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16.25 Taxon Summary: kaalae

2 Photographer: J. Lau 4 Scientific name: Schiedea kaalae Wawra 6 Hawaiian name: None known Family: (Pink family) 8 Federal status: Listed endangered

10 Description and biology: Schiedea kaalae is a perennial herb with short stems usually trailing on the ground. Each of the main stems ends in a rosette of leaves. The leaves are 14-24 cm (5.5- 12 9.4 in) long. The flowers are borne on open panicles measuring up to 40 cm (15.6 in) or rarely up to 60 cm (23.4 in) long. The flowers are perfect (possessing both male and female 14 reproductive parts). The tiny seeds are contained in capsules measuring about 4 mm (0.16 in) long. 16 Schiedea kaalae is known to be capable of self-pollination through the study of in 18 cultivation (Weller pers. comm. 2000). It is probably either insect pollinated or largely self- pollinating (Wagner et al. 1995). The species has been observed in flower from March through 20 June (Nagata 1980). Its dispersal agents are unknown. The longevity of individuals of this species is unknown, but since the is an herb, its longevity is presumed to be less than 10 22 years, and it is therefore a short-lived taxon for the purposes of the Implementation Plan.

24 Known distribution: Schiedea kaalae is endemic to both mountain ranges of Oahu. In the Waianae Mountains it has been documented from the windward side of the northern and 26 southern portions of the mountain range. In the Koolaus it has been found on the windward side of the north-central part of the mountain range, ranging from Punaluu in the south to the Hauula 28 area in the north. The species occurs at elevations of 210-790 m (700-2,600 ft).

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30 Population trends: The number of plants of S. kaalae has been steadily decreasing. The Makaua population unit, for instance, has over the last 15 years decreased from about 30 known 32 plants to only two known plants today, probably as a result of a large increase in the number of pigs in the gulch over that time period. 34 Current status: Schiedea kaalae is still found in both the Waianae and Koolau Mountains. 36 Fewer than 25 wild plants are known to be extant. About 18 plants are known in the Waianaes and about six plants are known in the Koolaus. However, in the Koolau Mountains there 38 remains much potential habitat for the species that has never been botanically surveyed. Within the Makua action area there are three known plants, all of which are in Pahole Gulch, which 40 adjoins the Makua Military Reservation. The species' current population units are listed in Table 16.73 and their sites are plotted on Maps 16.37 and 16.38. The sites of the population units 42 proposed for management for stability are characterized in Table 16.74 and threats to the plants at these sites are identified in Table 16.75. 44 Habitat: Schiedea kaalae in the Waianae Mountains is consistently found growing in the 46 understory of diverse mesic forests, usually in gulch bottoms or low to mid-gulch slopes. The plants are usually found growing in soil or a mix of soil and rocks. They are often found on 48 slopes whose groundcover is sparse. Occasionally they are seen growing in cracks in rock embankments. 50 In the Koolau Mountains, S. kaalae has been found in habitats that range from mesic to fairly 52 wet. The species occurs there in gulch bottoms and on lower gulch slopes. Some plants grow on gentle to moderate slopes, while others are found growing on steep rock embankments and 54 nearly vertical cliffs. Some Koolau S. kaalae sites are constantly wet from seeping water.

56 Taxonomic background: The endemic Hawaiian genera Schiedea and constitute a complex of species descended from a single colonizing ancestor (Wagner et al. 1995). 58 Schiedea kaalae belongs to a subgroup of the genus Schiedea that includes S. nuttallii and S. pentandra. 60 Outplanting considerations: In many cases, S. kaalae is located in the same drainages as its 62 relatives S. nuttallii, S. pentandra, S. hookeri, and Alsinidendron obovatum. In such cases S. kaalae is usually found in parts of the drainages that are drier than where these related taxa are 64 growing. Hybridization between Schiedea species has been documented in the wild, and hybridization is not uncommon when Schiedea species are grown together in cultivation. In 66 order to avoid inadvertently causing unnatural hybridization, S. kaalae should not be outplanted near any related species with which it does not naturally occur. 68 Plants from the Koolau and Waianae Mountain Ranges should not be mixed in reintroductions. 70 Since many miles of unsuitable habitat separate the Waianae Range and Koolau Range populations, it is presumed that genetic communication between the two populations was rare 72 under natural conditions. Additionally, since the Waianae and Koolau S. kaalae habitats are rather different, it may be especially important when reintroducing this species to utilize stock 74 originating from the same mountain range where the reintroduction is attempted. Such stock is

