Vegetation of the Milton Ranch
by H. Wayne Phillips
Introduction
The Milton Ranch is a land of rolling hills, clothed with grasses, numerous wildflowers, sagebrush, and pine woodlands. On the north side of the ranch the rolling hills are dominated by the Big Wall, a long, pine covered sandstone ridge. An intermittent tributary of North Willow Creek, winds it’s sinuous, northerly course through the ranch, and ultimately turns easterly around the Big Wall and drains northeast to join the Musselshell River, a tributary of the great Missouri River watershed.
The Milton Ranch is a land of rolling hills, clothed with grasses, numerous wildflowers, sagebrush, and pine woodlands. On the north side of the ranch the rolling hills are dominated by the Big Wall, a long, pine covered sandstone ridge. An intermittent tributary of North Willow Creek, winds it’s sinuous, northerly course through the ranch, and ultimately turns easterly around the Big Wall and drains northeast to join the Musselshell River, a tributary of the great Missouri River watershed.
The Ranch includes 14,646 acres located in south-central Montana, about 14 miles northeast of Roundup and 65 miles northeast of Montana’s largest city, Billings. Elevation ranges from about 3260 to 3580 feet above sea level. The Ranch is within Townships 9 and 10 North, Range 26 and 27 East, Montana Principal Meridian. Latitude is about 46 degrees, 35 minutes north; and longitude is about 108 degrees, 25 minutes west. Annual precipitation averages 13 inches. The average frost-free period is about 140 days, between the second week of May and the end of September.
The ranch land lies within the Northwestern Great Plains Eco-region, a subdivision of the Great Plains Dry Steppe Province. This eco-region is characterized by un-glaciated, semiarid, rolling plains, underlain by shale, siltstone, and sandstone. The native vegetation is short-grass prairie, consisting principally of wheatgrasses, needlegrasses, gramagrasses, milkvetches, sagebrush, and rabbitbrush. It contains some broken terrain punctuated with buttes, badlands, and ephemeral, intermittent streams, and a few perennial rivers. Low precipitation and high summer evapo-transpiration rates restrict groundwater recharge. The ranch lies largely within the Montana Central Grasslands subdivision of the Northwestern Great Plains Eco-region, with elements of the adjacent Pine Scoria Hills subdivision in the Bull Mountains.
The diverse vegetation of Milton Ranch is described below, both in terms of its flora and its plant communities. The flora section discusses the vascular plant families and species that are known to occur on the ranch, including flowering plants, conifers, ferns, mosses, horsetails, and club mosses. Non-vascular plants (algae, liverworts, mosses, and fungi), while they do occur on the ranch, have not been inventoried as of this writing, and therefore are not discussed.
The plant community section describes the aspect of the vegetation, that is, the groupings of plant species growing together on particular habitats of the ranch, such as: grasslands, where grasses and forbs are the dominant vegetation; shrublands, where sagebrush, greasewood, or yucca are the dominant species along with grasses; and pine woodlands, dominated by ponderosa pine trees, grasses and forbs. We often refer to these plant communities as vegetation types.
The plant communities occurring on the Milton Ranch have developed in response to complex biotic and abiotic factors of their habitat, such as: geological parent material, soil texture, soil pH, soil biota, cardinal direction of slope aspect, slope steepness, fire history, and cultural events, such as ground breaking and cropping. For example, pine woodlands occur on the shallow, sandy soils associated with sandstone outcrops, while greasewood shrubland is found on clayey, clay pan and overflow sites. Grasslands of introduced grasses, such as crested wheatgrass, are found where the native prairie was broken with the plow for growing crops, and eventually seeded with introduced grass species. These disturbed areas initially lost the entire native plant diversity found on the undisturbed lands of the ranch, however, native species are gradually invading these areas, with plant succession now occurring back toward native plant community vegetation.
FLORA OF THE MILTON RANCH
a. Introduction
Milton Ranch flora includes at least 260 vascular plant species in 175 genera and 53 plant families. “Vascular Plants of Montana” by Robert D. Dorn, Mountain West Publishing, 1984, was the botanical manual used in the classification of plant species on the Ranch. The list of vascular species, arranged alphabetically by genus and species, is found in Appendix #1.
Among the 53 plant families represented in the Milton Ranch flora, four families stand out as together having over half of the species found. The aster family (Asteraceae) leads the way with 57 species, followed by the grass family (Poaceae) with 38 species, the bean family (Fabaceae) with 28 species, and the mustard family (Brassicaceae) with 20 species. The remaining 49 plant families are represented by fewer than 10 species each, with the majority having only a single species per plant family. The list of 253 vascular species found on the ranch, arranged alphabetically by plant family, is found on Appendix #2.
There are 12 milkvetch species on the ranch, by far the highest number of species of any genus in the flora. Milkvetches are in the genus Astragalus of the bean family (Fabaceae).
Milkvetches of the Milton Ranch:
Standing milkvetch, Astragalus adsurgens, purple flowers
Field milkvetch, Astragalus agrestis, purple flowers
Two-grooved milkvetch, Astragalus bisulcatus, purple flowers
The ranch land lies within the Northwestern Great Plains Eco-region, a subdivision of the Great Plains Dry Steppe Province. This eco-region is characterized by un-glaciated, semiarid, rolling plains, underlain by shale, siltstone, and sandstone. The native vegetation is short-grass prairie, consisting principally of wheatgrasses, needlegrasses, gramagrasses, milkvetches, sagebrush, and rabbitbrush. It contains some broken terrain punctuated with buttes, badlands, and ephemeral, intermittent streams, and a few perennial rivers. Low precipitation and high summer evapo-transpiration rates restrict groundwater recharge. The ranch lies largely within the Montana Central Grasslands subdivision of the Northwestern Great Plains Eco-region, with elements of the adjacent Pine Scoria Hills subdivision in the Bull Mountains.
The diverse vegetation of Milton Ranch is described below, both in terms of its flora and its plant communities. The flora section discusses the vascular plant families and species that are known to occur on the ranch, including flowering plants, conifers, ferns, mosses, horsetails, and club mosses. Non-vascular plants (algae, liverworts, mosses, and fungi), while they do occur on the ranch, have not been inventoried as of this writing, and therefore are not discussed.
The plant community section describes the aspect of the vegetation, that is, the groupings of plant species growing together on particular habitats of the ranch, such as: grasslands, where grasses and forbs are the dominant vegetation; shrublands, where sagebrush, greasewood, or yucca are the dominant species along with grasses; and pine woodlands, dominated by ponderosa pine trees, grasses and forbs. We often refer to these plant communities as vegetation types.
The plant communities occurring on the Milton Ranch have developed in response to complex biotic and abiotic factors of their habitat, such as: geological parent material, soil texture, soil pH, soil biota, cardinal direction of slope aspect, slope steepness, fire history, and cultural events, such as ground breaking and cropping. For example, pine woodlands occur on the shallow, sandy soils associated with sandstone outcrops, while greasewood shrubland is found on clayey, clay pan and overflow sites. Grasslands of introduced grasses, such as crested wheatgrass, are found where the native prairie was broken with the plow for growing crops, and eventually seeded with introduced grass species. These disturbed areas initially lost the entire native plant diversity found on the undisturbed lands of the ranch, however, native species are gradually invading these areas, with plant succession now occurring back toward native plant community vegetation.
