|
|
FEIS Home Page |
SPECIES: Descurainia pinnata
Choose from the following categories of information.
 |
|
| photo by Michael L. Charters |
AUTHORSHIP AND CITATION:
Howard, Janet L. 2003. Descurainia pinnata.
In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station,
Fire Sciences Laboratory (Producer). Available:
https://www.fs.usda.gov/database/feis/plants/forb/despin/all.html [
].
Revisions: On 19 April 2018, the common name of this species was changed in FEIS
from:
pinnate tansymustard to: western tansymustard.
FEIS ABBREVIATION:
DESPIN
SYNONYMS:
Descurainia pinnata var. brachycarpa (Richards.) Fern.
D. p. var. filipes (Gray) Peck.
D. p. var. glabra (Wooton & Standl.) Detl.
D. p. var. halictorum (Cockerell) Peck.
D. p. var. intermedia (Rydb.) Peck.
D. p. var. nelsonii (Rydb.) Peck. [49,162,172,175]
D. p. var. osmiarum (Cockerell) Shinners [175]
D. p. var. pinnata [49]
D. p. var. paysonii Detl. [175]
NRCS PLANT CODE: [166]:
DEPI
DEPIB
DEPIF
DEPIG
DEPIH
DEPII
DEPIM
DEPIN
DEPIO2
DEPIP2
DEPIP3
COMMON NAMES:
western tansymustard
green tansymustard
pinnate tansymustard
Menzies' tansymustard
Nelson's tansymustard
Payson's tansymustard
TAXONOMY:
The scientific name of western tansymustard is Descurainia pinnata (Walt.) Britt.
(Brassicaceae) [27,49,56,75,89,110,119,150,184]. Currently recognized infrataxa are:
D. p. subsp. brachycarpa (Richards.) Detl. [27,56,89,110,119], western tansymustard
D. p. subsp. filipes (Gray) Detl. [89], western tansymustard
D. p. subsp. glabra (Wooton & Standl.) Detl. [75,89,91,110], western tansymustard
D. p. subsp. halictorum (Cockerell) Detl. [27,56,75,89,91]
D. p. subsp. intermedia (Rydb.) Detl. [56,75,89], western tansymustard
D. p. subsp. menzeisii (DC.) Detl. [75,89], Menzies' tansymustard
D. p. subsp. nelsonii (Rydb.) Detl. [89], Nelson's tansymustard
D. p. subsp. ochroleuca (Woot.) Detl., western tansymustard
D. p. subsp. paysonii Detl. [89,91], Payson's tansymustard
D. p. subsp. pinnata [27,89], western tansymustard
Infrataxa designations are somewhat arbitrary [27,175]. There are intergradation and introgression among the subspecies; consequently, the subspecies are often difficult to distinguish [27,75].
LIFE FORM:| Location | Rank |
| Georgia | SR: Reported from the state, but without persuasive documentation [48] |
| Missouri (D. p. subsp. pinnata) | SH: Historical. Has not been relocated within the last 20 years, but may be rediscovered [117] |
| New Hampshire | SX: Extirpated from the state [126] |
| New York (D. p. subsp. brachycarpa) | S1: Critically imperiled because of extreme rarity (< 5 sites or very few remaining individuals) or extremely vulnerable to extirpation due to biological factors [195] |
| Vermont | S1: Very rare; generally 1-5 occurrences, believed to be extant, and/or some factor(s) making it especially vulnerable to extirpation from the state [169] |
| West Virginia | SH: Historical. Has not been relocated within the last 20 years, but may be rediscovered [176] |
| Wyoming (D. p. subsp. paysonii) | S2: Imperiled because of rarity (often known from 6-20 occurrences) or because of factors demonstrably making it vulnerable to extinction [167] |
| Devil's Tower National Monument, Wyoming | S3: Sparse (widely distributed but restricted to small, patchy habitats) [39] |
The following biogeographic classifications demonstrate
western tansymustard could
potentially be found. These lists are speculative and may not be
accurately restrictive or complete.
ECOSYSTEMS [47]:
FRES10 White-red-jack pine
FRES11 Spruce-fir
FRES12 Longleaf-slash pine
FRES13 Loblolly-shortleaf pine
FRES14 Oak-pine
FRES15 Oak-hickory
FRES16 Oak-gum-cypress
FRES17 Elm-ash-cottonwood
FRES18 Maple-beech-birch
FRES19 Aspen-birch
FRES21 Ponderosa pine
FRES23 Fir-spruce
FRES28 Western hardwoods
FRES29 Sagebrush
FRES30 Desert shrub
FRES31 Shinnery
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES35 Pinyon-juniper
FRES36 Mountain grasslands
FRES37 Mountain meadows
FRES38 Plains grasslands
FRES39 Prairie
FRES40 Desert grasslands
FRES41 Wet grasslands
FRES42 Annual grasslands
STATES/PROVINCES: (key to state/province abbreviations)
UNITED STATES
| AZ | AR | CA | CO | CT | DE | FL | GA | ID |
| IL | IN | IA | KS | KY | LA | ME | MD | MA |
| MI | MN | MS | MO | MT | NE | NV | NJ | NM |
| NY | NC | ND | OH | OK | OR | PA | RI | SC |
| SD | TN | TX | UT | VT | VA | WA | WI | WY |
| DC |
| AB | BC | MB | NT | NU | ON | PQ | SK | YK |
| B.C.N. | Chih. | Sin. | Son. |
Western tansymustard also occurs in mesquite (Prosopis spp.), salt-desert shrubland, blackbrush/Indian ricegrass (Coleogyne ramosissima/Achnatherum hymenoides), and desert grassland communities [24,63]. In velvet mesquite (P. velutina) woodland of southeastern Arizona, western tansymustard occurs with Wright's buckwheat (Eriogonum wrightii) and plains lovegrass (Eragrostis intermedia) [15]. Associates on the Desert Tortoise Research Natural Area in the Mojave Desert of southern California include creosotebush (Larrea tridentata), white bursage (Ambrosia dumosa), and other annuals, the most common being cutleaf filaree (Erodium cicutarium), red brome (Bromus madritensis subsp. rubens), and Mediterranean grass (Schismus spp.) [20,21].
Western tansymustard is not as important in plains grasslands and communities further east as it is in desert shrublands [79]. It is usually listed as a "waste place" or disturbance-indicator weed in the Great Plains and ecosystems to the east (e.g., [27,49,56,108,119,172]).
Western tansymustard is a native winter annual. Mature plants are 2.3 to 3.3 feet (0.7-1 m) in height. Stems are coarse, glandular, and sparsely to densely pubescent, depending on the subspecies. They are 1 to several at the base, branching towards the top. Leaves are basal or cauline. Basal leaves are biwestern and may be as long as 4 inches (10 cm), becoming western and smaller up the stem. The inflorescence is a glandular raceme of perfect flowers that spreads out 45o to 90o from the stem. The fruit is a dehiscent, 2-capsuled silique 4-20 mm in length, bearing 1 to 20 small seeds per capsule. Seeds are 0.5 to 1 mm long; their average mass is 0.12 mg [40,49,56,75,91,141,162,175]. Tansymustards (Descurainia spp.) have a short taproot [125,186].
Stand structure: Plant communities where tansymustard is important have an open structure, with sparse to no overstory. For example, structure of a Colorado pinyon-Utah juniper burn in northeastern Utah consisted of the skeletons of burned conifers and a ground cover of western tansymustard and other annual forbs [51]. Excepting communities dominated by cheatgrass (e.g., [83,159,190]), descriptions of open-canopy stands dominated by annuals are sparse in the literature. Further studies of stand structure (including year-to-year fluctuations due to climate changes) in such communities would increase understanding of fuel loading, fire behavior, and current fire regimes in communities with a large component of western tansymustard and other annuals.
RAUNKIAER [142] LIFE FORM:Breeding system: Mustards (Brassicaceae) are cross-pollinated. Selfing also occurs [74].
Pollination is insect-mediated. The sepals contain nectaries that attract insect pollinators [74].
Seed production: No information
Seed dispersal: Neither fruits nor seeds have specialized appendages for dispersal [92,95], and most western tansymustard seed falls near the parent plant [147]. Wind, water, machinery, and animals transport seed long distances [115,147]. Animals disperse tansymustard seeds when the sticky seedcoat adheres to feathers or fur [192].
Seed banking: Western tansymustard has soil-stored seed [24,26,66,76]. Soil samples from a needle-and-thread grass-blue grama (Hesperostipa comata-Bouteloua gracilis) community in Yellowstone National Park supported a mean of 13 western tansymustard germinants/m2 in the greenhouse [26] .
Germination: Western tansymustard has a temperature-dependent afterripening requirement that lessens with time and exposure to cold temperatures [192]. It is adapted to establishing in soils that may dry quickly. The seedcoat forms a thin layer of mucilage after wetting; the sticky layer helps germinating seeds retain water [189,192]. Best germination occurs with ample soil moisture, however. Seedling establishment is closely tied to favorable moisture levels at time of germination, and western tansymustard cover fluctuates from year to year [31]. In undisturbed creosotebush-white bursage in the northern Mojave Desert of Nevada (where western tansymustard germinates in winter), spring density of western tansymustard ranged from 18 plants/m2 (the driest winter) to 212/m2 (the wettest winter) over 6 years [16].
In a study on germination of California chaparral species, heat treatments had no significant effect on germination of western tansymustard; however, germination of western tansymustard seeds was significantly (p <0.1) enhanced by treatment with an infusion of chamise (Adenostoma fasciculatum) foliage, and by application of charred, finely ground chamise stems to the seeds [96].
