Burning does not always increase tall tumblemustard cover [112,132,147].
In his classic study of postfire succession of tall tumblemustard and other
exotics in big sagebrush, Piemeisel [96] 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."
Frequency of tall tumblemustard on 50 Ã 50-cm
plots burned under prescription on 15 September 1983 on the Shoshone District,
Idaho BLM, was 8.8% in autumn 1982 (prefire), 1.3% in 1983 (postfire), 23.8% in 1984,
and 86.3% in 1986. Burning was conducted in threetip sagebrush (Artemisia
tripartita) and successfully reduced persistent litter. Macrobiotic soil
crusts began recovery in postfire year 3. Burning conditions were [19]:
Tall tumblemustard is native to Eurasia. It is widely naturalized throughout most of the world [119] including most of Canada and the United States. Tall tumblemustard does not occur in eastern Nunavut, western Newfoundland, or Alabama [75], and is rare in Florida [140]. It is mostly absent from Mexico, occurring only in the northern tip of Baja California Norte [136]. Tall tumblemustard was probably introduced in North America as a contaminant in imported crop seed [78]. Plants database provides a map of tumble mustard's distribution in the Untied States.
The following biogeographic classification systems are presented as a guide to where tall tumblemustard may be found. Precise distribution information is limited. Because it is so widespread, it is difficult to exclude many ecosystems as potential hosts of tall tumblemustard plants or populations; therefore, these lists are speculative.
Fire adaptations: Tall tumblemustard establishes from soil-stored seed after fire [41,45,108,137]. Wind, machinery, and animal transport from off-site may provide additional sources of seed [145] or introduce tall tumblemustard on burns where it was not already present in the soil seed bank. Fire creates conditions favorable for tall tumblemustard establishment (bare soil, open canopy, reduced growth interference) [97]. As a shade-intolerant, invasive species, tumble mustard can thrive in early postfire environments [26,71,72,139].
FIRE REGIMES: Introduced species can alter the probability of occurrence of fire, the rate of fire spread, and the intensity of fire in an ecosystem [30]. The degree of change and impacts on native ecosystems vary with differences in species composition and structure of invaded plant communities [17,111]. Historic FIRE REGIMES in big sagebrush/bunchgrass ecosystems, where tumble mustard is common, are variable. Fire return intervals range between 10 and 70 years [7,18,87,92,125,148]. The introduction and increasing dominance of cheatgrass has changed the seasonal occurrence, frequency, and size of wildfires in these ecosystems, thus altering successional patterns [13,95,131,134,143]. Tumble mustard invaded the western Unites States shortly before cheatgrass [78,88]. There is no evidence suggesting that tall tumblemustard alone has altered historic fire patterns in sagebrush steppe, but interactive effects of tumble mustard and cheatgrass are largely unstudied. Further research is needed on the impacts of tall tumblemustard invasion in sagebrush steppe and other ecosystems where weeds have drastically altered FIRE REGIMES.
Because tall tumblemustard is widespread, it is difficult to exclude many ecosystems as potential hosts of tall tumblemustard plants or populations. The following table provides some fire regime intervals for plant communities where tall tumblemustard may be important. For further information, see the FEIS summary on the dominant species listed below. Find further 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".
