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A RARE SURVEY IN THE NATIONAL WILDLIFE REFUGE, KOOLAU MOUNTAINS, OAHU, SEPTEMBER 3-5, 2003

Hawaii Natural Heritage Program ( University of at Manoa Center for Conservation and Training Honolulu, Hawaii

November 2003 l ( Table of Contents

INTRODUCTION AND BACKGROUND 3

METHODS ...... •...... 3

RESULTS 5

RARE PLANT TAXA OBSERVED WITHIN THE REFUGE. 5 RARE PLANT TAXA OBSERVED JUST BEYOND THE REFUGE BOUNDARy 7 DISCUSSION...... •...... 8

CITATIONS 8

TABLE 1. RARE PLANT DATA

FIGURE 1. SURVEY AREA

FIGURE 2. SURVEY ROUTES

FIGURE 3. RARE PLANT LOCATIONS ( )'

( Introduction and Background

This rare plant survey was funded by the Koolau Mountains Watershed Partnership as part of an effort to obtain information on the current status ofrare in areas of the Koolau Mountains where such information is lacking. The survey was conducted by the Hawaii Natural Heritage Program (HINHP) in the U.S. Fish and Wildlife Service's Oahu Forest National Wildlife Refuge, located in the central leeward of the Koolau Mountains. The refuge is comprised of the eastern, upper elevation part of the land section ofWaipio, and includes most of the native forest in the land section. The refuge inoludes the headwaters of the Waikakalaua and Kipapa Gulches, along with the northernmost portion of the Waiawa Gulch's headwaters. The two major trails in the refuge are the Koolau Summit Trail and the Kipapa Trail. The Koolau Summit Trail runs along the summit divide of the Koolau Mountains from the Pupukea area in the extreme northern end of the Koolau Mountains to the southern portion of the Oahu National Wildlife Refuge. Most of the Kipapa Trail runs along the ridge between the Kipapa and Waiawa Drainages. At the Koolau summit area it joins the southern end of the Koolau Summit Trail. The Kipapa Trail is the only established trail that provides access to the refuge from the west.

There is little current information on the rare plants of the refuge, and the historical rare plant records are few. Much of the recorded information on rare plants of the Waipio land section is from the first half of the 1900's. A large proportion of the historical rare plant records for the refuge was gathered during fieldwork in the early 1930's by E. Y. Hosaka in connection with his floristic and ecological study of Kipapa Gulch (Hosaka 1937). In recent decades, little botanizing has taken place on the land now included in the refuge because of a combination of the relative remoteness of the area, restricted access to the formerly privately-owned land, and poor maintenance of the Kipapa and Koolau Summit Trails.

Methods

The rare plant survey was conducted on September 3-5, 2003 by a HINHP botanist, 1. Q.c. Lau, and a botanist contracted by HINHP, K. R. Wood. They were accompanied by and assisted by personnel of the U.S. Fish and Wildlife Service's Oahu National Wildlife Refuge Complex and personnel from the state of Hawaii's Division of Forestry and Wildlife of the Department of Land and Natural Resources. Survey participants were divided into two teams, and each team was flown by helicopter to a campsite in the summit region on the morning of September 3. The field teams were flown out by helicopter in the afternoon of September 5. The survey participants spent the nights at the campsites. Fieldwork was conducted on day hikes starting from the campsites.

The targeted plant taxa were those considered to be globally rare by HINHP and are currently being tracked and mapped by HINHP. These include Jll native Hawaiian plants that are federally listed as endangered or threatened, as well as ones that are candidates for listing as endangered or threatened. Also included are certain taxa that have not been listed as

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endangered or threatened, nor have been designated as candidates for listing, but which are nevertheless globally rare. (

This survey was intended to serve as an initial effort to create a comprehensive inventory of the refuge's rare plants. A goal of the survey was to document the occurrence of as many taxa of rare plants as possible within the limited timeframe of the survey. The survey area was therefore delineated in the high elevation wet zone of the refuge adjacent to the Koolau summit divide. This zone is thought to harbor the largest number of rare plant taxa based on the recorded patterns of distribution of rare plants in the areas of the central and northern Koolau Mountains that have been most intensively searched for rare plants, such as certain portions of the Kawailoa Training Area and Schofield Barracks Military Reservation's East Range to the north of the refuge, and portions of the Waimano land section to the south of the refuge. This zone is also expected to have denser concentrations of rare plant populations than any other zone of the refuge. The survey area included the upper reaches of Waikakalaua and Kipapa Gulches up to the main dividing ridge of the Koolau Mountains. A map showing the survey area is given in Fig. 1.