FLORA OF THE MILTON RANCH
a. Introduction
Milton Ranch flora includes at least 260 vascular plant species in 175 genera and 53 plant families. “Vascular Plants of Montana” by Robert D. Dorn, Mountain West Publishing, 1984, was the botanical manual used in the classification of plant species on the Ranch. The list of vascular species, arranged alphabetically by genus and species, is found in Appendix #1.
Among the 53 plant families represented in the Milton Ranch flora, four families stand out as together having over half of the species found. The aster family (Asteraceae) leads the way with 57 species, followed by the grass family (Poaceae) with 38 species, the bean family (Fabaceae) with 28 species, and the mustard family (Brassicaceae) with 20 species. The remaining 49 plant families are represented by fewer than 10 species each, with the majority having only a single species per plant family. The list of 253 vascular species found on the ranch, arranged alphabetically by plant family, is found on Appendix #2.
There are 12 milkvetch species on the ranch, by far the highest number of species of any genus in the flora. Milkvetches are in the genus Astragalus of the bean family (Fabaceae).
Milkvetches of the Milton Ranch:
Standing milkvetch, Astragalus adsurgens, purple flowers
Field milkvetch, Astragalus agrestis, purple flowers
Two-grooved milkvetch, Astragalus bisulcatus, purple flowers
Ground plum, Astragalus crassicarpus, white-purple flowers
Drummond’s milkvetch, Astragalus drummondii, white flowers
Cushion milkvetch, Astragalus gilviflorus, white to cream-colored flowers
Slender milkvetch, Astragalus gracilis, lavender flowers
Missouri milkvetch, Astragalus missouriensis, lavender flowers
Tine-leaved milkvetch, Astragalus pectinatus, white flowers
Pursh milkvetch, Astragalus purshii, white-purple flowers
Draba milkvetch, Astragalus spatulatus, purple flowers
Bent-flowered milkvetch, Astragalus vexilliflexus, white-purple flowers
The genus with the second most species (7) on the Milton Ranch is wheatgrass (wild-rye), in the genus Elymus of the grass family (Poaceae). For a listing of the seven wheatgrasses see the table below under “Native Grassess of the Milton Ranch”.
b. Life forms of the Ranch Flora
Plants on the Milton Ranch have been classified as to their life form: forbs, graminoids, shrubs, cacti, ferns and fern allies, and trees. As mosses and lichens are inventoried, they will be added to the list. Forbs are non-woody, broad-leaved herbaceous plants that are often referred to as “wildflowers”. Graminoids are grasses and grass-like plants, including sedges, rushes, and bull-rushes.
The 253 known vascular plant species include 169 (67%) forbs, 47 (19%) graminoids, 28 (11%) woody shrubs, 4 trees, 4 cacti, and 1 fern/fern allies. The inventory of ferns and fern allies is very incomplete, and it is expected that more will be discovered as this life form is further inventoried. For a complete listing of the Ranch flora, arranged in order of life form, see Appendix #3.
(1) Forbs
There are more species of forbs, or wildflowers, on the ranch, than any other plant life form. Wildflowers are of special interest because of their seasonally beautiful shows of colorful floral displays. Some of the more showy wildflowers on the ranch are listed below by the season of their blooming. These are all native forbs. Many of these herbaceous broadleaf plants also provide important forage for livestock and wildlife.
April wildflowers
Plains cymopterus, Cymopterus acaulis, white flowers
Hood’s phlox, Phlox hoodii, white flowers
Yellow bell, Fritillaria pudica, yellow flowers
Goldenpea, Thermopsis rhombifolia, yellow flowers
Fennel-leaved desert-parsley, Lomatium foeniculaceum, yellow flowers
May wildflowers
Star lily, Leucocrinum montanum, white flowers
Wallflower, Erysimum asperum
Shining beardtongue, Penstemon nitidus, blue flowers
Silver crazyweed, Oxytropis sericeus, white flowers
Tine-leaved milkvetch, Astragalus pectinatus, white flowers
June wildflowers
Downy paintbrush, Castilleja sessiliflora, purplish and yellow flowers
Blue flax, Linum lewisii, blue flowers
Starry solomon’s seal, Smilacina stellata, white flowers
American vetch, Vicia Americana, blue flowers
Two-grooved milkvetch, Astragalus bisulcatus, purple flowers
Scarlet globemallow, Sphaeralcea coccinea, orange to red flowers
Nuttall’s sego lily, Calochortus nuttallii, white flowers with lilac tinge & purple spot
July wildflowers
Purple prairie-clover, Dalea purpurea, purple flowers
Slender-flowered scurfpea, Psoralea tenuiflora, lavender flowers
Buff fleabane, Erigeron ochroleucus, white and yellow flowers
Yarrow, Achillea millefolium, white flowers
August wildflowers
Prairie coneflower, Ratibida columnifera, yellow and brown flowers
Curly cup gumweed, Grindelia squarrosa, yellow flowers
Dotted gayfeather, Liatris punctata, purple flowers
(2) Grasses and grass-like plants (graminoids)
Drummond’s milkvetch, Astragalus drummondii, white flowers
Cushion milkvetch, Astragalus gilviflorus, white to cream-colored flowers
Slender milkvetch, Astragalus gracilis, lavender flowers
Missouri milkvetch, Astragalus missouriensis, lavender flowers
Tine-leaved milkvetch, Astragalus pectinatus, white flowers
Pursh milkvetch, Astragalus purshii, white-purple flowers
Draba milkvetch, Astragalus spatulatus, purple flowers
Bent-flowered milkvetch, Astragalus vexilliflexus, white-purple flowers
The genus with the second most species (7) on the Milton Ranch is wheatgrass (wild-rye), in the genus Elymus of the grass family (Poaceae). For a listing of the seven wheatgrasses see the table below under “Native Grassess of the Milton Ranch”.
b. Life forms of the Ranch Flora
Plants on the Milton Ranch have been classified as to their life form: forbs, graminoids, shrubs, cacti, ferns and fern allies, and trees. As mosses and lichens are inventoried, they will be added to the list. Forbs are non-woody, broad-leaved herbaceous plants that are often referred to as “wildflowers”. Graminoids are grasses and grass-like plants, including sedges, rushes, and bull-rushes.
The 253 known vascular plant species include 169 (67%) forbs, 47 (19%) graminoids, 28 (11%) woody shrubs, 4 trees, 4 cacti, and 1 fern/fern allies. The inventory of ferns and fern allies is very incomplete, and it is expected that more will be discovered as this life form is further inventoried. For a complete listing of the Ranch flora, arranged in order of life form, see Appendix #3.
(1) Forbs
There are more species of forbs, or wildflowers, on the ranch, than any other plant life form. Wildflowers are of special interest because of their seasonally beautiful shows of colorful floral displays. Some of the more showy wildflowers on the ranch are listed below by the season of their blooming. These are all native forbs. Many of these herbaceous broadleaf plants also provide important forage for livestock and wildlife.