Community or Ecosystem Dominant Species Fire Return Interval Range (years) maple-beech-birch Acer-Fagus-Betula > 1,000 silver maple-American elm Acer saccharinum-Ulmus americana < 35 to 200 sugar maple A. saccharum > 1,000 sugar maple-basswood A. saccharum-Tilia americana > 1,000 [127] California chaparral Adenostoma and/or Arctostaphylos spp. 92] bluestem prairie Andropogon gerardii var. gerardii-Schizachyrium scoparium 79,92] Nebraska sandhills prairie A. gerardii var. paucipilus-S. scoparium < 10 bluestem-Sacahuista prairie A. littoralis-Spartina spartinae 92] silver sagebrush steppe Artemisia cana 5-45 [60,98,138] sagebrush steppe A. tridentata/Pseudoroegneria spicata 20-70 [92] basin big sagebrush A. tridentata var. tridentata 12-43 [105] mountain big sagebrush A. tridentata var. vaseyana 15-40 [7,18,87] Wyoming big sagebrush A. tridentata var. wyomingensis 10-70 (40**) [125,148] 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 [92] plains grasslands Bouteloua spp. 92,138] blue grama-needle-and-thread grass-western wheatgrass B. gracilis-Hesperostipa comata-Pascopyrum smithii < 35 [92,104,138] blue grama-buffalo grass B. gracilis-Buchloe dactyloides 92,138] grama-galleta steppe Bouteloua gracilis-Pleuraphis jamesii < 35 to < 100 blue grama-tobosa prairie B. gracilis-P. mutica 92] cheatgrass Bromus tectorum 95,134] California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100 [92] sugarberry-America elm-green ash Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica 127] paloverde-cactus shrub Cercidium microphyllum/Opuntia spp. 92] curlleaf mountain-mahogany* Cercocarpus ledifolius 13-1,000 [8,107] mountain-mahogany-Gambel oak scrub C. ledifolius-Quercus gambelii 92] Atlantic white-cedar Chamaecyparis thyoides 35 to > 200 [127] blackbrush Coleogyne ramosissima < 35 to < 100 Arizona cypress Cupressus arizonica 92] beech-sugar maple Fagus spp.-Acer saccharum > 1,000 [127] California steppe Festuca-Danthonia spp. 92,116] black ash Fraxinus nigra 127] juniper-oak savanna Juniperus ashei-Quercus virginiana < 35 Ashe juniper J. ashei < 35 western juniper J. occidentalis 20-70 Rocky Mountain juniper J. scopulorum < 35 cedar glades J. virginiana 3-7 tamarack Larix laricina 35-200 creosotebush Larrea tridentata < 35 to < 100 Ceniza shrub L. tridentata-Leucophyllum frutescens-Prosopis glandulosa 92] yellow-poplar Liriodendron tulipifera 127] wheatgrass plains grasslands Pascopyrum smithii < 5-47+ [92,98,138] Great Lakes spruce-fir Picea-Abies spp. 35 to > 200 northeastern spruce-fir Picea-Abies spp. 35-200 [34] southeastern spruce-fir Picea-Abies spp. 35 to > 200 [127] black spruce P. mariana 35-200 [34] pine-cypress forest Pinus-Cupressus spp. pinyon-juniper Pinus-Juniperus spp. 92] jack pine P. banksiana 34] Mexican pinyon P. cembroides 20-70 [89,118] shortleaf pine P. echinata 2-15 shortleaf pine-oak P. echinata-Quercus spp. 127] Colorado pinyon P. edulis 10-400+ [44,53,92] slash pine P. elliottii 3-8 slash pine-hardwood P. elliottii-variable < 35 sand pine P. elliottii var. elliottii 25-45 [127] longleaf-slash pine P. palustris-P. elliottii 1-4 [90,127] longleaf pine-scrub oak P. palustris-Quercus spp. 6-10 [127] Pacific ponderosa pine* P. ponderosa var. ponderosa 1-47 [6] interior ponderosa pine* P. ponderosa var. scopulorum 2-30 [6,9,82] Arizona pine P. ponderosa var. arizonica 2-15 [9,29,109] Table Mountain pine P. pungens 127] red pine (Great Lakes region) P. resinosa 10-200 (10**) [34,48] red-white-jack pine* P. resinosa-P. strobus-P. banksiana 10-300 [34,58] pitch pine P. rigida 6-25 [16,59] pocosin P. serotina 3-8 pond pine