Environmental factors affecting bee diversity in urban and remote grassland plots in Boulder, Colorado

By C. Kearns, D. Oliveras. Journal of Insect Conservation, 2009

139 citations recorded by the source corpus.

Insects provide essential ecological services in both the natural environment and in human-dominated habitats. Because pollinator declines associated with land use change have been reported across the globe, there is great concern that pollinators and the ecosystem services they provide will be negatively affected. This study examines the diversity and abundance of bee pollinators in grasslands in Boulder County, Colorado, USA. Over five years, 5,200 bees were collected in grassland plots with different levels of urbanization. Most of the difference in species composition among three levels of urbanization was due to rare species that may not have been discovered in all plots. Neither the number of species nor their abundance differed significantly among the plot types, although the trend indicated increasing diversity with increasing distance from urbanization. Most notably, measures of urbanization, such as the amount of pavement and development, were not correlated with diversity. The most important factor affecting bee abundance, particularly for ground-nesting bees, was grazing regime. Bee abundance also was positively related to the number of flowering plant species. Other studies of different insects (grasshoppers and butterflies) in these plots showed results similar to ours. In contrast, previous studies on song-birds, raptors, and rodents showed significant differences between urban edge and remote plots in terms of organism abundance and diversity. Together, these results suggest that factors other than the degree of urbanization are important in determining insect abundance and diversity.

Subfields: Ecology, Evolution, Behavior and Systematics, Genetics, Insect Science

View Paper: https://www.semanticscholar.org/paper/d61cd82fc1b5b5a2ac4c8a4aa7ce03b849c5f2b5

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Citations in the corpus

Wild bee abundance declines with urban warming, regardless of floral density (2018, background): “2014); some have found that urbanization favors social bees over solitary bees (Kearns and Oliveras 2009; Banaszak-Cibicka and Żmihorski 2012) whereas others have not (Carper et al.”
Effects of grazing intensity on pollinator abundance and diversity, and on pollination services (2016, background): “…of pollinating insects, however, have mostly found linear relationships (e.g. Vulliamy et al., 2006; Xie et al., 2008; Kimoto et al., 2012; but see Kearns & Olivera, 2009) with contrasting effects (i.e. positive or negative) and strengths (i.e. steepness of the relationship), depending on the…”
Novel urban ecosystems, biodiversity, and conservation. (2011, background): “Generally, less mobile species seem to be sensitive to fragmentation, which usually increases towards urban centers, while mobile species such as birds or bees are more affected by habitat features (e.g., Marzluff, 2001; Angold et al., 2006; Croci et al., 2008; Kearns and Oliveras, 2009).”
The role of resources and risks in regulating wild bee populations. (2011, background): “Generally, increased grazing intensity negatively affects bee populations (53, 64, 136).”
The effect of repeated, lethal sampling on wild bee abundance and diversity (2015, background): “Thus, a large number of bees can be collected each time the protocol is used, and bees are typically sampled repeatedly in the same site over the course of a season and sometimes for multiple years (e.g. Wilson, Griswold & Messinger 2008; Kearns & Oliveras 2009; Jha & Vandermeer 2010).”
Short-term responses of native bees to livestock and implications for managing ecosystem services in grasslands (2012, background): “In contrast to our results, Kearns and Oliveras (2009) found some support for the intermediate disturbance hypothesis in grasslands of Colorado, where bee diversity was positively correlated with flowering richness, and flowering richness was highest in plots with intermediate grazing disturbance.”