Abstract:
Coring and excavations in a large sinkhole and cave system formed in an
eolianite deposit on the south coast of Kaua‘i in the Hawaiian Islands reveal a fossil site
with remarkable preservation and diversity of plant and animal remains. Radiocarbon dating
and investigations of the sediments and their fossil contents, including diatoms, invertebrate
shells, vertebrate bones, pollen, and plant macrofossils, provide a more complete picture
of prehuman ecological conditions in the Hawaiian lowlands than has been previously
available. The evidence confirms that a highly diverse prehuman landscape has been completely
transformed, with the decline or extirpation of most native species and their replacement
with introduced species.
The stratigraphy documents many late Holocene extinctions, including previously undescribed
species, and suggests that the pattern of extirpation for snails occurred in three
temporal stages, corresponding to initial settlement, late prehistoric, and historic impacts.
The site also records land-use changes of recent centuries, including evidence for deforestation,
overgrazing, and soil erosion during the historic period, and biological invasion
during both the Polynesian and historic periods. Human artifacts and midden materials
demonstrate a high-density human presence near the site for the last four centuries. Earlier
evidence for humans includes a bone of the prehistorically introduced Pacific rat (Rattus
exulans) dating to 822 yr BP (calendar year [cal yr] AD 1039–1241).
Vegetation at the site before human arrival consisted of a herbaceous component with
strand plants and graminoids, and a woody component that included trees and shrubs now
mostly restricted to a few higher, wetter, and less disturbed parts of the island. Efforts to
restore lowland areas in the Hawaiian Islands must take into account the evidence from
this study that the prehuman lowlands of dry leeward Kaua‘i included plants and animals
previously known only in wetter and cooler habitats. Many species may be restricted to
high elevations today primarily because these remote locations have, by virtue of their
difficult topography and climate, resisted most human-induced changes more effectively
than the coastal lowlands.
