Draba paucifructa

Clokey & C.L. Hitchc.

Charleston Draba

G1Critically Imperiled (G1G2) Found in 1 roadless area NatureServe Explorer →
G1Critically ImperiledGlobal Rank
High - mediumThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.141968
Element CodePDBRA111V0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderCapparales
FamilyBrassicaceae
GenusDraba
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Taxonomic Comments
D. paucifructa combines traits associated with different lineages in Draba; like D. crassifolia, it appears to be morphologically intermediate between members of the white-flowered euploid clade (D. lonchocarpa and allies) and yellow-flowered D. albertina (Windham 2003). It has the same chromosome number as D. crassifolia (n = 20), but Windham (2003) believes that the morphological data favor an independent origin of D. paucifructa through hybridization between D. lonchocarpa and D. albertina, rather than D. paucifructa being an isolated, southern derivative of D. crassifolia.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2021-11-19
Change Date1990-09-05
Edition Date2021-11-19
Edition AuthorsKnight, Teri (1988), rev. K. Gravuer (2009), rev. C. Nordman (2021).
Threat ImpactHigh - medium
Range Extent<100 square km (less than about 40 square miles)
Number of Occurrences6 - 20
Rank Reasons
Narrowly endemic to higher elevations in the Spring Mountains of Clark County, Nevada, where restricted to just a few areas of the core mountains (Lee Canyon, Mummy Mountain, Charleston Peak, upper Kyle Canyon). Approximately 25 sites, which might be aggregated into approximately 9 occurrences, are believed extant. Plants are apparently sparse to occasional at many of the occupied sites. All occurrences are within the Spring Mountains National Recreation Area of the Toiyabe National Forest, and the majority are within the Mount Charleston Wilderness Area portion of the NRA. A Conservation Agreement signed in 1998 promotes cooperation among agencies to implement conservation measures in the NRA, such as routing recreational development away from sensitive areas. Threats include spring diversions, recreational activities, and competition from exotic species.
Range Extent Comments
Draba paucifructa occurs in the western United States. It is endemic to the Spring Mountains in southern Nevada's Clark County. It occurs at Charleston Peak and ridgeline, upper Kyle and Lee Canyons, and Rainbow Falls. The range extent is about 30 square kilometers (NatureServe 2021, SEINet 2021).
Occurrences Comments
Approximately 25 documented occurrences are believed extant, with an additional five considered historical. However, many of these are close to each other, and might not be distinct occurrences. The total could be closer to nine extant occurrences if the closely adjacent sites are considered the same occurrence. Systematic surveys for this species have been conducted and are largely complete (Morefield 2001), so it is unlikely that large numbers of occurrences remain to be discovered.
Threat Impact Comments
Draba paucifructa is threatened by current and past modifications of its spring habitat, such as flow reductions due to piped diversions. It is also impacted by recreational activities such as use of its spring habitat by hikers; recreational pressure may increase in the future as southern Nevada's human population increases. Competition from exotic plants such as dandelion (Taraxacum officinale) has also been noted at some sites; in addition, some sites have been used by wild horses. In the Spring Mountains National Recreation Area generally, fire suppression has been noted as a threat to the ecological integrity of the high elevation forest/woodland zone in which this species in found. Localized infrastructure development and exploration/development of mining claims are also potential threats within the NRA (USFS, NV-DCNR, & USFWS 1998).
Ecology & Habitat

Description

A low perennial with one to several crowns of leaves, with each crown giving rise to one to four hairless stems. The leaves are mostly in basal rosettes, obovate (egg-shaped with the narrower end basal) or slightly narrower, with toothless or faintly toothed edges, 3-15 mm long and densely hairy with star-shaped hairs. The elongate inflorescence bears relatively few flowers (3-12), on individual flower stalks 1-5 mm long. the hairy sepals are 1.5 mm long and the while petals are almost spatula-shaped and about 2.5 mm long. Characteristically the petals are light yellow as the flower begins to open, but this color is soon lost (fades to white). The capsules are linear/lance-shaped to slightly broader and 5-11 mm long with a very short style at the tip (0.1-0.3 mm) (adapted from Mozingo and Williams 1980).

Diagnostic Characteristics

Differs from D. stenoloba in its glabrous (vs. strigose) stems, its pale yellow turning to white (vs. yellow) flowers, its perennial (vs. annual, biennial, or short-lived perennial) lifespan, and its short 0.1-0.2 mm long styles (vs. lack of styles) (Mozingo and Williams 1980, Kartesz 1988, Weixelman and Atwood 1990). Differs from D. crassifolia by its densely pubescent (vs. glabrous to sparsely hairy) leaves, its flowers turning from pale yellow to white soon after opening (vs. flowers yellow when fully open, turning white only upon fading), and its short 0.1-0.2 mm long styles (vs. lack of styles) (Mozingo and Williams 1980, Kartesz 1988, Weixelman and Atwood 1990). Differs from D. jaegeri by its flowers pale yellow when opening (vs. white), its short styles less than 2 mm long (vs. greater than 2 mm long), and its moist (vs. dry and rocky) habitat.

