5-YEAR REVIEW Short Form Summary Species Reviewed: Poa mannii (Mann’s bluegrass) Curre nt Classification: Endangered Federal Register Notice announcing initiation of this review: [USFWS] U.S. Fish and Wildlife Service. 2008. Endangered and threatened wildlife and plants; initiation of 5-year status reviews of 70 species in Idaho, Montana, Oregon, Washington, and the Pacific Islands. Federal Register 73(83):23264- 23266. Lead Region/Field Office: Re gio n 1 /Pacific Islands Fish and Wildlife Office, Honolulu, Hawaii Name of Reviewer(s): Marie Bruegmann, Pacific Islands Fish and Wildlife Office, Plant Recovery Coordinator Marilet A. Zablan, Pacific Islands Fish and Wildlife Office, Assistant Field Supervisor for Endangered Species Jeff Newman, Pacific Islands Fish and Wildlife Office, Acting Deputy Field Supervisor Methodology used to complete this 5-year review: This review was conducted by staff of the Pacific Islands Fish and Wildlife Office of the U.S. Fish and Wildlife Service (USFWS), beginning on April 29, 2008. The review was based on the final critical habitat designation for Poa mannii and other species from the is la nd o f Kauai (USFWS 2003), as well as a review of current, available information. The National Tropical Botanical Garden provided an initial draft of portions of the 5-year review and recommendations for conservation actions needed prior to the next five-year review. The evaluation of Samuel Aruch, biological consultant, was reviewed by the Plant Recovery Coordinator. The document was then reviewed by the Assistant Field Supervisor for Endangered Species and Acting Deputy Field Supervisor b e fore submission to the Field Supervisor for approval. Background: For information regarding the species listing history and other facts, please refer to the Fish and Wildlife Service’s Environmental Conservation On-line System (ECOS) database for threatened and endangered species (http://ecos.fws.gov/tess_public). Application of the 1996 Distinct Population Segment (DPS) Policy: This Policy does not apply to plants. Review Analysis: Please refer to the final critical habitat designation for Kokia kauaiensis published in the Federal Register on February 23, 2003 (USFWS 2003) for a complete review of the species’ status (including biology and habitat), threats, and management efforts. No new threats and no significant new information regarding the species’ biological status have come to light since listing to warrant a change in the Federal listing status of P. mannii. When Poa mannii was listed in 1994, fo ur populations were known, containing a total of approximately 125 individuals. These were located in the northwestern and north-central regions of the island of Kauai, in Kalalau, Makaha, Koaie, and Waialae Valleys (USFWS 1994). In 2003, when critical habitat was designated, a total of 6 populations with approximately 268 individuals were known. These were in the right and left branches of Kalalau Valley, Awaawapuhi Valley, Kuia Valley, Kauhao Valley, Na Pali Coast State Park-Na Pali-Kona Forest Reserve, and Waimea Canyon State Park (USFWS 2003). From observations between 1991 and 2008, at least 13 populations are now known. Based on observations since 2000, these populations total at least 100 individuals. In Awaawapuhi Valley in May 1994, Poa mannii was seen at 1,067 meters (3,500 feet) elevation over a stream bank on north-facing slopes (Lorence and Flynn 1995; Perlman 2008). Poa mannii was seen in Hanakoa Valley in June 2000 at 366 meters (1,200 feet) elevation, and again in 2008. Approximately 30 individuals of P. mannii were seen at the end of the main trail, in the back of the valley on the west fork of the stream, on the southeast side, near the waterfall and plunge-pool, along lower seeping walls adjacent to the rushing waterfall at 366 meters (1,200 feet) elevation (National Tropical Botanical Garden 2008; Wood 2009). Around the Kalalau Valley rim, Poa mannii was seen many times between 1991 and 1998 at various locations from 550 to 1,203 meters (1,804 to 3,950 fee t) elevation. In June 1996, the species was observed at 335 meters (1,099 feet) elevation, and in May 2004, at 1,128 meters (3,700 feet) elevation (Perlman 2008; Wood 2009). The numbers of individuals were not recorded. O n Kauhao Ridge, in Kokee State Park, a clump of P. mannii was observed growing near the gauging station and ditch, on north fac ing me s ic fo rest cliffs at 926 meters (3,040 feet), in March 1991 (Lorence and Flynn 1995; Wood 2009). In Kawaiula Valley in April 2000, about 30 individual clumps of Poa mannii were seen growing in a 100-square-meter (1,020-square-foot) area in rocky mesic drainage with moderately steep slopes at 823 meters (2,700 feet) e le vatio n (Wood 2009). Alo ng the Koaie River in Waimea Canyon 1 to 2 kilometers (0.62 to 1.2 miles) upstrea m from Lonomea Shelter, on