P. serotina 3-8 eastern white pine P. strobus 35-200 eastern white pine-eastern hemlock P. strobus-Tsuga canadensis 35-200 eastern white pine-northern red oak-red maple P. strobus-Quercus rubra-Acer rubrum 35-200 loblolly pine P. taeda 3-8 loblolly-shortleaf pine P. taeda-P. echinata 10 to < 35 Virginia pine P. virginiana 10 to < 35 Virginia pine-oak P. virginiana-Quercus spp. 10 to < 35 sycamore-sweetgum-American elm Platanus occidentalis-Liquidambar styraciflua-Ulmus americana 127] galleta-threeawn shrubsteppe Pleuraphis jamesii-Aristida purpurea < 35 to < 100 eastern cottonwood Populus deltoides 92] aspen-birch P. tremuloides-Betula papyrifera 35-200 [34,127] mesquite Prosopis glandulosa 86,92] mesquite-buffalo grass P. glandulosa-Buchloe dactyloides < 35 Texas savanna P. glandulosa var. glandulosa 92] black cherry-sugar maple Prunus serotina-Acer saccharum > 1,000 [127] mountain grasslands Pseudoroegneria spicata 3-40 (10**) [5,6] California mixed evergreen Pseudotsuga menziesii var. m.-Lithocarpus densiflorus-Arbutus menziesii < 35 California oakwoods Quercus spp. 6] oak-hickory Quercus-Carya spp. 127] oak-juniper woodland (Southwest) Quercus-Juniperus spp. 92] northeastern oak-pine Quercus-Pinus spp. 10 to 127] oak-gum-cypress Quercus-Nyssa-spp.-Taxodium distichum 35 to > 200 [90] southeastern oak-pine Quercus-Pinus spp. 127] coast live oak Q. agrifolia 2-75 [57] white oak-black oak-northern red oak Q. alba-Q. velutina-Q. rubra 127] canyon live oak Q. chrysolepis <35 to 200 blue oak-foothills pine Q. douglasii-P. sabiniana 6] northern pin oak Q. ellipsoidalis 127] Oregon white oak Q. garryana 6] bear oak Q. ilicifolia 127] California black oak Q. kelloggii 5-30 [92] bur oak Q. macrocarpa 127] oak savanna Q. macrocarpa/Andropogon gerardii-Schizachyrium scoparium 2-14 [92,127] shinnery Q. mohriana 92] chestnut oak Q. prinus 3-8 northern red oak Q. rubra 10 to < 35 post oak-blackjack oak Q. stellata-Q. marilandica < 10 black oak Q. velutina < 35 live oak Q. virginiana 10 to127] interior live oak Q. wislizenii 6] cabbage palmetto-slash pine Sabal palmetto-Pinus elliottii 90,127] blackland prairie Schizachyrium scoparium-Nassella leucotricha < 10 Fayette prairie Schizachyrium scoparium-Buchloe dactyloides < 10 little bluestem-grama prairie S. scoparium-Bouteloua spp. 92] baldcypress Taxodium distichum var. distichum 100 to > 300 pondcypress T. distichum var. nutans 90] western redcedar-western hemlock Thuja plicata-Tsuga heterophylla > 200 [6] eastern hemlock-yellow birch Tsuga canadensis-Betula alleghaniensis > 200 [127] western hemlock-Sitka spruce T. heterophylla-Picea sitchensis > 200 [6] elm-ash-cottonwood Ulmus-Fraxinus-Populus spp. 34,127] *fire return interval varies widely; trends in variation are noted in the species summaryOn native soils in the Middle East, tall tumblemustard grows on desert foothills. Tall tumblemustard is a common agricultural weed in its native Asia and throughout most of the rest of the world [78]. In North America it is a common weed of old fields, roadsides, and other disturbed places [56,66,68,83,91,126] such as alluvial fans [145] and disturbed rangelands [122].
Soils: Tall tumblemustard grows in soils of all textures, and is common on sand [91]. It readily establishes on loose, highly disturbed soils such as rodent mounds [106,115], but can also grow on compacted soils. On a Mojave Desert restoration site in Antelope Valley, California, native seeded-in species did not establish on a highly disturbed site with compacted soil; however, tall tumblemustard colonized the site and established dense cover [55].
