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Wildlife, Animals, and Plants |
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DISTRIBUTION AND OCCURRENCE
GENERAL DISTRIBUTION:Diffuse knapweed is native to grasslands and shrub steppes of the eastern Mediterranean and western Asia [66] and was introduced into Central Europe and North America [71]. It is thought to have been introduced to North America as a contaminant in alfalfa (Medicago sativa) seed from Asia Minor-Turkmenistan or in hybrid alfalfa seed from Germany [58]. The earliest record of diffuse knapweed in North America is from an alfalfa field in Washington state in 1907 [86]. It is currently found from Yukon in the north, throughout most of western Canada, east to Ontario. In the United States, the primary range of diffuse knapweed is the western states, from Washington, Idaho and Montana south to New Mexico and Arizona [42]. Maddox [59] notes that diffuse knapweed is more common on the western side of the Great Basin, and spotted knapweed is more common on the eastern side. Diffuse knapweed has also spread east into several midwestern states and is found in Massachusetts, Connecticut, and New Jersey on the east coast [42]. The Plants database provides a distribution map of diffuse knapweed in the United States. The following table reflects estimates of spotted knapweed acreage as reported by surveyed states or provinces in 1988 and again in 2000 (from [20]):
Although inventories are more common and more accurate in the year 2000 than in 1988, 50% of these states reported only 50% accuracy, while 31% reported 51 to 75% accuracy, and 2 states reported 75 to 100% accuracy [20]. The following lists reflect ecosystems and cover types in which diffuse knapweed is known or thought to be invasive. Diffuse knapweed occurs in some midwestern and eastern states and provinces, primarily along roadsides and in "waste places", but it is unclear, from the available literature on these areas, which ecosystems and cover types it occurs in. These lists are not, therefore, exhaustive, as the plant may be invasive in other types as well. ECOSYSTEMS [29]:FRES20 Douglas-fir FRES21 Ponderosa pine FRES22 Western white pine FRES23 Fir-spruce FRES26 Lodgepole pine FRES29 Sagebrush FRES35 Pinyon-juniper FRES36 Mountain grasslands FRES38 Plains grasslands FRES40 Desert grasslands STATES:
BLM PHYSIOGRAPHIC REGIONS [10]:1 Northern Pacific Border 2 Cascade Mountains 3 Southern Pacific Border 4 Sierra Mountains 5 Columbia Plateau 6 Upper Basin and Range 7 Lower Basin and Range 8 Northern Rocky Mountains 9 Middle Rocky Mountains 10 Wyoming Basin 11 Southern Rocky Mountains 12 Colorado Plateau KUCHLER [48] PLANT ASSOCIATIONS:K005 Mixed conifer forest K010 Ponderosa shrub forest K011 Western ponderosa forest K012 Douglas-fir forest K013 Cedar-hemlock-pine forest K014 Grand fir-Douglas fir forest K015 Western spruce-fir forest K018 Pine-Douglas-fir forest K019 Arizona pine forest K023 Juniper-pinyon woodland K024 Juniper steppe woodland K050 Fescue-wheatgrass K051 Wheatgrass-bluegrass K053 Grama-galleta steppe K055 Sagebrush steppe K056 Wheatgrass-needlegrass shrubsteppe K063 Foothills prairie K064 Grama-needlegrass-wheatgrass K066 Wheatgrass-needlegrass SAF COVER TYPES [23]:205 Mountain hemlock 206 Engelmann spruce-subalpine fir 210 Interior Douglas-fir 215 Western white pine 218 Lodgepole pine 220 Rocky Mountain juniper 224 Western hemlock 235 Cottonwood-willow 237 Interior ponderosa pine 238 Western juniper 239 Pinyon-juniper 243 Sierra Nevada mixed conifer 244 Pacific ponderosa pine-Douglas-fir 245 Pacific ponderosa pine 247 Jeffrey pine SRM (RANGELAND) COVER TYPES [103]:101 Bluebunch wheatgrass 102 Idaho fescue 104 Antelope bitterbrush-bluebunch wheatgrass 105 Antelope bitterbrush-Idaho fescue 107 Western juniper/big sagebrush/bluebunch wheatgrass 109 Ponderosa pine shrubland 110 Ponderosa pine-grassland 301 Bluebunch wheatgrass-blue grama 302 Bluebunch wheatgrass-Sandberg bluegrass 303 Bluebunch wheatgrass-western wheatgrass 304 Idaho fescue-bluebunch wheatgrass 305 Idaho fescue-Richardson needlegrass 306 