Comments:
Seabird and Vegetation Surveys of
Awaawapuhi, Kaua`i, Hawai`i
1—1000 ft. elev.
September 2004
K. R. Wood, kenwood@pelea.org
D. Boynton, boyntons001@hawaii.rr.com
During the period of 23—24 August 2004, the authors conducted a biological inventory within the lower valley of Awaawapuhi with a special focus on documenting seabirds as they arrived in the early evening and returned to sea during the pre-dawn hours. In addition, we documented Awaawapuhi’s vascular plant communities from sea level to ca. 300 m (1000 ft) elevation and compiled a checklist of vascular plant species. Previous to this survey there has been no recorded vascular plant inventory of this small Na Pali coast valley. The most significant discoveries were a) finding a new cliff location where Band-rumped storm-petrels appear to be nesting b) discovering the winged remains of a Band-rumped storm-petrel below the nesting site which appeared to be predated by an owl; and c) documenting a new location for Hedyotis st.-johnii, a Federally Listed as Endangered species, known from fewer than 50 individuals at this time.
Awaawapuhi Valley. As a result of ancient human settlements, agriculture, burning, invasive weeds, and the long term degradation of native vegetation by goats, most of Kauai’s smaller Na Pali coast valleys, with the exception of their cliffs, are now dominated by non-native plant species (Wood and Boynton 2004). This is true with lower Awaawapuhi which is a narrow valley of flatland and gentle slopes varying between 50—100 m (160—320 ft) in width and only around 1000 m (3280 ft) in depth, with sparsely vegetated black basalt walls that tower 300—600 m (1000—2000 ft) in height. Awaawapuhi lies just to the northeast of Nu’ololo and to the southwest of Honopu. This region falls within the jurisdiction of the Department of Land and Natural Resources (DLNR), Division of State Parks.
Seabird Survey. During the period of 23—24 August 2004, the authors conducted Band-rumped Storm-Petrel (`ake`ake) and Newell’s Shearwater (`a`o) counts at approximately 90 m (300 ft) elev. in the lower valley of Awaawapuhi. Our methods included climbing up to the northern cliff walls to escape the noise of the main stream which flowed past our camp, thereby positioning ourselves in a quiet location to get the best possible audio perception. We considered a single individual `ake`ake or `a`o as only those birds that gave a clearly identifiable call as they arrived in the valley and could be tracked by their calls as they flew from the lower valley on up to or beyond the general area of our camp (Wood and Boynton 2004).
With this method we estimated seven individual Band-rumped Storm-Petrel and 37 individual Newell’s Shearwaters were nesting in the general area. These individuals arrived between 7:40 pm and 9:00 pm during the evening of August 23rd 2004 and seemed to be spending the night in the cliff regions surrounding us. The nesting habitat of these close-by `ake`ake calls was a lowland diverse dry to mesic native cliff community.
While exploring the above mentioned cliff region that sounded to be the site location for `ake`ake calls, we discovered the winged remains of an `ake`ake which appeared to have be predated by an owl. A collection was made of two complete wings which will be sent to Bishop Museum for positive identification. In addition to the `ake`ake remains, and within a few meters of the site, was the carcass of an `a`o with its head and legs missing. This location occurs around 180 m (590 ft) elev. with a north aspect. The cliff had a 50% vegetation cover dominated by 30% cliff coverage of Artemisia australis and with a secondary dominant of 10 % Nototrichium sandwicense cover. The primary invasive non-native in the area was Erigeron karvinskianus.
Plant Communities. A general ecological list of Awaawapuhi Valley’s vegetation zones include:
a) Coastal sea cliff
b) Lowland dry secondary herbland/grassland/shrubland
c) Lowland dry Hibiscus tiliaceus forest
d) Lowland diverse dry to mesic native cliff
Coastal Sea Cliff and Hedyotis st.-johnii. The coastal sea cliff of Awaawapuhi is accentuated by a 20 m (70 ft) waterfall which is fed from both the main stream in addition to spurting seeps which spring from cracks in the cliff face and fall to a small 250 m (820 ft) long boulder rock beach. Vertical walls are covered with Scaevola taccada, Polypogon viridis, Artemisia australis, Colocasia esculenta, and Lycium sandwicense.
