Biological soil crust survey of the Birch Creek area, Malheur County, Oregon

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Abstract:

The Birch Creek area in southeast Oregon’s Malheur County is known for its spectacular geology as well as serving as the primary take-out for floaters on the lower section of the Owyhee Wild and Scenic River. Birch Creek is also the location of the Birch Creek Historic Ranch, whose buildings and remains offer a glimpse of the earliest Euro-American settlement in the Owyhee Canyonlands. <br>

Although the rhyolite spires and volcanic tuff of Birch Creek are much less extensive than those found to the northeast in Leslie Gulch, they are spectacular and unique nonetheless. Consolidated volcanic ash (known as Leslie Gulch Tuff) makes up the bulk of these formations. It is a rhyolite ash that erupted from the Mahogany Mountain caldera (a large volcanic depression nearby) in a series of violent explosions about 15.5 million years ago. Much of the material fell back into the volcano as a gaseous deposit of fine ash and rock fragments up to 1,000 feet thick. About 100,000 years later, volcanic eruptions from the Three Fingers caldera, located to the northeast, deposited another layer of rhyolite tuff in Birch Creek and surrounding areas. Today the tuff is beautifully displayed as steep slopes and vertical towers weathered by time. <br>

Because of the unique geology found in Birch Creek and Leslie Gulch, a number of unusual or rare plant species have evolved in these areas. Consequently, their vascular plant floras have interested botanists for many years and they have been relatively well explored. This has not been the case for the lower plants (lichens, bryophytes, liverworts), or for the fungi. Even less emphasis has been placed on these organisms when they occupy the soil, often collectively known as biological soil crusts. <br>

Biological soil crusts are a close association between soil particles and cyanobacteria, microfungi, algae, lichens, and bryophytes (mosses, liverworts) which live within or on top of the uppermost millimeters of soil (Belnap et al. 2001). They are found in all dryland regions of the world and in all vegetation types within these lands, including the arid and semi-arid regions of North America (Rosentreter et al. 2007). Also known as cryptobiotic crusts, biotic crusts, microbiotic crusts, and cryptogamic crusts, biological soil crusts are often overlooked and are thus seldom collected. Due to the small size and fragility of the specimens, they can be difficult to return to the lab intact and suitable for species determination. However, the ecological importance of these organisms in nutrient cycling, moisture storage, and soil stabilization has been well documented (Belnap et al. 2001, Hilty et al. 2004, Deines et al. 2007, Ponzetti et al. 2007, Rosentreter et al. 2007, Serpe et al. 2007), and will not be further discussed in this report. <br>

The objectives of this project were to: (1) identify which lichen and bryophyte species are present in the Birch Creek area, (2) determine differences (if any) between habitats and soil types, (3) provide reference specimens for future agency inventory and monitoring training needs, and (4) prepare a report summarizing these findings.

Notes:

Reference Code: U08DEB01IDUS <br>

Full Citation: DeBolt A. 2008. Biological soil crust survey of the Birch Creek area, Malheur County, Oregon. Prepared for the Bureau of Land Management, Oregon State Office, Portland, Oregon. 16 pp. <br>

Location: ELECTRONIC FILE - BOTANY: MULTIPLE SPECIES <br>

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