the southeast s ide o f the river, Poa mannii was seen at 540 to 560 meters (1,772 to 1,837 feet) elevation in April 1991 (Lorence and Flynn 1995). Poa mannii was seen again in Koaie Canyon in June 2005 (Tangalin 2009). The numbers of individuals were not reported. In K uia Valley, in the fall of 1993, Poa mannii was seen at 731 meters (2,400 feet) elevation (Perlman 2008; Wood 2009). Poa mannii was again seen in 1997, in the K uia Natural Area Reserve, on north facing slopes at 701 meters (2,300 feet) elevation. In April 2000, about 20 individuals of P. mannii were observed at 814 meters (2,670 feet) elevation in Kuia drainage, below the confluence of its upper branches (Wood 2009). Several scattered clumps of P. mannii were seen in Mahanaloa Valley in January 1994 and April 1996, at 549 to 610 meters (1,800 to 2,000 feet) ele vatio n (Perlman 2008; 2 Wood 2009). One hundred individuals were also seen in January 1994 on steep north facing slopes at 671 to 732 meters (2,200 to 2,400 feet) elevation (Wood 2009). At Makaha Ridge and Makaha Valley in the Puu Ka Pele Forest Reserve, Poa mannii was observed between 1988 and 1996, on rock walls in a steep narrow canyon with a seasonal stream at 460 to 549 meters (1,509 to 1,800 feet) elevation (Lorence and Flynn 1995; Perlman 2008; Wood 2009). Twenty individuals were observed in January 1993 at 549 meters (1,800 feet) elevation. Thirty individuals were seen there in November 1994, at 853 to 914 meters (2,800 to 3,000 feet) elevation, and it was also seen in 1995 at 823 to 853 meters (2,700 to 2,800 feet) e le vatio n. In 2007, about 15 individuals of P. mannii were observed on steep slopes in the north fork of Makaha’s upper drainage at 899 meters (2,950 feet) elevation (Wood 2009). Poa mannii was observed in Nualolo Valley be lo w the trail on the north side at 991 meters (3,250 feet) in December 1994 (Wood 2009). One hundred or more individuals of P. mannii were observed in Poomau Canyon in January 1993, up a side stream to the le ft (Perlman 2008; Wood 2009). Poa mannii was observed on a r id ge between Waialae and Nawaimaka Valleys, above Waialae Falls, between 950 and 1,050 meters (3,117 and 3,445 feet) in May 1991 (Lorence and Flynn 1995). Poa mannii was observed in Waimea Canyon State Park, Kukui Trail, past its junction with Iliau Loop Trail in March 1985, and on the trail b e lo w the hunter check-in station at 877 meters (2880 feet) elevation in April 1991 (Lorence and Flynn 1995). Although described as a perennial, Poa mannii appears to die back each year, with few rhizomes surviving to the following year. During this dieback period, several invasive introduced plant species have been noted to overtake its cliff habitat, especially Erigeron karvinskianus (daisy fleabane), which can completely cover basalt cliff habitats in short periods of time. Numbers of individuals fluctuate because P. mannii is an annual (Wood 2009). All three native species of Poa in the Hawaiian Islands are endemic to the island of Kaua i. Poa mannii is distinguished from both Poa siphonoglossa and Poa sandvicensis by its fringed ligule (thin outgrowth where the lea f and leafstalk meet) and from Poa sandvicensis by its shorter panicle (a branched cluster of flowers in which the branches have unbrached flowers) branches (USFWS 1994). Poa mannii typically grows on moist vertical cliff faces or dripping, wet rock faces often on northern exposures in partial shade, where it is rare or scattered but occasionally frequent. It grows in lowland or montane diverse mixed mesic, Metrosideros polymorpha (o hia ), or Acacia koa (koa) – M. polymorpha forest or shrubland between elevations of 327 and 1,222 meters (1,072 and 4,009 feet) (USFWS 2003). Poa mannii grows in Hanakoa, adjacent to introduced Aleurites moluccana (kukui) fo res t associated with relic mesic vegetation dominated by introduced vegetation, with Asplenium unilaterale (pamoho), Boehmeria grandis (akolea), Carex meyenii (no common name [NCN]), Deparia cataracticola (NCN), Diospyros sandwicensis (lama), 3 Eragrostis variabilis (kawelu), Hibiscus kokio (kokio ula), Isachne pallens (NCN), Kadua affinis (manono), K. cookiana (awiwi), K. elatior (awiwi), Lipochaeta connata (nehe), Machaerina angustifolia (uki), Munroidendron racemosum (NCN), Plantago princeps var. longibracteata (laukahi kuahiwi), Psydrax odorata (alahee), Rauvolfia sandwicensis (hao), Selaginella arbuscula (lepelepe a moa), Sphenomeris chinensis (palapalaa), and Syzygium cumini (java plum) (National Tropical Botanical Garden 2008). On Kauhao Rid ge, Poa mannii grows in mesic forest with Acacia koa, Alphitonia ponderosa (kauila), Dubautia latifolia (koholapehu), Melicope anisata (mokihana), Metrosideros polymorpha, Panicum nephelophilum (konakona), Pleomele aurea (hala pepe), Pouteria sandwicensis (alaa), Zanthoxylum dipetalum (kawau), and Z.