April wildflowers
Plains cymopterus, Cymopterus acaulis, white flowers
Hood’s phlox, Phlox hoodii, white flowers
Yellow bell, Fritillaria pudica, yellow flowers
Goldenpea, Thermopsis rhombifolia, yellow flowers
Fennel-leaved desert-parsley, Lomatium foeniculaceum, yellow flowers
May wildflowers
Star lily, Leucocrinum montanum, white flowers
Wallflower, Erysimum asperum
Shining beardtongue, Penstemon nitidus, blue flowers
Silver crazyweed, Oxytropis sericeus, white flowers
Tine-leaved milkvetch, Astragalus pectinatus, white flowers
June wildflowers
Downy paintbrush, Castilleja sessiliflora, purplish and yellow flowers
Blue flax, Linum lewisii, blue flowers
Starry solomon’s seal, Smilacina stellata, white flowers
American vetch, Vicia Americana, blue flowers
Two-grooved milkvetch, Astragalus bisulcatus, purple flowers
Scarlet globemallow, Sphaeralcea coccinea, orange to red flowers
Nuttall’s sego lily, Calochortus nuttallii, white flowers with lilac tinge & purple spot
July wildflowers
Purple prairie-clover, Dalea purpurea, purple flowers
Slender-flowered scurfpea, Psoralea tenuiflora, lavender flowers
Buff fleabane, Erigeron ochroleucus, white and yellow flowers
Yarrow, Achillea millefolium, white flowers
August wildflowers
Prairie coneflower, Ratibida columnifera, yellow and brown flowers
Curly cup gumweed, Grindelia squarrosa, yellow flowers
Dotted gayfeather, Liatris punctata, purple flowers
(2) Grasses and grass-like plants (graminoids)
Although grasses and grass-like plants are second in species abundance, they are first in canopy cover, that is, they cover more of the land surface of the ranch than any other plant life form. Grassland is the dominant vegetation community type on the ranch, and the other community types (pine woodland, greasewood shrubland, yucca shrubland, etc.) include grasses (and other graminoids) as a major component of the vegetation. Both native and introduced grasses are found on the ranch, but native grass species are far more abundant than the introduced species on most of the ranch lands. Of the 30 native grasses listed below, four are most abundant and important in grazing value: needle-and-thread grass, thickspike wheatgrass, western wheatgrass, and blue grama. Another native graminoid, thread-leaved sedge (Carex filifolia, family Cyperaceae) is perhaps equal in abundance and importance with these four native grasses. Bluebunch wheatgrass, green needlegrass, sand reedgrass, and little bluestem are native grasses that are locally abundant on certain areas of the ranch, although they are not as widespread in abundance as the first four grass species above. The most abundant introduced grasses are crested wheatgrass, cheatgrass, Japanese brome, six-weeks fescue, and Kentucky bluegrass.
Native Grasses (family Poaceae) of the Milton Ranch, 30 species
Meadow foxtail, Alopecurus pratensis
Three-awn grass, Aristida purpurea
Little bluestem, Bouteloua gracilis
Reedgrass, Calamagrostis sp.
Sand reedgrass, Calamovilfa longifolia
Alkali saltgrass, Distichlis stricta
Canada wildrye, Elymus canadensis
Basin or Giant wildrye, Elymus cinereus
Squirreltail, Elymus elymoides
Thickspike wheatgrass, Elymus lanceolatus
Western wheatgrass, Elymus smithii
Bluebunch wheatgrass, Elymus spicatus
Bearded wheatgrass, Elymus trachycaulus
Mannagrass, Glyceria grandis
Meadow barley, Hordeum brachyantherum
Foxtail barley, Hordeum jubatum
Junegrass, Koeleria macrantha
Plains Muhly, Muhlenbergia cuspidata
Alkali muhly, Muhlenbergia asperfolia
Indian ricegrass, Oryzopsis hymenoides
Little ricegrass, Oryzopsis micrantha
Plains bluegrass, Poa arida
Sandberg’s bluegrass, Poa secunda
Alkaligrass, Puccinellia sp.
Tumblegrass, Schedonnardus paniculatus
Alkali cordgrass Spartina gracilis
Prairie cordgrass, Spartina pectinata
Sand dropseed, Sporobolus cryptandrus
Needle-and-thread grass, Stipa comata
Green needlegrass, Stipa viridula
Introduced Grasses (family Poaceae) of the Milton Ranch, 12 species
Crested wheatgrass, Agropyron cristatum
Redtop, Agrostis stolonifera
Smooth brome, Bromus inermus
Japanese brome, Bromus japonicus
Cheatgrass, Bromus tectorum
Bristlegrass, Setaria glauca
Green bristlegrass, Setaria viridis
Barnyard grass, Echinochloa crusgalli
Six-weeks fescue, Festuca octoflora
Kentucky bluegrass, Poa pratensis
Bristlegrass, Setaria glauca
Green bristlegrass, Setaria viridis
(3) Shrubs
There are 28 species of woody shrubs and half-shrubs on the Ranch. Most abundant are big sagebrush (Artemisia tridentata), silver sagebrush (Atremisia cana), rubber rabbitbrush (Chrysothamnus nauseosus), broom snakeweed (Gutierrezia sarothrae), greasewood (Sarcobatus vermiculatus), fringed sagewort (Artemisia frigida), common juniper (Juniperus communis), Rocky Mountain juniper (Juniperus scopulorum), and yucca (Yucca glauca). Big sagebrush, greasewood and yucca form the dominant overstory canopy on three of the Ranch’s major plant communities, discussed in the Plant Community section below.
(4) Trees, cacti, and ferns
Ponderosa pine (Pinus ponderosa, family Pinaceae) is by far the most abundant tree on the ranch, and is the dominant overstory on the pine woodlands plant community, a major vegetation type on the Ranch. An interesting botanical feature of the ponderosa pine trees on the Ranch is that the needle fascicles usually have only two needles each, or sometimes three. In Western Montana and westward, ponderosa pine is known to consistently have three needles per fascicle. On May 11, 1805 in the vicinity of present-day Fort Peck Lake, Montana, Meriwether Lewis remarked: “saw today some high hills…whose summits were covered with pine.” Lewis was perhaps the first man of European heritage to observe and record ponderosa pine, which he referred to in his journals as “long-leaved pine.”
Other trees on the ranch, plains cottonwood (Populus deltoides), peach-leaved willow (Salix amygdaloides), and Russian olive (Elaeagnus angustifolia) are found in widely scattered locations, a novelty of the vegetation, rather than an important feature. . Rocky mountain juniper (Juniper scopulorum), discussed above as a shrub, sometime attains the single stem growth form and height of tree status, especially within the pinelands plant community. American elm (Ulmus americana) and spruce (Picea sp.) are found in the ranch headquarters landscaping, but are not included in the listing of flora.
There are four species of cacti on the Ranch: prickly pear (Opuntia polyacantha), fragile prickly pear (Opuntia fragilis), yellow pincushion (Coryphantha missouriensis), and purple pincushion (Coryphantha vivipara). Of these four, prickly pear is by far the most abundant.
