气候变化常常改变在一个地区植物繁盛的地点和种类，这可能导致依赖特定植物为食的动物物种的灭绝。Catherine Badgley及其同事研究了来自巴基斯坦北部化石丰富的Siwalik化石记录中的哺乳动物化石，结果发现了该地区的气候在数百万年的时间里从热带森林转变为稀树草原的过程中，许多动物物种没能适应环境而灭绝了。这些结果与此前的发现相反，此前的发现认为全球气候变化对哺乳动物多样性的影响较小，人们认为哺乳动物可以轻易地迁移或者适应变化的气候。
Siwalik沉积物群包含了全世界得到了最好的研究和最完整的哺乳动物化石记录之一，在一个2英里厚的沉积岩中含有从100万年前到1800万年前在该地区活动的哺乳动物的遗迹。大约在800万年前，随着那里的气候从热带森林气候变成类似于今天东非的稀树草原气候，几乎所有依赖森林食物（例如水果和阔叶植物）的哺乳动物都灭绝了。这组作者说，牙齿化石显示甚至一些食草动物也灭绝了，而且几乎没有新物种取代了那些消失的物种。相关论文发表在美国《国家科学院院刊》（PNAS）上。（生物谷Bioon.com）
生物谷推荐原始出处：
PNAS， doi: 10.1073/pnas.0805592105，Catherine Badgley，David Pilbeam
Ecological changes in Miocene mammalian record show impact of prolonged climatic forcing
Catherine Badgley*,†, John C. Barry‡, Michèle E. Morgan‡, Sherry V. Nelson§, Anna K. Behrensmeyer¶, Thure E. Cerling*,‖, and David Pilbeam‡
+Author Affiliations
Abstract
Geohistorical records reveal the long-term impacts of climate change on ecosystem structure. A 5-myr record of mammalian faunas from floodplain ecosystems of South Asia shows substantial change in species richness and ecological structure in relation to vegetation change as documented by stable isotopes of C and O from paleosols. Between 8.5 and 6.0 Ma, C4 savannah replaced C3 forest and woodland. Isotopic historical trends for 27 mammalian herbivore species, in combination with ecomorphological data from teeth, show three patterns of response. Most forest frugivores and browsers maintained their dietary habits and disappeared. Other herbivores altered their dietary habits to include increasing amounts of C4 plants and persisted for >1 myr during the vegetation transition. The few lineages that persisted through the vegetation transition show isotopic enrichment of δ13C values over time. These results are evidence for long-term climatic forcing of vegetation structure and mammalian ecological diversity at the subcontinental scale.
