1
Distribution within R2
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A
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Previously there was only one known population, located on private land, approx. 0.1 from FS land. A new population has been found on FS land. Only one individual found in 2010, no collections were made. More surveys are needed in 2011.
Confidence in Rank High
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2
Distribution outside R2
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A
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Species is restricted to Region 2
Confidence in Rank High
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CNHP 2006
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Decker, K. 2006. Draba weberi
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Price & Rollins. A technical conservation assessment
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3
Dispersal Capability
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A
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Dispersal is possible through three possible routes: water borne, carried by browsing animals (rodents), or attached to animals by a mucilaginous seed coat (common in Brassicaceae). These dispersal methods will display different patterns of dispersal. Water borne will result in downstream dispersal, browsing animal will likely keep the dispersal within the same drainage, and the mucilaginous seed coat could result in long distance dispersal if attached to a highly mobile animal (bird), but there is no guarantee of suitable habitat in other locations.
Confidence in Rank High
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Lyon, p. Personal observation
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Decker, K. 2006. Draba weberi
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Price & Rollins. A technical conservation assessment
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Ladyman 2004a
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McNeill, R. 2010. Personal observation
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4
Abundance in R2
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A
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There are only two known populations, with approximately 30 individuals. This species is ranked G1/S1 by CNHP.
Confidence in Rank High
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CNHP database
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CNHP Rare Plant Survey for WRNF 2006
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Decker, K. 2006. Draba weberi
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Price & Rollins. A technical conservation assessment
-
McNeill, R. 2010. Personal observation
|
5
Population Trend in R2
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A
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The original survey in 1991 estimated the population as “perhaps 100 individuals”, the latest published survey in 2006 found 31 individuals.
Confidence in Rank High
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Decker, K. 2006. Draba weberi
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6
Habitat Trend in R2
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B
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The previous known occupied habitat is apparently stable, but may be subject to changes with manipulation of the water source and maintenance of the roads and dam. The new population is near a popular recreation trail.
Confidence in Rank High
| -
CNHP database
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CNHP Rare Plant Survey for WRNF 2006
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Decker, K. 2006. Draba weberi
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Price & Rollins. A technical conservation assessment
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McNeill, R. 2010. Personal observation
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7
Habitat Vulnerability or Modification
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A
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The previously known habitat has been substantially modified the dam upstream. It is unknown if the species was more widespread before the modification. The new population is near the McCullough Gulch trail (see attached map). Threats include habitat alterations from dam and road maintenance, exotic species, recreation and mining.
Confidence in Rank High
| -
CNHP Rare Plant Survey for WRNF 2006
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Decker, K. 2006. Draba weberi
-
Price & Rollins. A technical conservation assessment
-
McNeill, R. 2010. Personal observation
|
8
Life History and Demographics
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A
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This species is believed to be apomictic, not requiring pollination. Successful reproduction is probably limited by scarcity of suitable sites for seed germination.
Confidence in Rank High
| -
CNHP 2006
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Decker, K. 2006. Draba weberi
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Price & Rollins. A technical conservation assessment
|
Evaluator(s):
Rick McNeill, EZ Botanist, WRNF
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Date:
Oct. 26, 2010
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