VIII. Coptis trifolia (L.) Salisb (threeleaflet goldthread).

Area of Application: Throughout the area covered by the Northwest Forest Plan.

A. Introduction

Coptis trifolia is an evergreen perennial rhizomatous herb with shiny, three-parted basal leaves in the Ranunculaceae (buttercup family). The common name, threeleaf goldthread, refers to the 3 leaflets that comprise each basal leaf.

Coptis trifolia is described as inhabiting small wetland areas (i.e., seeps, bogs) located within mature Western Hemlock and Silver Fir forests. It is classified as a Survey and Manage Strategy 1 and 2 species under the FSEIS/ROD (USDA Forest Service and USDI Bureau of Land Management 1994a, 1994b). Coptis trifolia is on List 2 (threatened or endangered in Oregon, but more stable or common elsewhere) of the Oregon Natural Heritage Program (1998); it is a Bureau of Land Management Assessment Species in Oregon and Washington; and it is on the U.S. Forest Service Region 6 Regional Forester's Sensitive Species List.

B. Unique Characteristics, Biology, and Ecology

Coptis trifolia is an evergreen, perennial herb from 4-10 cm (1.6-4.0 inches) tall. Leaves are shiny and dark above, paler below, and are basally attached. Each leaf is divided into 3 subsessile, toothed leaflets. The leaf blade measures 1-2 cm (0.4-0.8 inches) in length. Plants form small, compact mats due to its rhizomatous habit. The rhizomes are bright yellow in color, a characteristic common to all species in the genus and which accounts for its common name, goldthread. Each plant may produce one flower that has 5 whitish sepals 5-10 mm (0.2-0.4 inches) long and 5 hollow, fleshy, club-shaped orange petals, which produce nectar at the tip. The petals are about half as long as the sepals. Fruits are a follicle measuring 5-10 mm (0.2-0.4 inches) long and are cup shaped with a suture on the upper surface (Hitchcock et al. 1964; Pojar and MacKinnon 1994; Hulten 1968).

Coptis trifolia most closely resembles Coptis occidentalis (western goldthread), which does not occur within the range of the northern spotted owl. Within the known range of Coptis trifolia in Oregon, Coptis laciniata (cut-leaf goldthread) differs in having leaflets that are deeply lobed, as opposed to leaftets that are not appreciably lobed. Flowering generally occurs in June. Observations of Oregon populations suggest that this species reproduces both vegetatively from rhizomes and from seed. The nectiferous petals appear to be attractive to solitary bees and hover flies (Syrphidae).

C. Specific Habitat Associations

Coptis trifolia is described as inhabiting boggy, wet seepage areas (Pojar and MacKinnon 1994), sphagnum hummocks (Calder and Taylor 1968), muskegs to deep woods (Hitchcock et al. 1964), and mossy places (Hulten 1968). In Oregon, C. trifolia sites are associated with small wetland areas located within mature coniferous forests in the Western Hemlock Zone (Halverson et al. 1986) and Silver Fir Zone (Hemstrom et al. 1982) at an elevation of 1000-1160 m (3280-3800 feet) above sea level. Soils are poorly drained histosols. This habitat is not uniformly wet, but a mosaic of small stream channels and boggy depressions interspersed with slightly higher, drier hummocks. The hummocks are the remains of large downed wood and the root masses of windthrown trees, while the depressions are likely the holes left by the displaced root masses. Typically, C. trifolia is found on the hummocks immediately above the level of saturated soil. This habitat often forms a narrow zone approximately 10 to 40 cm (3.9-15.7 inches) in width. Plants may be growing in either mineral soil or organic substrates, including decomposing wood. Canopy closure of the overstory conifers varies from 25 to 60 percent. Snags and live trees with broken tops or sparse crowns are often present. Herbaceous vascular plants, mosses, and liverworts provide a ground cover of between 80 and 100 percent. Associated vascular and non-vascular species include Tsuga heterophylla, Thuja plicata, Pinus monticola, P. contorta, Abies amabilis, Picea engelmannii, Rhododendron macrophyllum, Menziesia ferruginea, Alnus incana, Taxus brevifolia, Vaccinium ovalifolium, Gaultheria ovatifolium, Kalmia occidentalis, Cornus canadensis, Caltha biflora, Linnaea borealis, Senecio triangularis, Listera cordata, Lysichitum americanum, Mitella pentandra, Sanguisorba occidentale, Pleurozium schreberi, Rhytidiadelphus loreus, R. triquetrus, Philonotis fontana, Eurhynchium praelongum, Dicranium fuscescens, Rhytidiopsis robusta, Hylocomnium splendens, Sphagnum sp., and Scapania americana.

