More info for the terms: association, bog, cover, fen, fern, ferns, forb, frequency, hardwood, lichens, mesic, nonnative species, peat, prescribed fire, shrubs, tree
Orange hawkweed occurs in a variety of plant communities within its North American distribution, including grasslands and other open areas, forests, and wetlands. A management guide suggests that sites most vulnerable to orange hawkweed establishment in the Pacific Northwest are disturbed areas, including roadsides, pastures, hay fields, abandoned farmland, mountain meadows, logged areas, and forest clearings [108].
Open plant communities: Floras commonly report orange hawkweed occurring in fields [24,26,27,60,67,76,79,85,102,110], pastures [76,102], meadows [26,67], and open hillsides [67]. On Prince Edward Island, orange hawkweed occurred in old fields regenerating into red spruce (Picea rubens) forest and was not found in forest interiors [14]. An extension service publication from Montana reports that orange hawkweed is closely associated with habitats that support oxeye daisy (Leucanthemum vulgare), sulfur cinquefoil (Potentilla recta) and spotted knapweed (Centaurea maculosa) [75]. Distribution records from Washington document orange hawkweed occurring on a dry gravel roadside with common St Johnswort (Hypericum perforatum), red alder (Alnus rubra), broom (Cytisus), pearly everlasting (Anaphalis), and field horsetail (Equisetum arvense) [74].
As of this writing (2010), there were few descriptions of open, native plant communities with orange hawkweed. On Nantucket Island, Connecticut, orange hawkweed was found on sand dunes [4]. It occurred infrequently in sand barren plant communities in southeastern Ontario. Sand barrens were dry openings surrounded by and interspersed with jack pine (Pinus banksiana) forest [13]. Orange hawkweed was one of several nonnative species to dominate upland bracken fern-grasslands in northern Wisconsin. Bracken fern-grasslands contained western bracken fern (Pteridium aquilinum), slender wheatgrass (Elymus trachycaulus), arctic brome (Bromus kalmii), poverty oatgrass (Danthonia spicata), and roughleaf ricegrass (Oryzopsis asperifolia) [15]. In another Wisconsin upland bracken-grassland on ridges and hillsides, orange hawkweed, poverty oatgrass, and lichens dominated the understory [100]. Orange hawkweed was infrequently encountered in heavily grazed pastures and ungrazed, native tallgrass prairie in north-central Oklahoma. Native tallgrass prairie contained indiangrass (Sorghastrum nutans), big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), paintbrush bluestem (Andropogon ternarius), and silver bluestem (Bothriochloa saccharoides) [52]. Orange hawkweed was also documented in the Palouse Prairie region of western Idaho [5]. A nonnative species guide to Alaska reported that orange hawkweed was rapidly expanding within a native forb and fern meadow on Camp Island in the Kodiak National Wildlife Refuge [35].
Forested plant communities: Orange hawkweed occurs in forested plant communities throughout its North American distribution. Forested plant community descriptions below are organized by forests that are primarily coniferous, primarily deciduous, or mixed coniferous-deciduous.
Coniferous forests: Orange hawkweed occurs in coniferous forests in the Northeast, Great Lakes region, and Northwest.
In southeastern New Brunswick, orange hawkweed was found in 3- to 8-year-old black spruce (Picea mariana) plantations (25% frequency). Surrounding forest contained red spruce, white spruce (P. glauca), balsam fir (Abies balsamea), sugar maple (Acer saccharum), red maple (A. rubrum), yellow birch (Betula alleghaniensis), and paper birch (B. papyrifera) [99]. In Maine, orange hawkweed occurred in large, recent (<15-year-old) clearcuts in red spruce forests [17]. In the southern Adirondack Mountains of New York, orange hawkweed occurred in forest openings in old-growth eastern white pine-eastern hemlock (Pinus strobus-Tsuga canadensis) forest [65]. In southeastern Ontario, orange hawkweed occurred at 10% to 45% frequency in approximately 70-year-old coniferous forests containing white spruce, eastern white pine,
balsam fir, and black spruce [61].
In northern Michigan, orange hawkweed was detected infrequently in mesic forests dominated by white spruce and balsam fir [62]. It was common 2 years after prescribed fire in a 35-year-old jack pine forest in northern Lower Michigan [1]. In northern Wisconsin, orange hawkweed was found along the edges and in the interior of jack pine and red pine (P. resinosa) plantations [21]. In northern Wisconsin, orange hawkweed was detected with low frequency (5%) in jack pine barrens consisting of open, shrubby areas with scattered young jack pine and infrequent older red pine.
Scattered patches of regenerating or mature aspen
(Populus spp.), oak (Quercus spp.), and maple (Acer spp.) were also present [8].
