IX. Corydalis aquae-gelidae Peck & Wilson (cold-water corydalis)
Area of Application: Throughout the area covered by the Northwest Forest Plan.
A. Introduction
Corydalis aquae-gelidae is a herbaceous perennial with hollow stems arising from deep-seated, fleshy, tuberous roots in the family Fumariaceae. The Fumariaceae has been included in the Papaveraceae (poppy family) by Hickman (1993). Both cold-water corydalis and Clackamas corydalis have been used as common names.
Corydalis aquae-gelidae is considered to be closely associated with riparian areas within old-growth habitat, and 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). C. aquae-gelidae is considered to be endangered and threatened throughout its range (List 1) by the Oregon Natural Heritage Program (1998). It is a Oregon State Candidate for listing as a Threatened or Endangered species. It is a Washington State Threatened species. It is on the U.S. Forest Service Region 6 Sensitive Species List, and is a Oregon/Washington BLM Bureau Sensitive species. These designations for C. aquae-gelidae reflect concern for the long-term viability of this species.
B. Unique Characteristics, Biology, and Ecology
The following is a technical description of Corydalis aquae-gelidae:
Herbaceous perennial with hollow stems arising from deep-seated, fleshy, tuberous roots. Plants are typically from 0.3-1.1 m (1-3.5 ft.) tall. Leaves are 4 to 6 divided with numerous elliptic terminal leaflets 5-12 mm (0.2-0.5 inches) long and 2-5 mm (0.1-0.2 inches) broad. The showy rose-lavender flowers are 12-20 mm (0.5-0.8 inches) long, bilabiate, with a prominent spur. Arrangement is in a 30-60 flowered, simple to compound raceme. The fruit is an elliptic capsule 10-15 mm (0.4-0.6 inches) long with 2 mm (0.1 inch) long seeds (Hitchcock et al. 1964).
Corydalis aquae-gelidae is most similar in morphology to Corydalis caseana, which ranges from northeast Oregon and Idaho to California. Within the range of Corydalis aquae-gelidae, C. scouleri is relatively common but differs by having less dissected leaves with larger leaflets and flowers. Flowering occurs from May through August. Bumblebees are probably the main pollinators.
A number of tuberous rooted species of Corydalis are known to reproduce vegetatively from offsets, although it appears that Corydalis aquae-gelidae reproduces by seed only (Goldenberg 1990). C. aquae-gelidae typically produces 100-1500 seeds per plant with occasional plants producing up to an estimated 3000 seeds per plant, higher than seed production for the related C. scouleri (Goldenberg 1992). When the seed capsules are mature they dehisce explosively, dispersing the seed up to several meters. Dispersion may also be facilitated by a fleshy food body attached to the seed, which may be attractive to ants (Goldenberg 1992).
Goldenberg (1992) determined that germination occurs when seed is stratified at 3oC (37oF) for a 6 to 7 month period. Germination also occurs at temperatures of 17o to 27C (63o-81oF), much greater than those expected under natural conditions, if substrates are kept saturated. Conversely, poor germination results when seed is allowed to dry (Goldenberg 1992; Guerrant 1995; Olson 1997). Seedlings appear to establish readily if a moist substrate of gravely-sand is available but establishment and recruitment is poor in organic substrates that are not well watered.
Demographic studies in Oregon (Goldenberg 1990) found Corydalis aquae-gelidae to be comprised of 38 percent seedlings, 48 percent juveniles, 3 percent non-reproductive adults, and 11 percent reproductive adults. These data give the appearance that juveniles are 2 to several years old, adult plants remain in a nonreproductive stage for a relatively short period, and that adult plants are long-lived.
C. Specific Habitat Associations
All known sites of Corydalis aquae-gelidae are located within the Western Hemlock Zone (Halverson et al. 1986; Topik et al. 1986) and the Pacific Silver Fir Zone (Hemstrom et al. 1982; Brockway et al. 1983). Additionally, all known sites are located between 370-1310 m (1200-4260 feet) in elevation.
Corydalis aquae-gelidae is associated with perennial streams, seeps, and springs with relatively cold water and a substrate of gravely-sand. Goldenberg (1990) found the horizontal distance of individual plants to water ranged from 0 to 290 cm (0-9.6 feet) with a mean of 37 cm (15 inches) for Oregon populations. The mean water temperature at these sites was 9.6oC (49oF) during the growing season. Plants are absent from organic substrates such as marshes and bogs.
Diaz and Mellen (1996) have described the Corydalis aquae-gelidae plant community that occupies cool, wet, shady environments, and is restricted to sand/gravel deposits very close to the normal high-water line, where the substrate is often saturated by flowing water for a considerable portion of the growing season. Light levels appear to be an important determinant of suitable habitat. Gamon (1983) reports that where canopy closure approaches 100 percent, the number of individual plants decrease as does the flowering. Goldenberg (1992) observed plants growing within clearcuts to have yellowed foliage, poor growth, and no seedling recruitment. This may not only be a factor of intense insolation, but also an inability to compete with aggressive pioneer species. Densiometer readings within Oregon populations found the percent canopy closure to range from 0 to 100 percent with a mean of 84 percent (Goldenberg 1992). Both Goldenberg and Gamon came to a similar conclusion, that the species seems best suited to habitats in which a high, partial canopy allows sufficient light for growth and reproduction, but hinders the establishment of competing vegetation.
