american samoa - University of Hawaii at Manoa

introduced weeds, many of the Polynesian weeds have
been severely reduced or have disappeared from
American Samoa. Polynesian weeds reported on
'Tutuila but not collected on the island in the last half
century include Amaranthus viridus (Amaranthaccae),
Cyathula prostrata (Amaranthaceae), Senna
.sophc~rti (I:abaccae), and Urcrria lagopodoides
(Pabaceae).
The dominant weedy plants found on managed land
are Mikania micrantha (mile-a-minute vine, fue
saina), Nephrolepis hirsutula (sword fern, vao
tuaniu), Bidens alba (beggar's-tick), and Paspalum
conjugatum (T-grass, vao lima). Many other species
may be common, depending upon soil, moisture, and
type of management. About 250 species introduced
species have become naturalized in the archipelago
(Whistler 1988b), and about 168 of these occur on
Tutuila (Appendix A); most of these are weeds that
thrive in sunny disturbed areas; most are flowering
plants, but a few are ferns. Mikania, unlike the other
three most abundant weed species, is a vine than can
smother other herbaceous or shrubby vegetation, and
may inhibit timely regeneration of forest from
disturbed land.
The dominant plants on the margins of the Alava
Ridge road include Brachiaria mutica (California
grass), Mikania micrantha, Calopogonium muco-
noides, Mimosa pudica (sensitive plant, vao fefe), and
Ludwigia actovalvis (primrose willow). There is very
little if any current management, since the road is
largely abandoned, so these are often mixed with
shrubs and trees characteristic of secondary scrub.
The roadway itself is dominated by a different set of
species that do not thrive in the dense shade of the
taller roadside plants; the most common plants here
include Ludwigia octovalvis, Eleusine indica (goose
grass, ta'ata'a), Cuphea carthagenensis, and Paspa-
lum conjugatum. The roadsides from Afono to Vatia
are dominated by weeds such as Desmodium tortuo-
.sum (especially in places that have not recently been
sprayed or cut), Bidens alba, Paspalum conjugatum,
and Calopogonium muconoides.
lioadcuts are similar to cliffs in that erosion on the
steep surfaces prevents a stable climax vegetation
from becoming established. On the Alava Ridge road,
the dominant species are weedy vines, such as
Mikania micrantha and Dioscorea bulbifera (bitter
yam, soi), secondary scrub species, such as Pipturus
argenteus, secondary forest trees, such as Neonau-
clea forsteri (afa), and ferns, such as Pneumato-
pteris glandulosa, Angiopteris evecta (king fern,
nase), Pleisoneuron attenuatum, and Macrothe-
lyptris polypodioides. Also common is the large
' native reed Miscanthus floridulus (u). The road-
cuts on the eastern part of the park are dominated
mostly by secondary forest trees, such as Maca-
ranga harveyana (lau pata), Pipturus argenteus
(soga), and Morinda citrijiolia (Indian mulberry,
nonu), and herbaceous species such as Dioscorea
bulbifera (bitter yam, soi), Mikania micrantha,
Nephrolepis hirsutula (vao tuaniu), and Macro-
thebpteris polypodoides. In some places Dicra-
nopteris linearis (asaua, false staghorn fern) is
dominant, especially on cliffs forming the edge of
the road.
Other than the taro, coconut, and banana
plantations around the fringes of the villages and
along roads, there is hardly any current agricul-
tural activity within the park boundaries. Only
one person, a non-Samoan residing in Vatia, is
currently known to have any inland plantations.
One is on the hillside west of Amalau Valley,
another is on Toa Ridge about halfway between
the TV transmitter and the north coast, and another
is reportedly on the ridge just to the west of Tafeu
Bay. The Toa Ridge plantation is an area of
Dicranopteris linearis, which is suggestive of
ancient village or plantation sites. Currently only a
few orange trees and a mango are planted there, all
of them quite young. The area west of Tafeu Bay
has some coconuts, possibly a remnant of former
human activity (the name of the area is Nu'utoga,
literally "Tongan village," which may indicate its
ancient status). The farmer using this area
believes that some of the trees there may be old
cultivated species that he doesn't recognize, but
unfortunately the area was not visited because of
weather conditions.
9. Secondary Scrub
This is the type of disturbed vegetation that is
dominated by shrubs and small trees. It is usually
a successional stage between managed land, or
land disturbed naturally (as by a landslide), and
secondary forest. The species that dominate here
are mostly woody rather than herbaceous. When
the land is managed, or weeded in the case of
plantations, these woody plants are kept in check,