The ferns and fern allies have not been aggressively inventoried, and work is needed to adequately represent them in the Ranch flora. The only species recorded in the flora is horsetail (Equisetum sp., family Equisetaceae) although spikemoss (Selaginella sp., family Selaginellaceae) and ferns of the Fern Family, Polypodiaceae are known to occur.
(5) Special interest plant species
Several plant species occurring on the Ranch are of special interest, some because of their rarity, and/or because of occurring on the periphery of their natural range in Montana.
Western spiderwort, Tradescantia occidentalis (Commelinaceae) occurs on shallow, sandy, southerly slopes of the Big Wall. Narrow-leaved purple coneflower, Echinacea angustifolia (Asteraceae) occurs in scattered, mostly sandy, locations of the Ranch. Both of these species are near the western extension of their botanical range in Montana, and the coneflower is apparently not represented in the regional herbaria from Musselshell County.
Blue-eyed grass, Sisyrinchium montanum (Iridaceae) has only been found on a single small site of the Ranch. While it is known to occur in moist grasslands of the Great Plains of Montana, it is none-the-less of special interest in the Ranch flora because of its rarity. .
Cliff anemone, Anemone multifida (Ranunculaceae) finds its eastern extension in Montana in Musselshell County. It is rare on the Ranch, where it grows in sheltered, cool habitats protected by sandstone boulders.
PLANT COMMUNITIES OF THE MILTON RANCH
a. Introduction
Milton ranch includes diverse grasslands, pine woodlands, sagebrush shrublands, greasewood shrublands, and yucca shrublands. Areas of rocky outcrop, with unique vegetation elements also occur.
Plant communities are very dynamic and subject to change with changing environmental conditions. For example, an intense, crowning wildfire sweeping across the Ranch could change the pine woodlands to grassland in a single years time. Plant succession back to woodland could take decades, depending on the size of the area of woodlands removed, the distance and direction to the next pine seed source, and subsequent fire frequency.
Big sagebrush shrubland would, likewise, convert to grassland following wildfire, but would more likely return to a sagebrush plant community much sooner, because of sagebrush seed stored on the soil surface, that is, if fire does not return for a sufficient period of time.
A mountain pine beetle attack of the pine woodlands would change the plant composition of the woodlands, but less so than an intense, crowning wildfire. Many, if not all, of the large pine trees would likely be killed by the beetles, however, the junipers and seedling/sapling pine trees would survive the beetle attack, and the plant community would remain pine/juniper woodland.
Livestock grazing has an influence on plant composition as well. The holistic grazing system practiced on the Ranch over the last three decades appears to be facilitating grassland succession toward the potential natural vegetation of the grasslands, according to on-going monitoring studies.
Climate change, much discussed in the media at present, will have a major influence on plant composition on the Ranch over time. The warming climate has already increased the probability of wildfire and mountain pine beetle attacks in the West. The change in certain bird and animal ranges, likely the result of climate change, has also been documented. A warming of the climate could also bring Southern Great Plains species into the flora of southeastern Montana, and a decline of certain Northern Great Plains species, especially those on the southern periphery of their range.
The plant communities described in the discussion below is, thus, a “snapshot” of the vegetation of the Ranch at this point in time, that is, the current plant community composition of the Ranch.
b. Grassland
Over half of the Ranch, about 60%, is grassland. The dominant species in these vegetation communities is both native and introduced grasses, native sedges, and native forbs. Native species of cacti and low shrubs also occur.
(1) Native grasslands on silty soils (NRCS Ecosites Si and SiLy)
Native Grasses (family Poaceae) of the Milton Ranch, 30 species
Meadow foxtail, Alopecurus pratensis
Three-awn grass, Aristida purpurea
Little bluestem, Bouteloua gracilis
Reedgrass, Calamagrostis sp.
Sand reedgrass, Calamovilfa longifolia
Alkali saltgrass, Distichlis stricta
Canada wildrye, Elymus canadensis
Basin or Giant wildrye, Elymus cinereus
Squirreltail, Elymus elymoides
Thickspike wheatgrass, Elymus lanceolatus
Western wheatgrass, Elymus smithii
Bluebunch wheatgrass, Elymus spicatus
Bearded wheatgrass, Elymus trachycaulus
Mannagrass, Glyceria grandis
Meadow barley, Hordeum brachyantherum
Foxtail barley, Hordeum jubatum
Junegrass, Koeleria macrantha
Plains Muhly, Muhlenbergia cuspidata
Alkali muhly, Muhlenbergia asperfolia
Indian ricegrass, Oryzopsis hymenoides
Little ricegrass, Oryzopsis micrantha
Plains bluegrass, Poa arida
Sandberg’s bluegrass, Poa secunda
Alkaligrass, Puccinellia sp.
Tumblegrass, Schedonnardus paniculatus
Alkali cordgrass Spartina gracilis
Prairie cordgrass, Spartina pectinata
Sand dropseed, Sporobolus cryptandrus
Needle-and-thread grass, Stipa comata
Green needlegrass, Stipa viridula
Introduced Grasses (family Poaceae) of the Milton Ranch, 12 species
Crested wheatgrass, Agropyron cristatum
Redtop, Agrostis stolonifera
Smooth brome, Bromus inermus
Japanese brome, Bromus japonicus
Cheatgrass, Bromus tectorum
Bristlegrass, Setaria glauca
Green bristlegrass, Setaria viridis
Barnyard grass, Echinochloa crusgalli
Six-weeks fescue, Festuca octoflora
Kentucky bluegrass, Poa pratensis
Bristlegrass, Setaria glauca
Green bristlegrass, Setaria viridis
(3) Shrubs
There are 28 species of woody shrubs and half-shrubs on the Ranch. Most abundant are big sagebrush (Artemisia tridentata), silver sagebrush (Atremisia cana), rubber rabbitbrush (Chrysothamnus nauseosus), broom snakeweed (Gutierrezia sarothrae), greasewood (Sarcobatus vermiculatus), fringed sagewort (Artemisia frigida), common juniper (Juniperus communis), Rocky Mountain juniper (Juniperus scopulorum), and yucca (Yucca glauca). Big sagebrush, greasewood and yucca form the dominant overstory canopy on three of the Ranch’s major plant communities, discussed in the Plant Community section below.
(4) Trees, cacti, and ferns
Ponderosa pine (Pinus ponderosa, family Pinaceae) is by far the most abundant tree on the ranch, and is the dominant overstory on the pine woodlands plant community, a major vegetation type on the Ranch. An interesting botanical feature of the ponderosa pine trees on the Ranch is that the needle fascicles usually have only two needles each, or sometimes three. In Western Montana and westward, ponderosa pine is known to consistently have three needles per fascicle. On May 11, 1805 in the vicinity of present-day Fort Peck Lake, Montana, Meriwether Lewis remarked: “saw today some high hills…whose summits were covered with pine.” Lewis was perhaps the first man of European heritage to observe and record ponderosa pine, which he referred to in his journals as “long-leaved pine.”