Elevation: Tall tumblemustard has been recorded at the following ranges:
State Elevation CA < 8,200 ft (2,500 m) [62] NM 5,000-7,000 ft (1,500-2,100 m) [83] NV 1,400-6,500 ft (430-2,000 m) [76] UT 2,660-7,190 ft (820-2,410 m) [130]Impacts: Next to cheatgrass, tumble mustard is the 2nd most invasive alien plant species in the Great Basin [144,149]. Allen and Knight [2] suggest tall tumblemustard's success as an invasive weed is due to more effective seed dispersal compared to native herbaceous perennials, morphological plasticity in response to density stress (tall tumblemustard plants are short with shallow roots when crowded, but still produce numerous seeds), and earlier germination and more rapid seedling growth compared to native herbs.
Range: Tall tumblemustard is uncommon on good- to excellent-condition rangeland, and is an indicator of deteriorating rangeland quality [69]. Rangelands dominated by tall tumblemustard and other annuals show poor productivity compared to ranges dominated by perennial grasses [94]. Tall tumblemustard increases in response to grazing [93]. In mountain grasslands of central Utah, it was among the most important invaders on overgrazed plots in bluebunch wheatgrass-Sandberg bluegrass (Poa secunda) along with cheatgrass, Russian-thistle, cutleaf filaree, and yellow salsify (Tragopogon dubius) [22]. Daubemire [31] described tall tumblemustard as a seral species that benefits from grazing by release from the competition of more palatable species, but declines in frequency when successionally replaced.
Cropland: Tall tumblemustard is a serious crop weed [122,153]. Hay or grain infested with tall tumblemustard seeds is unpalatable to cattle and horses [122]. Tall tumblemustard is an alternate host for several crop diseases including potato leafroll virus [47,120].
Tall tumblemustard absorbs soil contaminants such as heavy metals and radioactive waste. Due to its tumbling habit, it may spread the contaminants to other sites [128].
Control: Tall tumblemustard 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 tall tumblemustard over time.
Prevention: Since tall tumblemustard is an early seral species, minimizing soil disturbance and seed dispersal and maintaining a healthy plant community is the best way to prevent establishment of tumble mustard [28]. Anderson and Inouye [3] found sagebrush steppe ecosystems of southeastern Idaho were statistically more resistant to invasion by tall tumblemustard and other exotic annuals when cover of native species was high (R2=0.16, P=0.008).
Integrated management: Land management practices that promote later-successional species can exclude tall tumblemustard from most plant communities [28]. Managers are encouraged to use combinations of control techniques that are appropriate to the site objectives, desired plant community, available resources, and timing of application. For information on integrated weed management without herbicides, see the Bio-Integral Resource Center (BIRC) website.
Physical/mechanical: Small infestations of tumble mustard can be controlled by hand pulling rosettes in the fall or early spring [28].
Fire: See Fire Management Considerations.
Biological: In free-choice trials, tall tumblemustard was the most palatable of 18 early successional annuals and biennials to native and introduced slug species [21].
Chemical: Herbicides are effective in gaining initial control of a new invasion or a severe infestation, but are rarely a complete or long-term solution to weed management [20]. Herbicides are more effective on large infestations when incorporated into long-term management plans that include replacement of weeds with desirable species, careful land use management, and prevention of new infestations. Control with herbicides is temporary, as it does not change those conditions that allow infestations to occur [151]. See the Weed Control Methods Handbook for considerations on the use of herbicides in natural areas and detailed information on specific chemicals.
Tall tumblemustard is susceptible to broadleaf herbicides including 2,4-D, MCPA, bromoxynil, atrazine, and chlorsulfon [1,36,77,117]. Phenoxy herbicides such as 2,4-D and MCPA provide best control (90-99%) [1,77,117].
Cultural: No informationAll classes of livestock consume minor to moderate amounts of tall tumblemustard, depending upon availability of other, more palatable forage [69]. For example, Rocky Mountain mule deer consume minor amounts of tall tumblemustard throughout the growing season [81]. Black-tailed jackrabbit in southern Idaho ate minor amounts of tall tumblemustard in summer [43]. Tall tumblemustard was a minor item in the spring diet of Townsend's ground squirrels on the Arid Land Ecology Reserve of Washington [72,73].