Seedling establishment/growth: Although western tansymustard establishes on open, dry sites, establishment may be facilitated by shrubs, especially big sagebrush, which has been shown to increase water content of surface soil through hydraulic lift [144]. In Theodore Roosevelt National Park, North Dakota, western tansymustard showed better establishment when in close proximity to big sagebrush plants compared to density of western tansymustard away from big sagebrush crowns. Silver sagebrush crowns also enhanced western tansymustard establishment, although the number of tansymustard plants was considerably less in the silver sagebrush community compared to the big sagebrush community. The average number of western tansymustard growing within a circle around sagebrush stems (using the stems as the center of the radii) varied as follows [67]:
| Species | 0-30.4 cm away from stem base | 30.4-43 cm away | 43-52.7 cm away |
| Big sagebrush | 92 plants | 60 plants | 23 plants |
| Silver sagebrush | 6 plants | 1 plant | 0 plants |
Growth is enhanced on wet, nitrogen-rich sites. On the Jornada Experimental Range of New Mexico, western tansymustard showed best growth (peak biomass=3.2 g/m2) on sites fertilized with nitrogen and given 25 mm of supplemental water/per week [61]. Nitrogen-fixing plants may increase western tansymustard cover (review by [106]).
SITE CHARACTERISTICS:Soils: Western tansymustard is common on sandy, gravelly, and eroded soils [27,28,40,54,75,76,81,108,141,172]. Hinds and Sauer [76] found western tansymustard was associated with eroded soils on the Arid Lands Ecology Reserve of Washington. Western tansymustard tolerates alkaline and limestone soils [27,28,50,75,119,172]. In the San Bernardino National Forest, California, western tansymustard was a constant species on singleleaf pinyon (P. monophylla)-Utah juniper sites previously mined for limestone, and on noncarbonate soils [50].
Aspect/topography: Western tansymustard occurred on both cool northern and warm southern exposures following fall prescribed fire in a pinyon-juniper community in the Green River corridor of Utah [53].
Elevational range by state is:
| Arizona | <7,000 feet (2,100 m) [91] |
| California | 8,200 feet (2,500 m) [75] |
| Colorado | 4,000-8,000 feet (1,200-2,400 m) [65] |
| New Mexico | 4,500-7,500 feet (1,400-2,300 m) [110] |
| Utah | 2,500-10,700 feet (750-3,250 m) [175] |
| Wyoming | 6,000 to 7,200 feet (2,000-2,200) [40] |
SUCCESSIONAL STATUS:
Western tansymustard is an early seral species. It occurs on open, disturbed sites such as railroad
rights-of-way [40,172], overgrazed rangelands [14,19], and early seral burns
[32,33,51,53]. Western tansymustard and other annuals are common following
disturbances such as fire or grazing. They become increasingly
scarce as the canopy closes [3,32,33,51,104].
Western tansymustard does not form mycorrhizal associations [14,134]; thus, it can
occur on sterile sites and on sites undergoing primary succession.
A common pattern of succession in disturbed sagebrush steppe begins with Russian-thistle. Western tansymustard, herb sophia, and/or tall tumblemustard follow successionally. Russian-thistle may in turn reinvade the mustard stands with grazing disturbance, but more commonly, the mustards are succeeded by cheatgrass [68,78,78,139,185]. In desert environments, cheatgrass usually requires litter for successful germination and establishment. The dried skeletons of western tansymustard and other annual forbs may facilitate cheatgrass establishment by providing litter [34,125]. Western tansymustard and other annual forbs achieve greater cover in early seral sagebrush communities when cheatgrass is absent [193]. For information on the interactions of western tansymustard and cheatgrass, see FEIS reviews on herb sophia and cheatgrass.
Western tansymustard and the exotic herb sophia are apparently equally invasive, and fill similar ecological niches [118]. They sometimes codominate in early seral communities [2].
Western tansymustard may persist into late succession if the canopy remains open [150]. For example, western tansymustard was common (20% frequency) in a relict, 80-year-old Colorado pinyon-Utah juniper burn in northeastern Utah. It was less common, but present (2% frequency), on another relict Colorado-pinyon-Utah juniper site that had not experienced stand-replacement fire for at least 150 years. Structure at both sites was very open, with few, scattered trees [52]. Sagebrush communities may also retain open conditions into late succession [171,188]. In the Columbia River Basin of south-central Washington, western tansymustard occurs in big sagebrush communities through all stages of succession but is most common in early successional stages. It is the most common native annual on newly disturbed sites and old fields [18]. Western tansymustard occurs in pristine, late-successional communities. For example, it occurs in undisturbed, climax mountain meadows (Idaho fescue-bearded wheatgrass (Festuca idahoensis-Elymus caninus)) in Grand Teton National Park [174].
SEASONAL DEVELOPMENT:Fire regimes: In wet years, the dried skeletons of western tansymustard and other annuals provided the fine, flashy fuels that helped spread fire in presettlement desert ecosystems. Year-to-year fluctuations and longer-term southern oscillations resulted in variable cover of annuals and their subsequent fuel loads [164], so fire return intervals in presettlement desert ecosystems were highly variable. Historic fire return intervals in desert ecosystems ranged from 10 to 100 or more years [8,23,114,133,171,194]. Expansion of annual alien grasses has dramatically changed fire regimes and plant communities over vast areas of western rangelands by creating an environment where fires are easily ignited, spread rapidly, cover large areas, and occur frequently [190]. Cheatgrass, red brome, and Mediterranean grasses (Schismus spp.) provide large amounts of persistent flammable fuels [20,21,116]; consequently, fire may return every 10 years or sooner in desert systems infested with exotic grasses [135,180]. Western tansymustard's role in facilitating establishment of cheatgrass and other weedy species in dry environments by providing litter (and subsequently, more mesic conditions for germination and seedling growth of other species) [34,35] needs further investigation.
Historic fire return intervals ranged from 10 to 70 years in sagebrush-dominated ecosystems [8,23,114,133,171,194]. Fire was historically uncommon in salt-desert shrubland ecosystems [22,84,129]. Native annuals such as western tansymustard, lacey phacelia (Phacelia tanacetifolia), and small fescue (Vulpia microstachys) provided fuels, but frequent breaks in the continuity of fuels hindered fire spread [20,21].
The following table provides fire return intervals where western tansymustard may be an important component of the vegetation. For further information on fire regimes in these communities, see the FEIS summary on the dominant species listed below.
| Community or Ecosystem | Dominant Species | Fire Return Interval Range (years) |
| maple-beech-birch | Acer-Fagus-Betula | > 1000 [173] |
| California chaparral | Adenostoma and/or Arctostaphylos spp. | < 35 to < 100 [133] |
| bluestem prairie | Andropogon gerardii var. gerardii-Schizachyrium scoparium | < 10 [100,133] |
| silver sagebrush steppe | Artemisia cana | 5-45 [73,140,183] |
| sagebrush steppe | A. tridentata/Pseudoroegneria spicata | 20-70 [133] |
| basin big sagebrush | A. tridentata var. tridentata | 12-43 [148] |
| mountain big sagebrush | A. tridentata var. vaseyana | 15-40 [8,23,113] |
| Wyoming big sagebrush | A. tridentata var. wyomingensis | 10-70 (40**) [171,191] |
| coastal sagebrush | A. californica | < 35 to < 100 |
| saltbush-greasewood | Atriplex confertifolia-Sarcobatus vermiculatus | < 35 to < 100 |
| desert grasslands | Bouteloua eriopoda and/or Pleuraphis mutica | 5-100 [133] |
| plains grasslands | Bouteloua spp. | < 35 [133,183] |
| blue grama-needle-and-thread grass-western wheatgrass | B. gracilis-Hesperostipa comata-Pascopyrum smithii | < 35 [133,146,183] |
| blue grama-buffalo grass | B. gracilis-Buchloe dactyloides | < 35 [133,183] |
| grama-galleta steppe | B. gracilis-Pleuraphis jamesii | < 35 to < 100 [133] |
| cheatgrass | Bromus tectorum | < 10 [135,180] |
| California montane chaparral | Ceanothus and/or Arctostaphylos spp. | 50-100 [133] |
| curlleaf mountain-mahogany* | Cercocarpus ledifolius | 13-1000 [9,151] |
| mountain-mahogany-Gambel oak scrub | C. ledifolius-Quercus gambelii | < 35 to < 100 |
| blackbrush | Coleogyne ramosissima | < 35 to < 100 [133] |
| California steppe | Festuca-Danthonia spp. | < 35 [133,161] |
| juniper-oak savanna | Juniperus ashei-Q. virginiana | < 35 |
| western juniper | J. occidentalis | 20-70 |
| Rocky Mountain juniper | J. scopulorum | < 35 |
| cedar glades | J. virginiana | 3-7 |
| creosotebush | Larrea tridentata | < 35 to < 100 [133] |
| wheatgrass plains grasslands | Pascopyrum smithii | < 5-47+ [133,140,183] |
| Great Lakes spruce-fir | Picea-Abies spp. | 35 to > 200 |
| northeastern spruce-fir | Picea-Abies spp. | 35-200 |
| black spruce | P. mariana | 35-200 [30] |
| pine-cypress forest | Pinus-Cupressus spp. | < 35 to 200 [7] |
| pinyon-juniper | Pinus-Juniperus spp. | < 35 [133] |
| Mexican pinyon | P. cembroides | 20-70 [120,163] |
| shortleaf pine | P. echinata | 2-15 |
| shortleaf pine-oak | P. echinata-Quercus spp. | < 10 [173] |
| Colorado pinyon | P. edulis | 10-400+ [42,55,93,133] |
| slash pine | P. elliottii | 3-8 |
| slash pine-hardwood | P. elliottii-variable | < 35 [173] |
| longleaf-slash pine | P. palustris-P. elliottii | 1-4 [124,173] |
| longleaf pine-scrub oak | P. palustris-Quercus spp. | 6-10 [173] |
| Pacific ponderosa pine* | P. ponderosa var. ponderosa | 1-47 [7] |
| interior ponderosa pine* | P. ponderosa var. scopulorum | 2-30 [7,10,105] |
| red pine (Great Lakes region) | P. resinosa | 10-200 (10**) [30,46] |
