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16.27 Taxon Summary: filiforme

2 Photographer: J. Jacobi 4 Scientific name: Sherff var. filiforme and T. filiforme Sherff var. 6 polyphyllum (Sherff) Lowrey Hawaiian name: None known 8 Family: (Sunflower family) Federal status: Listed endangered 10 Description and biology: Tetramolopium filiforme is a dwarf shrub 5-15 cm (2-6 in) tall, and is 12 often mounded in shape. The narrow leaves are clustered at the branch tips, and measure 1-2 cm (0.4-0.8 in) long. The flower heads are purplish-white, and are held up above the foliage on long 14 slender stalks. The ray florets are female, and their rays are white to pale lavender. The disk florets are functionally male, and are colored maroon or rarely yellow. The achenes (a type of 16 dry, seed-like fruit) measure 2-2.7 mm (ca. 0.1 in) long, bear sparse short glandular hairs or are hairless, and are tipped with bristles almost as long as the achenes. 18 Flowering usually occurs in the late winter and spring (Lowrey 1986). The are capable of 20 self-pollination (Lowrey 1986). Tetramolopium filiforme is likely insect-pollinated, as are most conspicuous-flowered species in the sunflower family. 22 Tetramolopium filiforme is presumed to be wind-dispersed, as bristle-bearing achenes are 24 characteristic of the wind-dispersed members of the sunflower family. The species may additionally be bird-dispersed, as the bristles can cause the achenes to stick to birds’ feathers 26 (Lowrey 1995). Another characteristic of Tetramolopium achenes indicating dispersal by birds are sticky glandular hairs on the achenes, which would contribute to their adherence to feathers. 28 With T. filiforme, however, this feature is either not well developed, or completely absent (Lowrey 1986). 30

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Tetramolopium filiforme reproduces by seed. By their second year, greenhouse plants show 32 signs of old age. They live until they are about three years old (Lowrey 1986). Wild plants appear to be able to live to an age of 5-10 years (Lau pers. comm. 2000). 34 Known distribution: Tetramolopium filiforme is narrowly endemic to the northern leeward 36 Waianae Mountains. Outside of its center of abundance on Ohikilolo Ridge on the Makua Military Reservation it is found only in small outlying populations, which are located from 38 Kahanahaiki in the north to Kamaileunu Ridge and Puhawai in the south. These plants occurring beyond Ohikilolo Ridge all represent var. filiforme. Only on Ohikilolo Ridge do both varieties 40 occur. Variety polyphyllum is found only at the higher and wetter portion of Ohikilolo Ridge. The plants on the low, dry, seaward end of the ridge are all morphologically typical var. 42 filiforme. As one ascends the ridge into higher wetter habitats, plants showing var. polyphyllum traits begin to show up growing together with var. filiforme-looking plants. At the highest 44 portion of the ridge, the majority of the plants show var. polyphyllum traits to some degree. However, it appears that nowhere along the ridge do all the plants represent var. polyphyllum. 46 The species ranges from 340-900 m (1,100-3,000 ft) in elevation. The low elevation plants of 48 the species, as well as the plants at the highest elevation at Puhawai, are of var. filiforme morphology. 50 Population trends: Feral goats have brought the number of plants on Ohikilolo Ridge down 52 significantly over the last few decades. In the 1970s there were many plants growing along the crest of the ridge (Obata pers. comm. 2000). Due to the subsequent increase in the number of 54 goats on the ridge in the 1980s and 1990s, the species is no longer abundant on the accessible portions of the ridge top. That the species has not declined more steeply than it has, and still 56 numbers in the thousands, is due to the large number of plants found on cliff faces inaccessible to goats. 58 Current status: Tetramolopium filiforme is conservatively estimated to number at least 5,000 60 mature plants on Ohikilolo Ridge, in addition to many immature ones. The other populations are miniscule in comparison. At Kahanahaiki, there are about 50 plants. There were an estimated 62 25 plants in the Keaau colony at last report in 1990. Only 12 plants were found when recently counted at the Puhawai site. A single was known in Waianae Kai, but it was no longer 64 there when the site was visited in 2001. All known plants of the species are located within the Makua Action Area, with the exception of the 12 plants at Puhawai. 66 The species' current population units are listed in Table 16.79 and their sites are plotted on Map 68 16.40. All sites are proposed for management for stability. The sites are characterized in Table 16.80 and threats to the plants at these sites are identified in Table 16.81. 70 Habitat: Tetramolopium filiforme is growing in a dry habitat at the seaward extreme of the 72 Ohikilolo population unit. The higher, more inland plants are in dry-mesic and mesic habitats. In general, the species grows on exposed rocky ridges and on sparsely vegetated, nearly vertical 74 cliffs, and are often rooted in cracks in the rock.