Idaho fescue-slender wheatgrass 309 Idaho fescue-western wheatgrass 314 Big sagebrush-bluebunch wheatgrass 315 Big sagebrush-Idaho fescue 317 Bitterbrush-bluebunch wheatgrass 318 Bitterbrush-Idaho fescue 320 Black sagebrush-bluebunch wheatgrass 321 Black sagebrush-Idaho fescue 401 Basin big sagebrush 402 Mountain big sagebrush 403 Wyoming big sagebrush 404 Threetip sagebrush 405 Black sagebrush 406 Low sagebrush 407 Stiff sagebrush 408 Other sagebrush types 409 Tall forb 412 Juniper-pinyon woodland 420 Snowbrush 421 Chokecherry-serviceberry-rose 612 Sagebrush-grass 613 Fescue grassland 614 Crested wheatgrass HABITAT TYPES AND PLANT COMMUNITIES:Pacific Northwest: Diffuse knapweed is found primarily in the eastern part of Washington state, on the northwest slopes of the Columbia River Basin. Here it may be found in shrub steppe, natural grassland, and dry forest steppe types [87]. Diffuse knapweed demonstrates superior invasiveness in antelope bitterbrush (Purshia tridentata)/bluebunch wheatgrass (Pseudoroegneria spicata) communities, with or without needle-and-thread grass (Hesperostipa comata) in eastern Washington [85,115]. It may also be dominant in bitterbrush habitat types with or without an overstory of ponderosa pine (Pinus ponderosa). Diffuse knapweed is also common in ponderosa pine/shrub, Douglas-fir/common snowberry (Pseudotsuga menziesii/Symphoricarpos albus), and Douglas-fir/ninebark (Physocarpus malvaceus) habitat types that have been cleared and either converted to pasture or support tree regeneration. Most dryland pastures now dominated by diffuse knapweed were previously dominated by Kentucky bluegrass (Poa pratensis). On the east slope of the Cascades, diffuse knapweed can be found at middle to low elevations from ponderosa pine and bunchgrass habitats into big sagebrush (Artemisia tridentata)/bunchgrass types [85], where it may be found with bluebunch wheatgrass, Sandberg bluegrass (Poa secunda), Russian-thistle (Salsola kali), and cheatgrass (Bromus tectorum) [96]. In Utah, the antelope bitterbrush/bunchgrass shrub steppe is highly susceptible to invasion by diffuse knapweed [85]. In Colorado, diffuse knapweed invades the shortgrass steppe along the Front Range, including the foothills. Adjacent montane zones and the lower elevation pinyon-juniper-oak (Pinus-Juniperus-Quercus spp.) brush zones are also susceptible [85]. Diffuse knapweed is also found on upland sites in pinyon and juniper woodlands in the interior west [114]. In Montana, diffuse knapweed infestations are found primarily on grasslands and fringe forest areas near Helena, Big Timber, and Ennis [49]. It is well adapted to open-forested areas, especially after logging or other disturbances [27]. Canada: The interior natural grasslands and fringe forest areas of southern British Columbia and the shortgrass prairies of Alberta and Saskatchewan are considered vulnerable to diffuse knapweed invasion [36,68]. Native bunchgrasses may be replaced with annual grasses, sagebrush (Artemisia spp.), and diffuse and spotted knapweed [80]. Diffuse knapweed may be found with bluebunch wheatgrass, Idaho fescue (Festuca idahoensis), bluegrasses (Poa spp.), needle-and-thread grass, Columbia needlegrass (Achnatherum nelsonii ssp. dorei), sand dropseed (Sporobolus cryptandrus), and slender wheatgrass (Elymus trachycaulus) [11,41,68]. In British Columbia, diffuse knapweed is also found in areas supporting ponderosa pine, Douglas-fir, antelope bitterbrush, and ninebark communities. Diffuse knapweed has also established on dry subzones of the ponderosa pine, interior Douglas-fir, montane spruce, and interior cedar-hemlock biogeoclimatic zones in southern interior of British Columbia. Here it may be found with Douglas-fir, lodgepole pine (Pinus contorta), Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa), and understory components such as pinegrass (Calamagrostis rubescens), fireweed (Epilobium angustifolium), and Vaccinium spp. [79].HABITAT TYPES AND PLANT COMMUNITIES:
Related categories for SPECIES: Centaurea diffusa | Diffuse Knapweed |
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