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16.24 Taxon Summary: mariversa

2 Photographer: J. Lau 4 Scientific name: Sanicula mariversa Nagata & Gon 6 Hawaiian name: None known Family: (Parsley family) 8 Federal status: Listed endangered

10 Description and biology: Sanicula mariversa is a perennial herb with its leaves, stems, and flowering and fruiting stalks above the ground. The has a thick underground storage root. 12 The basal leaves are three to five-lobed, and measure up to 23 cm (9 in) across. Flowers and fruits are borne in masses on stems up to 0.7 m (27 in) in height. Some of the yellow flowers are 14 perfect (possessing male and female reproductive parts) and others are staminate (possessing only male reproductive parts). The fruits are 4-6 mm (ca. 0.2 in) long, and are covered with 16 hooked bristles.

18 The leaves and stems of S. mariversa die back to the storage root usually in May. The are dormant through the warm and dry summer months until new growth emerges at the onset of the 20 wet season. This appearance of new growth takes place usually in October or November. The species flowers from February through May, and their fruits mature in April and May (Kawelo 22 pers. comm. 2000).

24 The massed yellow flowers of this species suggest pollination by insects. The fruit’s bristles indicate that the fruits are capable of dispersal by birds. The age at which wild plants mature is 26 not known. However, with respect to a cohort of four year old plants currently under cultivation, a few are flowering and fruiting for the first time, but the majority still have not flowered 28 (Kawelo pers. comm. 2000). The longevity of individuals of the species is unknown, but since the plant is a small herb, its longevity is presumed to be less than 10 years, and it is therefore a 30 short-lived taxon for the purposes of the Implementation Plan.

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Known distribution: Sanicula mariversa is endemic to the Waianae Mountains. It was not 32 discovered until the late1970's when it was found on Ohikilolo Ridge. There is also a sizeable colony in Keaau Valley, on the ridge separating Keaau Valley from Makaha Valley. It has also 34 been reported at Puu Kanehoa, which is south of Kolekole Pass. An immature plant was seen there sometime in the 1970's (Obata pers. comm. 2000). The species is also known to occur on 36 Kamaileunu Ridge, which includes the peak of Puu Kawiwi.

38 Population trends: Population trends of S. mariversa populations have not been detected due to the paucity of data. Fewer than 25 years have passed since the species was discovered, and for 40 most of those years the Ohikilolo and Keaau population units were seldom visited. Furthermore, the plants cannot be observed when dormant. Over the last few years the Ohikilolo and Keaau 42 population units have been monitored annually. There have been considerable differences from year to year in the number of plants reported (Kawelo pers. comm. 2000). It is not known 44 whether the recorded differences reflect actual fluctuations in population numbers.

46 Current status: Approximately 300 individuals of S. mariversa are known, all but two of which are on Ohikilolo Ridge or in Keaau Valley. Both of these sites are within the Makua action area. 48 The two plants outside the action area were recently found at Puu Kawiwi on Kamaileunu Ridge. The species' current population units are listed in Table 16.70 and their sites are plotted on Map 50 16.36. All of the sites are proposed for management for stability. The sites are characterized in Table 16.71 and threats to the plants at these sites are identified in Table 16.72. 52 Habitat: Sanicula mariversa is found at mesic sites, usually on north-facing slopes just off the 54 ridge tops. Most of the known plants grow in deep soil. However, the two plants recently found at Puu Kawiwi were observed to be growing in the cracks of a nearly vertical rock face (Perlman 56 pers. comm. 2000).

58 On Ohikilolo Ridge and in Keaau Valley, most S. mariversa plants are growing at sites now dominated by the annual, non-native grasses fescue ( sp.) and bromegrass (Bromus sp.). 60 The remnants of the native vegetation at these sites, together with the composition of similar, but more intact locations in the Waianae Mountains, indicate that the native vegetation was 62 originally a mix of native sedges, grasses, herbs, ferns, and shrubs, with a good percentage of the ground covered by and (Lau pers. comm. 2000). At one of the sites on Ohikilolo 64 Ridge the plants are growing where ohia (Metrosideros spp.) shrubland grades into open slopes.

66 Taxonomic background: Sanicula mariversa is the only Sanicula recorded in the Waianae Mountains. It is one of the four species of Sanicula occurring in Hawaii, all of which are 68 endemic to Hawaii.

70 Outplanting considerations: There are no hybridization concerns with respect to the outplanting of S. mariversa in the Waianae Mountains since no other species of Sanicula occur 72 in the mountain range.

74 Threats: Feral goats seriously threaten S. mariversa, even though they apparently do not browse on it very much (Kawelo pers. comm. 2000). They threaten the species by denuding the slopes 76 where the plants grow, and by disturbing the substrate, thereby accelerating the process of

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erosion. Erosion scars grow progressively larger, and in addition to eroding out individual 78 plants, the scars destroy the deep-soiled slopes, which constitute S. mariversa's prime habitat supporting the highest densities of the species. An erosion scar had been eating into a slope 80 containing most of the plants on Ohikilolo Ridge until erosion control measures were initiated within the last five years. Goats have been practically eliminated from the Makua side of 82 Ohikilolo Ridge where the Ohikilolo population unit is located, but a large number of goats continue to impact the population unit in Keaau. 84 Alien shrubs and trees, and the taller and denser of the alien grasses constitute serious threats to 86 S. mariversa. The short alien grass dominating the sites at Ohikilolo Ridge and Keaau does not seem to be extremely detrimental to the species. Removing the grass may cause more harm than 88 good, unless it can somehow be replaced with native groundcover.

90 Human disturbance impacts S. mariversa plants at the Keaau site. A trail runs directly through the densest part of the population unit. Several of the plants are right alongside the trail, and are 92 at risk of being trampled by hunters and hikers. On Ohikilolo Ridge, some of the plants are within 2 m (6.6 ft) of the ridge top fence and the trail running alongside the fence (Rohrer pers. 94 comm. 2000). Fence maintenance and human traffic could possibly harm these plants.

96 Table 16.70 Current Population Units of Sanicula mariversa. The numbers of 98 individuals include mature and immature plants, and do not include seedlings. Population units proposed for management are shaded. 100 Island Population Unit Name Total No Management Number of Management Proposed Individuals Proposed Oahu: Kamaileunu 26 0 26 Keaau 141 0 141 Ohikilolo 143 0 143 Puu Kawiwi 2 0 2

102

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Table 16.71 Site Characteristics for Population Units of Sanicula mariversa 104 Proposed for Management for Stability. Population Unit: Site Characteristics: Habitat Quality Terrain Accessibility Existing Fence

Kamaileunu Medium-Low Steep to Vertical Low to Medium None

Keaau Medium-Low Flat to Steep Low None

Ohikilolo Medium-Low Moderate to Vertical Low Large

Puu Kawiwi Medium-Low Vertical Low None

106 Table 16.72 Threats to Population Units of Sanicula mariversa 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 Kamaileunu Low High High Unknown N/A Unknown Unknown Very Medium Medium Low to A A A high High Keaau Low High Medium Unknown N/A Unknown Unknown Very Medium High Medium A A A high Ohikilolo Low Medium Medium Unknown N/A Unknown Unknown Very Medium High High A A A high Puu Kawiwi Low High High Unknown N/A Unknown Unknown Very Medium Low Low A A A high 108

110

112

114

116

118

Final DACA83-96-D-0007/0055 Implementation Plan for Makua Military Reservation, Island of Oahu Chapter 16.24 Taxon Summary: Sanicula mariversa 16-149

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