BOTANICAL NOTES AND OBSERVATIONS: Cook Ranch, Albany County, Wyoming Prepared by : Bonnie Heidel, Botanist Wyoming Natural Diversity Database - University of Wyoming 30 August 2001 Cook Ranch encompasses the matrix grassland and sagebrush steppe of the Laramie basin, and a segment of the Laramie Range escarpment with predominantly shrubland and grassland cover. Characteristic palustrine and riverine features are inlaid on these basin and escarpment landscapes, contributing to plant species and vegetation diversity. Laramie Basin grassland Mixed grass prairie is the most extensive vegetation feature, with a sparse, low-stature component of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) over most of the vast, well-drained alluvial fans and terraces. Sagebrush cover drops out at the north end on finer­ textured soils, with patches of silver sagebrush (Artemisia cana). In the grasslands, only Sandberg's bluegrass and junegrass (Poa secunda and Koeleria macrantha, resp.) were conspicuous at the time of visit. Dominants and codominants among the grassland plant associations include at least needle-and-thread, western wheatgrass, and thread­ leaved sedge (Stipa coma ta, Elymus smithii, and Carex filifolia, resp.). Cover composition estimates and plant association characterizations were not made because foot travel was concentrated on unrepresentative overlook points, the drought restricted some species from heading out to bias the windshield survey, and this investigator did not have firsthand experience in the setting. The many ridges and rims associated with the rolling topography support many plains cushion plant species including Phlox muscoides, Haplopappus acaulis, Arenaria hookeri, Astragalus spathulatus and Eriogonum .. The grassland communities showed little or no skewing of plant composition under a long history of grazing. Even in the drought year, much less than 50% of the grass canopy cover was removed by livestock. Laramie River corridor The 15-mile corridor of the Laramie River is an open gentle river valley with braided segments that provide extensive emergent wetland habitat. This habitat was not evaluated on foot, and livestock had been moved onto the River pastures last month, limiting interpretation. Shrub and tree cover were intermittent or absent. Graminoid dominants include at least threesquare (Scirpus pungens) and tufted hairgrass (J)eschampsia cespitosa.) Bank erosion and hummock topography from trampling were not evident. Laramie Basin wetlands Long Lake is an alkali lake that was entirely dry at the time of visit. It is fed by Middle and Wallrock Creeks early in the season and may connect to the Laramie River in highwater conditions. There are many other natural wetland basins ranging from over 200 acres to less than 1 acre, with no surface flow connecting them. They include temporary, seasonal and semi-permanent systems of varying alkalinity. There are also reservoirs on the plains. Springs and seeps associated with the riverine and palustrine systems are said to be common in the Spring Creek area at the north end of the Ranch. North of Long Lake is a lakebed cut off from the Laramie River by early owners. It is ten feet lower than the River elevation, and has incised cutbank walls along most of the perimeter. It represents some of the most fertile and productive habitat on the ranch, and large areas have been planted into exotic species for hay. In the south end of the large lakebed is Lake Ione, a small waterbody with narrow-leaved cattail (Typha angustifolia) filling one area, and open water dominated by sego pondweed (Potamogeton pectinatus) filling another large portion. Elsewhere in the lakebed, isolated areas of native vegetation persist, with salt-affected composition that includes Alkali grass, foxtail barley and povertyweed (Puccinnellia nuttalliana, Hordeum jubatum, Iva axillaries, resp.) Laramie Basin sagebrush steppe Wyoming big sagebrush sagebrush (Artemisia tridentata ssp. wyomingensis] increases in stature and cover with elevation gain to the east. It prevails in the Wallrock Canyon unit. It spans a subtle gradient between grassland and steppe, and most of the Ranch has Wyoming big sagebrush present albeit at low height and canopy cover. Outcrops Limestone, sandstone, shale, and igneous outcrops are present and were not characterized. Several of the rare species are substrate-specific. Laramie basin desert shrubland Grasslands are inset with large areas of desert shrubland including the Gardner's saltbush desert shrubland (dominated by Atriplex gardneri) found in north-central upland outcrops ofbentonite. Greasewood desert shrublands (dominated by Sarcobatus vermiculatus) are found on the lowlands east of Long Lake. Laramie Escarpment shrublands and grasslands