On the coastal cliff just to the northeast of the river mouth at 200 ft elev. are two plants of Hedyotis st.-johnii, an extremely rare and critically endangered plant species growing on basalt lichen cliff with Artemisia australis and Capparis sandwichiana. Hedyotis st.-johnii is a halophytic cliff dwelling species with green fleshy flowers and broad succulent leaves. It is a narrow-endemic restricted to the Na Pali coast of Kaua`i. Presently, Hedyotis st.-johnii is estimated to have less than 50 plants remaining. Although surveys conducted by the lead author over the last five years show approximately 84 individuals along the Na Pali coast, we believe these numbers have since dropped around 30% and will continue to drop over the next decade, until extinction (Wood et al. 2002). Drought, feral goats, poor regeneration, and the current trend in population decline within dry and mesic regions of the Hawaiian archipelago, all have contributed to the drop in population and attempts should be made to evaluate these sites and make additional seed collections for conservation.
During this research, we were able to collect seed from one individual of Hedyotis st.-johnii (K. R. Wood & D. Boynton 10919) which was subsequently accessioned at the National Tropical Botanical Garden (NTBG) in Lawa`i, Hawai`i.
Just above the ocean at the eastern end of Awaawapuhi’s boulder rock beach and talus coastal rubble is a small seepy concave coastal cliff which is fed by a spring 110 m (360 ft) above. This wet coastal cliff has numerous individuals of Cyrtandra wawrae, one of Kauai’s native Gesneriaceae. The occurrence of C. wawrae within coastal beach spray is of phytogeographical interest. It is recommended that seed collections be made from this population for horticulture and conservation. Also within this zone we observed Myoporum sandwicense, Scaevola taccada, Cordyline fruticosa, and Artemisia australis. It should be noted that an additional population of Cyrtandra wawrae was also observed around wet intermittent waterfall faces in the back of the lower valley at 210 m (600 ft) elevation.
Lowland Dry Secondary Herbland/Grassland/Shrubland. Awaawapuhi’s valley bottom is dominated by non-native invasive plant species including Salvia occidentalis, Kalanchoë pinnata, Lantana camara, Conyza bonariensis, and Opuntia ficus-indica. Common grasses include the non-native Setaria parviflora and Eragrostis pectinacea, in addition to the native Agrostis avenacea. The native fern Doryopteris decipiens can be commonly seen emerging around the base of boulder outcrops.
Besides a small 3000 sq m lowland dry Hibiscus tiliaceus forest at the mouth of Awaawapuhi, only four trees remain in the valley bottom including a single individual of the native Pisonia sandwicensis. This Pisonia is near mid-valley (ca. 120 m [400 ft] elev.), 9 m tall with a 2 m diameter girth and stands in the company of three non-native Aleurites moluccana.
Lowland Dry Hibiscus tiliaceus Forest. A Hibiscus tiliaceus forest of approximately 100 m long x 30 m wide covers the mouth of the valley at 15—20 m elevation above the coastal waterfall. The Hibiscus stands 5—7 m tall and is thickly entwined together making passage through the stand of trees extremely difficult. No other species of trees were observed within the grove.
Lowland Diverse Dry To Mesic Native Cliff. The lichen covered cliffs of Awaawapuhi’s lower valley rise vertically between 300—600 m (1000—2000 ft) above the bottom land, reaching up to relatively bare ridges that enclose the lower valley. These ridges are frequented by goats and remain desolate until they climb into the upper eastern forest regions of Awaawapuhi where the rich mesic forests of Kokee still stand.
Lower Awaawapuhi’s dominant cliff species include native shrubs of Artemisia australis, Nototrichium sandwicense, Chamaesyce celastroides var. hanapepensis, Lipochaeta connata var. acris, Bidens sandvicensis subsp. sandvicensis, and Schiedea apokremnos. Several tree species are occasionally seen along the cliffs including Dodonaea viscosa, Metrosideros polymorpha var. glaberrima, Myoporum sandwicense, Psydrax odorata, and Wilkesia gymnoxiphium. Common ferns on the cliffs include Psilotum nudum and Doryopteris decipiens.
Generally, the vegetative cover of these cliffs range between 5%—50% with the remainder bare or with scattered green-white lichen. We also observed that west facing walls had the higher percentage of cover.
