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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >How many tree species are there in the Amazon and how many of them will go extinct?
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How many tree species are there in the Amazon and how many of them will go extinct?

机译：亚马逊有多少种树种，其中有几种会灭绝？

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New roads, agricultural projects, logging, and mining are claiming an ever greater area of once-pristine Amazonian forest. The Millennium Ecosystems Assessment (MA) forecasts the extinction of a large fraction of Amazonian tree species based on projected loss of forest cover over the next several decades. How accurate are these estimates of extinction rates? We use neutral theory to estimate the number, relative abundance, and range size of tree species in the Amazon metacommunity and estimate likely tree-species extinctions under published optimistic and nonoptimistic Amazon scenarios. We estimate that the Brazilian portion of the Amazon Basin has (or had) 11,210 tree species that reach sizes >10 cm DBH (stem diameter at breast height). Of these, 3,248 species have population sizes >1 million individuals, and, ignoring possible climate-change effects, almost all of these common species persist under both optimistic and nonoptimistic scenarios. At the rare end of the abundance spectrum, however, neutral theory predicts the existence of 5,308 species with < 10,000 individuals each that are expected to suffer nearly a 50% extinction rate under the nonoptimistic deforestation scenario and an 37% loss rate even under the optimistic scenario. Most of these species have small range sizes and are highly vulnerable to local habitat loss. In ensembles of 100 stochastic simulations, we found mean total extinction rates of 20% and 33% of tree species in the Brazilian Amazon under the optimistic and nonoptimistic scenarios, respectively.
机译：新的道路，农业项目，伐木场和采矿场占据了原始亚马逊森林面积越来越大的地步。千年生态系统评估（MA）根据预计的未来几十年的森林覆盖率损失，预测了大部分亚马逊树种的灭绝。这些估计的灭绝率有多精确？我们使用中性理论来估计亚马逊元社区中树木种类的数量，相对丰度和范围大小，并估计在已发布的乐观和非乐观亚马逊情景下可能的树种灭绝。我们估计，亚马逊河流域的巴西部分已经（或曾经有）11,210种树种，其大小超过10厘米DBH（胸高处的茎直径）。在这些物种中，有3248种的种群规模> 100万个个体，并且在不考虑可能的气候变化影响的情况下，几乎所有这些常见物种在乐观和非乐观的情况下都将继续存在。然而，在丰富光谱的稀有末端，中性理论预测存在5308个物种，每个物种<10,000个人，在非乐观的森林砍伐情况下，预计灭绝率将接近50％，即使在乐观的情况下也将遭受37％的灭绝率场景。这些物种大多数都具有较小的范围，并且极易遭受当地生境丧失的影响。在100个随机模拟中，我们发现在乐观和非乐观情况下，巴西亚马逊地区树木的平均总灭绝率分别为20％和33％。

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