Other trees on the ranch, plains cottonwood (Populus deltoides), peach-leaved willow (Salix amygdaloides), and Russian olive (Elaeagnus angustifolia) are found in widely scattered locations, a novelty of the vegetation, rather than an important feature. . Rocky mountain juniper (Juniper scopulorum), discussed above as a shrub, sometime attains the single stem growth form and height of tree status, especially within the pinelands plant community. American elm (Ulmus americana) and spruce (Picea sp.) are found in the ranch headquarters landscaping, but are not included in the listing of flora.
There are four species of cacti on the Ranch: prickly pear (Opuntia polyacantha), fragile prickly pear (Opuntia fragilis), yellow pincushion (Coryphantha missouriensis), and purple pincushion (Coryphantha vivipara). Of these four, prickly pear is by far the most abundant.
The ferns and fern allies have not been aggressively inventoried, and work is needed to adequately represent them in the Ranch flora. The only species recorded in the flora is horsetail (Equisetum sp., family Equisetaceae) although spikemoss (Selaginella sp., family Selaginellaceae) and ferns of the Fern Family, Polypodiaceae are known to occur.
(5) Special interest plant species
Several plant species occurring on the Ranch are of special interest, some because of their rarity, and/or because of occurring on the periphery of their natural range in Montana.
Western spiderwort, Tradescantia occidentalis (Commelinaceae) occurs on shallow, sandy, southerly slopes of the Big Wall. Narrow-leaved purple coneflower, Echinacea angustifolia (Asteraceae) occurs in scattered, mostly sandy, locations of the Ranch. Both of these species are near the western extension of their botanical range in Montana, and the coneflower is apparently not represented in the regional herbaria from Musselshell County.
Blue-eyed grass, Sisyrinchium montanum (Iridaceae) has only been found on a single small site of the Ranch. While it is known to occur in moist grasslands of the Great Plains of Montana, it is none-the-less of special interest in the Ranch flora because of its rarity. .
Cliff anemone, Anemone multifida (Ranunculaceae) finds its eastern extension in Montana in Musselshell County. It is rare on the Ranch, where it grows in sheltered, cool habitats protected by sandstone boulders.
PLANT COMMUNITIES OF THE MILTON RANCH
a. Introduction
Milton ranch includes diverse grasslands, pine woodlands, sagebrush shrublands, greasewood shrublands, and yucca shrublands. Areas of rocky outcrop, with unique vegetation elements also occur.
Plant communities are very dynamic and subject to change with changing environmental conditions. For example, an intense, crowning wildfire sweeping across the Ranch could change the pine woodlands to grassland in a single years time. Plant succession back to woodland could take decades, depending on the size of the area of woodlands removed, the distance and direction to the next pine seed source, and subsequent fire frequency.
Big sagebrush shrubland would, likewise, convert to grassland following wildfire, but would more likely return to a sagebrush plant community much sooner, because of sagebrush seed stored on the soil surface, that is, if fire does not return for a sufficient period of time.
A mountain pine beetle attack of the pine woodlands would change the plant composition of the woodlands, but less so than an intense, crowning wildfire. Many, if not all, of the large pine trees would likely be killed by the beetles, however, the junipers and seedling/sapling pine trees would survive the beetle attack, and the plant community would remain pine/juniper woodland.
Livestock grazing has an influence on plant composition as well. The holistic grazing system practiced on the Ranch over the last three decades appears to be facilitating grassland succession toward the potential natural vegetation of the grasslands, according to on-going monitoring studies.
Climate change, much discussed in the media at present, will have a major influence on plant composition on the Ranch over time. The warming climate has already increased the probability of wildfire and mountain pine beetle attacks in the West. The change in certain bird and animal ranges, likely the result of climate change, has also been documented. A warming of the climate could also bring Southern Great Plains species into the flora of southeastern Montana, and a decline of certain Northern Great Plains species, especially those on the southern periphery of their range.
The plant communities described in the discussion below is, thus, a “snapshot” of the vegetation of the Ranch at this point in time, that is, the current plant community composition of the Ranch.
b. Grassland
Over half of the Ranch, about 60%, is grassland. The dominant species in these vegetation communities is both native and introduced grasses, native sedges, and native forbs. Native species of cacti and low shrubs also occur.
(1) Native grasslands on silty soils (NRCS Ecosites Si and SiLy)
These are the most abundant grasslands on the Milton Ranch, covering about 35% of the Ranch lands. Within these grassland plant communities, the co-dominant native grasses are needle-and-thread grass, which averages about 20% canopy cover; and thickspike wheatgrass and western wheatgrass, which together also average about 20% canopy cover. In the inventory of the Ranch vegetation we lumped thickspike and western wheatgrass, because of the difficulty in separating them in the field.
The sub-dominant graminoids are native thread-leaved sedge, blue grama grass, and introduced Japanese brome, each species averaging about 10% canopy cover.
However, the abundance of these six graminoid species varies considerably from place to place within the native grasslands of the silty eco-sites. For example, threadleaved sedge was the dominant graminoid on one of the plots sampled, and blue grama was dominant on another, so all six of these graminoids could be said to play an overall co-dominant role in the vegetation on these silty eco-sites.
Forbs play a lesser role in the vegetation of this vegetation community, than they do on native grasslands of shallow and sandy soil eco-sites. An average of only about 8 species of forbs were found per 1/10 acre plot samples in this plant community, while native grasslands of shallow soil eco-sites averaged 18 forb species within the 1/10 acre sample plots. None of the forb species inventoried had more than a 3% canopy cover value, and most were 1% or less in canopy cover within this vegetation community.
Forbs, or wildflowers, found within this plant community include scarlet globemallow, dandelion, salsify, death camas, slim-flowered scurfpea, standing milkvetch, downy paintbrush, cushion milkvetch, star lily, rush skeletonweed, white beardtongue, and buff fleabane.
Shrubs are represented in this plant community by a few scattered occurrences of silver sagebrush, big sagebrush, prairie rose, and the common occurrence of the half-shrub fringed sagewort, which has an average canopy cover of 3%, and ranges up to 10% in some parts of the plant community. Prickly pear cactus is common within this plant community, but never abundant enough to exceed 1% canopy cover.
(2.) Native grasslands on sandy and shallow soils (NRCS Ecosites Sy, Sw, SL)
The sub-dominant graminoids are native thread-leaved sedge, blue grama grass, and introduced Japanese brome, each species averaging about 10% canopy cover.
However, the abundance of these six graminoid species varies considerably from place to place within the native grasslands of the silty eco-sites. For example, threadleaved sedge was the dominant graminoid on one of the plots sampled, and blue grama was dominant on another, so all six of these graminoids could be said to play an overall co-dominant role in the vegetation on these silty eco-sites.
Forbs play a lesser role in the vegetation of this vegetation community, than they do on native grasslands of shallow and sandy soil eco-sites. An average of only about 8 species of forbs were found per 1/10 acre plot samples in this plant community, while native grasslands of shallow soil eco-sites averaged 18 forb species within the 1/10 acre sample plots. None of the forb species inventoried had more than a 3% canopy cover value, and most were 1% or less in canopy cover within this vegetation community.
