[Pollinator] Two new bee papers

[David Inouye]

Kearns, C. A. and D. M. Oliveras. 2009. Boulder County bees 
revisited:  A resampling of Boulder Colorado bees a century later. 
Journal of Insect Conservation. DOI 10.1007/s10841-009-9211-8

Historic species lists for a region can be of great interest to 
biologists surveying modern faunas. In 2001, we initiated a 5-year 
field study to examine the status of insect pollinators in Boulder 
County grasslands, Boulder, Colorado. Century-old records of the bee 
fauna were available from bee specialist Cockerell's publication 
(University of Colorado Studies, Boulder, 1907) The Bees of Boulder 
County. We predicted that 116 species originally found by Cockerell 
would occur in grassland habitats. We recorded 110 species, including 
several species not present in the 1907 collection. We conclude that 
the bees of the grasslands of Boulder County have been largely 
conserved, and we hypothesize that the large amount of preserved 
habitat in the county has contributed to maintaining the insects.


Kearns, C. A. and D. M. Oliveras. 2009. Environmental factors 
affecting bee diversity in urban and remote grassland plots in 
Boulder, Colorado. Journal of Insect Conservation. DOI 
10.1007/s10841-009-9215-4

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.