Ute Ladies Tresses (Spiranthes diluvialis) in Idaho: 1999 and 2000 Status Reports

This 1999 status report for Ute ladies tresses is meant to compliment the 1997 and 1998 reports (Moseley 1998a; 1998b) and only contains new or updated information about the species in Idaho. I follow the same format in this update as I did in the previous reports, which should be consulted for information not covered here.

New findings reported here include:

• The discovery that eight occurrences on the upstream end of its distribution are mixed populations of Spiranthes diluvialis and S. romanzoffiana. We also recognize the distinct possibility that the upstream-most occurrence at Sq___ Creek Islands may not contain any S. diluvialis at all. I discuss the reasons for these humbling discoveries.
• We permanently monumented the transect at the Warm Springs Bottom population that was extirpated during the 1997 flood. I review the two years of plant composition and structure data. We discovered one new occurrence along the Snake River, within the known distribution.
• The total number of occurrences in Idaho is now 22.
• We collected new plant composition and structure information in habitats at three sites.
• We characterized the substrate stratigraphy underlying Ute ladies tresses in 25 soil pits at 18 occurrences. I summarize the results.
• We surveyed 20 flood plain cross-sections through Ute ladies tresses and adjacent habitats. I provide a summary of the vertical relationships of the habitats in reference to river flows.
• Finally, I outline the Ute ladies tresses conservation work being planned for the Snake River populations in 2000, which will again focus on population and habitat monitoring, as well as continued research on the habitat-flood plain succession relationships.