Habitat

Draba paucifructa occurs in moist to wet, often sheltered soils on drainage banks, stream edges, rock ledges, near seeps and springs, in avalanche chutes, and near late-lying snowdrifts. It seems to prefer wetland margin areas. Soils range from silty clay loam to cobbles/gravels; underlying substrate is typically limestone. In the high mountains, it is usually found in openings in subalpine conifer forest/woodland communities dominated by bristlecone pine (Pinus longaeva) and/or limber pine (Pinus flexilis), sometimes with Abies concolor (white fir) or Populus tremuloides (aspen); occasionally found in the alpine. Co-occurring species include Dodecatheon redolens, Ribes montigenum, Heuchera rubescens, Aquilegia formosa, Bromus marginatus, Castilleja martinii var. clokeyi, Anemone multifida, Aquiligea formosa, Boykinia jamesii, Cystopteris fragilis, Erigeron clokeyi, Rosa woodsii, Trisetum spicatum, Valeriana acutiloba, Antennaria rosea, Artemisia ludoviciana, Botrychium crenulatum, Epilobium angustifolium, Eriogonum umbellatum, Festuca brachyphylla, Juniperus communis, Oxytropis oreophila, Valeriana puberulenta, Haplopappus sp., Jamesia sp., and mosses; as well as other rare plants including Synthyris ranunculina, Cirsium clokeyi, Antennaria soliceps, Penstemon leiophyllus var. keckii, Potentilla beanii, Draba jaegeri, Angelica scabrida, Pedicularis semibarbata var. charlestonensis, Lesquerella hitchcockii, and Sphaeromeria compacta. It occurs at elevations of 2500-3470 m.
Terrestrial Habitats
Forest/WoodlandForest - ConiferWoodland - ConiferAlpineBare rock/talus/scree
Palustrine Habitats
HERBACEOUS WETLANDRiparian
Other Nations (1)
United StatesN1
ProvinceRankNative
NevadaS1Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentSmall (1-10%)Serious - moderateHigh (continuing)
1.3 - Tourism & recreation areasSmall (1-10%)Serious - moderateHigh (continuing)
6 - Human intrusions & disturbanceSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
6.1 - Recreational activitiesSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
7 - Natural system modificationsLarge - restrictedModerate or 11-30% pop. declineHigh (continuing)
7.1 - Fire & fire suppressionRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
7.2 - Dams & water management/useSmall (1-10%)Moderate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)

Plant Characteristics
DurationPERENNIAL
Economic Value (Genus)No
Roadless Areas (1)
Nevada (1)
AreaForestAcres
Charleston - CarpenterHumboldt-Toiyabe National Forest17,828
References (9)
  1. Flora of North America Editorial Committee (FNA). 2010. Flora of North America north of Mexico. Vol. 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press, New York. xxii + 797 pp.
  2. Kartesz, J.T. 1988. A flora of Nevada. Ph.D. dissertation. Univ. of Nevada, Reno. 3 volumes. 1729 pp.
  3. Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
  4. Morefield, J.D., editor. 2001. Nevada rare plant atlas [with rare plant fact sheets]. Available as a pdf file at: http://heritage.nv.gov/atlas/atlas.html. Compiled by the Nevada Natural Heritage Program, Carson City, for the U.S. Fish and Wildlife Service, Reno, Nevada.
  5. Mozingo, H.N., and M. Williams. 1980. The threatened and endangered plants of Nevada. U.S. Fish and Wildlife Service and Bureau of Land Management, Portland, OR. 268 pp.
  6. Rollins, R.C. 1993a. The Cruciferae of continental North America: Systematics of the mustard family from the Arctic to Panama. Stanford Univ. Press, Stanford, California. 976 pp.
  7. U.S. Forest Service Intermountain Region, State of Nevada Department of Conservation and Natural Resources, and U.S. Fish and Wildlife Service Pacific Region (USFS, NV-DCNR and USFWS). 1998. Conservation Agreement for the Spring Mountains National Recreation Area, Clark and Nye Counties, Nevada. April 13, 1998. [http://ecos.fws.gov/docs/plan_documents/tcca/tcca_450.pdf]
  8. Weixelman, D., and D. Atwood. 1990. Toiyabe National Forest sensitive plants field guide. U.S. Forest Service, Intermountain Region, Ogden, UT. 123 pp.
  9. Windham, M. D. 2003 [2004]. Chromosome counts and taxonomic notes on <i>Draba </i>(Brassicaceae) of the Intermountain West. 2: Idaho, Nevada, and vicinity. Madrono 50(4): 221-231.