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76 Taxonomic background: The Tetramolopium has an unusual disjunct distribution. There are species in Hawaii and New Guinea, in addition to a single species on Mitiaro, a small 78 island in the Cook Islands in the South Pacific. Of the approximately 36 species in the genus, 11 are Hawaiian. The genus is divided into three sections: section Alpinum, section Tetramolopium, 80 and section Sandwicense. Although T. filiforme is best placed in the section Tetramolopium, the species also possesses characteristics that are otherwise unique to the section Sandwicense. This 82 combination of characteristics of two sections of the genus in T. filiforme is hypothesized to be the result of a hybridization event in the distant past between two different species of 84 Tetramolopium. One parental species is thought to be an undetermined member of the section Tetramolopium. The other parental species is thought to be T. lepidotum, which is a member of 86 the section Sandwicense, and is the only member of the genus recorded from the Waianae Mountains besides T. filiforme (Lowrey 1986, Okada et al.1997). This hypothesis is supported 88 by the results of molecular genetic analysis (Okada et al.1997).

90 The two varieties of T. filiforme are differentiated primarily by their leaf characteristics, particularly the leaf shape and the presence or absence of teeth along the leaf margin. Variety 92 filiforme has extremely narrow, linear leaves with no teeth along the leaf margins, whereas var. polyphyllum has leaves that widen towards the leaf apex, and its leaf margins bear prominent 94 teeth.

96 It had been thought that the two varieties on Ohikilolo Ridge are distinct, and are geographically separated (Lowrey 1986), but it has been observed over the last few years that the two 98 morphological types are not clearly separated geographically (Lau pers. comm. 2000). In any given subpopulation along the higher portion of the ridge, plants are found that fit the description 100 of one of the two varieties, as well as plants with characteristics intermediate between the two varieties. The of T. filiforme on Ohikilolo Ridge needs to be clarified through further 102 study.

104 Outplanting considerations: The Hawaiian Tetramolopiums are all highly interfertile with one another. In greenhouse experiments, all of the Hawaiian species except the two not available at 106 the time were crossed in all combinations, producing first, second, and third generation hybrid progeny (Lowrey 1986). In the wild, the various Hawaiian species appear to be maintained as 108 separate entities through either geographical or ecological separation.

110 As mentioned above, the other species of Tetramolopium recorded from the Waianae Mountains is T. lepidotum. It has been recorded from most parts of the mountain range not occupied by T. 112 filiforme. Its habitat requirements are similar to T. filiforme’s. Its numbers have always been much lower than T. filiforme’s numbers. Its two currently known populations contain a total of 114 fewer than 200 plants. The species has been documented at locations not far removed from T. filiforme’s range. A specimen was collected at the head of Makua Valley near the valley rim in 116 1932, not very far from T. filiforme locations on Ohikilolo Ridge; and a small colony is known on the eastern side of Waianae Kai, not far from the Waianae Kai T. filiforme site. It is possible 118 that other colonies of T. lepidotum occur near the edges of T. filiforme’s range. In order to minimize the chance of inadvertently causing the genetic swamping of any unrecorded 120 populations of T. lepidotum, an out-planting line for T. filiforme has been drawn. The line cuts across the ridges of Ohikilolo and Kamaileunu next to the furthest inland recorded T. filiforme

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122 sites, and away from T. lepidotum sites and areas that potentially harbor unrecorded plants of T. lepidotum. The southeastern end of the outplanting line includes the Puhawai population unit of 124 T. filiforme within the area considered acceptable for outplanting T. filiforme.

