Biotic attrition from tropical forests correcting for truncated temperature niches
Biotic attrition from tropical forests correcting for truncated temperature niches
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DOI：
10.1111/j.1365-2486.2009.02085.x
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发表时间：
2010-06-01
影响因子：
11.6
通讯作者：
Silman, Miles R.
中科院分区：
文献类型：
--
作者：
Feeley, Kenneth J.;Silman, Miles R.
气候变暖引起的物种迁移预计将导致“生物损耗”，即当地多样性的丧失，在这些地区，迁移或灭绝的物种数量超过了迁移的物种数量。生物磨损预计将特别严重的低洼炎热的热带地区，因为高温可能超过观察到的耐受性，大多数现存物种。然而，许多物种的估计温度生态位可能是不准确的，并且由于在当前全球气候下没有更热的地区而被截断。如果是这样的话，这些物种将能够在未来温度超过当前温度的某些地区持续存在，从而降低生物消耗率。在这里，我们使用自然历史收集数据来估计南美洲热带森林中> 2000种植物的已实现的热生态位。与截断假说雅阁，我们发现来自热低地地区的物种的热生态位比来自较冷地区的物种的热生态位窄几度。我们估计南美热带森林的生物损耗率，由于温度升高1至5摄氏度，并根据两个生态位的假设。第一个是所观察到的热生态位真实地反映了植物的耐受性，生态位宽度的减少是由于专业化程度的提高。二是低地物种与非低地和非赤道物种具有相同的平均热生态位宽度。这两种模式之间的差异是戏剧性的。例如，使用观测到的热生态位，我们预测由于5摄氏度的温度升高，大多数南美热带森林的植物多样性几乎完全丧失，但校正可能的生态位截断，我们估计大多数森林将保留其当前物种丰富度的50-70%。不同的预测突出了使用基本与实现生态位在预测物种对全球气候变化的反应的重要性。
Species migration in response to warming temperatures is expected to lead to 'biotic attrition,' or loss of local diversity, in areas where the number of species emigrating or going locally extinct exceeds the number immigrating. Biotic attrition is predicted be especially severe in the low-lying hot tropics since elevated temperatures may surpass the observed tolerances of most extant species. It is possible, however, that the estimated temperature niches of many species are inaccurate and truncated with respect to their true tolerances due to the absence of hotter areas under current global climate. If so, these species will be capable of persisting in some areas where future temperatures exceed current temperatures, reducing rates of biotic attrition. Here, we use natural history collections data to estimate the realized thermal niches of > 2000 plant species from the tropical forests of South America. In accord with the truncation hypothesis, we find that the thermal niches of species from hot lowland areas are several degrees narrower than the thermal niches of species from cooler areas. We estimate rates of biotic attrition for South American tropical forests due to temperature increases ranging from 1 to 5 degrees C, and under two niche assumptions. The first is that the observed thermal niches truly reflect the plant's tolerances and that the reduction in niche breadth is due to increased specialization. The second is that lowland species have the same mean thermal niche breadth as nonlowland and nonequatorial species. The differences between these two models are dramatic. For example, using observed thermal niches we predict an almost complete loss of plant diversity in most South American tropical forests due to a 5 degrees C temperature increase, but correcting for possible niche truncation we estimate that most forests will retain > 50-70% of their current species richness. The different predictions highlight the importance of using fundamental vs. realized niches in predicting the responses of species to global climate change.