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2. Littoral Shrubland Two types of littoral shrubland are present in the park, one on the sandy beaches where it alternates with littoral forest and herbaceous strand, and the other on the rocks of Sunitao and steep maritime cliff running inland along most of the length of the park. The most common shrub mixed in with the other littoral plants on the sandy beach is the beach sunflower Wollastonia bijlora (beach sunflower, skate), with lesser amounts of Scaevola taccada (to'ito'i), Sophora tomentosa, Colubrina asiatica (fisoa), and Clerodendrum inerme (aloalo tai). Sophora should be considered a rare plant in Samoa; it is known in the archipelago from only one beach on 'Upolu, one on Tutuila (Nu'uuli Point), the south part of 'Aunu'u, and this Ofu beach. The littoral shrubland on the steep sides of Sunitao and the cliffs of the main part of Ofu are much more complex and inaccessible. The slopes of Sunitao are dominated by a mixture of littoral trees and shrubs. Because the trees are often dwarfed, it is perhaps best to consider this vegetation as littoral shrubland, as was done with the vegetation of Pola Islet and the cliffs of Pola'uta Ridge on Tutuila. Littoral forests, however, are present on the gentler slopes of Sunitao and are discussed below. The dominant plants in the littoral shrubland of Sun itao are Dendrolobium umbellatum (lala), Clerodendrum inerme, Hibiscus tiliaceus (beach hibiscus, fau), and Pisonia grandis (pu'avai). To label the vegetation between the littoral forest and lowland forest on the cliffs on the main part of Ofu as littoral shrubland seems a bit incongruous since this community is supposed to be between the shore and the littoral forest. However, since it is compo- sed of shrubby species rather than trees, it is best to consider it littoral shrubland, regardless of its location. The dominant species on the steep slopes are Dendrolohium umbellatum, Phymatosorus scolo- pendria, Davallia solida (laugasese), Clerodendrum inerme, and Wollastonia bipora. Other species noted here include Morinda citrifolia (Indian mul- berry, nonu), Syzygium dealatum (asi vai), Ipomoea macrantha, Pipturus argenteus (soga), Pisonia grandis, Macaranga harveyana (lau pata), Colu- hrina asiafica, and GarugafIoribunda (vivao). Two other less common species were also noted here. The first, Gossypium hirsutum (vavae), is the native species of cotton that is very rare on Tutuila (one location recorded) and 'Aunu'u, and this was a surprising record for Ofu. The other, Plumbago zeylanica, was reported twice from the adjacent Olosega, but this is a new record for Ofu. Both species should be considered rare in American Samoa. 3. Littoral Forest The division between this community and littoral shrubland is not very distinct on Ofu, especially when the slopes get steeper and trees get more shrubby. However, three types of littoral forest were recorded. The first is found on the rocky shores of Sunitao. Some of these slopes have been disturbed--the forest has been cut down and the area replanted with coconuts and bananas. This is parti- cularly the case on the east side of the mountain. Probably the natural littoral forest there was dominated by Barringtonia asiatica, as it is on the southwest side, and is similar to what is found in the Tutuila park unit. The gentle slopes leading up to the steeper slopes and cliffs are dominated by the second kind of littoral forest. A sample on the southwest side, inland of the Barringtonia littoral forest, showed it to be dominated by a mixture of littoral forest trees. In descending order of dominance, these are Hernan- dia nymphaeifolia (Chinese lantern-tree, pu'a), Erythrina variegata (coral tree, gatae), and Pisonia grandis (pu'avai). Of lesser importance are Diospy- ros samoensis ('au'auli), which was the most common tree present, Hibiscus tiliaceus (beach hibiscus, fau), Dysoxylum samoense (mamala), Ficus scabra (ma ti), Guettarda speciosa (pua pua), Syzygium dealatum (asi vai), and Sterculia fanaiko (fana'io). Strangely, there was no Barringtonia in the sample on this slope. The understory was strongly dominated by seedlings and saplings of Syzygium dealatum and Diospyros samoensis, with lesser amounts of Psychotria insularum (matalafi), and Morinda citrifolia. Other significant plants included the bird's-nest fern Asplenium nidus (laugapapa) and Cordyline fruticosa (ti), with a few other species. The ground cover was relatively light, with perhaps only 15% cover. The only vines noted were Epipremnum pinnatum, Dioscorea bulbifera (bitter yam, soi), and Faradaya amicorum (mamalupe). A