In order to locate as many rare plant taxa as possible, all major habitat types were examined, but special attention was paid to those habitats with the best potential for harboring rare plant taxa based on the field experience of the botanists on the survey teams. Much of the land in the survey area is difficult to traverse due to the steep terrain and the relatively impenetrable vegetation due to the prevalence of the uluhe (Dicranopteris linearis), which is a fern whose fronds form a tangled layer usually 0.5-2 m deep. In order to gain quick access to areas of interest, the survey routes oJten followed trails, ridge tops, and streambeds. The survey routes ( are shown in Figure 2.

Areas of interest were not identified until the survey participants were in the field and able to scan the landscape for vegetation that appeared to have a high potential for rare plants. At vantage points along the survey routes binoculars were used to help locate rare plants. Certain rare plants of the refuge are readily identifiable from a distance, particularly the Tetraplasandra gymnocarpa. The locations of T gymnocarpa identified only from afar were plotted as accurately as possible by comparing the topography of the area with topographical maps.

Attempts were made to take Global Positioning System (GPS) readings for rare plant locations and important locations along the survey route. Readings for some points were obtained. However, at other points, particularly in the gulches, readings were not obtainable. In such cases, rare plant locations and survey routes were mapped as accurately as possible by consulting topographic maps and utilizing altimeters and compasses.

4 ( Results

Six rare plant taxa were found on the survey, including five listed endangered taxa. Another rare plant is not listed as endangered or threatened, but is considered to be a " of concern" by the USFWS. Two ofthe listed endangered taxa were seen just outside the refuge boundary, but could possibly occur within the refuge as well. The locations of the observed rare plants are mapped in Figure 3, and information on the rare plants is included on Table 1.

Rare Plant Taxa Observed Within the Refuge

Chamaesyce rockii (C. Forbes) Croizat & Degener Hawaiian Name: Akoko : Euphorbiaceae Federal Status: Endangered

Chamaesyce rockii is a or small tree endemic to the Koolau Mountains of Oahu, where it occurs in wet and shrublands.

The species was seen on survey at a location in Waikakalaua Gulch and at a second location in Kipapa Gulch. The Kipapa Gulch colony of C. rockii, which had not been recorded prior to this survey, consisted Qf seven mature . At the Waikakalaua Gulch site 1. Lau was able to ( locate eight mature shrubs in a population that he first observed in 1989, when he estimated the population to number 40-50 mature plants (1. Lau, pers. com. 2003). These plants are scattered in an area adjacent to a newly established campsite and its associated helipad. While the accessibility of the plants will allow for frequent monitoring and management of the plants and their habitat, care should be taken that activities associated with the campsite and helipad do not adversely affect the population.

Cyanea humboldtiana (Gaudich.) Lammers, Givnish & Sytsma Hawaiian Name: Ohawai, haha Family: Campanulaceae Federal Status: Endangered

Cyanea humboldtiana is a shrub endemic to wet forests and shrublands of the Koolau Mountains of Oahu.

Four immature plants of this species were found growing within 2 m of the Koolau Summit Trail in a small drainage upslope of the trail. The plants were growing within a few centimeters of one another and could possibly be the result of vegetative reproduction. They are growing in the deep shade of a heavy undergrowth of Koster's Curse (Clidemia hirta), whic~ is a serious invasive alien l 5 shrub. A gradual thinning of this undergrowth so that more sunlight can reach the ( Cyaneas would likely be beneficial to the plants.

As the observed plants were immature and vegetative, they could not be identified with absolute certainty as C. humboldtiana. There is a slight chance that they instead represent C. crispa, which is also a federally listed endangered species. However, that seems unlikely on the basis of the vegetative characteristics of the plants and the recorded distributions and habitat requirements of the two species.

Doodia lyonii Degener Hawaiian Name: ­ Family: Blechnaceae Federal Status: None; considered a "Species of Concern" by the Pacific Ecoregion office of the U.S. Fish and Wildlife Service

Doodia lyonii is a fern endemic to the Hawaiian Islands. It has been recorded from , Oahu (a single record from the Waianae Mountains and many records from the Koolau Mountains), West and East Maui, and from the Kohala Mountains on the of Hawaii (single report). It typically grows on rocky streamside embankments in wet forests, or rarely in mesic forests.

