It is curious that your graphs go to 1920 and no further back, despite the availability of data. Looking solely at the summer temperatures it appears that 1922 and 23 have a considerable impact on the trend. Alas I've not been able to duplicate the sort of figures you're produced but messing around on the site seems to indicate a very, very different trend if you include 1895 through to 1993.
Also, if you skim through the Beever et al. 2003 paper, you'll find that pika are purportedly quite sensitive to what you seem to view as small temperature changes, and that it is maximums not averages that seem to be primary factors. Ned Dochtermann Quoting Paul Cherubini <[EMAIL PROTECTED]>: > Lucas Moyer-Horner wrote: > > > Anita, Below are two excellent case studies that are near > > and dear to my heart. As far as i know, this is the first > > evidence of a small-medium sized mammal being extirpated > > by rising temperatures. > > > Beever, E.A., Brussard, P.F. and Berger, J. 2003. Patterns of > > apparent extirpation among isolated populations of pikas > > (Ochotona princeps) in the Great Basin. Journal of Mammalogy > > 84(1):37-54 > > > Grayson, D.K. 2005. A brief history of Great Basin Pikas. > > Journal of biogeography 32:2103-2111. > > Lucas, according to this article: > http://www.hcn.org/servlets/hcn.Article?article_id=15849 > > "In the early 1990s, E.A Beever revisited 25 Great Basin pika > populations recorded by Eugene Raymond Hall and others > about half a century earlier and found six of the 25 populations > had completely disappeared." > > The 25 pika populations that were monitored were located > primarily within Nevada: > http://i85.photobucket.com/albums/k75/4af/pikaa.jpg > > Now lets look at how much temperatures rose in Nevada > between 1920 and 1993 using National Climate Center Data > http://www.ncdc.noaa.gov/oa/climate/research/cag3/cag3.html > > Here is the winter (Dec-Feb) temperature graph for Nevada > the period 1920-1993: > http://i85.photobucket.com/albums/k75/4af/pikab.jpg > A very slight warming trend is apparent > > Here is the summer (June-August) temperature graph for > Nevada for the period 1920-1993: > http://i85.photobucket.com/albums/k75/4af/pikad.jpg > A slight cooling trend is apparent. > > Here is the overall annual temperature graph for > Nevada for the period 1920-1993: > http://i85.photobucket.com/albums/k75/4af/pikac.jpg > A very slight cooling trend is apparent. > > Lucas, I am now wondering why you and other scientists > think the Great Basin pika "is the first evidence of a > small-medium sized mammal being extirpated by rising > temperatures". > > Paul Cherubini > El Dorado, Calif. >
