Community structure of Pleistocene coral reefs of Curaçao, Netherlands Antilles

The Quaternary fossil record of living coral reefs is fundamental for understanding modern ecological patterns. Living reefs generally accumulate in place, so fossil reefs record a history of their former biological inhabitants and physical environments. Reef corals record their ecological history especially well because they form large, resistant skeletons, which can be identified to species. Thus, presence-absence and relative abundance data can be obtained with a high degree of confidence. Moreover, potential effects of humans on reef ecology were absent or insignificant on most reefs until the last few hundred years, so that it is possible to analyze "natural" distribution patterns before intense human disturbance began. We characterized Pleistocene reef coral assemblages from Curacao, Netherlands Antilles, Caribbean Sea, focusing on predictability in species abundance patterns from different reef environments over broad spatial scales. Our data set is composed of >2 km of surveyed Quaternary reef. Taxonomic composition showed consistent differences between environments and along secondary environmental gradients within environments. Within environments, taxonomic composition of communities was markedly similar indicating nonrandom species associations and communities composed of species occurring in characteristic abundances. This community similarity was maintained with little change over a 40-km distance. The nonrandom patterns in species abundances were similar to those found in the Caribbean before the effects of extensive anthropogenic degradation of reefs in the late 1970s and early 1980s. The high degree of order observed in species abundance patterns of fossil reef coral communities on a scale of tens of kilometers contrasts markedly with patterns observed in previous small-scale studies of modern reefs. Dominance of Acropora palmata in the reef crest zone and patterns of overlap and nonoverlap of species in the Montastraea ''annularis'' sibling species complex highlight the tendency for distribution and abundance patterns of Pleistocene corals to reflect environmental preferences at multiple spatial scales. Wave energy is probably the most important physical environmental variable structuring these coral communities. The strong similarity between ancient and pre-1980s Caribbean reefs and the nonrandom distribution of coral species in space and time indicate that recent variability noted at much smaller time scales may be due to either unprecedented anthropogenic influences on reefs or fundamentally different patterns at varying spatio-temporal scales

Charcoal Stratigraphies for Kaua'i and the Timing of Human Arrival

Evidence from microscopic charcoal particle stratigraphy is presented from nine locations distributed throughout Kaua'i in the Hawaiian Islands, including windward and leeward coastal sites and interior bogs at elevations ranging up to 1220 m. The overall trends are comparable with those reported for other mesic tropical island areas lacking strong seasonality, beginning with a general dearth of charcoal in sediments that predate evidence for humans on the island, followed by an increase of an order of magnitude or more at a time that probably represents first human presence at the site. In most cases, this initial peak or plateau of increased charcoal from presumably anthropogenic sources is followed by a prehistoric decrease and a second peak after European contact. Charcoal evidence presented here suggests a human presence in leeward coastal areas beginning ca. 830 ± 50 yr B.P. (1050-1095, 1140-1280 cal yr A.D.). One windward site, Limahuli Bog, may show charcoal evidence for humans as early as 1470 ± 60 yr B.P. (440-670 cal yr A.D.), but resolution is poor in the upper part of that core. Charcoal and sedimentological evidence suggests that Hawaiians were constructing fishponds as early as about eight centuries ago and that the massive stoneworks forming the Alekoko or Menehune Fishpond, probably the largest prehistoric stone structure in the Hawaiian Islands, may have been completed by 580 ± 30 yr B.P. (1305-1420 cal yr A.D.). Charcoal peaks in prehuman times, particularly at 3800 ± 40 yr B.P. (4080-4290 cal yr B.P.), may be associated with prolonged drought conditions. Charcoal particles are virtually absent from the late Pleistocene sediments collected from interior bogs

Appendix A. A review of the proposed causes of the Late Pleistocene extinctions in North America.

A review of the proposed causes of the Late Pleistocene extinctions in North America

A chronology for late prehistoric Madagascar

A database has been assembled with 278 age determinations for Madagascar. Materials 14C dated include pretreated sediments and plant macrofossils from cores and excavations throughout the island, and bones, teeth, or eggshells of most of the extinct megafaunal taxa, including the giant lemurs, hippopotami, and ratites. Additional measurements come from uranium-series dates on speleothems and thermoluminescence dating of pottery. Changes documented include late Pleistocene climatic events and, in the late Holocene, the apparently human-caused transformation of the environment. Multiple lines of evidence point to the earliest human presence at ca. 2300 14C yr BP (350 cal yr BC). A decline in megafauna, inferred from a drastic decrease in spores of the coprophilous fungus Sporormiella spp. in sediments at 1720 ± 40 14C yr BP (230–410 cal yr AD), is followed by large increases in charcoal particles in sediment cores, beginning in the SW part of the island, and spreading to other coasts and the interior over the next millennium. The record of human occupation is initially sparse, but shows large human populations throughout the island by the beginning of the Second Millennium AD. Dating of the “subfossil” megafauna, including pygmy hippos, elephant birds, giant tortoises, and large lemurs, demonstrates that most if not all the extinct taxa were still present on the island when humans arrived. Many taxa overlapped chronologically with humans for a millennium or more. The extinct lemurs Hadropithecus stenognathus, Pachylemur insignis, Mesopropithecus pithecoides, and Daubentonia robusta, and the elephant birds Aepyornis spp. and Mullerornis spp., were still present near the end of the First Millennium AD. Palaeopropithecus ingens, Megaladapis edwardsi, and Archaeolemur sp. (cf. edwardsi) may have survived until the middle of the Second Millennium A.D. One specimen of Hippopotamus of unknown provenance dates to the period of European colonization