Receptiveness of Foraging Wild Bees to Exotic Landscape Elements

Hinners, Sarah J.; Hjelmroos-Koski, Mervi

doi:10.1674/0003-0031-162.2.253

Cited by 22 publications

(22 citation statements)

References 34 publications

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“…Our findings also highlight that a diversity of plant species can contribute to bee conservation in cities. Red and white clover (T. pretense and T. repens) were the most attract plants within vacant lots, demonstrating the role that weedy exotic plants can play in supporting an urban bee species pool [30,32,66] in self-assembled, minimally-managed greenspaces. In urban farms, the most frequently visited plants per observation period included both harvestable crops and ornamental flowers.…”

Section: Discussionmentioning

confidence: 99%

“…Within a city, urban greenspaces offer a varied breadth and quality of dietary resources [12,[26][27][28][29]. Exotic plant species can make up a substantial portion of the floral resources found in urban areas [30]. Although some exotic species common within vacant lots have been found to be highly attractive [31,32], these resources may also be most suitable for polylectic [33] and/or exotic bees [31].…”

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confidence: 99%

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Unique Bee Communities within Vacant Lots and Urban Farms Result from Variation in Surrounding Urbanization Intensity

2018

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We investigated the relative importance of vacant lot and urban farm habitat features and their surrounding landscape context on bee community richness, abundance, composition, and resource use patterns. Three years of pan trap collections from 16 sites yielded a rich assemblage of bees from vacant lots and urban farms, with 98 species documented. We collected a greater bee abundance from vacant lots, and the two forms of greenspace supported significantly different bee communities. Plant-pollinator networks constructed from floral visitation observations revealed that, while the average number of bees utilizing available resources, niche breadth, and niche overlap were similar, the composition of floral resources and common foragers varied by habitat type. Finally, we found that the proportion of impervious surface and number of greenspace patches in the surrounding landscape strongly influenced bee assemblages. At a local scale (100 m radius), patch isolation appeared to limit colonization of vacant lots and urban farms. However, at a larger landscape scale (1000 m radius), increasing urbanization resulted in a greater concentration of bees utilizing vacant lots and urban farms, illustrating that maintaining greenspaces provides important habitat, even within highly developed landscapes.to urban gradients [16,17]. At the same time, landscape features at the city-wide scale can act as strong environmental filters, influencing if taxa from a given species pool are able to colonize distinct greenspace patches [12]. For instance, isolation from other greenspaces can lead to reduced bee species richness within urban forest fragments [18] and connectivity with other greenspaces positively predicts bee abundance on green roofs [19]. In some cases, landscape variables also influence the functional trait distribution found within groups [17,20]. For instance, highly fragmented urban landscapes tend to favor smaller species and cavity nesting species [21,22].At a local scale, species interactions among bees and floral resources can drive patterns of pollinator community assembly [12]. Increasing bee species richness is often linked to floral species richness [23], which frequently increases with the degree of urbanization [4,24,25]. Within a city, urban greenspaces offer a varied breadth and quality of dietary resources [12,[26][27][28][29]. Exotic plant species can make up a substantial portion of the floral resources found in urban areas [30]. Although some exotic species common within vacant lots have been found to be highly attractive [31,32], these resources may also be most suitable for polylectic [33] and/or exotic bees [31]. Urban agroecosystems are likely to have a wider breadth of floral resources, including food crops, native and exotic ornamentals, and many of the same weedy species found in vacant lots. Adding flowering resources, principally native species aimed at supporting pollinators and other beneficial insects, increases available nectar and pollen resources [34] and results in a greater richness and ...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Unique Bee Communities within Vacant Lots and Urban Farms Result from Variation in Surrounding Urbanization Intensity

2018

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“…In a similar finding, Winfree et al (2006) found greater bee abundance and diversity in forested heath surrounded by agriculture and urbanization than in the same habitat type surrounded by more native habitat. Other research in the Denver grassland system has shown that bees caught in suburban habitat fragments carried a minimum of 1.5-7.5% of matrixderived pollen, depending on the season (Hinners and Hjelmroos-Koski 2009).…”