Doodia lyonii was found to be not uncommon on the stream banks of the Waikakalaua Stream, which was the only sizeable stream sampled on this survey. All of the observed plants were ( growing on the often vertical or overhanging streamside embankments. Along the stretch of stream upstream of the major confluence at about 1,820 ft (555 m) about 560 mature plants were seen, along with immature plants and sporelings. The plants also occurred at scattered locations downstream of the confluence, but due to time constraints no attempt was made at estimating the number of plants along this stretch of the stream. Plants were seen near the lower end of the survey route along the stream, and it seems likely that they occur further downstream as well.

Doodia lyonii appears to be present in considerable numbers in many ofthe major drainages on the leeward side of the central and northern Koolau Mountains. However, the species is apparently much less common in the rest of its range.

Tetraplasandra gymnocarpa (Hillebr.) Sherff Hawaiian Name: Oheohe Family: Federal Status: Endangered

Tetraplasandra gymnocarpa is a tree endemic to the Koolau Mountains of Oahu. Most of the grow in the highest and wettest parts of the mountain range. However, a few can be found in lower elevation mesic forests.

6 Seven trees of this species were located, two of which were seen only from a distance. The ( species co-occurs with the common T. oahuensis, but the two are usually distinguishable from afar based on several morphological characters. Even though T. gymnocarpa can be seen and identified from a great distance, some individuals in the vicinity of the survey routes could. very well remain undetected. Plants could be hidden by the surrounding vegetation, particularly since the mature plants of this species can be only 2 m tall or shorter.

Rare Plant Taxa Observed Just Beyond the Refuge Boundary

Two rare plant taxa were found on this survey not within the refuge, but just beyond the refuge's eastern boundary, which follows the Koolau summit divide. These observations are included in this report since these rare plants would be of concern to the managers of the refuge and since these populations may be found to extend onto refuge land with further survey.

Cyanea calycina (Cham.) Lammers Hawaiian Name: Ohawai, haha Family: Campanulaceae Federal Status: Endangered

Cyanea calycina is endemic to the island of Oahu, where it occurs in both the Koolau and ( Waianae Mountain Ranges. Five small mature plants were seen at a single location on the windward side of the Koolau summit divide. The plants were single-stemmed, and 25-40 em tall. The plants were not fertile.

Lobelia oahuensis Rock Hawaiian Name: Family: Campanulaceae Federal Status: Endangered

Lobelia oahuensis is endemic to the Koolau Mountains of Oahu, where it occurs in areas on or adjacent to the wet summit divide of the mountain range, often in exposed, windswept areas. The plant is usually a single-stemmed shrub that flowers once after a number of years of vegetative growth, and then dies after flowering and fruiting.

Three mature, flowering individuals of this species were seen on this survey, in addition to two sterile mature plants. All of the plants were growing within 15 m of Koolau summit divide. l 7 Discussion (

The rare plant taxa found on the survey are ones predicted to occur in this portion of the Koolau Mountains. No range extensions were documented. Since little rare plant searching had taken place in the survey area before, most of the occurrences seen had not been previously recorded. None of the rare plant taxa found are one of the extremely rare Hawaiian plant taxa that urgently need to be safeguarded outside of the wild, for example by cultivating the plants or by maintaining viable seeds in storage.

Further investigation is needed to establish the identity of certain plants seen on survey. The immature plants thought most likely to represent Cyanea humboldtiana should be monitored for flowering to verify their identity. Also, near the southern colony of Chamaesyce rockii, a plant was encountered that may represent the listed endangered subspecies of Lobelia gaudichaudii, L. gaudichaudii subsp. koolauensis. The plant was growing with plants of the more common L. gaudichaudii subsp. gaudichaudii, and may merely represent an abnormal individual of that subspecies.

Only a small percentage of the survey area could be covered in the three survey days due to the rugged terrain and thick vegetation typical of the Koolau Mountains. It is expected that the survey area and the rest of the land in the high elevation wet zone of the refuge will, with further exploration, yield additional finds ofrare plant taxa, including plants recorded from the zone historically, as well as those previously unrecorded. This survey represents only a first step towards a comprehensive inventory of the refuge's rare plant taxa. ( Citations

Hosaka, E. Y. 1937. Floristic and ecological studies in Kipapa Gulch, Oahu. Occas. Pap. Bernice P. Bishop Mus. 13(17): 175-232.