Forbs, or wildflowers, found within this plant community include scarlet globemallow, dandelion, salsify, death camas, slim-flowered scurfpea, standing milkvetch, downy paintbrush, cushion milkvetch, star lily, rush skeletonweed, white beardtongue, and buff fleabane.
Shrubs are represented in this plant community by a few scattered occurrences of silver sagebrush, big sagebrush, prairie rose, and the common occurrence of the half-shrub fringed sagewort, which has an average canopy cover of 3%, and ranges up to 10% in some parts of the plant community. Prickly pear cactus is common within this plant community, but never abundant enough to exceed 1% canopy cover.
(2.) Native grasslands on sandy and shallow soils (NRCS Ecosites Sy, Sw, SL)
Native grasslands on sandy and shallow soils occupies about 15% of the area of the Ranch, or about half as common as native grassland on silty eco-sites. The dominant species on both of these plant communities is needle-and-thread grass, but average canopy cover of this grass is greater on the sandy soils (60%) than on the shallow soils (20%). Western and thickspike wheatgrasses are sub-dominant species on both of these plant communities, but also higher in canopy cover on the sandy soils (10%) than on the shallow soils (3%). Blue grama grass is also sub-dominant, but higher in canopy cover on the shallow soils (10%), than on the sandy soils (5%). Another sub-dominant species on both plant communities is Japanese brome. Thread-leaved sedge, at 10% canopy cover, is a co-dominant species on the shallow soils, but not on the sandy soils that were sampled. Sand reedgrass was abundant (10% canopy cover) on one of the shallow sites sampled. Blue-bunch wheatgrass, at 20% canopy cover, was a co-dominant on one of the shallow sites sampled.
Fringed sagewort, slim-flowered scurfpea, and scarlet globemallow occurred on both of these plant communities. Other forb and shrub species were less consistent between the two. Forbs on the sandy soils include death camas, white beardtongue, purple coneflower, and northern sweet-vetch.
On the grasslands of the shallow soil eco-site, forbs were abundant and very diverse, with 18-19 species per 1/10 acre sample plot. The abundance of forbs may be because of less competition from grasses, which are lower in canopy cover here than grasslands on silty or sandy eco-sites. Forbs on grasslands of the shallow-site eco-site include narrow-leaved purple coneflower, plains yellow primrose, hairy golden-aster, dotted gay-feather, Bessey’s crazyweed, northern sweetvetch, Hooker’s sandwort, greenthread, Missouri milkvetch, wavy-leaved thistle, silver-leaf scurfpea, and dandelion.
(3.) Grasslands of introduced grasses
Fringed sagewort, slim-flowered scurfpea, and scarlet globemallow occurred on both of these plant communities. Other forb and shrub species were less consistent between the two. Forbs on the sandy soils include death camas, white beardtongue, purple coneflower, and northern sweet-vetch.
On the grasslands of the shallow soil eco-site, forbs were abundant and very diverse, with 18-19 species per 1/10 acre sample plot. The abundance of forbs may be because of less competition from grasses, which are lower in canopy cover here than grasslands on silty or sandy eco-sites. Forbs on grasslands of the shallow-site eco-site include narrow-leaved purple coneflower, plains yellow primrose, hairy golden-aster, dotted gay-feather, Bessey’s crazyweed, northern sweetvetch, Hooker’s sandwort, greenthread, Missouri milkvetch, wavy-leaved thistle, silver-leaf scurfpea, and dandelion.
(3.) Grasslands of introduced grasses
Grasslands of introduced grasses occur on lands broken by the plow, where crops were grown for a time, and ultimately planted with introduced perennial species, mostly crested wheatgrass and alfalfa. About 8% of the Ranch is occupied with introduced grassland vegetation, on a variety of soils, sandy, silty and clayey (NRCS Ecosites Sy, Si, and Cy).
Crested wheatgrass, with about 35% canopy cover, is the dominant plant species on these previously cultivated lands, on both clayey and sandy soils. Alfalfa and broom snakeweed, with about 10% canopy cover, are sub-dominant species on the clayey soils. . Five species of native forbs per 1/10 acre plot occurred on the clayey soil plot: scarlet gaura, Missouri milkvetch, scarlet globemallow, and blue flax.
Native needle-and-thread grass was co-dominant with crested wheatgrass on the sandy site sampled, and native Indian ricegrass was present at 3% canopy cover. The sandy soil site had 10 native forbs per 1/10 acre plot, including scarlet gaura, Missouri milkvetch, scarlet globemallow, silver leaf scurfpea, white penstemon, tine-leaved milkvetch, wallflower, wavy-leaved thistle, and textile onion. Yucca and two introduced forbs were also present on the sandy site sampled.
Although crested wheatgrass remains the dominant plant cover, these previously cultivated sites show strong indications that plant succession is advancing toward native grassland vegetation.
(4.) Native grassy wetlands (NRCS Ecosite SU)
Crested wheatgrass, with about 35% canopy cover, is the dominant plant species on these previously cultivated lands, on both clayey and sandy soils. Alfalfa and broom snakeweed, with about 10% canopy cover, are sub-dominant species on the clayey soils. . Five species of native forbs per 1/10 acre plot occurred on the clayey soil plot: scarlet gaura, Missouri milkvetch, scarlet globemallow, and blue flax.
Native needle-and-thread grass was co-dominant with crested wheatgrass on the sandy site sampled, and native Indian ricegrass was present at 3% canopy cover. The sandy soil site had 10 native forbs per 1/10 acre plot, including scarlet gaura, Missouri milkvetch, scarlet globemallow, silver leaf scurfpea, white penstemon, tine-leaved milkvetch, wallflower, wavy-leaved thistle, and textile onion. Yucca and two introduced forbs were also present on the sandy site sampled.
Although crested wheatgrass remains the dominant plant cover, these previously cultivated sites show strong indications that plant succession is advancing toward native grassland vegetation.
(4.) Native grassy wetlands (NRCS Ecosite SU)
Although only about 3% of the Ranch is sub-irrigated land along the intermittent streams, the native grassy wetlands there provide high forage productivity per acre, and important plant diversity not found elsewhere on the Ranch.
The co-dominant species are these native grass and grass-like species: plains bluegrass, clustered field sedge, three-square bulrush, creeping spike-rush, foxtail barley, Baltic rush, wooly sedge, Nebraska sedge, beaked sedge, water sedge, and likely other wetland sedge species. With 5-60% canopy cover each, these dominant grasses and grass-like plants form complex wetland plant communities on these sub-irrigated sites, having the highest plant cover density of any site on the Ranch.
Although much lower in canopy cover than the dominant species listed above, several other wetland graminoid species of interest include river bulrush, alkali bulrush, hardstem bulrush, and reed mannagrass.
Forbs are insignificant in these plant communities, with only 3 or 4 species per 1/10 acre plot sampled. However, some forbs found here are wetland species, found nowhere else on the Ranch, such as seaside arrowgrass, water buttercup, silverweed, giant goldenrod, and Eaton’s aster.
c. Pine woodland (within NRCS Ecosite Sw)
The co-dominant species are these native grass and grass-like species: plains bluegrass, clustered field sedge, three-square bulrush, creeping spike-rush, foxtail barley, Baltic rush, wooly sedge, Nebraska sedge, beaked sedge, water sedge, and likely other wetland sedge species. With 5-60% canopy cover each, these dominant grasses and grass-like plants form complex wetland plant communities on these sub-irrigated sites, having the highest plant cover density of any site on the Ranch.