| red-white-jack pine* | P. resinosa-P. strobus-P. banksiana | 10-300 [30,69] |
| loblolly pine | P. taeda | 3-8 |
| loblolly-shortleaf pine | P. taeda-P. echinata | 10 to < 35 [173] |
| galleta-threeawn shrubsteppe | Pleuraphis jamesii-Aristida purpurea | < 35 to < 100 |
| eastern cottonwood | Populus deltoides | < 35 to 200 [133] |
| aspen-birch | P. tremuloides-Betula papyrifera | 35-200 [30,173] |
| quaking aspen (west of the Great Plains) | P. tremuloides | 7-120 [7,60,112] |
| mesquite | Prosopis glandulosa | < 35 to < 100 [111,133] |
| mesquite-buffalo grass | P. glandulosa-Buchloe dactyloides | < 35 |
| Texas savanna | P. glandulosa var. glandulosa | < 10 [133] |
| mountain grasslands | Pseudoroegneria spicata | 3-40 (10**) |
| California oakwoods | Quercus spp. | < 35 [7] |
| oak-hickory | Quercus-Carya spp. | < 35 [173] |
| oak-juniper woodland (Southwest) | Quercus-Juniperus spp. | < 35 to < 200 [133] |
| northeastern oak-pine | Quercus-Pinus spp. | 10 to < 35 [173] |
| oak-gum-cypress | Quercus-Nyssa-spp.-Taxodium distichum | 35 to > 200 [124] |
| southeastern oak-pine | Q.-Pinus spp. | < 10 [173] |
| coast live oak | Q. agrifolia | 2-75 [57] |
| canyon live oak | Q. chrysolepis | <35 to 200 |
| blue oak-foothills pine | Q. douglasii-P. sabiniana | <35 |
| Oregon white oak | Q. garryana | < 35 [7] |
| bur oak | Q. macrocarpa | < 10 [173] |
| oak savanna | Q. macrocarpa/Andropogon gerardii-Schizachyrium scoparium | 2-14 [133,173] |
| shinnery | Q. mohriana | < 35 [133] |
| interior live oak | Q. wislizenii | < 35 [7] |
| cabbage palmetto-slash pine | Sabal palmetto-Pinus elliottii | < 10 [124,173] |
| blackland prairie | Schizachyrium scoparium-Nassella leucotricha | < 10 |
| Fayette prairie | S. scoparium-Buchloe dactyloides | < 10 |
| little bluestem-grama prairie | S. scoparium-Bouteloua spp. | < 35 |
| tule marshes | Scirpus and/or Typha spp. | < 35 [133] |
| elm-ash-cottonwood | Ulmus-Fraxinus-Populus spp. | < 35 to 200 [30,173] |
FIRE REGIMES: Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes"
Western tansymustard is common in early postfire communities [121]. It typically occurs in the earliest, annual-dominated stage of postfire succession in pinyon-juniper and sagebrush communities [51]. In a mountain big sagebrush community in Idaho, frequency of western tansymustard was more than 100% greater (p <0.05) in fall-burned compared to unburned control plots [109]. Although fire creates an open canopy and bare mineral soil, which favors tansymustard establishment, western tansymustard is not an obligate "fire follower." Any area with bare ground, open sunlight, and a seed source is vulnerable to western tansymustard invasion [71,72]. In greenhouse trials, there was no significant difference in emergence of western tansymustard seedlings from unburned, "lightly" burned, and severely burned soils. Greenhouse emergence of western tansymustard (seedlings/m2) from soil samples collected after prescribed burning near Burns, Oregon was as follows [25]:
| Control | "Cool" burn | "Hot" burn |
|
Basin big sagebrush site |
||
| 5.5 | 4.5 | 7.3 |
|
Wyoming big sagebrush site |
||
| 8.8 | 21.3 | 15.3 |
Fire may not increase postfire cover of western tansymustard [190]. In his classic study of postfire succession of western tansymustard and other annuals in big sagebrush, Piemeisel [138] wrote "the mere statement that a field has been burned is not sufficient information to foretell what the effect will be on the succeeding plant cover." For example, a 1977 June wildfire burned rough fescue (Festuca altaica)-bluebunch wheatgrass mountain grassland in Missoula, Montana. In fall 1977, spring 1978, and summer 1978, western tansymustard was present in low amounts on burned and unburned sites, with no significant differences (p <0.05) between western tansymustard cover on burned and unburned sites [4]. Piemesel [138] stated that site grazing history, postfire weather patterns, and level of postfire cheatgrass cover will affect cover and relative abundance of tansymustards and other early successional forbs.
Because it is an annual, western tansymustard population size is highly dependant upon year-to-year variations in postfire climate [123]. Following 1964 wildfires in northeastern Nevada, western tansymustard frequency fluctuated greatly for the next 3 years (41% in 1965, 6% in 1966, and 66% in 1967; pooled from 32 plots on 3 burns) [153]. Western tansymustard was found on fall-burned plots in postfire years 4 and 11 (but not other years) in a pinyon-juniper community in the Green River corridor of Utah [53].
Western tansymustard cover generally decreases with postfire succession. In Colorado pinyon-Utah juniper stands in Mesa Verde National Park, western tansymustard showed 44% frequency on a 4-year-old burn. It was not present on 30- or 90-year-old burns [33]. However, western tansymustard may remain a component of postfire vegetation as long as the site remains open.
Fuels: It is unclear how western tansymustard
contributed to fuel spread in the Southwest when presettlement fire regimes were
functioning. Researchers have speculated that following a wetter-than-average
growing season, dead, dry native annuals provided the fuels that carried
infrequent spring or summer fire [55]. In a creosotebush-white bursage community
in the Mojave Desert of southern California, however, experimental fires set in August
1995 were fueled entirely by red brome, cheatgrass, and Mediterranean
grasses (Schismus spp.). Precipitation the preceding winter was 200% of
average, so cover of annuals was high (~36% for all annual species). Where
exotic grasses dominated, mean spring (prefire) cover of annuals was
approximately 58%, whereas mean spring cover where native annuals dominated was
approximately 30%. (At 30%, western tansymustard cover matched overall forb
cover.) Fire did not spread
in areas dominated by native annuals due to low fuel loads [20]. This
suggests that in desert shrublands of the Southwest, presettlement fires were probably small and
patchy.
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE:
Disturbance level and fire severity:
Fire disturbance generally favors western tansymustard; however, severe fire may
reduce western tansymustard's seed bank. On singleleaf pinyon-Utah juniper of west-central Utah,
western tansymustard was about equally frequent on burned plots and on plots
that were burned and chained [131]. After wildfire in a Utah juniper community
in Nevada, western tansymustard was present at postfire year 1, with abundance
peaking at postfire year 4. Sites where severe fire killed the junipers and
reduced the understory to ash were devoid of vegetation until postfire year 4,
when western tansymustard and cheatgrass established [153]. Absence of
vegetation prior to postfire year 4 on severely burned sites suggests that the seedbank was destroyed,
and western tansymustard and cheatgrass seeds were transported to the site after fire.
Fall prescribed burning in a basin big sagebrush community in east-central Oregon had no significant effect on western tansymustard frequency in postfire year 1 or 2 [148]. See the Research Project Summary of this work for more information on fire effects on western tansymustard and 60 additional forb, grass, and woody plant species.
The Research Project Summary Nonnative annual grass fuels and fire in California's Mojave Desert also provides information on prescribed fire and postfire response of western tansymustard and other plant community species.
FIRE MANAGEMENT CONSIDERATIONS:| Cover type | Western tansymustard | Herb sophia |
|
1997 |
||
| Gambel oak/Utah serviceberry* mountain shrubland | 3 | 16 |
| Gambel oak-Colorado pinyon-Utah juniper | 1 | 12 |
| Colorado pinyon-Utah juniper | 2 | 10 |
|
1998 |
||
| Gambel oak/Utah serviceberry mountain shrubland | 31 | 0 |
| Gambel oak-Colorado pinyon-Utah juniper | 24 | 0 |
| Colorado pinyon-Utah juniper | 27 | 0 |
Interactions with cheatgrass: On dry sites where fire or other disturbance has consumed the litter, western tansymustard may pioneer, building up litter for subsequent cheatgrass establishment [34,35]. Postfire climate may greatly affect relative coverage of annual species. West [177] noted that in the Curlew Valley of northwestern Utah, western tansymustard and clasping pepperweed were common in the extremely wet period of 1983-1984, an El Niño year. The 2 forbs dominated and were the main source of fuels in shadscale (Atriplex confertifolia) and Gardner's saltbush (A. gardneri) communities; bottlebrush squirreltail (Elymus elymoides) dominated the understory of winterfat communities. Although cheatgrass typically follows tansymustard and other mustards successionally [138,139], during the El Niño event cheatgrass was "less abundant ... than it had been before or since." Cheatgrass dominated the site after El Niño passed [177].
Fire as a control agent: There are no published studies on using fire to control western tansymustard, but given its strong response to increased light and nutrients and open ground, fire alone is unlikely to provide control. If western tansymustard is already onsite in the seed bank, or as a few plants, fire is likely to increase the species' importance in the early postfire community.Large grazing animal use of western tansymustard varies, but is generally heaviest for new growth. On the Jornada Experimental Range of south-central New Mexico, cattle grazed western tansymustard in March (31% of diet) and December (8% of diet) [62]. Cattle on the Arid Land Ecology Reserve of eastern Washington used it lightly in spring [168]. Desert mule deer in Arizona and New Mexico consumed western mustard lightly (1-5% of diet) to moderately (6-15% of diet) in winter and spring [99,155,156]. A review by Kufeld and others [102] notes Rocky Mountain mule deer use western tansymustard in spring, summer, and fall. Pronghorn in northeastern Colorado preferred western tansymustard in the spring, and ate it in trace amounts in summer [152].