126 There are also concerns about outplanting var. polyphyllum into areas beyond its known range on Ohikilolo Ridge into areas where only strict var. filiforme is known to occur, such as the ridge of 128 Kamaileunu where the Waianae Kai plant was located. Such outplantings should not be conducted pending further taxonomic and ecological study of the two recognized varieties. 130 Threats: Feral goats and pigs threaten T. filiforme, for although many of the plants grow on 132 steep cliffs where they cannot be reached by the ungulates; many others are within their reach and are vulnerable. Furthermore, the animals degrade the plants’ habitat by hastening the spread 134 of invasive weeds. They also disturb substrates above the cliffs, thereby increasing the size and frequency of landslides and rock falls on the cliff faces. These disturbances directly affect even 136 the plants inaccessible to the ungulates.

138 Alien plants threaten T. filiforme by altering the species’ habitat and competing with it for moisture, nutrients, and growing space. Also, the spread of highly flammable alien grasses 140 increases the incidence and destructiveness of wildfires. Tetramolopium filiforme is one of the Makua target taxa most threatened by fire. Over the last two decades fires have burned into the 142 lower reaches of the Ohikilolo Ridge population unit, and have almost reached the Kahanahaiki colony. 144 Infestations of at least two species of non-native scale insects have been observed on T. filiforme 146 (Lau pers. comm. 2000). Elsewhere in the Waianae Mountains, scale insects have been observed on T. lepidotum being tended by ants. When tended by ants, scale infestations can become very 148 serious. No evidence of scale insects being tended by ants have yet been reported on T. filiforme plants, but T. filiforme populations should be monitored for it. 150

152 Table 16.79 Current Population Units of Tetramolopium filiforme. The numbers of individuals include mature and immature plants, and do not include seedlings. Population 154 units proposed for management are shaded. Island Population Name Total No Management Number of Management Proposed Individuals Proposed Oahu: Kahanahaiki 50 0 50 Keaau 25 0 25 Ohikilolo Makai 2500+ 0 2500+ Ohikilolo Mauka (both varieties) 2500+ 0 2500+ Puhawai 12 0 12 Waianae Kai 0* 0 0* * The known plant has died. However, viable seeds may still exist in a seed bank at the site. 156

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158 Table 16.80 Site Characteristics for Population Units of Tetramolopium 160 filiforme Proposed for Management for Stability. Population Unit: Site Characteristics: Habitat Quality Terrain Accessibility Existing Fence

Keaau Medium-Low Steep to Vertical Low to Medium None

Kahanahaiki High-Medium Vertical Low None

Ohikilolo Makai Medium-Low to Moderate to Vertical Low to Medium Large High-Medium Ohikilolo Mauka (both Medium-Low to Moderate to Vertical Low to Medium None, Large varieties) High- Medium Puhawai High-Medium Flat to Vertical Low to Medium None

162 Table 16.81 Threats to Population Units of Tetramolopium filiforme Proposed 164 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 Keaau Low Low to Medium N/A N/A Unknown Unknown Very High Low Low to High to High A B high High Kahanahaiki Low Low Low N/A N/A Unknown Unknown Very High Low Low A B high Ohikilolo Makai Low Low to Low to N/A N/A Unknown Low Very Medium Low to Low to Medium High A high to High Medium High Ohikilolo Mauka Low Low to Low to N/A N/A Unknown Low Very Medium Low to Low to (both varieties) Hgh High A high Medium High Puhawai Low N/A Medium N/A N/A Unknown Unknown Low Medium Low Low to A B Medium

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