similar forest is probably found on the same kind of slopes below the cliffs on the main part of Ofu, often mixed with lowland forest trees. This area is further discussed below. 'Two other significant small trees are found here. Chionanthus vitiensis is a new record for American Samoa, and was collected on Tutuila (Vatia) and on Ofu. It is known from only two records in Western Samoa; only a single tree was found in each of these four records. Ervatamia obtusiuscula is uncommon on Ofu, and has not been collected on Tutuila since 1894. Both of these species should be considered to be rare in American Samoa. The littoral forest on the sandy beach was differ- ent in species composition. In most places it is highly disturbed and dominated by planted and naturalized coconuts. At the east end this was a mixture of coconuts and Hernandia nymphaeifolia, which were shattered by one or more of the recent hurricanes. Also present on the beach is Terminalia samoensis (talie), which is not present in the Tutuila park unit. The west end of the beach, just to the east of the airstrip, is rocky and narrow (between the beach and the road), and is dominated by a combination of Hernandia nymphaeifolia, Thespesia populnea (Pacific rosewood, milo), Barringtonia asiatica, and Hibiscus tiliaceus. Much less common there are Terminalia catappa, Morinda citrifolia, Guettarda speciosa, Macaranga harveyana, and Erythrina variegata. 4. Coastal Marsh The wetland situation on Ofu is similar to that on 'htuila: on both there is a coastal marsh just outside the boundaries of the park. But since this is an important type of vegetation, and it is so close to the park, it is discussed here. Although the two marshes are similar in their geological structure, they differ greatly in their vegetation. While the Vatia marsh has been abandoned, the one on Ofu is actively being cultivated. It was, that is, until storm waves of a recent hurricane swept across it. Today it is still mostly barren mud, probably unable to support a native marsh or cultivated taro because of the residual salt concentration. It is a habitat for native ducks (toloa). Originally the vegetation was dominated by Eleocharis dulcis, possibly in combination with Cyclosorus interruptus, and these species will probably return to dominate the uncultivated portions of the marsh. Also present is the small fragrant herb Limnophila fragrans. This plant is currently known in the territory only from the Ta' village marsh, the Ofu marsh, the Olosega marsh, and the Vatia marsh, and should be considered rare in Samoa. It is probably even rarer in Western Samoa. It was found to be present in small quan- tities in the brackish mud of Ofu marsh, and will probably become more common as the marsh returns to its normal state. 5. Lowland Forest The lowland forest within the park is disturbed -on the gentler slopes by past and present agriculture, and on the steeper slopes by landslips. A plot was sampled in this vegetation in the 1976 survey (Whistler 1980) on the talus slope east of the airstrip (Appendix B: plot no. 14, modified from the original to correspond to the methods used in the present study). The dominant species in that plot were Hibiscus tiliaceus (18% relative dominance), Dysoxylum samoense (1 8%), Terminalia catappa (13%), Myristica fatua (12%), Neonauclea forsteri (1 I%), Guettarda speciosa (1 I%), and Diospyros samoensis (8%). Other species noted to be present on the slopes and cliffs during the June 1992 survey are Pisonia grandis, Sterculia fanaiho, Pometia pinnata, and Ficus obliqua. This vegetation is best classified as a disclimax lowland forest and probably best corresponds to the "Dysoxylum lowland forest on talus slopes and cliffs" noted in the Ta'u report (Whistler 1992b) as occurring in similar situations on that island. It is also similar to the vegetation in the Tutuila park between Alava Ridge road and Fagas, and probably on the steep slopes of Alava Ridge above Pago Pago (which are mostly outside the Tutuila park boundaries). MONTANE FOREST The vegetation on top of the ridge above the Ofu park area was also briefly examined. The top of the island has been extensively disturbed by past and recent agriculture and by the recent hurricanes. There is also a road leading from Ofu village up to the summit of the island (Mt. Tumu) to a microwave station. Since the summit is at 500 m elevation, the forest is or was probably best classified as montane forest, similar to that on Tutuila, but with fewer species. In
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COOPERATIVE NATIONAL PARK RESOURCES
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TABLE OF CONTENTS I . INTRODUCTION
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LEGEND B \ PROPOSED PARK AREA OFU I
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Figure 3 VEGETATION TYPE MAP Tutuil
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Figure 4. Pago Pago Bay, with Mt. M
