasa for interview and farm survey. Socio-cultural factors known to influence agroforestry adoption, including household characteristics, land tenure status, farm size, current agricultural practices, labor requirement, access to external support and farmers’ perception of current environmental issues were recorded. 86.4% of interviewed households were in favor of agroforestry. Provision of shade was perceived by farmers as the main function of trees on farmlands. 73.9% of respondents had planted or retained trees on their farms or gardens. Fruit production and shading were listed as top reasons for social acceptability of agroforestry. Lack of land ownership, high investment cost and long-term nature of the investment were perceived as main constraints to agroforestry adoption by 13.6% of respondents. Sequential tree-crop systems with spatial arrangement of fruit tree along farm or garden borders were identified as preferred agroforestry. The study identified farmers' education level and farm size as important factors that positively influence farmers' decision to adopt urban and peri-urban agroforestry.
Green roofs, especially productive ones (e.g. of edible biomass), are urban ecosystems developed in response to the scarcity of arable areas in urban environments. Their installation is also perceived as a possible way to preserve biodiversity in cities. However, the effectiveness of green roofs in supporting biodiversity, especially soil biodiversity, has rarely been studied. In order to orient the ecological engineering of green roofs, it is crucial to understand the resulting biodiversity patterns. We hypothesised that a functional trait-based approach could be used to investigate different ways of colonisation. We investigated collembolan communities in both extensive and productive green roofs. Surprisingly, no difference was observed in either taxonomic or functional structures of collembolan diversity between extensive and productive green roofs. Conversely, according to the functional composition, two ways of colonisation are suggested: a passive wind dispersal − the “flying” collembolans − and a settlement through compost inputs. We conclude that stakeholders should take into account the spatial connections of green roofs with other green spaces in order to support soil biodiversity. Further studies are needed to more accurately elucidate the importance of green roof types for collembolan communities and associated ecological networks.