Interestingly, the lower cliffs from their base up to 2.5—3 m are dominated by non-native plant taxa such as Kalanchoë pinnata, Salvia occidentalis, Pluchea carolinensis, Nephrolepis multiflora, Christella dentata, Blechnum occidentale, Adiantum hispidulum, Adiantum raddianum, Setaria parviflora, Lantana camara, and Erigeron karvinskianus. Very few native species were observed along the 3 m grazing zone of goats and estimates average approximately 2% native cover remaining. Above the 3 m mark throughout the lower valley of Awaawapuhi there is a 95% native dominated cliff community of the afor mentioned species. The vertical nature of these cliffs make a natural barrier whereby goats can not impact the cliff vegetation. This long term natural exclusion of grazing mammals clearly show the effects that introduced goats have on natural ecosystems.
The richest cliff community occurs within the first four southern folds of Awaawapuhi’s inland cliffs, from west to east respectively. The first and second southern folds, which enclose a steep loose talus-rubble slope, are characterized by walls of Artemisia australis, Nototrichium sandwicense, and Chamaesyce celastroides var. hanapepensis. Similarly, the third and fourth southern folds remain dominated by native cliff species with noteworthy additions of two Federally Listed as Endangered species including five plants of Lobelia niihauensis and 50 Schiedea apokremnos (i.e., third fold), in addition to around ten Lobelia niihauensis and approximately 50 Schiedea apokremnos within the fourth fold. While in the fourth southern fold we noted that the eastern wall had a 5% vegetation cover and the western wall had approximately a 50% cover. This general pattern of vegetation cover was evident throughout the southern cliffs.
The single stream which swiftly flowed past our camp and meandered through the lower valley had remarkably cool clear running water which originated from several springs and seeps located between ca. 120—180 m (400—600 ft) elevation and of which emerged from open talus boulders mainly on the northeastern side of the stream. At 170 m (550 ft) elev. just above the stream on its northeast side is one of the more prominent talus springs. We collected drinking water at this site and noted localized non-native species such as Commelina diffusa, Eleocharis geniculata and a vigorous population of the native maiden-hair fern Adiantum capillus-veneris, in addition to the indigenous herb Hydrocotyle verticillata.
References
Wood, K. R. & D. Boynton 2004. Seabird and Vegetation Surveys of Honopu, Kaua`i, Hawai`i (1—1000 ft. elev.). Special Report Prepared for The Department of Land and Natural Resources, Division of State Parks, Technical Report, 14 pp. May 2004
Wood, K. R., M. Chapin, S. Perlman, & M. Maunder. 2002. Final Report on Field Research Conducted Under USFWS Grant No. 122000G001. Critically Endangered Hawaiian Plant Taxa & Conservation Collections within the Genetic Safety Net (GSN). Technical Report, 40 pp. February 2002.
Checklist of Vascular Plants
Awaawapuhi Valley
Kaua`i, Hawai`i
1—1000 ft. elev.
Aug 2004
K. R. Wood, kenwood@pelea.org
D. Boynton, boyntons001@hawaii.rr.com
[Note: Names for flowering plants follow W. L. Wagner et al. 1990. Names for pteridophytes follow D. Palmer 2002]
Symbols: end=Endemic Pol=Polynesian Introduction V=Vulnerable
ind=Indigenous E=Endangered VH= Vulnerable in Hawaii
nat=Naturalized R=Rare SIE=Single Island Endemic
Checklist reflects the following days of research: K. R. Wood & D. Boynton: 23—24 Aug 2004,
Angiosperms-Dicots
Amaranthaceae
Amaranthus viridis L. (nat )
Nototrichium sandwicense (A. Gray) Hillebr. (end )
Apiaceae
