Developing biogeographically based population introduction protocols for at-risk Willamette Valley plant species: Agrostis howellii (Howell’s bentgrass) Aster curtus (white-topped aster), Aster vialis (wayside aster), Delphinium leucophaeum (hot rock larkspur), Delphinium pavonaceaum (peacock larkspur), Erigeron decumbens var. decumbens (Willamette daisy), Horkelia congesta ssp. congesta (shaggy horkelia), Lomatium bradshawii (Bradshaw’s desert parsley), Lupinus sulphureus ssp. kincaidii (Kincaid’s lupine), Montia howellii (Howell’s montia), Sidalcea spp. (Willamette Valley checkermallows) Prepared by Steven D. Gisler Native Plant Conservation Program Oregon Department of Agriculture with contributions by Oregon Department of Agriculture staff for U.S. Fish and Wildlife Service Grant OR-EP-2, segment 13 Acknowledgements: We would like to thank the many people who contributed to the completion of this report. Thanks to Andy Robinson and Kathy Pendergrass (USFWS) for providing funding and encouragement (Grant no. OR-EP-2, segment 13). Kelly Amsberry, Rebecca Currin, and R.J. Meinke contributed to text completion and review, and Melissa Carr provided invaluable assistance in compiling data. Thanks also to the staff, interns and students who provided plant and habitat photos, and to Erin Amsberry Abood for assistance in final report preparation. Contact Information: Robert J. Meinke Kelly Amsberry Native Plant Conservation Program Native Plant Conservation Program Oregon Department of Agriculture Oregon Department of Agriculture Dept. of Botany and Plant Pathology Dept. of Botany and Plant Pathology Oregon State University Oregon State University Corvallis, OR 97331 Corvallis, OR 97331 (541) 737-2317 (541) 737-4333 [email protected] [email protected] Report format: The following species are presented in alphabetical order: Agrostis howellii (Howell’s bentgrass), Aster curtus (white-topped aster), Aster vialis (wayside aster), Delphinium leucophaeum (hot rock larkspur), Delphinium pavonaceaum (peacock larkspur), Erigeron decumbens var. decumbens (Willamette daisy), Horkelia congesta ssp. congesta (shaggy horkelia), Lomatium bradshawii (Bradshaw’s desert parsley), Lupinus sulphureus ssp. kincaidii (Kincaid’s lupine), Montia howellii (Howell’s montia), Sidalcea sp. (Willamette Valley checkermallows). Each species’ section consists of segments covering Conservation Status, Range and Habitat, Species Description, Seed Production, Seed Germination, Vegetative Reproduction, Breeding System, Hybridization, Cultivation, Transplanting and Introduction Attempts, Population Monitoring, and Land Use Threats and other Limitations, followed by a final segment outlining a specific Population Introduction/Augmentation Strategy. Literature citation: Gisler, S.D. 2004. Developing biogeographically based population introduction protocols for at-risk Willamette Valley plant species. Report to US Fish and Wildlife Service, Portland, Oregon. Native Plant Conservation Program, Oregon Department of Agriculture, Salem, Oregon. Table of Contents page Agrostis howellii 1 (Howell’s bentgrass) Aster curtus 19 (white-topped aster) Aster vialis 41 (wayside aster) Delphinium leucophaeum 63 (hot rock larkspur) Delphinium pavonaceum 84 (peacock larkspur) Erigeron decumbens var. decumbens 105 (Willamette daisy) Horkelia congesta ssp. congesta 126 (shaggy horkelia) Lomatium bradshawii 141 (Bradshaw’s desert parsley) Lupinus sulphureus ssp. kincaidii 159 (Kincaid’s lupine) Montia howellii 180 (Howell’s montia) Sidalcea spp. 195 (Willamette Valley checkermallows) Developing biogeographically based population introduction protocols for at-risk Willamette Valley plant species: Agrostis howellii (Howell’s bentgrass) Developing biogeographically based population introduction protocols for at-risk Willamette Valley plant species: 1 Agrostis howellii. Agrostis howellii (Howell’s bentgrass) Conservation status With its extremely localized geographic distribution and inhabitation of only 20 extant sites, Agrostis howellii (Figure 1) is considered one of the rarest grass species in the Pacific Northwest. Accordingly, it is currently recognized as a Species of Concern by the U.S. Fish and Wildlife Service, and a Candidate for Listing as Threatened or Endangered by the State of Oregon. It is on the Oregon Natural Heritage Program List 1 (threatened or endangered throughout its range), and has a Natural Heritage Network Rank of G2/S2 (imperiled throughout its range/imperiled in Oregon) (ONHP 2001). Figure 1. Agrostis howellii, growing near Tanner Creek in Oregon’s Columbia River Gorge. (Photo by Teresa Brainard.) Developing biogeographically based population introduction protocols for at-risk Willamette Valley plant species: 2 Agrostis howellii. The