Nebraskaland

12 Nebraskaland • August-September 2020 IN THE FIELD The small white lady's-slipper orchid (Cypripedium candidum) is one of Nebraska's most bizarre and beautiful wildflowers. A finicky plant, conservationists are exploring methods to manage this orchid's prairie and meadow habitats to ensure the survival of this state threatened species. Historically, the white lady's-slipper ranged over much of northeastern Nebraska, extending westward on the Niobrara River to Cherry County and the Platte River to Lincoln County. Today, it is found in 30 sites in the Loup and upper Elkhorn river drainages. The long-lived orchid grows as a single stem or in clumps reaching 4 to 12 inches tall. Each stem supports several broad, lance-shaped leaves with prominent parallel veins. The waxy-white flowers, which bloom from late-May into June, have an inflated lower petal that forms a pouch, the slipper, designed for intricate insect pollination. The narrow, green capsules mature in late summer and contain thousands of tiny, wind-dispersed seeds. Loss of its prairie habitat and competition from invasive plants, such as non-native smooth brome and reed canary grass, have played a key role in the orchid's decline. The orchid also appears to be sensitive to long-term livestock grazing as it is known from only one pasture in our state, and there, in Valley County, the plants grow in a wet, hummocky area rarely touched by cattle. Today, the orchid, and many other prairie wildflowers, are most abundant in meadows hayed in late summer after their seeds have ripened and the plants are mostly dormant. Unfortunately, most Nebraska hay meadows are traditionally cut in mid-summer when grasses are at the peak of growth and nutrient content. This practice eliminates the orchid's seed capsules and the leaves it needs to restock root reserves for the next year's growth through photosynthesis. At several meadows, annual haying has eliminated the lady's-slipper, but it persists in adjacent, un-mowed road ditches. I once saw a strange phenomenon: On an otherwise bare, gravel ridge pushed up by a road grader grew hundreds of young lady's-slippers. Their source: seeds from plants in an adjacent meadow. Historically, flooding and bison grazing and trampling often created similar bare habitats, and I speculate that, free of grass competition, this is where orchid seedlings thrived and grew to adulthood. Such habitats are now rare or non-existent in prairies and meadows. A management scenario to promote similar habitats might include periodic prescribed fire followed by heavy livestock grazing to stress grass regrowth and create openings for lady's- slipper seedlings. Late summer haying in the intervening years would allow mature plants to seed and store nutrients. Another conservation concern is the difficulty of establishing new lady's-slipper populations. I once tried to move 20 orchids that grew in a meadow and adjacent road ditch near Columbus slated for development. Transplanted to meadows on the central Platte and Elkhorn river floodplains, the plants lingered for a year and then died. The soils at these sites apparently lacked the specific chemistry, moisture content and/or fungi needed by the orchid. Regarding the latter, the white lady's-slipper grows only in soils harboring certain soil fungi, which aid its roots in absorption of water and nutrients. The plant's specific habitat needs also make it extremely difficult to establish from seed. The difficulty of transplanting and seeding the white lady's-slipper necessitates preservation of its wild populations. In Nebraska, all but one of these occur on private lands, mandating that conservationists work with farmers and ranchers to conserve the species. Only through such partnerships will the rare orchid survive in our state. By Gerry Steinauer THREATENED AND ENDANGERED: THE SMALL WHITE LADY'S-SLIPPER ORCHID PHOTO BY JON FARRAR

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