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likely to be better adapted to the environmental conditions of the reintroduction site than stock 76 from the other mountain range.

78 There is a large gap between the recorded locations for S. kaalae in the northern Waianaes and recorded locations in the southern Waianaes. As it is possible that the northern and southern 80 plants are genetically distinct because of the gap, the northern and southern stocks should be preserved separately. Outplanting lines have been drawn limiting the outplanting of the northern 82 and southern stocks to their respective ends of the mountain range.

84 Threats: Major threats to S. kaalae include feral pigs, which degrade the species’ habitat, and harm the plants by feeding on them, trampling them, or uprooting them while rooting for food. 86 Alien plants threaten the species by altering the species’ habitat and competing with it for sunlight, moisture, nutrients, and growing space. Also, the spread of highly flammable alien 88 grasses increases the incidence and destructiveness of wildfires.

90 Seedlings and immature plants are seldom seen, especially in populations in the Waianae Mountains (Lau pers. comm. 2000). This may be the result of seedling predation by introduced 92 slugs and snails (Weller pers. comm. 2000). Experiments have been conducted using barriers to prevent mollusks from gaining access to the areas around mature plants of the S. kaalae relative, 94 Alsinidendron obovatum. The installation of these barriers has resulted in the appearance of numerous seedlings within the barriers, whereas the areas under neighboring plants not so 96 protected have shown no such regeneration (Rohrer pers. comm. 2000).

98 Low levels of genetic diversity in S. kaalae populations may not be detrimental to the species, as plants from populations that appear to have undergone repeated self-fertilization are vigorous in 100 cultivation, and are among the most vigorously growing of Schiedeas under greenhouse conditions (Weller pers. comm. 2000). However, if there are indications that the species' 102 naturally-occurring or reintroduced populations are being affected by inbreeding depression, controlled experiments on the ramifications of mixing different stocks should be conducted. 104

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Table 16.73 Current Population Units of Schiedea kaalae. The numbers of 120 individuals include mature and immature plants, and do not include seedlings. Population units proposed for management are shaded. 122 Island Population Unit Name Total No Management Number of Management Proposed Individuals Proposed Oahu: Huliwai 1-2 0 1-2 Maakua (Koolaus) 4 0 4 Makaua (Koolaus) 2 0 2 North Branch of South 3 0 3 Ekahanui North Kaluaa 2 0 2 North Palawai 1 0 1 Pahole 3 0 3 South Branch of South 7 0 7 Ekahanui

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152 Table 16.74 Site Characteristics for Population Units of Schiedea kaalae Proposed for Management for Stability.

Population Unit: Site Characteristics: Habitat Quality Terrain Accessibility Existing Fence

North Branch of South Medium – Low Moderate High None Ekahanui North Kaluaa Medium – Low Moderate High None

Pahole Medium – Low Steep High Large

South Branch of South High – Medium Moderate High None, Small, Large Ekahanui 154

156 Table 16.75 Threats to Population Units of Schiedea kaalae Proposed for 158 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 High N/A High Unknown Unknown Unknown Unknown High Medium Medium Medium South Ekahanui A A B A North Kaluaa High N/A High Unknown Unknown Unknown Unknown Very Medium Low Medium A A B A high Pahole Low N/A High Unknown Unknown Unknown Unknown Very Medium Low Medium A A B A high South Branch of Low to N/A Medium Unknown Unknown Unknown Unknown High Medium Medium Medium South Ekahanui High A A B A

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