Palatability/nutritional value: Tall tumblemustard is palatable to livestock when young. Palatability of mature plants is low. The seeds are unpalatable to livestock [122]. Palatability of tall tumblemustard for livestock and wildlife has been rated as follows [33]:
MT ND UT WY cattle poor poor poor fair domestic sheep fair fair fair fair horses poor poor fair ---- pronghorn ---- ---- fair ---- elk poor ---- fair ---- mule deer poor ---- fair ---- small mammals ---- ---- fair ---- small nongame birds ---- ---- fair ---- upland game birds ---- ---- fair ---- waterfowl ---- ---- poor ----Cover value of tall tumblemustard for Utah wildlife has been rated as follows [33]:
pronghorn poor elk poor mule deer poor small mammals fair small game birds fair upland game birds fair waterfowl poorTall tumblemustard is a honeybee and butterfly plant [75]. It helps bind fine-textured soils [88].
Native Americans made meal from ground tumble mustard seeds. The greens can be used in salads [88].
Tall tumblemustard establishes from soil-stored seed and seed blown or transported in after fire [41,45,108,137]. It is most frequent on early seral burns [26,72]. For example, in a Idaho fescue-prairie Junegrass (Festuca idahoensis-Koeleria macrantha) community of northeastern Oregon, tumble mustard and mountain tansymustard (Descurainia richardsonii) pioneered on severely burned sites, but were absent by the 5th postfire year [72]. In Colorado pinyon-Utah juniper (Juniperus osteosperma) stands of west-central Utah, tall tumblemustard occurred on 6- and 11-year-old burns, but not older burns [10].
Tall tumblemustard cover (%) on burned and unburned plots after a June 1977 fire on Mt. Sentinel in Missoula, Montana, is shown below. The cover type is rough fescue (Festuca altaica)-Idaho fescue-bluebunch wheatgrass mountain grassland [4].
Autumn 1977 Spring 1978 Summer 1979 unburned burned unburned burned unburned burned <0.05% 0.6 0.3 2.6** 0.4 3.0* *=differences between burned and unburned significant (p **=differences between burned and unburned significant (pAnother study of plant cover the after same fire showed similar effects. Although tall tumblemustard cover (%) was low on burned and unburned plots, tall tumblemustard increased with fire. Measurements were taken in November 1977, 5 months after the Mt. Sentinel Fire [85]:
unburned burned 0.05 0.58* *=differences between burned and unburned significant (p<0.01)One year after a July wildfire in a ponderosa pine/bluebunch wheatgrass community of British Columbia, tall tumblemustard established as follows [71]:
Frequency (%) Basal cover (%) Aerial cover (%) unburned burned unburned burned unburned burned 0.0 20.0 0.0 trace 0.0 0.2±4.80Although fire creates the open canopy and bare mineral soil that favors tall tumblemustard establishment, tall tumblemustard is not an obligate "fire follower." Any area with bare ground, open sunlight, and a seed source is vulnerable to tall tumblemustard invasion [70].
As an annual, tall tumblemustard reproduces solely from seed.
Breeding system: Mustards (Brassicaceae) are cross-pollinated. Selfing also occurs [61].
Pollination is by insects [61].
Seed production: Tall tumblemustard is a prolific seed producer. A single plant can produce up to 12,500 siliques and 1.5 million seeds [24,88].
Seed dispersal: Seeds disperse when the dead, dried parent plant breaks at the stem base and tumbles or slides across the ground by wind or other movement [88,122,142]. The fruits are tough and shatter slowly, so only a few seeds at a time are released. Consequently, the dried plant may disperse seeds throughout fall and winter, across many miles [78,88,122,135]. Animals disperse seeds when the wet, mucilaginous seed coat sticks to feathers or fur [149]. Machinery can pick up branches and whole plants, transporting seeds hundreds to thousands of miles. Tall tumblemustard's initial expansion westward was probably facilitated by railroad cars. One of the species' common names, Jim Hill mustard, comes from the name of the early railroad magnate [88,129].