Small mammals consume western tansymustard. Grazing rodents and lagomorphs eat western tansymustard [88,107,187]. Black-tailed jackrabbit in southern Idaho showed greatest use in August (12.4% of the total diet) and least in June (2.2% of total diet) [38]. Granivorous rodents also use western tansymustard. In sand shinnery oak-honey mesquite/threeawn (Quercus harvardii-Prosopis glandulosa/Aristida spp.) communities of New Mexico, capture/stomach analyses trials showed Ord's kangaroo rat, spotted ground squirrel, and northern grasshopper mouse ate western tansymustard seeds [13]. On the Arid Land Ecology Reserve, eastern Washington, western tansymustard seeds formed 8% of the Townsend ground squirrel diet [87].
Western tansymustard is a larval food for several species of butterfly [82] including the desert orangetip (Anthocharis cethura pima), a sensitive subspecies in Region 3 (Southwest) of the U.S. Forest Service [6].
Palatability/nutritional value: Western tansymustard is palatable and nutritious. In the Mojave desert of California, domestic sheep showed strong preference for western tansymustard early in the growing season [137]. In free-choice trials, Montana cattle preferred western tansymustard to herb sophia. From the rosette to bud stage, average protein and phosphorus content of western tansymustard in Montana was 22.4% and 0.38%, respectively [136]. Nutritional content of western tansymustard forage collected in the great Basin of Nevada and Utah was [157]:
| Cal/kg | 3,660 |
| protein (%) | 27.2 |
| carbohydrates (%) | 63.3 |
| fat (%) | 0.50 |
| ash (%) | 2.9 |
| moisture (%) | 6.1 |
Cover value: No information
VALUE FOR REHABILITATION OF DISTURBED SITES:Horticulturalists plant western tansymustard in butterfly gardens to attract orangetip, white checkered, and white cabbage butterflies [82].
OTHER MANAGEMENT CONSIDERATIONS:Grazing appears to favor western tansymustard in disturbed communities. Moderate grazing in late-seral communities may not increase western tansymustard cover, although the data are limited and further studies are needed. In west-central Utah, western tansymustard cover was similar (3%) in basin big sagebrush communities with moderate cattle grazing and without grazing (13-year exclusion) [179]. In southern Alberta, moderate to heavy levels of stocking in undisturbed needle-and-thread grass-blue grama prairie slightly increased western tansymustard; however, in old fields, western tansymustard cover was greatly increased on grazed plots compared to ungrazed plots. Cover (%) of western tansymustard was [29]:
| Prairie | Old field | ||
| grazed | ungrazed | grazed | ungrazed |
| 1.9 | 1.5 | 10.4 | 0.1 |
Western tansymustard can persist on open sites free of grazing or other disturbance. In a shadscale-winterfat community of west-central Utah, western tansymustard occurred on a variety of domestic sheep grazing treatments (exclosure, light, moderate, and heavy grazing; and early- to mid-winter vs. late-winter grazing, with intensity ignored). It was most common in exclosures, but was found on plots of all treatments [64]. In the Grand Canyon, western tansymustard occurs on sites with a long history of livestock grazing, and on relict sites that have never supported livestock and have seldom burned [150].
Western tansymustard may differentially affect seed production of desert shrubs in heavily grazed and ungrazed areas. On the Desert Experimental Range Station of west-central Utah, seed production of shadscale and winterfat was enhanced by presence of western tansymustard on sites that had not been grazed for >50 years, but depressed by western tansymustard on heavily grazed sites [45]. Mechanisms by which western tansymustard may have affected shrub seed production were not studied.
In a big sagebrush community of northeastern Nevada, western tansymustard, cheatgrass, and clasping pepperweed volunteered on post-wildfire rehabilitation sites that were contour ripped and seeded to crested wheatgrass (Agropyron cristatum). However, seedling density of western tansymustard and exotic species was much greater on untreated burn plots compared to the ripped, seeded-in burn plots. Western tansymustard density exceeded that of cheatgrass on the untreated burns [153].
Western tansymustard is an agricultural weed [5,118] and an alternate host for beet leafhoppers, which transmit curly top virus to sugar beet (Beta vulgaris) crops [77].
Control: Western tansymustard does not usually persist in late-seral communities and may not require special control measures. Canopy closure, litter accumulation and/or growth interference from later-successional species tend to exclude tansymustard over time. Probably because it is a native invader that is largely controlled by succession, there is scant wildland-management interest in using resource monies to control western tansymustard with fire (see Fire as a control agent), herbicides, or other treatments.
Western tansymustard seedlings are sensitive to most herbicides at relatively low application rates. Glyphosate and 2,4-D give excellent control [165,182], as do many other herbicides [103,182]. Herbicide choice and rates are influenced by growth stage, stand density, and environmental conditions (e.g. drought or cold temperatures). Check with state or county weed specialists for appropriate local use rates and timing.1. Akinsoji, Aderopo. 1988. Postfire vegetation dynamics in a sagebrush steppe in southeastern Idaho, USA. Vegetatio. 78: 151-155. [6944]
2. Anderson, Jay E.; Inouye, Richard S. 2001. Landscape-scale changes in plant species abundance and biodiversity of a sagebrush steppe over 45 years. Ecological Monographs. 71(4): 531-556. [39482]
3. Anderson, Val Jo; Thompson, Robert M. 1993. Chemical and mechanical control of false hellebore (Veratrum californicum) in an alpine community. Res. Pap. INT-469. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 6 p. [22526]
4. Antos, Joseph A.; McCune, Bruce; Bara, Cliff. 1983. The effect of fire on an ungrazed western Montana grassland. The American Midland Naturalist. 110(2): 354-364. [337]
5. Archibold, O. W. 1981. Buried viable propagules in native prairie and adjacent agricultural sites in central Saskatchewan. Canadian Journal of Botany. 59: 701-706. [26128]
6. Arizona Game and Fish Department. 2001. Anthocharis cethura pima, [Online]. Unpublished abstract. In: Heritage Data Management System. Available: http://www.azgfd.com/pdfs/wildlife_conservation/hdms/Invertibrates/Anthcepi.fo.pdf [2003, January 13]. [43139]
7. Arno, Stephen F. 2000. Fire in western forest ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 97-120. [36984]
8. Arno, Stephen F.; Gruell, George E. 1983. Fire history at the forest-grassland ecotone in southwestern Montana. Journal of Range Management. 36(3): 332-336. [342]
9. Arno, Stephen F.; Wilson, Andrew E. 1986. Dating past fires in curlleaf mountain-mahogany communities. Journal of Range Management. 39(3): 241-243. [350]
10. Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. [14986]
11. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. [434]
12. Best, K. F. 1977. The biology of Canadian weeds. 22. Descurainia sophia (L.) Webb. Canadian Journal of Plant Science. 57: 499-507. [44054]
13. Best, Troy L.; Skupski, Marian P.; Smartt, Richard A. 1993. Food habits of sympatric rodents in the shinnery oak - mesquite grasslands of southeastern New Mexico. The Southwestern Naturalist. 38(3): 224-235. [22136]
14. Bethlenfalvay, Gabor J.; Dakessian, Suren. 1984. Grazing effects on mycorrhizal colonization and floristic composition of the vegetation on a semiarid range in northern Nevada. Journal of Range Management. 37(4): 312-316. [439]
15. Biggs, Thomas Howard. 1997. Fire frequency, nutrient concentrations and distributions, and 13C of soil organic matter and plants in a southeastern Arizona grassland. Tucson, AZ: University of Arizona. 193 p. Dissertation. [35581]
16. Bowers, Michael A. 1987. Precipitation and the relative abundances of desert winter annuals: a 6-year study in the northern Mohave Desert. Journal of Arid Environments. 12: 141-149. [4850]
17. Bradley, W. G. 1965. A study of the blackbrush plant community of the Desert Game Range. Transactions, Desert Bighorn Council. 11: 56-61. [4380]
18. Brandt, C. A.; Rickard, W. H. 1994. Alien taxa in the North American shrub-steppe four decades after cessation of livestock grazing and cultivation agriculture. Biological Conservation. 68(2): 95-105. [23456]
19. Branson, Farrel A. 1985. Vegetation changes on western rangelands. Range Monograph No. 2. Denver, CO: Society for Range Management. 76 p. [5172]
20. Brooks, Matthew L. 1999. Alien annual grasses and fire in the Mojave Desert. Madrono. 46(1): 13-19. [34386]
21. Brooks, Matthew Lamar. 1998. Ecology of a biological invasion: alien annual plants in the Mojave Desert. Riverside, CA: University of California. 186 p. Dissertation. [37220]
22. Brown, David E.; Minnich, Richard A. 1986. Fire and changes in creosote bush scrub of the western Sonoran Desert, California. The American Midland Naturalist. 116(2): 411-422. [537]
23. Burkhardt, Wayne J.; Tisdale, E. W. 1976. Causes of juniper invasion in southwestern Idaho. Ecology. 57: 472-484. [565]