Section: Bee Abundance and Species Richnessmentioning

confidence: 97%

Roles of scale, matrix, and native habitat in supporting a diverse suburban pollinator assemblage

Hinners

Kearns

Wessman

2012

Ecological Applications

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Wild pollinators provide important services to both wild and human-dominated ecosystems, yet this group may be threatened by widespread anthropogenic landscape change. Suburban sprawl is one of the fastest growing types of land use change in North America, and it has certain characteristics, such as abundant floral resources, that may be beneficial for many pollinators. We examined the effects of sprawl on the wild bee assemblage of the shortgrass steppe on the Front Range of Colorado, USA. Diversity, abundance, and community composition of bees in remnant grassland fragments surrounded by suburban residential land use were compared with those in extensive, continuous grassland. No overall effect of suburbanization on bee abundance was observed, and abundance was extremely variable even within study sites. Bee species richness was positively but nonlinearly related to grassland habitat area. Bee species density was higher and more variable in suburban sites. Suburban sites and smaller habitat area were both related to relative increases in the proportions of small bee species, social bees, and solitary cavity-nesting bees in the assemblage; small suburban habitat areas also favored species of the family Halictidae over Apidae, and individuals of the genus Halictus over those of the genus Lasioglossum. In this landscape, large native habitat areas surrounded by suburban sprawl may actually increase species richness and species density over that of continuous grassland, probably by means of habitat complementation or supplementation between grassland remnants and the surrounding suburban matrix. However, at habitat areas < 20 ha, species richness became quite variable; sites < 8 ha contained less than half the species of controls.

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“…Sampling floral resource availability is entirely missing in many pollinator studies, often only species lists, i.e. presence-absence data are recorded as an estimate , or resource availability is concluded from indirect proxies such as consumption rates (Bąkowski & Boroń 2005;Hinners & Hjelmroos-Koski 2009;Aronne et al 2012). Further studies estimate the amount of floral resource, and the count variables can be the abundances of flowers as a proxy (Goulson & Darvill 2004;Kovács-Hostyánszki et al 2013) or even nectar and pollen amounts (Potts et al 2004;Hicks et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Comparing two methods for estimating floral resource availability for insect pollinators in semi-natural habitats

Szigeti

Kőrösi

Harnos

et al. 2016

Annales de la Société entomologique de France (N.S.)

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Pollinator and flowering plant interactions play a critical role in maintaining most terrestrial ecosystems, including agroecosystems. Although estimates of floral resource availability are essential to understand plant-pollinator relationships, no generally accepted methodology exists to date. We compared two methods for sampling floral resources in a single meadow.About every three days, we recorded species lists of insect-pollinated plants with abundance categories assigned to each species (hereafter referred to as scanning) and we counted the flowering shoots in 36 2×2 m quadrats (hereafter quadrat sampling). These methods were compared with respect to (i) the number of species detected, (ii) estimated floral resource abundance, and (iii) temporal changes in flowering. With scanning, we found more potential nectar-plant species and species were found earlier than with quadrat sampling. With the latter, abundant species were found with higher probability than the scarce. Flower abundances were correlated between the two methods. We predicted that a cover of 6.3±3.6%should be used for an appropriate estimate of flower abundance in our study site, although the optimal cover probably varies across different habitats. Furthermore, flower abundance changed 6% per day compared to the flowering peak. Overall, scanning seems to be more appropriate for detecting presence and the timing of species, while quadrats may provide higher resolution for abundance estimates. Increased sampling coverage and frequency may enhance research accuracy and using scanning and quadrat sampling simultaneously may help to optimize research effort. We encourage further development of sampling protocols. Résumé

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Receptiveness of Foraging Wild Bees to Exotic Landscape Elements

Cited by 22 publications

References 34 publications

Unique Bee Communities within Vacant Lots and Urban Farms Result from Variation in Surrounding Urbanization Intensity

Unique Bee Communities within Vacant Lots and Urban Farms Result from Variation in Surrounding Urbanization Intensity

Roles of scale, matrix, and native habitat in supporting a diverse suburban pollinator assemblage

Comparing two methods for estimating floral resource availability for insect pollinators in semi-natural habitats

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