Mountain mahogany (Cercocarpus montanus) prevails across the west-facing flanks of the Laramie Range, and on limestone canyon walls. Woodlands are in small patches, with small groves of quaking aspen (Populus tremuloides) in spring-fed valley settings, and pockets of limber pine (Pinus flexilis) on limestone breaks. Threetip sagebrush (Artemisia tripartita) is on at least the crest of the flanks. Escarpment grasslands in the canyons and on top were not characterized except to note their good-excellent condition. Species present include Stipa comata and Muhlenbergia filiculmis. Rare Plants There are no known records for Wyoming plant species of concern on Cook Ranch, though there is one record of pale blue-eyed grass (Sisyrinchium pallidum) based on a 1961 speciment collected east of Bosler, immediately upstream on the Laramie River. This species and the majority of the 12 species are regional endemics, i.e., species oflimited worldwide distribution for which their status in Wyoming is important in determining their rangewide status. The species, their ranks, and their habitats are summarized below. Wyoming plant species of concern potentially occurring on Cook Ranch Scientific name Common name Global State Potential habitat rank rank probability Aquilegia laramiensis Laramie columbine G2 S2 Low - granite escarpment at high elevation Carex oreocharis Mountain-loving G3 Sl High - limestone and sedge granite escarpment Eriogonum exilifolium Slender-leaved G3 S2 Moderate - foothills buckwheat slopes and clay/shale barrens Haplopappus wardii Ward's goldenweed G2G3 S2S3 High - basin bentonite outcrops and clay roadsides Hemicarpha drummondii Dward bulrush G4G5 Sl Moderate - basin sandy shores Machaeranthera Colorado tansy-aster G2? Sl High - basin redbeds, coloradoensis limey-sandstones outcrops, Niobrara shale outcrops Phacelia denticulata Rocky Mountain G3? S2 Low - sandy canyon phacelia bottom in foothills Phacelia neomexicana var. White scorpion- G4G5 Sl Moderate- granite alba weed escarpment Potamogeton stricifolius Strict-leaved GS Sl Moderate - perennial pondweed streams Potentilla ambigens Giant cinquefoil G3 SH Low - sandy canyon bottom Rorippa calycina Persistent sepal G3 G2G3 Moderate - basin shores yellowcress w/ sand or occasionally shale Sisyrinchium pallidum Pale blue-eyed grass G2G3 S2S3 High - basin riparian meadows Sphaeromeria simplex Laramie false G2 S2 High - basin and sagebrush escarpment limestone In the recent field visit, rare plant habitats were identified and potential habitat probability was assessed for the 12 Wyoming plant species of special concern. Systematic surveys are needed to document the rare plant significance of Cook Ranch, which would focus the survey effort on at least those seven globally rare species (Gl-G3) below that have a high or moderate probability of suitable habitat on the Cook Ranch. They are highlighted below and described in detail on an accompanying set of state species abstracts. Mountain-loving sedge is an upland plant of the southern Rocky Mountains, ranging from northern Arizona to southeastern Wyoming. In the state, it is known from a total of five locations in Albany and Laramie counties. It occupies dry, montane grassland over limestone and granite bedrock where it may be locally abundant. Slender-leaved buckwheat is an upland plant restricted to southcentral Wyoming and northcentral Colorado. In the state, it is known from a total of seven locations in Albany and Carbon counties. It occupies sparse cushion plant communities of plains and foothills on sandy­ clay gumbo flats, white shaley-gypsum ridges, red clay hills, and limestone outcrops where it may be locally common. Ward's goldenweed is an upland plant restricted to southcentral Wyoming. It occupies selenium-· rich shale-clay slopes where it may be locally common. It is known from about 25 locations to date, and may be more widely-distributed than previously known. It will be moved to the watch list in the 2001 Wyoming plant species of concern, in progress. Colorado tansy-aster is an upland plant restricted to southeastern Wyoming and central Colorado. In the state, it is known from a total of four locations in addition to a historical record. It occupies barren cushion plant and sparse grassland communities on limey-sandstone, shaley­ gypsum or redbed slopes on plains and foothills. It has not been found on BLM-administered lands to date, but is recognized as a Sensitive species by the U.S. Forest Service. Persistant sepal yellowcress is a wetland plant restricted to Wyoming plains, in addition to historic records in Montana and the Yellowstone River of North Dakota; plus two collections that seem to represent chance introductions by waterfowl in Montana and the Northwest Territories. It was formerly