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Turtles and tortoises (chelonians) have been integral components of global ecosystems for about 220 million years and have played important roles in human culture for at least 400,000 years. The chelonian shell is a remarkable evolutionary adaptation, facilitating success in terrestrial, freshwater and marine ecosystems. Today, more than half of the 360 living species and 482 total taxa (species and subspecies combined) are threatened with extinction. This places chelonians among the groups with the highest extinction risk of any sizeable vertebrate group. Turtle populations are declining rapidly due to habitat loss, consumption by humans for food and traditional medicines and collection for the international pet trade. Many taxa could become extinct in this century. Here, we examine survival threats to turtles and tortoises and discuss the interventions that will be needed to prevent widespread extinction in this group in coming decades.

It is becoming increasingly recognized that the cloud forests of tropical mountains are high on the list of the world's most threatened ecosystems. In many countries or regions, their rate of loss exceeds that of the lowland tropical rain forests that have received much public concern. Perhaps 90 percent of these tropical montane cloud forests (TMCFs) in the northern Andes have been lost. During the symposium, for which this publication is the proceedings, visual evidence presented by Dr. Alwyn Gentry and others, and the verbal descriptions given by many participants, attested to the loss not only for the Andes, but for all parts of the world where TMCF occurs. The original estimate (and it was only an estimate) given by Persson (1974) of 50 million ha of cloud forests was probably on the high side. He suggested that TMCF constituted one-quarter of montane and sub montane rain forest. We believe that TMCF is being lost at a rate considerably in excess of that of the muchabused, but much-publicized, lowland tropical rain forest. Indeed the first paper (Doumenge et al.) that follows indicates that annual forest loss in tropical hills and mountains is 1.1 percent compared with 0.8 percent for all forests of the tropics. Those on isolated volcanic mountains, especially where occurring on small oceanic islands, are particularly vulnerable, and their loss is a serious concern. Cutting of forest for firewood or for charcoal production, and conversion to agricultural uses (mainly grazing) are the principal villains. However, the threats and damaging activities are many. They will be discussed in this synthesis and in many of the papers that follow. L. S. Hamilton et al. (eds.), Tropical Montane Cloud Forests

A pollen record from Ka‘au Crater, O‘ahu, Hawai‘i contains evidence for changes in vegetation and climate since about 28,000 14C yr B.P. Zone 1 (ca. 28,100–ca. 22,800 14C yr B.P.) has pollen of dry to mesic forest species, including Pipturus-type, Dodonaea viscosa, Acacia koa, Chenopodium oahuense, Claoxylon sandwicense, Myrsine, and Metrosideros-type. In zone 2 (ca. 22,800–ca. 16,200 14C yr B.P.) Myrsine and Coprosma increase, with herbs, fern allies, and Grammitidaceae suggesting open canopies. Zone 3 (ca. 16,200–ca. 9700 14C yr B.P.) has pollen of wet forest species, including Freycinetia arborea, abundant Pritchardia, and Metrosideros-type. Zone 4 (ca. 9700–ca. 7000 14C yr B.P.) is similar, with less Pritchardia and more Metrosideros-type.Climate reconstruction was based on modern climatic ranges of flowering plants and an index derived from abundance of pollen in surface samples. Both methods agree on a qualitative reconstruction, although the ages are poorly constrained: 28,000–25,000 14C yr B.P. cool and dry; 25,000–23,000 14C yr B.P. dry and warmer; 23,000–20,000 14C yr B.P. moderately dry with declining temperature; 20,000–16,000 14C yr B.P. moderately dry and cool; 16,000–9000 14C yr B.P. warm and wet; 9000–7000 14C yr B.P. warm and possibly drier. Lower precipitation at Ka‘au Crater during the late glacial period and last glacial maximum is consistent with the interpretation that the North Pacific subtropical anticyclone was south of its present position. The pollen-derived temperature index yields an estimate of 3°–5°C temperature depression during the last glacial maximum.

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