D. Range of Coptis trifolia

1. Known Range

Coptis trifolia has a circumboreal distribution extending from Greenland across North America to Alaska and into eastern Siberia, south to Saskatchewan, British Columbia, Iowa, North Carolina, and northern Japan. The 3 known sites in Oregon are disjunct some 450 km (280 miles) south of the primary range in British Columbia (Madrono 1991). Subspecies trifolia includes those populations in Oregon, coastal British Columbia, Alaska, and Asia. Two of the Oregon sites occur within Clackamas County, both on lands managed by the Mt. Hood National Forest. One Wasco County site is located on the Confederated Tribes of the Warm Springs Lands (USDA Forest Service and USDI Bureau of Land Management 1994b, Oregon Natural Heritage Program 1998).

2. Suspected Range

It is thought to be highly likely that additional populations of C. trifolia will be discovered in the Washington Cascades and in the northern Oregon Cascades, on the Mt. Hood and Willamette National Forests.

E. Timing of Surveys

Surveys should be conducted during the flowering or fruiting period (June through September) when plants are most easily seen and identifiable.

F. Threats

Threats to C. trifolia can be summarized as follows:

• Actions that alter hydrologic function
• Actions that reduce the large tree component
• Actions that reduce the amount of coarse woody debris
• Mechanical damage to plants or soils

REFERENCES

Calder, J. A. and R. L. Taylor. 1968. Flora of the Queen Charlotte Islands Part 1. Department of Agriculture, Research Branch.

Halverson, N. M., C. Topik and R. Van Vickle. 1986. Plant Association and Management Guide for the Western Hemlock Zone. Mt. Hood National Forest. USDA Forest Service, Pacific Northwest Region, Portland, OR. R6-ECOL-232A-1986. 111 pp.

Hemstrom, M. A., W. H. Emmingham, N. M. Halverson, S. E. Logan, and C. Topik. 1982. Plant Association and Management Guide for the Pacific Silver Fir Zone, Mt. Hood and Willamette National Forests. USDA Forest Service, Pacific Northwest Region, Portland, OR. R6-ECOL-100-1982a. 104 pp.

Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1964. Vascular Plants of the Pacific Northwest. University of Washington Press, Seattle, WA.

Hulten, E. 1968. Flora of Alaska and Neighboring Territories. A Manual of the Vascular Plants. Stanford University Press. Stanford, CA. 1008 p.

Madrono. 1991. Noteworthy Collections - Oregon. Madrono, Vol. 38, No. 3, pp. 204-205.

Oregon Natural Heritage Program. 1998. Rare, Threatened and Endangered Species of Oregon. Oregon Natural Heritage Program, Portland, Oregon. 92 pp.

Pojar, J. and A. MacKinnon (eds). 1994. Plants of the Pacific Northwest Coast. B.C. Ministry of Forests and Lone Pine Publishing. Canada. 527 p.

USDA Forest Service and USDI Bureau of Land Management. 1994a. Final supplemental environmental impact statement on managing of habitat for late successional and old-growth species within the range of the northern spotted owl. Portland, Oregon.

USDA Forest Service and USDI Bureau of Land Management. 1994b. Final supplemental environmental impact statement on managing of habitat for late successional and old-growth species within the range of the northern spotted owl. Appendix J2, Results of Additional Species Analysis. Portland, Oregon.