24. Butler, Jack L.; Paintner, Kara J. 1991. Rangeland recovery potential: soil seed content and seed viability. In: Plumb, Glenn E., ed. University of Wyoming: National Park Service Research Center 15th annual report--1991. Laramie, WY: University of Wyoming: 130-135. [29951]
25. Champlin, Mark R. 1982. Big sagebrush (Artemisia tridentata) ecology and management with emphasis on prescribed burning. Corvallis, OR: Oregon State University. 136 p. Dissertation. [9484]
26. Clark, David Lee. 1991. The effect of fire on Yellowstone ecosystem seed banks. Bozeman, MT: Montana State University. 115 p. Thesis. [36504]
27. Diggs, George M., Jr.; Lipscomb, Barney L.; O'Kennon, Robert J. 1999. Illustrated flora of north-central Texas. Sida Botanical Miscellany No. 16. Fort Worth, TX: Botanical Research Institute of Texas. 1626 p. [35698]
28. Doescher, P. S.; Miller, R. F.; Swanson, S. R.; Winward, A. H. 1986. Identification of the Artemisia tridentata ssp. wyomingensis/Festuca idahoensis habitat type in eastern Oregon. Northwest Science. 60(1): 55-60. [815]
29. Dormaar, Johan F.; Adams, Barry W.; Willms, Walter D. 1994. Effect of grazing and abandoned cultivation on a Stipa-Bouteloua community. Journal of Range Management. 47(1): 28-32. [22922]
30. Duchesne, Luc C.; Hawkes, Brad C. 2000. Fire in northern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 35-51. [36982]
31. Dunigan, P. F. X., Jr.; Lei, W.; Rickard, W. H. 1980. Pocket mouse population response to winter precipitation and drought. Northwest Science. 54(4): 289-295. [26866]
32. Erdman, James A. 1970. Pinyon-juniper succession after natural fires on residual soils of Mesa Verde, Colorado. Brigham Young University Science Bulletin: Biological Series. 11(2): 1-26. [11987]
33. Erdman, James Allen. 1969. Pinyon-juniper succession after fires on residual soils of the Mesa Verde, Colorado. Boulder, CO: University of Colorado. 81 p. Dissertation. [11437]
34. Evans, Raymond A.; Young, James A. 1972. Microsite requirements for establishment of annual rangeland weeds. Weed Science. 20(4): 350-356. [878]
35. Evans, Raymond A.; Young, James A. 1987. Seedbed microenvironment, seedling recruitment, and plant establishment on rangelands. In: Frasier, Gary W.; Evans, Raymond A., eds. Seed and seedbed ecology of rangeland plants: proceedings of symposium; 1987 April 21-23; Tucson, AZ. Washington, DC: U.S. Department of Agriculture, Agricultural Research Service: 212-220. [3354]
36. Everett, Richard L. 1987. Plant response to fire in the pinyon-juniper zone. In: Everett, Richard L., compiler. Proceedings--pinyon-juniper conference; 1986 January 13-16; Reno, NV. Gen. Tech. Rep. INT-215. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 152-157. [4755]
37. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905]
38. Fagerstone, Kathleen A.; Lavoie, G. Keith; Griffith, Richard E., Jr. 1980. Black-tailed jackrabbit diet and density on rangeland and near agricultural crops. Journal of Range Management. 33(3): 229-233. [21756]
39. Fertig, Walter, compiler. 2001. The potential vascular plant flora of Devils Tower National Monument, [Online]. In: Wyoming Natural Diversity Database, University of Wyoming (Producer). Available: http://uwadmnweb.uwyo.edu/WYNDD/PDF_files/reprts_by_author/reports_fertig/Fertig%202001%20Devils%20Tower%20Plant%20List%20Report%20Final.pdf [2003, January 13]. [43137]
40. Fertig, Walter. 2000. State species abstract: Descurainia pinnata ssp. paysonii--Payson's tansymustard. In: Wyoming Natural Diversity Database. Laramie, WY: University of Wyoming (Producer) Available: http://uwadmnweb.uwyo.edu/WYNDD/PDF_files/Plant_Summaries/D/Descurainia%20pinnata%paysonii.pdf [2003, January 24]. [43292]
41. Fishel, Fred. 2003. Weeds of field crops and pastures: Tansy mustard. In: Missouri weeds, [Online]. Available: http://www.psu.missouri.edu/fishel/tansy_mustard.htm [2003, March 20]. [43670]
42. Floyd, M. Lisa; Romme, William H.; Hanna, David D. 2000. Fire history and vegetation pattern in Mesa Verde National Park, Colorado, USA. Ecological Applications. 10(6): 1666-1680. [37590]
43. Floyd-Hanna, Lisa; DaVega, Anne; Hanna, David; Romme, William H. 1997. Chapin 5 Fire vegetation monitoring and mitigation first year report. [Washington, DC: U.S. Department of the Interior, National Park Service, Mesa Verde National Park]. Unpublished report on file at: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. 7 p. [+ Appendices]. [34181]
44. Floyd-Hanna, Lisa; Hanna, David; Romme, William H. 1998. Chapin 5 Fire vegetation monitoring and mitigation annual report, year 2. Washington, DC: U.S. Department of the Interior, National Park Service, Mesa Verde National Park. 7 p. [+ Appendices]. Unpublished report on file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. [34460]
45. Freeman, D. Carl; Emlen, John M. 1995. Assessment of interspecific interactions in plant communities: an illustration from the cold desert saltbush grasslands of North America. Journal of Arid Environments. 31(2): 179-198. [27643]
46. Frissell, Sidney S., Jr. 1968. A fire chronology for Itasca State Park, Minnesota. Minnesota Forestry Research Notes No. 196. St. Paul, MN: University of Minnesota. 2 p. [34527]
47. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; Lewis, Mont E.; Smith, Dixie R. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998]
48. Georgia Department of Natural Resources, Natural Heritage Program. 2002. Watched plant species in Georgia, [Online]. Available: http://georgiawildlife.dnr.state.ga.us/content/watchedplants.asp [2003, February 14]. [43134]
49. Gleason, Henry A.; Cronquist, Arthur. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. 2nd ed. New York: New York Botanical Garden. 910 p. [20329]
50. Gonella, Michael P.; Neel, Maile C. 1995. Characterizing rare plant habitat for restoration in the San Bernardino National Forest. In: Roundy, Bruce A.; McArthur, E. Durant; Haley, Jennifer S.; Mann, David K., compilers. Proceedings: wildland shrub and arid land restoration symposium; 1993 October 19-21; Las Vegas, NV. Gen. Tech. Rep. INT-GTR-315. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 81-93. [24830]
51. Goodrich, Sherel. 1999. Multiple use management based on diversity of capabilities and values within pinyon-juniper woodlands. In: Monsen, Stephen B.; Stevens, Richard, compilers. Proceedings: ecology and management of pinyon-juniper communities within the Interior West: Sustaining and restoring a diverse ecosystem; 1997 September 15-18; Provo, UT. Proceedings RMRS-P-9. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 164-171. [30550]
52. Goodrich, Sherel; Gale, Natalie. 1999. Cheatgrass frequency at two relic sites within the pinyon-juniper belt of Red Canyon. In: Monsen, Stephen B.; Stevens, Richard, compilers. Proceedings: ecology and management of pinyon-juniper communities within the Interior West: Sustaining and restoring a diverse ecosystem; 1997 September 15-18; Provo, UT. Proceedings RMRS-P-9. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 69-71. [30494]
53. Goodrich, Sherel; Huber, Allen. 1999. Response of a seed mix and development of ground cover on northerly and southerly exposures in the 1985 Jarvies Canyon Burn, Daggett County, Utah. In: Monsen, Stephen B.; Stevens, Richard, compilers. Proceedings: ecology and management of pinyon-juniper communities within the Interior West: Sustaining and restoring a diverse ecosystem; 1997 September 15-18; Provo, UT. Proceedings RMRS-P-9. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 346-351. [30580]
54. Goodrich, Sherel; Nelson, Dwain; Gale, Natalie. 1999. Some features of Wyoming big sagebrush communities on gravel pediments of the Green River in Daggett County, Utah. In: McArthur, E. Durant; Ostler, W. Kent; Wambolt, Carl L., compilers. Proceedings: shrub ecotones; 1998 August 12-14; Ephraim, UT. Proceedings RMRS-P-11. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 159-167. [36077]
55. Gottfried, Gerald J.; Swetnam, Thomas W.; Allen, Craig D.; [and others]. 1995. Pinyon-juniper woodlands. In: Finch, Deborah M.; Tainter, Joseph A., eds. Ecology, diversity, and sustainability of the Middle Rio Grande Basin. Gen. Tech. Rep. RM-GTR-268. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 95-132. [26188]
56. Great Plains Flora Association. 1986. Flora of the Great Plains. Lawrence, KS: University Press of Kansas. 1392 p. [1603]
57. Greenlee, Jason M.; Langenheim, Jean H. 1990. Historic fire regimes and their relation to vegetation patterns in the Monterey Bay area of California. The American Midland Naturalist. 124(2): 239-253. [15144]
58. Greytak, Dan. 1992. A technique for producing riparian plants for Nevada. In: Landis, Thomas D., technical coordinator. Proceedings, Intermountain Forest Nursery Association; 1991 August 12-16; Park City, UT. Gen. Tech. Rep. RM-211. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 91-93. [20930]
59. Grilz, Perry L.; Romo, J. T. 1995. Management considerations for controlling smooth brome in fescue prairie. Natural Areas Journal. 15(2): 148-156. [25741]
60. Gruell, G. E.; Loope, L. L. 1974. Relationships among aspen, fire, and ungulate browsing in Jackson Hole, Wyoming. Lakewood, CO: U.S. Department of the Interior, National Park Service, Rocky Mountain Region. 33 p. In cooperation with: U.S. Department of Agriculture, Forest Service, Intermountain Region. [3862]