A general distinction can be made between Oregon and Washington populations in terms of the stream order with which they are associated. Oregon populations are most numerous in headwater areas (stream order 0) and 3rd, 4th, and 5th order streams, but largely absent from 1st and 2nd order streams. In Washington, most populations are associated with headwaters and 1st and 2nd order streams. This difference may simply be due to the greater number of 3rd, 4th, and 5th order streams, which occur within the range of Corydalis aquae-gelidae in Oregon. Within these stream orders, the geomorphology of the channels are described as Rosgen B and C.
C channel types are described as being low gradient, meandering, and with a broad, well defined floodplain (Rosgen 1994). B channel types have a higher gradient, more defined channel, and are less meandering. It can be expected that alluvial bars and gravel deposits currently occupied by Corydalis aquae-gelidae, particularly in C channel types, will shift over time. Sites vary in slope from 90 percent to flat and most often have an aspect of northwest to northeast, although all aspects have been recorded. Precipitation within the species' range varies from 1500-2500 mm (60-100 inches) annually.
Diaz and Mellen (1996) and sensitive plant sighting reports from the Mt. Hood and Gifford Pinchot National Forest and Salem BLM identify associated species for Corydalis aquae-gelidae to include Senecio triangularis, S. pseudaureus, Delphinium trollifolium, Aconitum columbianum, Aster modestus, Alnus incana, Physocarpus capitatus, Saxifraga arguta, Mimulus guttatus, Tolmiea menziesii, Tiarella unifoliata, Oxalis oregana, Isopyron hallii, Polystichum munitum, Veronica americana, Montia siberica, Alnus rubra, Oplopanax horridum, Acer circinatum, Ribes lacustre, Thuja plicata, Taxus brevifolia, Tsuga heterophylla, Abies procera, A. amabilis, and Pseudotsuga menziesii.
D. Range of Corydalis aquae-gelidae
1. Known Range
Corydalis aquae-gelidae is a regional endemic, known from 93 sites in Clackamas, Multnomah, Linn, and Marion Counties in Oregon, and Skamania and Clark Counties in Washington. This represents a range of approximately 90 air miles north-south and 35 miles east-west (USDA Forest Service and USDI Bureau of Land Management 1994b; Washington Natural Heritage Program 1994; Oregon Natural Heritage Program 1998).
Oregon sites are concentrated along the Upper Clackamas River, Oak Grove Fork Clackamas River, North Fork Clackamas River, and Eagle Creek. The Marion and Linn County sites on the Salem BLM District are the most disjunct.
Distribution in Washington is more sporadic with most sites occurring in the headwaters and tributaries (stream order 0-2) of Canyon Creek, Wind River, and East Fork Lewis River.
2. Suspected Range
The relatively recent (1993) discovery of the populations in Marion and Linn counties, Oregon represented a significant southern range extension. Therefore, it is possible to discover additional sites on adjacent administrative units.
E. Timing of Surveys
Surveys should be conducted during the flowering or fruiting periods (May through September) when plants are most easily seen and identifiable.
F. Threats
Management Recommendations (Stein 1998) indicate that the threats to C. aquae-gelidae may include activities that alter hydrologic function, increase stream temperature, increase vegetative competition, increase solar radiation, and cause mechanical damage to plants. Trampling from recreational activity is a concern but is judged to be minor at this time.
REFERENCES
Brockway, D. G., C. Topik, M. A. Hemstrom, and W. H. Emmingham. 1983. Plant Association and Management Guide for the Pacific Silver Fir Zone. Gifford Pinchot National Forest, USDA Forest Service, Pacific Northwest Region. Portland, OR. R6-ECOL-130a-1983. 122 pp.
Diaz, N. M. and T. K. Mellen. 1996. Riparian Ecology Types. Gifford Pinchot and Mt. Hood National Forest and Columbia River Gorge National Scenic Area. USDA Forest Service, Pacific Northwest Region. Portland OR. R6-NR-TP-96.
Gamon, J. 1983. Species Management Guide for Corydalis aquae-gelidae on the Gifford Pinchot National Forest. USDA Forest Service, Pacific Northwest Region. Portland, OR. 15 pp.
Goldenberg D. M. 1990. Draft Species Management Guide for Corydalis aquae-gelidae (Peck and Wilson). Unpublished report submitted to the Mt. Hood National Forest. Gresham, OR.
Goldenberg D. M. 1992. Ecology of Corydalis aquae-gelidae, a Rare Riparian Plant. Unpublished M.S. thesis, Oregon State University, Corvallis, OR.
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.
Hickman, J. (Ed.). 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, California.
Hitchcock, C. L., A. Cronquist, M. Ownbey, and J. W. Thompson. 1964. Vascular Plants of the Pacific Northwest. University of Washington Press, Seattle, WA.
Olson, E. 1997. Draft survey protocol outline: Corydalis aquae-gelidae. Unpublished manuscript.
Oregon Natural Heritage Program. 1998. Rare, Threatened and Endangered Species of Oregon. Oregon Natural Heritage Program, Portland, Oregon. 92 pp.
Rosgen, D. L. 1994. A Classification of Natural Rivers. CATENA, Vol. 22, pp. 169-199.
Stein, M. 1998. Management recommendation for cold-water corydalis (Corydalis aquae-gelidae). Unpublished manuscript.
Topik, C., N. M. Halverson, and D. G. Brockway. 1986. Plant Association and Management Guide for the Western Hemlock Zone. Gifford Pinchot National Forest. USDA Forest Service, Pacific Northwest Region, Portland, OR. R6-ECOL-230A1986. 132 pp.
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.
Washington Natural Heritage Program. 1994. Endangered, Threatened, and Sensitive Vascular Plants of Washington. Washington Department of Natural Resources, Olympia, WA. 42 pp.
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