Although much lower in canopy cover than the dominant species listed above, several other wetland graminoid species of interest include river bulrush, alkali bulrush, hardstem bulrush, and reed mannagrass.
Forbs are insignificant in these plant communities, with only 3 or 4 species per 1/10 acre plot sampled. However, some forbs found here are wetland species, found nowhere else on the Ranch, such as seaside arrowgrass, water buttercup, silverweed, giant goldenrod, and Eaton’s aster.
c. Pine woodland (within NRCS Ecosite Sw)
Pine woodland covers about 15% of the Ranch, but because of the prominence of the pine trees, it seems much more plentiful. These woodlands have the greatest plant diversity of any plant community on the Ranch, in both plant life form and number of plant species per unit of area. Shallow, sandy soils form the substrate for these pine communities, and prominent monoliths of sandstone sometimes stand like statues among the pine trees.
Trees, grasses, shrubs, half-shrubs, forbs, and cacti form variable plant community complexes on these woodlands, all having an over-story of the prevailing feature, ponderosa pine trees. The dominant under-story species, beneath the pine trees, are needle-and-thread grass and bluebunch wheatgrass. Blue grama grass, thick-spike wheatgrass, Indian ricegrass, Sandberg’s bluegrass, and thread-leaved sedge also occur either as sub-dominants, or only occasional low density plants within the grass species complexes.
Rocky mountain juniper sometimes grows among the pine trees in single-stemmed tree form, but is more often a tall, prominent shrub. Although never abundant, medium-sized shrub species also stand above the grasses in the pine woodlands communities. They include common juniper, fragrant sumac, Missouri currant, wax currant, big sagebrush, and yucca.
Low growing sub-shrubs, having woody stems only at their bases, are strewn among the other plant community elements, including fringed sagewort, broom snakeweed, and few-flowered buckwheat.
The abundance of colorful forb, or wildflower species is striking in the pine woodlands. An average of over 20 species of wildflowers per 1/10 acre plot, were found within the plots sampled in the pine woodlands. Native wildflower species include miner’s candle, purple prairie-clover, textile onion, standing milkvetch, wooly groundsel, cushion buckwheat, white penstemon, shining penstemon, silverleaf scurfpea, slimflower scurfpea, Indian breadroot, scarlet globemallow, scarlet gaura, clustered broomrape, wavy-leaved thistle, Missouri milkvetch, Hood’s phlox, whitlow wort, yellow flax, blue flax, white crazyweed, dotted gayfeather, spiny aster, greenthread, hymenoxis, hairy goldenaster, yarrow, wallflower, Missouri goldenrod, and pussytoes.
d. Sagebrush shrubland (within NRCS Ecosites Si, Cy, and Cp)
Trees, grasses, shrubs, half-shrubs, forbs, and cacti form variable plant community complexes on these woodlands, all having an over-story of the prevailing feature, ponderosa pine trees. The dominant under-story species, beneath the pine trees, are needle-and-thread grass and bluebunch wheatgrass. Blue grama grass, thick-spike wheatgrass, Indian ricegrass, Sandberg’s bluegrass, and thread-leaved sedge also occur either as sub-dominants, or only occasional low density plants within the grass species complexes.
Rocky mountain juniper sometimes grows among the pine trees in single-stemmed tree form, but is more often a tall, prominent shrub. Although never abundant, medium-sized shrub species also stand above the grasses in the pine woodlands communities. They include common juniper, fragrant sumac, Missouri currant, wax currant, big sagebrush, and yucca.
Low growing sub-shrubs, having woody stems only at their bases, are strewn among the other plant community elements, including fringed sagewort, broom snakeweed, and few-flowered buckwheat.
The abundance of colorful forb, or wildflower species is striking in the pine woodlands. An average of over 20 species of wildflowers per 1/10 acre plot, were found within the plots sampled in the pine woodlands. Native wildflower species include miner’s candle, purple prairie-clover, textile onion, standing milkvetch, wooly groundsel, cushion buckwheat, white penstemon, shining penstemon, silverleaf scurfpea, slimflower scurfpea, Indian breadroot, scarlet globemallow, scarlet gaura, clustered broomrape, wavy-leaved thistle, Missouri milkvetch, Hood’s phlox, whitlow wort, yellow flax, blue flax, white crazyweed, dotted gayfeather, spiny aster, greenthread, hymenoxis, hairy goldenaster, yarrow, wallflower, Missouri goldenrod, and pussytoes.
d. Sagebrush shrubland (within NRCS Ecosites Si, Cy, and Cp)
About 15% of the Ranch is sagebrush shrubland, occurring on silty, clayey and clay pan soils. The dominant species is big sagebrush with about 30% canopy cover. Western wheatgrass and/or thickspike wheatgrass are the most consistent dominant understory species with 10-20% canopy cover. Needle-and-thread grass, thread-leaved sedge, and blue grama grass are co-dominant grass species. Green needlegrass and Japanese brome grass are sub-dominant grasses. An average of seven forb species per 1/10 acre plot occurred as occasional scattered species within the shrublands, with very low canopy cover. Native forbs include scarlet globemallow, tine-leaved milkvetch, yarrow, white penstemon, buff fleabane, American vetch, and textile onion. Dandelion, yellow sweetclover, and annual allysum are common introduced forbs. Prickly pear and fringed sagewort also commonly occur in these sagebrush shrublands.
Wildfire can temporarily affect the abundance of sagebrush shrublands, by killing the big sagebrush and converting the burned lands to a grassland vegetation community, since grasses readily survive wildfire, normally. However, sagebrush may return as the dominant overstory species within 5-10 years, as there is usually sufficient residual sagebrush seed in the soil for its recovery. Although less abundant on the Ranch, silver sagebrush is able to survive wildfire by the re-sprouting of sub-surface buds.
e. Greaswood shrubland (NRCS Ecosites Cp, Ov)
Wildfire can temporarily affect the abundance of sagebrush shrublands, by killing the big sagebrush and converting the burned lands to a grassland vegetation community, since grasses readily survive wildfire, normally. However, sagebrush may return as the dominant overstory species within 5-10 years, as there is usually sufficient residual sagebrush seed in the soil for its recovery. Although less abundant on the Ranch, silver sagebrush is able to survive wildfire by the re-sprouting of sub-surface buds.
e. Greaswood shrubland (NRCS Ecosites Cp, Ov)
While uncommon, with only about 5 % or less of Ranch lands involved, greasewood shrubland none-the-less forms unique and distinctive plant communities on clay pan and overflow soils adjacent to the intermittent stream on the north end of the Ranch.
Greasewood shrubs 2-4 feet tall form the over-story at 20-30% canopy cover. Silver sagebrush, although low in canopy cover (1-3%) is a consistent overstory shrub species on these sites as well.
