16-45

2 16.7 Taxon Summary: Cyanea grimesiana subsp. obatae

4 Photographer: J. Obata

6 Scientific name: Cyanea grimesiana Gaud. subsp. obatae (St. John) Lammers Hawaiian name: Haha, ohawai 8 Family: Campanulaceae (Bellflower family) Federal status: Listed endangered 10 Description and biology: Cyanea grimesiana subsp. obatae is a shrub 1-3.2 m (3.3-10.5 ft) tall, 12 and is either single-stemmed or sparingly branched. The leaves are pinnately divided, measure 27-58 cm (11-23 in) long, and are clustered towards the tips of the stems. The six to 12 flowered 14 inflorescences are borne among the leaves. The corollas are curved, usually yellowish white, and measure 55-80 mm (2.2-3.2 in) long. The berries are orange at maturity, and measure 18-30 16 mm (0.7-1.2 in) long.

18 As with other Cyaneas with their long tubular flowers, this taxon is thought to have been pollinated by nectar-feeding birds. It is capable of self-pollination, evidenced by the fact that 20 isolated plants produce viable seeds. The taxon’s orange berries are indicative of seed dispersal by fruit-eating birds. Cyanea grimesiana subsp. obatae presumably lives for less than 10 years 22 like other Cyaneas of its size, and is thus a short-lived taxon for the purposes of the Implementation Plan. 24 Known distribution: Until the 1990s, C. grimesiana subsp. obatae was known only from the 26 southern Waianae Mountains. It is now also known to occur in the Mokuleia region of the northern Waianae Mountains. It ranges from 550-670 m (1,800-2,200 ft) in elevation. 28

Final DACA83-96-D-0007/0055 Implementation Plan for Makua Military Reservation, Island of Oahu

Chapter 16.7 Taxon Summary: Cyanea grimesiana subsp. obatae 16-46

Population trends: Most of the C. grimesiana subsp. obatae population units have not been 30 known for very long, but those that have been tracked for at least 15 or 20 years have either died out or have declined markedly. 32 Current status: There are a total of about 50 individuals of C. grimesiana subsp. obatae. The 34 Makua action area contains 13 of the plants. The current population units of C. grimesiana subsp. obatae are listed in Table 16.19 and their sites are plotted on Map 16.11. All of them are 36 proposed for management for stability. Their sites are characterized in Table 16.20 and threats to the plants at these sites are identified in Table 16.21. 38 Habitat: Cyanea grimesiana subsp. obatae grows in mesic forests, usually in shady locations in 40 gulch bottoms or on gulch slopes. The plants often grow on steep to vertical embankments consisting of rock or a mix of rock and soil. 42 Taxonomic background: Cyanea grimesiana includes one subspecies in addition to subsp. 44 obatae, namely subsp. grimesiana, which has been recorded primarily in the Koolau Mountains of Oahu, but which has also been found in the northern and central Waianae Mountains and on 46 Molokai. The two subspecies are distinguished by the size and shape of their calyx lobes. Certain Cyanea populations on Molokai, Maui, Lanai, and Hawaii formerly included in C. 48 grimesiana have recently been recognized as constituting three separate species (Lammers 1998). 50 Outplanting considerations: Cyaneas and Cyanea relatives potentially occurring with or near 52 C. grimesiana subsp. obatae are C. longiflora, C. superba subsp. superba, C. angustifolia, C. membranacea, C. calycina, C. acuminata, the Delisseas D. subcordata and D. sinuata, and the 54 Clermontias C. persicifolia, C. oblongifolia, C. kakeana, and C. fauriei (Lau pers. comm. 2000). It is common to find several Cyanea species and Cyanea relatives growing together, yet 56 to date there is no good evidence of hybridization between Cyanea taxa or between a Cyanea and a Cyanea relative. Consequently, concerns with respect to the possibility of inadvertently 58 allowing unnatural hybridization to occur through the outplanting of C. grimesiana subsp. obatae are minimal. 60 Both C. grimesiana subsp. obatae and C. grimesiana subsp. grimesiana have been recorded in 62 the northern and central Waianae Mountains. Although no subsp. grimesiana is known to be extant in the Waianae Mountains, there remains a chance that plants still survive there. It is 64 unclear what the relationship was between the two subspecies with respect to distribution and genetics. In any case, prior to establishing outplanting sites for C. grimesiana subsp. obatae the 66 potential area should be well searched for both subspecies.