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'IJpolu, and 'Ta'u as well). The on
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nu pucijicuJ; an Eurya? [Eurya pick
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category recognized in the report o
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Figure 10. Tuafanua Beach west of V
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Figure 12. Littoral shrubland veget
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Figure 14. Littoral shrubland veget
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Figure 16. Littoral forest north of
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Soils differ in origin and age of t
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example on Tutuila is the climbing
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When undisturbed, the floor of the
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incrme (aloalo tai) may also be com
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coastal ridges, decreases in import
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Scvcral other trees are characteris
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poIvon/l~os, Dtrvulliu solidu (whic
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Although Mauga-o-Tula lacks some of
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introduced weeds, many of the Polyn
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even mature secondary forest, it le
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there). No increased access should
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Whistler, W. A. 1976. Wetlands of A
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Acrostichum aureum L. [swamp fern]
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Uncommon in montane to cloud forest
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171 ; Setchell 393; Christophersen
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of the costa. Uncommon in montane t
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liom China to I'itcairn Island. USE
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lamina deeply cut into 1-10 lobes,
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Antrophyum alatum Bracken. VITTARIA
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weed in villages and along roadside
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650 111 clevi~tion. A modern introd
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Vernonia cinerea (L.) Less. [ironwe
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Uncomnion in secondary forest, prob
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from near sea level to 400 m elevat
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*Charnaesyce prostrata (Ait.) Small
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elevation. A modern introduction, n
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Macroptilium lathyroides (L.) Urb.
Page 80 and 81: Cyrtandra samoensis A. Gray momolea
Page 82 and 83: 'Thespesia populnea (L.) Sol. ex Co
Page 84 and 85: Ficus prolixa Forst. f. [banyan] ao
Page 86 and 87: found in Tonga, Futuna, and Fiji. S
Page 88 and 89: Peperomia pellucida (L,.) Kunth POL
Page 90 and 91: *Gardenia taitensis DC. "Hedyotis c
Page 92 and 93: elevation. This species should be t
Page 94 and 95: "Physalis angulata L. 1 wild cape g
Page 96 and 97: *Etatosterna scabriusculum Setchell
Page 98 and 99: Epipremnum pinnaturn (L.) Engl. Ili
Page 100 and 101: Mariscus secmannianus (Boeck.) Pall
Page 102 and 103: *Bulbophyllurn samoanum Schlechter
Page 104 and 105: Malaxis resupinata (Forst. f.) Kunt
Page 106 and 107: F. homhronii Mart.; it differs from
Page 108 and 109: this in D. ciliaris, but the two ha
Page 110 and 111: Paspalurn orbiculare Forst. f. Mcdi
Page 112 and 113: APPENDIX B: PLOT DATA (Basal area i
Page 114 and 115: PLOT 4: MULIULU LOWLAND RIDGE FORES
Page 116 and 117: PLOT 6: TIATAUALA LOWLAND RIDGE FOR
Page 118 and 119: PLOT 8: OLO LOWLAND RIDGE FOREST (2
Page 120 and 121: PLOT 10: AMALAU LOWLAND VALLEY FORE
Page 122 and 123: PLOT 12: ALAVA MONTANE FOREST* (400
Page 124 and 125: APPENDIX C: SEASONALITY OF IMPORTAN
Page 126 and 127: MORACEAE Ikus godcfl'royi 1;icus ob
Page 128 and 129: SPECIES FAMILY FLOWERING DATES FRUI
Page 132 and 133: the relatively undisturbed places,
Page 134 and 135: harvcyana (laupata), Morinda citrif
Page 136 and 137: APPENDIX F. SUMMARY OF THE VASCULAR
Page 138 and 139: VIlTAKIACEAE Amrophyurn alaturn Ant
Page 140 and 141: Species FAMILY Status* E I P M ....
Page 142 and 143: MYRSINACEAE Embelia vaupelii Maesa
Page 144 and 145: Species FAMILY Status* E I P M VEKB
Page 146: ...................................
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