8 ( Table 1. Rare Plant Data

Taxon Location Observer Observations Location details Chamaesyce la 1. Q.c. Lau 8 mature plants. Directly adjacent to a rockii (Waikakalaua) Shrubs up to 60 cm campsite and a tall. Flowering. helipad. Chamaesyce Ib (Kipapa) K. R. Wood 7 mature plants. UTM coordinates: rockii Compact shrubs, 613951E 2377061N 50 cm tall x 100 cm wide. Flowering. Cyanea 2 (Outside K. R. Wood 5 mature plants. On the windward calycina refuge) Plants single- slope of the main stemmed, 25-40 cm Koolau divide. tall. Sterile. UTM coordinates: 614452E 2376909N Cyanea 3 1. Q.C. Lau 4 immature plants. Within 2 m of the humboldtiana (Waikakalaua) Single-stemmed. Koolau Summit Trail Stems 5-15 cm in a small drainage long. upslope of the trail. The plants were Since the plants are growing within a few ( immature, their centimeters of one identification as C. another humboldtiana is UTM coordinates: not absolutely 614228.713E certain. There is a 2377939.913N slight possibility that the plants represent C. crispa.

Doodia lyonii 4 LQ.C. Lau Along the stretch Seen only right next (Waikakalaua) of stream upstream to the stream on of the major steep, vertical, or confluence at about overhanging stream 1,820 ft (555 m) banks. about 560 mature plants were seen, along with immature plants and sporelings. The plants also occurred at scattered locations downstream of the

9 confluence. ( Lobelia Sa 1. Q.C. Lau 3 mature plants (2 On the windward oahuensis (Outside flowering plants slope of the main refuge) and 1 plant sterile Koolau divide, but large enough to within 15 m of the flower). divide. UTM coordinates of the vantage point on the Koolau summit divide: 614238.595E 2377865.109N Lobelia Sb 1. Q.C. Lau Large mature plant. On the windward oahuensis (Outside Sterile. slope of the main .refuge) Koolau divide, ca. 4­ 5 m from the divide. UTM coordinates of the vantage point on the Koolau summit divide: 614228.860E 2377746.680N Tetraplasandra 6a 1. Q.C. Lau 1 mature tree. gymnocarpa (Waikakalaua) Seen from afar. Tetraplasandra 6b 1. Q.c. Lau 1 mature tree. gymn()carpa (Waikakalaua) Seen from afar. ( Tetraplasandra 6c 1. Q.c. Lau Mature tree. UTM coordinates: gymnocarpa (Waikakalaua) Flowering and 614023.512E fruiting. 2377688.973N Tetraplasandra 6d K. R. Wood Mature tree 3 m UTM coordinates: gymnocarpa (Kipapa) tall. With 614027E 2377194N immature fruits. Tetraplasandra 6e K. R. Wood Mature tree 3 m UTM coordinates: gymnocarpa (Kipapa) tall. With flowers 614062E 2377161N and immature fruits. Tetraplasandra 6f K. R. Wood Mature tree 2 m UTM coordinates: gymnocarpa (Kipapa) tall. With 614095E 2377110N immature fruits. Tetraplasandra 6g K. R. Wood Mature tree 4 m UTM coordinates: gymnocarpa (Kipapa) tall. Flowering. 613840E 2376989N

10 Fig,ure 1 Survey Area Oahu Forest National WIldlife Refuge

Survey Area Oahu Forest NWR. Bounduy . . •

Figure 2 Survey Routes Oa,hu Forest Natlona,f Wildlife Refuge

1\1SUrvey Routes C SUrvey Ar.ea OahuForesl NWR BoundalY

Hawaii Natu rat ritage Program, November 2003 · .

Flgl,ue 3 Rare Plant ocations Oahu Forest National Wildlife Refuge O/NT.onL~S: , Chtimaesyce rock/I 2 Cyanea oafycma 3 CyaMa h moofatlana 4 Doodia Iyoll G LQb8n808h~an$~ 6 TetrapJasandra gymnocarpa SUl1l-.y' Aru

Oahu Forest NWR. Boundary- PrQduced by Hawaii Na rat H ritasle Program, November 2003

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