Centella asiatica (L.) Urb. (nat )
Hydrocotyle verticillata Thunb. (ind )
Apocynaceae
Alyxia oliviformis Gaud. (end )
Asteraceae
Ageratum conyzoides L. (nat )
Artemisia australis Less. (end )
Bidens pilosa L. (nat )
Bidens sandvicensis Less. subsp. sandvicensis (end )
Conyza bonariensis (L.) Cronq. (nat )
Emilia fosbergii Nicolson (nat )
Erigeron karvinskianus DC (nat )
Lipochaeta connata (Gaud.) DC var. acris (Sherff) Gardner (end)
Pluchea carolinensis (Jacq.) G. Don (nat )
Wilkesia gymnoxiphium A. Gray (end)
Cactaceae
Opuntia ficus-indica (L.) Mill. (nat )
Campanulaceae
Lobelia niihauensis St. John (end E)
Capparaceae
Capparis sandwichiana DC (end V)
Caryophyllaceae
Drymaria cordata (L.) Willd. ex Roem. & Schult. var. pacifica Mizush. (nat )
Schiedea apokremnos St. John (end E)
Crassulaceae
Kalanchoë pinnata (Lam.) Pers. (nat )
Euphorbiaceae
Aleurites moluccana (L.)Willd. (pol )
Chamaesyce celastroides (Boiss.) Croizat & Degener var. hanapepensis (Sherff) Degener & I. Degener (end)
Chamaesyce hirta (L.) Millsp. (nat )
Gentianaceae
Centaurium erythraea Raf. subsp. erythraea (nat )
Gesneriaceae
Cyrtandra wawrae C.B. Clarke (end)
Goodeniaceae
Scaevola taccada (Gaertn.) Roxb. (ind )
Lamiaceae
Plectranthus parviflorus Willd. (ind )
Salvia occidentalis Sw. (nat )
Lythraceae
Lythrum maritimum Kunth (nat )
Malvaceae
Abutilon grandifolium (Willd.) Sweet (nat )
Hibiscus kokio Hillebr. ex Wawra subsp. saintjohnianus (M. Roe) D. Bates (end R)
Hibiscus tiliaceus L. (ind )
Sida fallax Walp. (ind )
Myoporaceae
Myoporum sandwicense A. Gray (ind )
Myrtaceae
Metrosideros polymorpha Gaud. var. glaberrima (H. Lev.) St. John (end )
Nyctaginaceae
Boerhavia repens L. (ind )
Pisonia sandwicensis Hillebr. (end )
Oxalidaceae
Oxalis corniculata L. (ind )
Piperaceae
Peperomia blanda (Jacq.) Kunth var. floribunda (Miq.) H. Huber (ind )
Plantaginaceae
Plantago lanceolata L. (nat )
Plantago major L. (nat )
Polygonaceae
Rumex obtusifolius L. subsp. obtusifolius (nat )
Primulaceae
Anagallis arvensis L. (nat )
Rubiaceae
Hedyotis st.-johnii B. Stone & Lane (end E)
Psydrax odorata (G. Forster) A. C. Smith & S. P. Darwin (ind )
Sapindaceae
Dodonaea viscosa Jacq. (ind )
Solanaceae
Lycium sandwicense A. Gray (ind )
Sterculiaceae
Waltheria indica L. (ind )
Thymelaeaceae
Wikstroemia oahuensis (A. Gray) Rock var. oahuensis (end )
Verbenaceae
Lantana camara L. (nat )
Stachytarpheta jamaicensis (L.) Vahl (nat )
Angiosperms--Monocots
Agavaceae
Cordyline fruticosa (L.) A. Chev. (pol )
Araceae
Colocasia esculenta (L.) Schott (pol )
Commelinaceae
Commelina diffusa Burm. f. (nat )
Cyperaceae
Carex meyenii Nees (ind )
Carex wahuensis C.A. Mey. subsp. wahuensis (end )
Eleocharis geniculata (L.) Roem. & Schult. (nat )
Kyllinga brevifolia Rottb. (nat )
Poaceae
Agrostis avenacea J.F. Gmelin (ind )
Chloris virgata Sw. (nat )
Chrysopogon aciculatus (Retz.) Trin. (ind )
Digitaria insularis (L.) Mez ex Ekman (nat )
Echinochloa colona (L.) Link (nat )
Eragrostis pectinacea (Michx.) Nees (nat )
Eragrostis variabilis (Gaud.) Steud. (end )
Heteropogon contortus (L.) P. Beauv. ex Roem. & Schult. (ind )
Polypogon viridis (Gouan) Breistr. (nat )
Setaria parviflora (Poir.) Kergulen (nat )
Sporobolus indicus (L.) R. Br. (nat )
Vulpia bromoides (L.) S.F. Gray (nat )
Pteridophytes
Blechnaceae
Blechnum occidentale L. (nat )
Dryopteridaceae
Nephrolepis multiflora (Roxb.) F.M. Jarrett ex C.V. Morton (nat )
Psilotaceae
Psilotum nudum (L.) P. Beauv. (ind )
Pteridaceae
Adiantum capillus-veneris L. (ind )
Adiantum hispidulum Sw. (nat )
Adiantum raddianum C. Presl (nat )
Doryopteris decipiens (J. Sm.) Hook. (end )
Thelypteridaceae
Christella dentata (Forssk.) Brownsey & Jermy (nat )
