Botany and Wetlands Study Report - McMillen, LLC

Botany and Wetlands Study ReportSoutheast Alaska Power AgencyThe proposed project would likely have direct effects on the population because it would beinundated by the 15‐foot increase in maximum pool elevation. There may be additionalundetected plants in the muskeg habitat, although the area was well searched. Indirect effectsto plants not inundated are also possible, potentially occurring as a result of light level changesor water table level changes resulting from inundation. The presence of additional undetectedpopulations in the analysis area is unlikely because the analysis area does not include additionalmuskeg habitat.4.2.6 Choris’ bog‐orchid (Platanthera chorisiana (Cham.) Reichenb.)Choris’ bog‐orchid is a diminutive orchid, with two clasping leaves located near the base of theplant and 5‐18 small greenish, sessile flowers in a crowded spike. It is an obligate wetlandspecies (Fuentes et al. 2007), which grows in wet places and Sphagnum bogs (Hulten 1968).Choris’ bog‐orchid ranges from Japan, through the Aleutian Islands and mainland of Alaska,southward through the Queen Charlotte Islands and Vancouver Island and British Columbiainterior into Washington State (Fuentes et al. 2007). It is not known from the Tongass NationalForest. On the 2008 AKNHP rare plant list, Choris’ bog‐orchid was assigned a rank of S2;however, on the 2012 list it was assigned a rank of S4 (AKNHP 2008; AKNHP 2012). The Rank S4indicates that the taxon is more common then previously thought and may include species thatwould be more accurately described as S4S5 or S5 (AKNHP 2012). Because of its S4 rank, it is nolonger actively tracked by the AKNHP. A single small Choris’ bog‐orchid population was locatedin the analysis area on a small muskeg on the south end of the analysis area. Two plants werelocated under a short tree.The proposed project would likely have direct effects on the population because the populationwould be inundated by the 15‐foot increase in maximum pool level. There may be additionalundetected plants in the muskeg although it was well searched. Indirect effects to plants notinundated are also possible; potentially occurring as a result of light level changes or water tablelevel changes resulting from inundation. The presence of additional undetected populations inthe analysis area is unlikely because the analysis area does not include additional muskeg habitatfor this species.4.2.7 Pacific Buttercup (Ranunculus pacificus (Hulten) L.D.Benson)Pacific buttercup is a perennial buttercup species with large yellow flowers and dissected leaves.Its habitat is along streams and in meadows (FNA 20). It is an Alaskan endemic known fromsoutheast Alaska and the Aleutian chain (USDA NRCS 2012). Prior to field surveys conducted inAugust 2012 for the Project, there were no known locations of Pacific buttercup on the TongassNational Forest. Pacific buttercup has been assigned a rank of S3S4 in Alaska (AKNHP 2012). TheRank S3S4 indicates that within Alaska this plant is vulnerable due to restricted range, relativelyfew populations, recent and widespread declines, or other factors making it vulnerable toextirpation (S3); apparently secure; uncommon but not rare (S4). A small Pacific buttercupSwan Lake Hydroelectric Project January 2013FERC Project No. 2911 Page 24 Version: Agency Review