Keeping Up with the Plants: Bee Pollinators Strive for Seasonal Synchrony
Bartomeus, I., Ascher, J.S., Wagner, D, Danforth, B.N., Colla, S., Kornbluth, S. and Winfree, R. 2011. Climate-associated phenological advances in bee pollinators and bee-pollinated plants. Proceedings of the National Academy of Sciences, USA 108: 20,645-20,649.
Against this backdrop, Bartomeus et al. explored this situation with real-world data, as opposed to suppositions, by presenting "an analysis of climate-associated shifts in the phenology of wild bees, the most important pollinators worldwide, and [comparing] these shifts to published studies of bee-pollinated plants over the same time period." More specifically, they say they "used long-term data to compare phenological shifts for 10 bee species to shifts in 106 native plant species that are visited by these same bee species," which typically "have annual cycles that include an obligatory larval or adult diapause before spring emergence." The plant data for this comparison were provided by Primack et al. (2004) and Miller-Rushing et al. (2006) for Massachusetts (AD 1885-2003), by Bradley et al. (1999) for Wisconsin (1936-1999), by Cook et al. (2008) for New York (1931-2008), and by Abu-Asab et al. (2001) for Washington, DC (1970-1999, which time interval brackets the period of greatest temperature increase), while the bee data were developed by Bartomeus et al.
The results of the analysis indicated that "over the past 130 years, the phenology of 10 bee species from northeastern North America has advanced by a mean of 10.4 ± 1.3 days," noting that "most of this advance has taken place since 1970, paralleling global temperature increases." And they indicate that "when the best available data are used to estimate analogous rates of advance for plants, these rates are not distinguishable from those of the bees."
Bartomeus et al. conclude that among the generalist bee species they studied, "bee emergence is keeping pace with shifts in host-plant flowering," and this finding suggests that historical global warming - which climate alarmists contend has been unprecedented over the past millennium or two - has not detrimentally interfered with the long-standing mutualistic relationship that exists between the concomitant emergence of adult wild bees and the flowering of the plants they visit.
Abu-Asab, M.S., Peterson, P.M., Shetler, S.G. and Orli, S.S. 2001. Earlier plant flowering in spring as a response to global warming in the Washington, DC, area. Biodiversity and Conservation 10: 597-612.
Bradley, N.L., Leopold, A.C., Ross, J. and Huffaker, W. 1999. Phenological changes reflect climate change in Wisconsin. Proceedings of the National Academy of Sciences, USA 96: 9701-9704.
Cook, B.I., Cook, E.R., Huth, P.C., Thompson, J.E. and Smiley, D. 2008. A cross-taxa phenological dataset from Mohonk Lake, NY and its relationship to climate. International Journal of Climatology 28: 1369-1383.
Miller-Rushing, A.J., Primack, R.B., Primack, D. and Mukunda, S. 2006. Photographs and herbarium specimens as tools to document phenological changes in response to global warming. American Journal of Botany 93: 1667-1674.
Primack, D., Imbres, C., Primack, R.B., Miller-Rushing, A.J. and Del Tredici, P. 2004. Herbarium specimens demonstrate earlier flowering times in response to warming in Boston. American Journal of Botany 91: 1260-1264.