61. Gutierrez, Julio R.; DaSilva, Oswaldo A.; Pagani, Maria I.; Weems, Danforth; Whitford, Walter G. 1988. Effects of different patterns of supplemental water and nitrogen fertilization on productivity and composition of Chihuahuan Desert annual plants. The American Midland Naturalist. 119(2): 336-343. [1445]
62. Hakkila, Mark D.; Holechek, Jerry L.; Wallace, Joe D.; [and others]. 1987. Diet and forage intake of cattle on desert grassland range. Journal of Range Management. 40(4): 339-342. [37909]
63. Harper, K. T.; Sanderson, Stewart C.; McArthur, E. Durant. 2001. Quantifying plant diversity in Zion National Park, Utah. In: McArthur, E. Durant; Fairbanks, Daniel J., compilers. Shrubland ecosystem genetics and biodiversity: proceedings; 2000 June 13-15; Provo, UT. Proc. RMRS-P-21. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 318-324. [41997]
64. Harper, Kimball T.; Van Buren, Renee; Kitchen, Stanley G. 1996. Invasion of alien annuals and ecological consequences in salt desert shrublands of western Utah. In: Barrow, Jerry R.; McArthur, E. Durant; Sosebee, Ronald E.; Tausch, Robin J., compilers. Proceedings: shrubland ecosystem dynamics in a changing environment; 1995 May 23-25; Las Cruces, NM. Gen. Tech. Rep. INT-GTR-338. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 58-65. [27031]
65. Harrington, H. D. 1964. Manual of the plants of Colorado. 2d ed. Chicago: The Swallow Press, Inc. 666 p. [6851]
66. Hassan, M. A.; West, N. E. 1986. Dynamics of soil seed pools in burned and unburned sagebrush semi-deserts. Ecology. 67(1): 269-272. [1103]
67. Hazlett, Donald L.; Hoffman, George R. 1975. Plant species distributional patterns in Artemisia tridentata- and Artemisia cana-dominated vegetation in western North Dakota. Botanical Gazette. 136(1): 72-77. [1111]
68. Hedrick, D. W.; Hyder, D. N.; Sneva, F. A.; Poulton, C. E. 1966. Ecological response of sagebrush-grass range in central Oregon to mechanical and chemical removal of Artemisia. Ecology. 47(3): 432-439. [1115]
69. Heinselman, Miron L. 1970. The natural role of fire in northern conifer forest. In: The role of fire in the Intermountain West: Proceedings of a symposium; 1970 October 27-29; Missoula, MT. Missoula, MT: Intermountain Fire Research Council: 30-41. In cooperation with: University of Montana, School of Forestry. [15735]
70. Herbiseed. 2003. Weeds of the world: Seed catalogue, [Online]. Available: http://www.herbiseed.com [2003, February 14]. [43457]
71. Hernandez, Helios. 1973. Natural plant recolonization of surficial disturbances, Tuktoyaktuk Peninsula region, Northwest Territories. Canadian Journal of Botany. 51: 2177-2196. [20372]
72. Hessing, M. B.; Johnson, C. D. 1982. Early secondary succession following restoration and reseeding treatments in northern Arizona. Journal of Range Management. 35(5): 667-669. [34929]
73. Heyerdahl, Emily K.; Berry, Dawn; Agee, James K. 1994. Fire history database of the western United States. Final report. Interagency agreement: U.S. Environmental Protection Agency DW12934530; U.S. Department of Agriculture, Forest Service PNW-93-0300; University of Washington 61-2239. Seattle, WA: U.S. Department of Agriculture, Pacific Northwest Research Station; University of Washington, College of Forest Resources. 28 p. [+ Appendices]. Unpublished report on file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. [27979]
74. Hickey, Michael; King, Clive J. 1981. 100 families of flowering plants. New York: Cambridge University Press. 567 p. [44073]
75. Hickman, James C., ed. 1993. The Jepson manual: Higher plants of California. Berkeley, CA: University of California Press. 1400 p. [21992]
76. Hinds, W. T.; Sauer, R. H. 1976. Soil erodibility, soil erosion, and revegetation following wildfire in a shrub-steppe community. In: Engelmann, R. J.; Sehmel, G. A., eds. Atmosphere-surface exchange of particulate and gaseous pollutants: Proceedings of a symposium; 1974 September 4-6; Richland, WA. [Place of publication unknown]: [Publisher unknown]: 571-590. Avaialble from NTIS, Springfield, VA 22161. On file with: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, Missoula, MT. [8092]
77. Hironaka, M. 1986. Piemeisel exclosures. Rangelands. 8(5): 221-223. [1157]
78. Hironaka, M.; Tisdale, E. W. 1963. Secondary succession in annual vegetation in southern Idaho. Ecology. 44(4): 810-812. [1160]
79. Hirsch, Kathie Jean. 1985. Habitat classification of grasslands and shrublands of southwestern North Dakota. Fargo, ND: North Dakota State University. 281 p. Dissertation. [40326]
80. Hitchcock, C. Leo; Cronquist, Arthur. 1973. Flora of the Pacific Northwest. Seattle, WA: University of Washington Press. 730 p. [1168]
81. Holiday, Susan. 2000. A floristic study of Tsegi Canyon, Arizona. Madrono. 47(1): 29-42. [38998]
82. Huffman, Margaret. 2003. Suggestions for L.A. butterfly gardeners, [Online]. Los Angeles, CA: North American Butterfly Association, Los Angeles Chapter (Producer). Available: http://www.naba.org/chapters/nabala/Gardens.htm [2003, February 14]. [43456]
83. Hull, A. C., Jr.; Pechanec, Joseph F. 1947. Cheatgrass--a challenge to range research. Journal of Forestry. 45(8): 555-564. [9930]
84. Humphrey, Robert R. 1974. Fire in the deserts and desert grassland of North America. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 365-400. [1217]
85. Jennings, W. Bryan. 2001. Comparative flowering phenology of plants in the western Mojave Desert. Madrono. 48(3): 162-171. [40717]
86. Johnson, Charles Grier, Jr. 1998. Vegetation response after wildfires in national forests of northeastern Oregon. R6-NR-ECOL-TP-06-98. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 128 p. (+ appendices). [30061]
87. Johnson, Mark K. 1977. Food of Townsend ground squirrels on the Arid Land Ecology Reserve (Washington). The Great Basin Naturalist. 37: 128. [26157]
88. Johnson, Mark K.; Hansen, Richard M. 1979. Foods of cottontails and woodrats in south-central Idaho. Journal of Mammalogy. 60(1): 213-215. [23859]
89. Kartesz, John T.; Meacham, Christopher A. 1999. Synthesis of the North American flora (Windows Version 1.0), [CD-ROM]. Available: North Carolina Botanical Garden. In cooperation with the Nature Conservancy, Natural Resources Conservation Service, and U.S. Fish and Wildlife Service [2001, January 16]. [36715]
90. Kartesz, John Thomas. 1988. A flora of Nevada. Reno, NV: University of Nevada. 1729 p. [In 3 volumes]. Dissertation. [42426]
91. Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2d ed. Berkeley, CA: University of California Press. 1085 p. [6563]
92. Keeley, J. E.; Morton, B. A.; Pedrosa, A.; Trotter, P. 1985. Role of allelopathy, heat and charred wood in the germination of chaparral herbs and suffrutescents. Journal of Ecology. 73: 445-458. [5564]
93. Keeley, Jon E. 1981. Reproductive cycles and fire regimes. In: Mooney, H. A.; Bonnicksen, T. M.; Christensen, N. L.; [and others], technical coordinators. Fire regimes and ecosystem properties: Proceedings of the conference; 1978 December 11-15; Honolulu, HI. Gen. Tech. Rep. WO-26. Washington, DC: U.S. Department of Agriculture, Forest Service: 231-277. [4395]
94. Keeley, Jon E. 1984. Factors affecting germination of chaparral seeds. Bulletin of the Southern California Academy of Sciences. 83(3): 113-120. [11029]
95. Keeley, Jon E. 1991. Seed germination and life history syndromes in the California chaparral. The Botanical Review. 57(2): 81-116. [36973]
96. Keeley, Sterling C.; Keeley, Jon E. 1982. The role of allelopathy, heat, and charred wood in the germination of chaparral herbs. In: Conrad, C. Eugene; Oechel, Walter C., technical coordinators. Proceedings of the symposium on dynamics and management of Mediterranean-type ecosystems; 1981 June 22-26; San Diego, CA. Gen. Tech. Rep. PSW-58. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 128-134. [6017]
97. Kemp, Paul R. 1983. Phenological patterns of Chihuahuan Desert plants in relation to the timing of water availability. Journal of Ecology. 71: 427-436. [5054]
98. Kingsbury, John M. 1964. Poisonous plants of the United States and Canada. Englewood Cliffs, NJ: Prentice-Hall, Inc. 626 p. [122]
99. Krausman, Paul R.; Kuenzi, Amy J.; Etchberger, Richard C.; [and others]. 1997. Diets of mule deer. Journal of Range Management. 50(5): 513-522. [27845]
100. Kucera, Clair L. 1981. Grasslands and fire. In: Mooney, H. A.; Bonnicksen, T. M.; Christensen, N. L.; [and others], technical coordinators. Fire regimes and ecosystem properties: Proceedings of the conference; 1978 December 11-15; Honolulu, HI. Gen. Tech. Rep. WO-26. Washington, DC: U.S. Department of Agriculture, Forest Service: 90-111. [4389]
101. Kuchler, A. W. 1964. United States [Potential natural vegetation of the conterminous United States]. Special Publication No. 36. New York: American Geographical Society. 1:3,168,000; colored. [3455]
102. Kufeld, Roland C.; Wallmo, O. C.; Feddema, Charles. 1973. Foods of the Rocky Mountain mule deer. Res. Pap. RM-111. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 31 p. [1387]
103. Kunzmann, Michael R; Bennett, Peter S. 1989. Arsenal as a control agent for saltcedar (tamarix). In: Kunzmann, Michael R.; Johnson, R. Roy; Bennett, Peter, technical coordinators. Tamarisk control in southwestern United States; 1987 September 2-3; Tucson, AZ. Special Report No. 9. Tucson, AZ: National Park Service, Cooperative National Park Resources Studies Unit, School of Renewable Natural Resources: 82-90. [11354]
