Friday, June 04, 2010

Impressions of last night's Sierra Foothills Audbon Soc. talk

Last night's Audubon Society talk was generously provided by Morgan Tingley of U.C. Berkeley, on his doctoral research on changes in avian ranges along Sierra transects since Joseph Grinnell first surveyed them a hundred years ago.

Tingley's work was part of the Grinnell Resurvey Project - and egads, what vision Grinnell had, saying:
“This value [of the Museum collections and other data they collected] will not, however, be realized until the lapse of many years, possibly a century... And this [value] is that the student of the future will have access to the original record of faunal conditions in California and the West, wherever we now work.”

The talk was good, Tingley knew his material, although - since it was about his research - it wasn't a "what seems to be in store and what we should do" talk, which - even from some audience commentary last night - seems to be what we in Nevada County most need to grasp, and is something we really, really aren't getting, from the local science folk.

Findings in a nutshell (filtered through my cranium) -
Compared to Grinnell's early-1900s surveys, Tingley's "maximum elevation" end of bird species ranges, like the ranges of Sierra mammals, has shifted upward for significantly more species than downward - which is also consistent with shifts in phenology (seasonality/timing) and in birds' latitude(northward)-range data. But he encountered lot of other variability in the results, it was by no means "ok everybody, take 10 steps uphill", so in no single instance can you attribute it to climate change. It's a pattern.

As for the talk we haven't been getting - calling Climate Central....


chip said...

-- it was by no means "ok everybody, take 10 steps uphill", so in no single instance can you attribute it to climate change. It's a pattern. --

Interesting comment. So in direct words what is your interpretation of his findings of changing bird patterns related to climate changes?

Anna Haynes said...

Hi Chip.
In a nutshell, I understood the results to be that overall, the range shifts are in an upward direction, but that that's the average, & there's still a lot of variability.

My own feeling - and someone brought this up, at the meeting - is that shifts in bird ranges can only give us very noisy (i.e. variable) information, since a year or two of abnormal weather - or possibly even a single season of such - will send the birds flying, as it were. And my recollection was that the Grinell Resurvey effort was a two-or-three-year thing, following on the heels of measurements taken a century ago - so it'd be vulnerable to whatever the weather happened to be like that year.
It'd be smart to run this by Tingley though, since I haven't done so (& I could have misunderstood).