by Carl Strang
Global climate change, like evolution, is a matter of debate among politicians, but not among scientists. At this point it’s a routine matter of measurement and documentation. One example from last year was a study published in Science (Chen, I-Ching, et al. 2011. Rapid range shifts of species associated with high levels of climate warming. Science 333:1024-1026).
They reviewed a variety of terrestrial organisms, including invertebrates, vertebrates and plants, and found that species distributions “have recently shifted to higher elevations at a median rate of 11.0 meters per decade, and to higher latitudes at a median rate of 16.9 kilometers per decade…The distances moved by species are greatest in studies showing the highest levels of warming,…However, individual species vary greatly in their rates of change.” While their data show most species shifting poleward, a few shifted in the opposite direction.
The round-tipped conehead is one of several singing insect species I have been finding with significant northward range shifts in the past 70 years.
The Chen et al. paper will allow me to compare their measurements with rates of expansion I can estimate from the literature and my observations of at least 4 species of crickets, katydids and cicadas. I’m pretty sure the movements of these species will prove to be consistent with their findings.