primary threats facing Agrostis howellii are the low number, small size, and limited geographic distribution of its extant populations--factors which cumulatively heighten the risk of overall demographic declines or extinction due to random environmental events (see “Land use threats and other limitations,” below). Fortunately, adverse human impacts to A. howellii currently appear quite low, as most extant populations occur on steep, rocky sites that do not lend themselves to urban or agricultural development. Moreover, the majority of A. howellii populations are further protected by virtue of their occurrence within protected areas of the Columbia River Gorge National Scenic Area and/or on lands administered by the U.S. Forest Service and other public agencies within the Columbia Gorge (Robin Dobson, Columbia River Gorge National Scenic Area, Hood River, Oregon, personal communication). The single population known from outside the Columbia River Gorge, located far to the south in southern Linn County, Oregon, also occurs on publicly owned land managed by the Eugene District BLM (Dick Brainerd, Salix Associates, Corvallis, Oregon, personal communication) (see “Range and habitat,” below), so it is similarly isolated from threats associated with private land development. Range and habitat Agrostis howellii was first collected by Wilhelm Suksdorf in 1885 at Bridal Veil Falls, Oregon, located at the western end of the Columbia River Gorge. The type collection for the species was made one year later by Thomas Howell in nearby Hood River, Oregon. For over a century A. howellii was believed to be wholly restricted to moist, shady habitats along waterfalls and streams on the south side of the Columbia River Gorge in Multnomah and Hood River Counties, Oregon. This long-held belief was recently debunked, however, with the discovery of the species nearly 100 miles to the south in the Coburg Hills of Linn County, Oregon (Simpson 1996). The occurrence of this distantly outlying population suggests the possibility that A. howellii might also occur on other basaltic hills (like those comprising the Coburg Hills) in the Willamette Valley, though to date there is no evidence indicating that it does. Currently, the Oregon Natural Heritage Program has 18 population records for Agrostis howellii in its rare plant database, 17 of which occur in the Columbia River Gorge Developing biogeographically based population introduction protocols for at-risk Willamette Valley plant species: 3 Agrostis howellii. (ONHP 2002). Here, habitat for A. howellii consists of steep, moist, mossy, basaltic canyon walls and talus slopes, in semi- or dense shade (Figure 2) (Carlbom 1967), often in the mist zone of waterfalls (Scofield 1980), at elevations ranging from 100-400 ft. (ONHP 2002). The species is reported to occur in association with Adiantum pedatum, Campanula rotundifolia, Elymus glaucus, Festuca subulata, Montia sp., Tolmiea menziesii, and various unidentified mosses (OSU herbarium label information and ONHP 2002). Figure 2. Most Agrostis howellii populations occur in shady, moist, mossy, rocky areas, typically located in the splash zone of turbulent streams and the mist zone of waterfalls in Oregon’s Columbia River Gorge. (Photo by Teresa Brainard.) Developing biogeographically based population introduction protocols for at-risk Willamette Valley plant species: 4 Agrostis howellii. In the Coburg Hills of southern Linn County, habitat occupied by Agrostis howellii is markedly different from that in the Columbia River Gorge. Dick Brainerd (personal communication), who discovered the Coburg Hills population, characterized the site as a broad, gently sloping swale in a moist Acer circinatum/Carex deweyana community with scattered Fraxinus latifolia, surrounded by mature Pseudotsuga menziesii forest. Other associated species include: Athyrium filix-femina, Galium triflorum, Hydrophyllum tenuipes, Rubus leucodermis, Senecio jacobaea, Solanum dulcamara, and Stachys mexicana. The elevation of the Coburg Hills site, 1480 ft., is substantially higher (over 1000 ft higher) than populations in the Columbia River Gorge. Description of species Agrostis howellii is a perennial grass with tufted culms, 40-70 cm tall, weakly ascending from a geniculate base. Blades are deep green, flat, lax, scabrous on both surfaces, 15-30 cm long, 3-5 mm wide, with ligules 4-6 mm long. Panicles are green, loose and spreading, 10-30 cm long, the lower branches in fascicles of 3’s to 5’s, the upper rays in 2’s. Spikelets are pale, pedicelled, 3-5 mm long; glumes are slightly unequal, acuminate, and scabrous on the keel; lemmas are slightly shorter than the glumes, with geniculate awns (6-8 mm long) arising from near the base (Hitchcock 1905, Peck 1961, Carlbom