Seed banking: Tall tumblemustard builds up a long-term seed bank [50,52,63,146,152]. Seed stored over 40 years has germinated in the laboratory (review by [133]). It is unclear how long seed remains viable in natural seed banks. In a Virginia pasture experiment, tumble mustard seed buried 8 inches (20 cm) deep in pots showed 10% germination after 2 years' burial, 21.5% after 4 years, 79% after 7 years, and 0% germination after 17 and 22 years [52].
Tall tumblemustard's soil seed bank is dynamic, reaching greatest seasonal density in fall and greatest year-to-year fluctuation in wet years. In Yellowstone National Park, mean seed bank density of tall tumblemustard (based on number of emergents in soil samples) was 53 plants/m2 [23]. A degraded big sagebrush-spiny hopsage/Thurber needlegrass (Grayia spinosa/Achnatherum thurberianum) community near Reno, Nevada, showed seasonal and spatial variation in density of tumble mustard seed as follows [146]:
StrataTime of sampling (seeds/m2)
Percent of total samples collected/layer Sept. Nov. Dec. Feb. May between shrubs: litter 200 1,350 100 ---- ---- 92 soil 100 25 ---- 25 8 under shrubs: litter 750 750 550 100 540 84 soil 175 100 100 25 80 16Germination: Tall tumblemustard seeds become mucilaginous upon wetting, which helps them retain moisture. Seeds can germinate on the seedbed surface without litter or soil covering [78,146]. In the absence of cheatgrass, tall tumblemustard may show better germination and establishment with litter; however, when cheatgrass is present in the seed bank, cheatgrass tends to outcompete tall tumblemustard [146]. Tall tumblemustard seeds are immediately germinable at temperatures from 32 to 68 degrees Fahrenheit (0-20 oC), with no stratification requirement. Best germination occurs on fine-textured soils with temperatures around 50 degrees Fahrenheit (10 oC) [149]. Near Reno, seeds showed best germination in May [146]. Germination rates are generally good, but irregular. In southern Idaho, tall tumblemustard seed stored for a year in an unheated shed showed 93% germination [67]. Seed lots collected in northern Nevada and northeastern California showed irregular germination; they did not all germinate at 1 time under "ideal" laboratory temperature and moisture conditions. Seed lots were collected over 4 consecutive years. Germination continued for 12 weeks, with some seeds germinating in their 2nd year [149]. Frequency of tall tumblemustard in a black sagebrush (Artemisia nova) community of west-central Nevada was highest in a year of above-average annual precipitation. Mean frequency (% and 1 standard error (SE)) varied as follows [150]:
Average ppt (n=4 years, µ=175 mm annual ppt) Dry year (1989, no April ppt; annual ppt not available) Wet year (1986, 225 mm annual ppt) 5 (0.9) 0 10 (0.8)Tall tumblemustard seeds show some ability to withstand short-term high temperatures. Seeds collected from Yellowstone National Park showed equal emergence (53/m2 ) from soil samples at room temperature and samples heated to 120 degrees Fahrenheit (50 oC). Emergence dropped to 13/m2 at 210 degrees Fahrenheit (100 oC) and 0 at 300 degrees Fahrenheit (150 oC) [23].
Seedling establishment/growth: Tall tumblemustard shows best establishment on mineral soil under an open canopy. In the Reno study discussed above, Young and Evans [146] found better tumble mustard establishment between shrubs compared to under shrubs. They attributed this to better litter and soil moisture conditions for cheatgrass under shrubs, where cheatgrass outcompeted tall tumblemustard.
Tall tumblemustard seedlings grow rapidly. In uncrowded stands, they form large rosettes before bolting [2]. Emergence and establishment are enhanced by uneven microtopography, with tall tumblemustard establishing best in pits and furrows [55,144,148].