68 Threats: Major threats to C. grimesiana subsp. obatae include feral pigs and goats. These ungulates degrade the taxon's habitat and harm the plants through feeding on them, trampling 70 them, or uprooting them when rooting for food. Alien plants threaten the C. grimesiana subsp. obatae by altering the taxon’s habitat and competing with it for sunlight, moisture, nutrients, and 72 growing space. Also, the spread of highly flammable alien grasses increases the incidence and destructiveness of wildfires. Rats pose a threat to the species through their predation of plant

Final DACA83-96-D-0007/0055 Implementation Plan for Makua Military Reservation, Island of Oahu Chapter 16.7 Taxon Summary: Cyanea grimesiana subsp. obatae 16-47

74 parts and fruits. Introduced slugs and snails threaten the species by feeding on its leaves, stems, and seedlings. 76 The long-billed, nectar-feeding native Hawaiian birds, which are the presumed pollinators of C. 78 grimesiana subsp. obatae, have been almost totally eliminated from the Waianae Mountains. Although the taxon is capable of selfing, the loss of its normal pollinating vectors is likely to 80 result in decreases in the genetic variability within its populations over successive generations.

82 The small number of individuals of C. grimesiana subsp. obatae remaining could potentially lead to inbreeding depression in the taxon's naturally-occurring or reintroduced populations. If 84 inbreeding depression in these populations is indicated, experiments on the ramifications of mixing the taxon's different stocks should be conducted. 86

88 Table 16.19 Current Population Units of Cyanea grimesiana subsp. obatae. The numbers of individuals include mature and immature plants, and do not include seedlings. 90 Population units proposed for management are shaded. Island Population Unit Name Total No Management Number of Management Proposed Individuals Proposed Oahu: North Branch of South 5 0 5 Ekahanui Pahole 6 0 6 Palikea (South Palawai) 28 0 28 Palikea Gulch 1 0 1 South Kaluaa 2 0 2 West Makaleha 7 0 7

92

94

96

Final DACA83-96-D-0007/0055 Implementation Plan for Makua Military Reservation, Island of Oahu Chapter 16.7 Taxon Summary: Cyanea grimesiana subsp. obatae 16-48

Table 16.20 Site Characteristics for Population Units of Cyanea grimesiana subsp. obatae Proposed for Management for Stability. Population Unit: Site Characteristics: Habitat Quality Terrain Accessibility Existing Fence

North Branch of South Medium – Low Moderate to Steep Medium Small Ekahanui Pahole High – Medium Moderate to Steep High Large

Palikea (South Palawai) Medium – Low Moderate to Steep High Small

Palikea Gulch High – Medium Moderate Medium Small

West Makaleha High – Medium Moderate to Steep High None

Table 16.21 Threats to Population Units of Cyanea grimesiana subsp. obatae Proposed for Management for Stability. Population Threats: Unit: Pigs Goats Weeds Rats Black Slugs Other Fire Fire Erosion Human Twig and Arthro- Ignition Fuels Distur- Borer Snails pods bance North Branch of Low N/A High Unknown N/A Unknown Unknown High Medium High Medium South Ekahanui B B B Pahole Low Low High Unknown N/A Unknown Unknown Very Medium High Medium B B B High Palikea (South Low N/A Medium Unknown N/A Unknown High High Low High High Palawai) B B Palikea Gulch Low High High Unknown N/A Unknown Unknown Very Medium Medium Medium B B B High West Makaleha High Medium Medium High N/A Unknown Unknown Very high Medium Medium Medium B B

Final DACA83-96-D-0007/0055 Implementation Plan for Makua Military Reservation, Island of Oahu Chapter 16.7 Taxon Summary: Cyanea grimesiana subsp. obatae 16-49

Final DACA83-96-D-0007/0055 Implementation Plan for Makua Military Reservation, Island of Oahu