On the claypan soils western wheatgrass is the dominant ground cover at 20-35% canopy cover. On overflow sites rush-leaved bluegrass, at 35% canopy cover is the dominant understory species. Foxtail barley, Japanese brome, alkali saltgrass, and blue grama, at 3-20% canopy cover, are the other important sub-dominant understory grasses in these plant communities.
Minor shrubs and cacti in these communities include moundscale, broom snakeweed, fringed sagewort, and prickly pear.
Forbs are inconspicuous, with an average of only 4 wildflower species per 1/10 acre plot of the plots sampled. Introduced forbs (dandelion, clasping peppergrass, salsify, and yellow sweetclover) are more common than the native wildflowers (gumweed, buff fleabane, and white prairie aster).
f. Yucca shrubland (NRCS Ecosite Sy, Sw)
Greasewood shrubs 2-4 feet tall form the over-story at 20-30% canopy cover. Silver sagebrush, although low in canopy cover (1-3%) is a consistent overstory shrub species on these sites as well.
On the claypan soils western wheatgrass is the dominant ground cover at 20-35% canopy cover. On overflow sites rush-leaved bluegrass, at 35% canopy cover is the dominant understory species. Foxtail barley, Japanese brome, alkali saltgrass, and blue grama, at 3-20% canopy cover, are the other important sub-dominant understory grasses in these plant communities.
Minor shrubs and cacti in these communities include moundscale, broom snakeweed, fringed sagewort, and prickly pear.
Forbs are inconspicuous, with an average of only 4 wildflower species per 1/10 acre plot of the plots sampled. Introduced forbs (dandelion, clasping peppergrass, salsify, and yellow sweetclover) are more common than the native wildflowers (gumweed, buff fleabane, and white prairie aster).
f. Yucca shrubland (NRCS Ecosite Sy, Sw)
Although occurring on 5% or less of Ranch lands, distinctive plant communities, dominated by yucca, grasses, and diverse native wildflowers are found on certain sandy and shallow soil areas of the Ranch. The dominant species are yucca, sand reedgrass, needle-and-thread grass, and blue grama, with about 20% canopy cover each. Sub-dominant species, with 3% canopy cover each are fringed sagewort, thread-leaved sedge, and junegrass. Other grasses of minor occurrence include foxtail barley, Japanese brome, and little bluestem.
Wildflowers are well distributed and diverse, with over 20 species per 1/10 acre plot sampled. Yucca shrubland thus rivals the distinction of highest plant diversity per unit area on the Ranch with the pine woodland, and grasslands on shallow and sandy soils are close behind. So, the highest plant diversity on the Ranch is consistently found in plant communities on sandy soils.
While no one forb (wildflower) species has a canopy cover of over 1%, when taken together the numerous forbs do form a significant component of the yucca shrubland plant community. Native wildflowers found here include whitlow wort, yellow buckwheat, cushion milkvetch, Missouri milkvetch, hymenoxis, Bessey’s crazyweed, textile onion, purple prairieclover, silverleaf scurfpea, wallflower, blue flax, Hood’s phlox, dotted gayfeather, yellow gromwell, Hooker’s sandwort, greenthread, hairy goldenaster, and white penstemon.
g. Rock outcrop vegetation (NRCS Ecosite Sw)
Wildflowers are well distributed and diverse, with over 20 species per 1/10 acre plot sampled. Yucca shrubland thus rivals the distinction of highest plant diversity per unit area on the Ranch with the pine woodland, and grasslands on shallow and sandy soils are close behind. So, the highest plant diversity on the Ranch is consistently found in plant communities on sandy soils.
While no one forb (wildflower) species has a canopy cover of over 1%, when taken together the numerous forbs do form a significant component of the yucca shrubland plant community. Native wildflowers found here include whitlow wort, yellow buckwheat, cushion milkvetch, Missouri milkvetch, hymenoxis, Bessey’s crazyweed, textile onion, purple prairieclover, silverleaf scurfpea, wallflower, blue flax, Hood’s phlox, dotted gayfeather, yellow gromwell, Hooker’s sandwort, greenthread, hairy goldenaster, and white penstemon.
g. Rock outcrop vegetation (NRCS Ecosite Sw)
Sandstone bedrock, and associated boulder to cobble-sized rubble, is exposed in numerous places on the Ranch, often in east-west trending ridges. The Big Wall ridge, stretching for at least 5 miles on the northern sector of the Ranch, is the most impressive expression of this feature, although numerous other sandstone ridges occur here.
These rock outcrops are associated with, and included within, the pine woodland, grassland of shallow soils, and yucca shrubland vegetation, previously discussed above. However, the specialized plants associated with the rock outcrops are worthy of further discussion in their own right.
Plants specialized in their adaptation to low water holding capacity grow on the exposed, thin soils associated with the rock outcrop. On these thin, drouthy soils they find less competition from the grasses that dominate areas with deeper soils. These plants are adapted to short growing seasons to take advantage of the moisture when it is available. The annual forb, rusty lupine, is a good example of a short growing season plant that grows here. Other forbs also develop low cushion growth forms, and cover their leaf surfaces with hair, to minimize wind resistance and associated water loss from evaporation and transpiration. Whitlow wort, Easter lily, cushion milkvetch, Pursh’s milkvetch, dusty maiden, Bessey’s crazyweed, cushion buckwheat, and Hooker’s sandwort are cushion plants growing here with this adaptation.
Other plants take advantage of the deeper, course sandy soil associated with the bedrock crevices, and the shelter from wind, sun and wildfire provided by the boulders. Wax currant, fragrant sumac, golden currant, common juniper, Rocky Mountain juniper, and western snowberry are woody shrubs that find refuge in the shelter of the boulders. The forb, Anemone multifida, has only been found on the Ranch growing in the cooler north side of the rock outcrops.
These rock outcrops are associated with, and included within, the pine woodland, grassland of shallow soils, and yucca shrubland vegetation, previously discussed above. However, the specialized plants associated with the rock outcrops are worthy of further discussion in their own right.
Plants specialized in their adaptation to low water holding capacity grow on the exposed, thin soils associated with the rock outcrop. On these thin, drouthy soils they find less competition from the grasses that dominate areas with deeper soils. These plants are adapted to short growing seasons to take advantage of the moisture when it is available. The annual forb, rusty lupine, is a good example of a short growing season plant that grows here. Other forbs also develop low cushion growth forms, and cover their leaf surfaces with hair, to minimize wind resistance and associated water loss from evaporation and transpiration. Whitlow wort, Easter lily, cushion milkvetch, Pursh’s milkvetch, dusty maiden, Bessey’s crazyweed, cushion buckwheat, and Hooker’s sandwort are cushion plants growing here with this adaptation.
Other plants take advantage of the deeper, course sandy soil associated with the bedrock crevices, and the shelter from wind, sun and wildfire provided by the boulders. Wax currant, fragrant sumac, golden currant, common juniper, Rocky Mountain juniper, and western snowberry are woody shrubs that find refuge in the shelter of the boulders. The forb, Anemone multifida, has only been found on the Ranch growing in the cooler north side of the rock outcrops.