As annuals, tall tumblemustard populations fluctuate in size depending upon climate and other factors [94,102]. In a big sagebrush/bluebunch wheatgrass (Pseudoroegneria spicata) community of eastern Washington, tall tumblemustard was absent from study plots in 1977, a drought year. Its mean biomass was 0.77 g/m2 in 1978, when precipitation was average [35]. In years of above-average precipitation, tall tumblemustard and other annuals can produce considerable biomass. With disturbance, the annuals may invade areas where they were sparse or absent before the frequent rains [37].
Tall tumblemustard requires an open to light canopy [69,124,146], and is most common in early stages of succession [2,22,25,31,96].
Tall tumblemustard occurrence in early sagebrush steppe succession is well documented. In big sagebrush of Wyoming, for example, tall tumblemustard occurred 2 and 3 years after disking near an abandoned oil drilling site [2]. A classic seral continuum is described by Piemeisel [96] and other authorities [40,113,121] where Russian-thistle pioneers on sagebrush steppe disturbed by fire or other means. Tall tumblemustard establishes next, followed by tansymustard (Descurainia spp.) and cheatgrass. Medusahead, Scotch thistle (Onopordum acanthium), and other species may extend or alter the classic continuum [40,41]. A 20-year study in southern Idaho showed old-field succession on former big sagebrush steppe was initially dominated by Russian-thistle, tall tumblemustard, and tansymustard. An increase in cheatgrass and bottlebrush squirreltail (Elymus elymoides) followed; after that, there was a temporary increase in mustards and a decrease in Russian-thistle. The community eventually stabilized as a cheatgrass-bottlebrush squirreltail cover type [64]. A similar pattern occurred in sagebrush steppe of Washington, where tall tumblemustard codominated recently disturbed sites along with Russian-thistle, prickly-lettuce (Lactuca serriola), and bur ragweed (Ambrosia acanthicarpa). Cheatgrass dominated slightly older seres such as old fields [15]. Some annual-dominated communities may be stable [64]. On the Atomic Energy Commission's Hanford Reservation, Washington, old fields have supported cheatgrass-tall tumblemustard-tansymustard communities for 30 or more years [27]. Tall tumblemustard is not highly invasive in undisturbed sagebrush communities. In lightly grazed and ungrazed sites in a big sagebrush/bluebunch wheatgrass community of eastern Washington, tall tumblemustard established in severely trampled areas where cattle congregated (watering troughs and fencelines), but did not invade other portions of the otherwise lightly grazed site or the ungrazed site [101].
Other communities: Tall tumblemustard's successional role is less well documented in plant communities other than sagebrush. Similar to its pattern of occurrence in early seral sagebrush, a few studies show early tumble mustard invasion in disturbed communities followed by tall tumblemustard's successional replacement by perennials. In western wheatgrass-buffalo grass-blue grama (Pascopyrum smithii-Buchloe dactyloides-Bouteloua gracilis) communities of Nebraska, tall tumblemustard occurs in wetland succession at the edges of ponds. On upland sites it occurs on deep, poorly bound, wind-deposited soils along with common sunflower (Helianthus annuus), prairie sunflower (H. petiolaris), and lambsquarters (Chenopodium album) [74]. In a shadscale community of south-central Idaho, tall tumblemustard, halogeton, clasping pepperweed, and cheatgrass invaded after a combination of drought and root-mining mealybugs killed most of the overstory shadscale. Six years after the shadscale dieback, the site was dominated by halogeton and annual weeds. Grasshopper populations were high the 7th year following the dieback, so halogeton, tall tumblemustard, and other annuals maintained dominance with grasshopper grazing. Shadscale, gooseberryleaf globemallow (Sphaeralcea grossulariifolia), and native perennial grasses gained dominance the next year, when the drought ended and the insect populations declined [110].
Tall tumblemustard is nonmycorrhizal [12,46]; therefore, it can colonize sterile sites or sites undergoing primary succession.