104. Lacey, John; Mosley, John. 2002. 250 plants for range contests in Montana. MONTGUIDE MT198402 AG 6/2002. Range E-2 (Misc.). Bozeman, MT: Montana State University, Extension Service. 4 p. [43671]
105. Laven, R. D.; Omi, P. N.; Wyant, J. G.; Pinkerton, A. S. 1980. Interpretation of fire scar data from a ponderosa pine ecosystem in the central Rocky Mountains, Colorado. In: Stokes, Marvin A.; Dieterich, John H., technical coordinators. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 46-49. [7183]
106. Lesica, Peter L.; DeLuca, Thomas H. 2000. Sweetclover: a potential problem for the northern Great Plains. Journal of Soil and Water Conservation. 55(3): 259-261. [40878]
107. MacCracken, James G.; Hansen, Richard M. 1984. Seasonal foods of blacktail jackrabbits and Nuttall cottontails in southeastern Idaho. Journal of Range Management. 37(3): 256-259. [25010]
108. Maier, Chris T. 1976. An annotated list of the vascular plants of Sand Ridge State Forest, Mason County, Illinois. Transactions, Illinois State Academy of Sciences. 69(2): 153-175. [37897]
109. Mangan, Larry; Autenrieth, R. 1985. Vegetation changes following 2,4-D application and fire in a mountain big sagebrush habitat type. In: Sanders, Ken; Durham, Jack, eds. Rangeland fire effects: A symposium: Proceedings; 1984 November 27-29; Boise, ID. Boise, ID: U.S. Department of the Interior, Bureau of Land Management, Idaho State Office: 61-65. [1519]
110. Martin, William C.; Hutchins, Charles R. 1981. A flora of New Mexico. Volume 2. Germany: J. Cramer. 2589 p. [37176]
111. McPherson, Guy R. 1995. The role of fire in the desert grasslands. In: McClaran, Mitchel P.; Van Devender, Thomas R., eds. The desert grassland. Tucson, AZ: The University of Arizona Press: 130-151. [26576]
112. Meinecke, E. P. 1929. Quaking aspen: A study in applied forest pathology. Tech. Bull. No. 155. Washington, DC: U.S. Department of Agriculture. 34 p. [26669]
113. Miller, Richard F.; Rose, Jeffery A. 1995. Historic expansion of Juniperus occidentalis (western juniper) in southeastern Oregon. The Great Basin Naturalist. 55(1): 37-45. [26637]
114. Miller, Richard F.; Seufert, Jamie M.; Hauferkamp, Marshall R. 1986. The ecology and management of bluebunch wheatgrass (Agropyron spicatum): a review. Station Bulletin 669. Corvallis, OR: Oregon State University, Agriculture Experiment Station. 39 p. [6666]
115. Milton, Suzanne J.; Dean, W. R. J.; Kerley, G. I. H.; [and others]. 1998. Dispersal of seeds as nest material by the cactus wren. The Southwestern Naturalist. 43(4): 449-452. [29454]
116. Minnich, Richard A. 1996. Fire ecology of exotic grasses in the California desert. In: Lovich, Jeff; Randall, John; Kelly, Mike, eds. Proceedings, California Exotic Pest Plant Council: Symposium '95; 1995 October 6-8; Pacific Grove, CA. Berkeley, CA: California Exotic Pest Plant Council: 61. Available: http://groups.ucanr.org/ceppc [2003, May 8]. [44031]
117. Missouri Department of Transportation. 2001. Endangered species checklist (flowering plants), [Online]. Available: http://www.conservation.state.mo.us/nathis/endangered/checklst [2002, February 22]. [40937]
118. Mitich, Larry W.; Kyser, Guy B. 1992. Impact of exotic weeds in the United States. In: Lym, Rodney G., ed. Proceedings, Western Society of Weed Science; 1992 March 10-12; Salt Lake City, UT. [Place of publication unknown]: Western Society of Weed Science: 86-93. [20616]
119. Mohlenbrock, Robert H. 1986. [Revised edition]. Guide to the vascular flora of Illinois. Carbondale, IL: Southern Illinois University Press. 507 p. [17383]
120. Moir, William H. 1982. A fire history of the High Chisos, Big Bend National Park, Texas. The Southwestern Naturalist. 27(1): 87-98. [5916]
121. Moomaw, James Curtis. 1956. Some effects of grazing and fire on vegetation in the Columbia Basin region, Washington. Pullman, WA: State College of Washington. 87 p. Dissertation. [1688]
122. Mulroy, Thomas W.; Rundel, Philip W. 1977. Annual plants: adaptations to desert environments. BioScience. 27(2): 109-114. [12919]
123. Murray, R. B.; Mayland, H. F.; Van Soest, P. J. 1978. Growth and nutritional value to cattle of grasses on cheatgrass range in southern Idaho. Research Paper INT-199. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 57 p. [1723]
124. Myers, Ronald L. 2000. Fire in tropical and subtropical ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 161-173. [36985]
125. Nelson, David L.; Harper, Kimball T.; Boyer, Kenneth C.; [and others]. 1989. Wildland shrub dieoffs in Utah: an approach to understanding the cause. In: Wallace, Arthur; McArthur, E. Durant; Haferkamp, Marshall R., compilers. Proceedings--symposium on shrub ecophysiology and biotechnology; 1987 June 30 - July 2; Logan, UT. Gen. Tech. Rep. INT-256. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 119-135. [5942]
126. New Hampshire Division of Forests and Lands. 2002. Rare plant species in New Hampshire: Plant tracking list, [Online]. New Hampshire Natural Heritage Inventory (Producer). Available: http://www.nhdfl.org/formgt/nhiweb/Douments/w_planT.pdf [2003, January 13]. [43140]
127. Nydegger, Nicholas C.; Smith, Graham W. 1986. Prey populations in relation to Artemisia vegetation types in southwestern Idaho. In: McArthur, E. Durant; Welch, Bruce L., compilers. Proceedings--symposium on the biology of Artemisia and Chrysothamnus; 1984 July 9-13; Provo, UT. Gen. Tech. Rep. INT-200. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 152-156. [1787]
128. O'Farrell, Thomas P.; Olson, Richard J.; Gilbert, Richard O.; Hedlund, John D. 1975. A population of Great Basin pocket mice, Perognathus parvus, in the shrub-steppe of south-central Washington. Ecological Monographs. 45: 1-28. [26872]
129. O'Leary, John F.; Minnich, Richard A. 1981. Postfire recovery of creosote bush scrub vegetation in the western Colorado Desert. Madrono. 28(2): 61-66. [3973]
130. Olson, Bret E. 1999. Impacts of noxious weeds on ecologic and economic systems. In: Sheley, Roger L.; Petroff, Janet K., eds. Biology and management of noxious rangeland weeds. Corvallis, OR: Oregon State University Press: 4-18. [35706]
131. Ott, Jeffrey E.; McArthur, E. Durant; Sanderson, Stewart C. 2001. Plant community dynamics of burned and unburned sagebrush and pinyon-juniper vegetation in west-central Utah. In: McArthur, E. Durant; Fairbanks, Daniel J., compilers. Shrubland ecosystem genetics and biodiversity: proceedings; 2000 June 13-15; Provo, UT. Proc. RMRS-P-21. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 177-191. [41971]
132. Patman, Jacqueline P.; Iltis, Hugh H. 1961. Preliminary reports on the flora of Wisconsin. No. 44. Cruciferae--Mustard family. Wisconsin Academy of Science, Arts and Letters. 50: 17-73. [37898]
133. Paysen, Timothy E.; Ansley, R. James; Brown, James K.; [and others]. 2000. Fire in western shrubland, woodland, and grassland ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-volume 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 121-159. [36978]
134. Pendleton, R. I.; Smith, B. N. 1983. Vesicular-arbuscular mycorrhizae of weedy and colonizer plant species at disturbed sites in Utah. Oecologia. 59: 296-301. [44055]
135. Peters, Erin F.; Bunting, Stephen C. 1994. Fire conditions pre- and postoccurrence of annual grasses on the Snake River Plain. In: Monsen, Stephen B.; Kitchen, Stanley G., compilers. Proceedings--ecology and management of annual rangelands; 1992 May 18-22; Boise, ID. Gen. Tech. Rep. INT-GTR-313. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 31-36. [24249]
136. Pfister, James A.; Lacey, John R.; Baker, Dale C.; [and others]. 1990. Is tansymustard causing photosensitization of cattle in Montana? Rangelands. 12(3): 170-172. [11797]
137. Phillips, Ralph L.; McDougald, Neil K.; Sullins, James. 1996. Plant preference of sheep grazing in the Mojave Desert. Rangelands. 18(4): 141-144. [26882]
138. Piemeisel, R. L. 1938. Changes in weedy plant cover on cleared sagebrush land and their probable causes. Technical Bulletin No. 654. Washington, DC: U.S. Department of Agriculture. 44 p. [1887]
139. Piemeisel, Robert L. 1951. Causes affecting change and rate of change in a vegetation of annuals in Idaho. Ecology. 32(1): 53-72. [1888]
140. Quinnild, Clayton L.; Cosby, Hugh E. 1958. Relicts of climax vegetation on two mesas in western North Dakota. Ecology. 39(1): 29-32. [1925]
141. Radford, Albert E.; Ahles, Harry E.; Bell, C. Ritchie. 1968. Manual of the vascular flora of the Carolinas. Chapel Hill, NC: The University of North Carolina Press. 1183 p. [7606]
142. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843]
143. Rea, Amadeo M. 1991. Gila River Pima dietary reconstruction. Arid Lands Newsletter. 31: 3-10. [18255]
144. Richards, J. H.; Caldwell, M. M. 1987. Hydraulic lift: substantial nocturnal water transport between soil layers by Artemisia tridentata. Oecologia. 73(4): 486-489. [16213]
145. Rickard, W. H. 1985. Biomass and shoot production in an undisturbed sagebrush-bunchgrass community. Northwest Science. 59(2): 126-133. [1981]
146. Rowe, J. S. 1983. Concepts of fire effects on plant individuals and species. In: Wein, Ross W.; MacLean, David A., eds. The role of fire in northern circumpolar ecosystems. SCOPE 18. New York: John Wiley & Sons: 135-154. [2038]
147. Salisbury, Edward J. 1961. Weeds and aliens. London: Collins. 330 p. [44074]