Distribution records from Montana documented orange hawkweed occurring in subalpine fir/dwarf huckleberry (A. lasiocarpa/Vaccinium caespitosum), grand fir/queencup beadlily (Abies grandis-Clintonia uniflora), and subalpine fir/queencup beadlily-beargrass (Xerophyllum tenax) plant communities [74]. It was detected in successional lodgepole pine (Pinus contorta) forests in northwestern Montana [43]. In British Columbia, orange hawkweed occurred at low levels in mixed Douglas-fir (Pseudotsuga menziesii)-lodgepole
pine forests that had undergone single seed-tree retention harvests 5 to 8 years prior to sampling [87]. Orange hawkweed was scarce in 6- to 10-year-old Engelmann spruce (Picea engelmannii)-subalpine fir plantations in southeastern British Columbia. [50].
Deciduous forests: Orange hawkweed occurs in deciduous forests in the Southeast, Northeast, Great Lakes region, and the Northwest.
A flora reports orange hawkweed occurring in openings in oak-hickory (Quercus-Carya) forests in North and South Carolina [72].
On Prince Edward Island, orange hawkweed occurred in interior upland hardwood forests, forest edge, and adjacent developed communities. Hardwood forests were dominated by yellow birch, sugar maple, and American beech (Fagus grandifolia) [59]. In northeastern New Brunswick, orange hawkweed occurred in the understory of 7- to 25 -year-old mixed-hardwood forests. Orange hawkweed cover ranged from 2% to 14%, with no clear pattern of cover relative to stand age. Mixed-hardwood forests contained a mixture of pin cherry (Prunus pensylvanica), red maple, quaking aspen (Populus tremuloides), and paper birch [58]. In central New York, orange hawkweed occurred in the interior of sugar maple forests adjacent to residential areas. American beech, basswood (Tilia americana), eastern hemlock, and white ash (Fraxinus americana) were other common overstory trees [68].
Orange hawkweed occurred in several aspen (Populus) plant associations in northern Lower Michigan. It occurred in seral forests dominated by bigtooth aspen (P. grandidentata), paper birch, and quaking aspen; hardwood forests with pin cherry, paper birch, red maple, American beech, sugar maple, and bigtooth aspen; and lowland or bog forests containing quaking aspen and bigtooth aspen [25]. In northern Michigan, orange hawkweed occurred on a sandy ridge in a pin cherry plant association. The forest was dominated by short (<33 feet (10 m) in height) pin cherry trees but also contained red maple and small amounts of black spruce [20]. On the Upper Peninsula of Michigan, orange hawkweed occurred in northern hardwood forests dominated by sugar maple, with lesser amounts of yellow birch, basswood, eastern hemlock, red maple, and eastern hophornbeam (Ostrya virginiana) [10]. In the same region, orange hawkweed dominated the understory of a dry, open area near a quaking aspen forest. It also occurred in the understory of a floodplain with speckled alder (Alnus incana subsp. rugosa), black ash (F. nigra), balsam poplar (P. balsamifera), and quaking aspen [86].
Distribution records from Idaho document orange hawkweed occurring in a "weedy aspen grove" [74].
Mixed coniferous-deciduous forests: In a beach-dune complex on the shores of Lake Michigan in eastern Wisconsin, orange hawkweed was infrequent in ridge forests codominated by red maple, northern whitecedar (Thuja occidentalis), eastern white pine, red pine, eastern hemlock, and paper birch [97]. In northern Wisconsin and the Upper Peninsula of Michigan, orange hawkweed was detected frequently in upland forests dominated by eastern white pine, eastern hemlock, and/or sugar maple [104].
Wetland plant communities: Orange hawkweed occurs in wetland plant communities with variable tree canopy cover. In north-central Massachusetts, orange hawkweed occurred in a small (500 feet (150 m) in diameter), herbaceous wetland adjacent to mixed-mesophytic forests of red maple, American beech, paper birch, gray birch (B. populifolia), white ash, northern red oak (Q. rubra), eastern white pine, and eastern hemlock [63]. Orange hawkweed occurred with high cover in a rich fen in southwestern New York [23]. Orange hawkweed was found in a bog mined for peat in southern Ontario. Quaking aspen and birch (Betula spp.) dominated disturbed areas, while open stands of birch were found on relatively undisturbed areas [44]. On the Upper Peninsula of Michigan, orange hawkweed occurred in a sedge (Cyperaceae) fen. Broadleaf deciduous forests dominated upland areas, while a mixture of sedges, grasses, and low shrubs dominated low wetland areas [49]. In Wisconsin, orange hawkweed occurred in sedge meadows used for commercial cranberry production. Sedge meadows were dominated by sedges, asters (Asteraceae), knotweeds (Polygonaceae), ferns (Osmundaceae, Polypodiaceae), and roses (Rosaceae) [45].
Orange hawkweed is described as a dominant groundlayer species in the following vegetation classification from Wisconsin:
- upland western bracken fern-grasslands; slender wheatgrass, arctic brome, poverty oatgrass, and roughleaf ricegrass are characteristic grass dominants [15]
