Sagebrush Distribution Observations

Mountain Sagebrush, Riddle Lake 5/27/09
Mountain Sagebrush, Riddle Lake 5/27/09

Read about the observations of Linda Bell and Jim Erdman on the distribution of Mountain Sagebrush in GVM and Red Feather Lakes. Jim also reviewed the recent changes in sagebrush taxomomy he first discussed in his post last fall.

From: jim To: LINDA BELL Sent: Saturday, May 16, 2009 12:15 PM

Linda,
Thanks for pointing out that outlier on the flank of the hill above the lake. I brought a sprig home, crushed the leaves in water, then zapped the mess with my black light (ultraviolet). Sure enough the water fluoresced the characteristic milky-blue color for the species, a water-soluble compound released. Although Weber & Wittmann don’t mention that feature, I recall reading about it years back when four subspecies of Big Sagebrush (Artemisia tridentata) were recognized: Basin (subsp. tridentata), tall and on deep soils; Mountain (subsp. vaseyana), lower shrubs of more rocky and shallow soils; Wyoming (subsp. wyomingensis); and X (subsp. x?) —I kid you not—from MT). The East Slope has only one common shrubby sagebrush having leaves with three short, broad lobes—tridentate. We’ve now four species of shrubby sagebrush, in the genus Seriphidium. A fifth species, S. tripartitum, “is common in the Laramie Basin of southern WY not far from the CO line, so should be expected in northern Larimer County.” Its leaves have three long, narrow lobes.

On my road trip to CA last October I’d collected sprigs of sagebrush from several locals, one where bitterbrush—common here—was a codominant. Till now I hadn’t zapped the leaves; and sure enough, the solution fluoresced milky-blue [under ultraviolet light]. At another site, lower down, I found sagebrush intermixed with greasewood in a saline environment. As I’d expected, that leaf solution didn’t fluoresce. Finally, I can discard those samples.   –Jim

—– Original Message —–
From: LINDA BELL To: Judy Corwin Sent: Wednesday, May 20, 2009 5:40 PM

Hi –I didn’t do a serious search but on my way back from RFL this afternoon I noted that mountain sagebrush seems to get going in our area right at Gate 12 and then North Rim Road. This fits with what the old-timers in RFL claim — that there is a demarcation in ecology just near the Boy Scout Road, where the air feels fresher, the grass is greener, the rattlesnakes stop, the ranches stop, and the alpine conditions of Red Feather start.

Gate 10 is quite different with all the old suspects on both sides of the main road; current predominant, then mountain mahogany, rabbit brush and a few bitterbrush.

My copy of Meet the Natives, The Amateur’s Field Guide to Rocky Mountain Wildflowers, Trees & Shrubs by Walter Pesman, has an elevation range of 4000′ to 8000′ for sagebrush; Artemisia tridentata. So that would explain a lot and why it is colonized at Riddle Lake, although that just doesn’t fit my personal observations. If anyone else can find a northern Colorado range for mountain sagebrush I’d be quite interested.

When I hike, my rule of thumb here is: sagebrush=no rattlers. And I’ve been hiking around here extensively for 15 years and so far, so good!!! Not to say in other climes and conditions that would be true….   Cheers. Linda

From: jim To: LINDA BELL Sent: Wednesday, May 20, 2009 7:31 PM

Re Mountain Sagebrush. As I waited at Gate 10 ~9:00AM, I looked around again and found none in GVM, as I expected. But, on crossing the Red Feather Lakes Road, using my binocs I was able to spot perhaps a dozen scattered shrubs well beyond the fence line. Then, after 3:00PM I decided to drive up to Red Feather Lakes, and, yes, did spot across from Gate 12 and farther up, across from the North Rim Road an outlier of sagebrush that dominated the landscape. BUT it wasn’t until I hit Parvin Lake that I could again see sagebrush where it’s the aspect dominant shrub up to RFL. Coming back via the Manhattan Road, it dominates down to the Log Cabin Road and back to CR74E.

As for rattlers and sagebrush, when living/working as plant ecologist on the Wetherill Mesa Archaeological Project, Mesa Verde NP, in the early ’60, rattlers and then-called Basin Big Sagebrush did mix. That, at ~7,500′. I serviced weather stations in Navajo Canyon where that sagebrush dominates the sandy terraces in the bottom. Far different soils than these shallow, rocky ones that support Mountain Sagebrush. I recall seeing a rattlesnake devouring a mouse beside the trail. I even helped collect rattlers up on the North Rim at 8,500′. I pulled my copy of Pesman off the shelf to find that he does not distinguish what 20 years ago were several subspecies of Big Sagebrush—Basin (Artemisia tridentata subsp. tridentata), Mountain (Artemisia tridentata subsp. vaseyana), Wyoming (Artemisia tridentata subsp wyomingensis). Weber & Wittmann in their Colorado Flora—Eastern Slope (3rd ed., 2001) now place all the woody, shrubby sagebrushes, including the three above as separate species, in the genus Seriphidium. That, based on its being “a genus in its own right, chemically and morphologically distinct from the American and Eurasian herbaceous, true Artemisia species.” I used to have a full file on sagebrush, including the proceedings from a special workshop on just sagebrush and rabbitbrush, but may have tossed it on my move from the San Luis Valley back in ’06. After sampling Big Sagebrush (for tissue analysis) all over its range in the West back in ’75, I never thought I’d be messing with it again. –Jim

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