148. Sapsis, David B. 1990. Ecological effects of spring and fall prescribed burning on basin big sagebrush/Idaho fescue--bluebunch wheatgrass communities. Corvallis, OR: Oregon State University. 105 p. Thesis. [16579]
149. Saunders, Dale V.; Young, James A.; Evans, Raymond A. 1973. Origin of soil mounds associated with clumps of Ribes velutinum. Journal of Range Management. 26(1): 30-31. [24588]
150. Schmutz, Ervin M.; Michaels, Charles C.; Judd, B. Ira. 1967. Boysag Point: a relict area on the North Rim of Grand Canyon in Arizona. Journal of Range Management. 20: 363-369. [2083]
151. Schultz, Brad W. 1987. Ecology of curlleaf mountain mahogany (Cercocarpus ledifolius) in western and central Nevada: population structure and dynamics. Reno, NV: University of Nevada. 111 p. Thesis. [7064]
152. Schwartz, Charles C.; Nagy, Julius G. 1976. Pronghorn diets relative to forage availability in northeastern Colorado. Journal of Wildlife Management. 40(3): 469-478. [4937]
153. Sheeter, Guy Richard. 1968. Secondary succession and range improvements after wildfire in northeastern Nevada. Reno, NV: University of Nevada. 203 p. Thesis. [41]
154. Shiflet, Thomas N., ed. 1994. Rangeland cover types of the United States. Denver, CO: Society for Range Management. 152 p. [23362]
155. Short, Henry L. 1979. Deer in Arizona and New Mexico: their ecology and a theory explaining recent population decreases. Gen. Tech. Rep. RM-70. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 25 p. [4489]
156. Short, Henry L.; Evans, Wain; Boeker, Erwin L. 1977. The use of natural and modified pinyon pine-juniper woodlands by deer and elk. Journal of Wildlife Management. 41(3): 543-559. [12036]
157. Simms, Steven R. 1985. Acquisition cost and nutritional data on Great Basin resources. Journal of California and Great Basin Anthropology. 7(1): 117-126. [267]
158. Stephens, H. A. 1980. Poisonous plants of the central United States. Lawrence, KS: The Regents Press of Kansas. 165 p. [3803]
159. Stewart, George; Hull, A.C. 1949. Cheatgrass (Bromus tectorum L.)--an ecologic intruder in southern Idaho. Ecology. 30(1): 58-74. [2252]
160. Stickney, Peter F. 1989. Seral origin of species originating in northern Rocky Mountain forests. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 10 p. [20090]
161. Stomberg, Mark R.; Kephart, Paul; Yadon, Vern. 2001. Composition, invasibility, and diversity in coastal California grasslands. Madrono. 48(4): 236-252. [41371]
162. Strausbaugh, P. D.; Core, Earl L. 1977. Flora of West Virginia. 2nd ed. Morgantown, WV: Seneca Books, Inc. 1079 p. [23213]
163. Swetnam, Thomas W.; Baisan, Christopher H.; Caprio, Anthony C.; Brown, Peter M. 1992. Fire history in a Mexican oak-pine woodland and adjacent montane conifer gallery forest in southeastern Arizona. In: Ffolliott, Peter F.; Gottfried, Gerald J.; Bennett, Duane A.; [and others], technical coordinators. Ecology and management of oak and associated woodlands: perspectives in the southwestern United States and northern Mexico: Proceedings; 1992 April 27-30; Sierra Vista, AZ. Gen. Tech. Rep. RM-218. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 165-173. [19759]
164. Swetnam, Thomas W.; Betancourt, Julio L. 1990. Fire-southern oscillation relations in the southwestern United States. Science. 249: 1017-1020. [12106]
165. Thomas, A. G.; Donaghy, D. I. 1991. A survey of the occurrence of seedling weeds in spring annual crops in Manitoba. Canadian Journal of Plant Science. 71(3): 811-820. [21781]
166. U.S. Department of Agriculture, National Resource Conservation Service. 2003. PLANTS database (2003), [Online]. Available: https://plants.usda.gov /. [34262]
167. University of Wyoming. 2002. Plant species of concern - D, [Online]. In: Wyoming Natural Diversity Database. Available: http://uwadmnweb.uwyo.edu/wyndd/Plants/PlantD/plantd.htm [2003, January 24]. [43291]
168. Uresk, Daniel W.; Rickard, W. H. 1976. Diets of steers on a shrub-steppe rangeland in south-central Washington. Journal of Range Management. 29(6): 464-466. [2402]
169. Vermont Agency of Natural Resources, Department of Fish and Wildlife. 1996. Vermont's rare and uncommon native plants, [Online]. Nongame and Natural Heritage Program (Producer). Available: http://www.anr.state.vt.us/fs/fwhome/nnhp/vt_plant.html [2003, January 10]. [43135]
170. Vestal, Paul A. 1952. Ethnobotany of the Ramah Navaho. Papers of the Peabody Museum of American Archeology and Ethnology. Reports of the Ramah Project: Report No. 4; Vol. 40 (4). Cambridge, MA: Harvard University. 94 p. [37064]
171. Vincent, Dwain W. 1992. The sagebrush/grasslands of the upper Rio Puerco area, New Mexico. Rangelands. 14(5): 268-271. [19698]
172. Voss, Edward G. 1985. Michigan flora. Part II. Dicots (Saururaceae--Cornaceae). Bull. 59. Bloomfield Hills, MI: Cranbrook Institute of Science; Ann Arbor, MI: University of Michigan Herbarium. 724 p. [11472]
173. Wade, Dale D.; Brock, Brent L.; Brose, Patrick H.; [and others]. 2000. Fire in eastern ecosystems. In: Brown, James K.; Smith, Jane Kapler, eds. Wildland fire in ecosystems: Effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station: 53-96. [36983]
174. Weaver, T.; Lichthart, J.; Gustafson, D. 1990. Exotic invasion of timberline vegetation, Northern Rocky Mountains, USA. In: Schmidt, Wyman C.; McDonald, Kathy J., compilers. Proceedings--symposium on whitebark pine ecosystems: ecology and management of a high-mountain resource; 1989 March 29-31; Bozeman, MT. Gen. Tech. Rep. INT-270. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 208-213. [11688]
175. Welsh, Stanley L.; Atwood, N. Duane; Goodrich, Sherel; Higgins, Larry C., eds. 1987. A Utah flora. The Great Basin Naturalist Memoir No. 9. Provo, UT: Brigham Young University. 894 p. [2944]
176. West Virginia Department of Natural Resources. 2000. Rare species list--plants, [Online]. West Virginia Nongame Wildlife and Natural Heritage Program (Producer). Available: http://www.dnr.state.wv.us/wvwildlife/plants.pdf [2003, January 13]. [43138]
177. West, Neil E. 1994. Effects of fire on salt-desert shrub rangelands. In: Monsen, Stephen B.; Kitchen, Stanley G., compilers. Proceedings--ecology and management of annual rangelands; 1992 May 18-22; Boise, ID. Gen. Tech. Rep. INT-GTR-313. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 71-74. [24256]
178. West, Neil E.; Hassan, M. A. 1985. Recovery of sagebrush-grass vegetation following wildfire. Journal of Range Management. 38(2): 131-134. [2513]
179. West, Neil E.; Provenza, Frederick D.; Johnson, Patricia S.; Owens, M. Keith. 1984. Vegetation change after 13 years of livestock grazing exclusion on sagebrush semidesert in west central Utah. Journal of Range Management. 37(3): 262-264. [7515]
180. Whisenant, Steven G. 1990. Postfire population dynamics of Bromus japonicus. The American Midland Naturalist. 123: 301-308. [11150]
181. Wiggins, Ira L. 1980. Flora of Baja California. Stanford, CA: Stanford University Press. 1025 p. [21993]
182. William, Ray D.; Ball, Dan; Miller, Terry L.; [and others], compilers. 2001. Pacific Northwest weed management handbook. Corvallis, OR: Oregon State University. 408 p. [38715]
183. Wright, Henry A.; Bailey, Arthur W. 1982. Fire ecology: United States and southern Canada. New York: John Wiley & Sons. 501 p. [2620]
184. Wunderlin, Richard P. 1998. Guide to the vascular plants of Florida. Gainesville, FL: University Press of Florida. 806 p. [28655]
185. Yensen, Dana L. 1981. The 1900 invasion of alien plants into southern Idaho. The Great Basin Naturalist. 41(2): 176-183. [2634]
186. Yensen, Dana. 1980. A grazing history of southwestern Idaho with emphasis on the Birds of Prey Study Area. Boise, ID: U.S. Department of Agriculture, Bureau of Land Management, Snake River Birds of Prey Research Project, Boise District. 82 p. [4148]
187. Yensen, Eric; Quinney, Dana L. 1992. Can Townsend's ground squirrels survive on a diet of exotic annuals? The Great Basin Naturalist. 52(3): 269-277. [20990]
188. Young, James A.; Eckert, Richard E., Jr.; Evans, Raymond A. 1979. Historical perspectives regarding the sagebrush ecosystem. In: The sagebrush ecosystem: a symposium: Proceedings; 1978 April; Logan, UT. Logan, UT: Utah State University, College of Natural Resources: 1-13. [2644]
189. Young, James A.; Evans, Raymond A. 1973. Mucilaginous seed coats. Weed Science. 21(1): 52-54. [5937]
190. Young, James A.; Evans, Raymond A. 1978. Population dynamics after wildfires in sagebrush grasslands. Journal of Range Management. 31(4): 283-289. [2657]
191. Young, James A.; Evans, Raymond A. 1981. Demography and fire history of a western juniper stand. Journal of Range Management. 34(6): 501-505. [2659]
192. Young, James A.; Evans, Raymond A.; Gifford, Richard O.; Eckert, Richard E., Jr. 1970. Germination characteristics of three species of Cruciferae. Weed Science. 18: 41-48. [9499]
193. Young, James A.; Evans, Raymond A.; Major, J. 1972. Alien plants in the Great Basin. Journal of Range Management. 25: 194-201. [2674]
194. Young, James A.; Evans, Raymond A.; Major, Jack. 1977. Sagebrush steppe. In: Barbour, Michael G.; Major, Jack, eds. Terrestrial vegetation of California. New York: John Wiley & Sons: 763-796. [4300]
195. Young, Stephen M., ed. 2002. New York rare plant status list, [Online]. New York Department of Environmental Conservation, Natural Heritage Program (Producer). Available: http://www.dec.state.ny.us/website/dfwmr/heritage/RPSL.pdf [2003, January 13]. [43136]