Fossil insect folivory tracks paleotemperature for six million years
Fossil insect folivory tracks paleotemperature for six million years
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DOI：
10.1890/09-2138.1
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发表时间：
2010-11-01
影响因子：
6.1
通讯作者：
Wilf, Peter
中科院分区：
文献类型：
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作者：
Currano, Ellen D.;Labandeira, Conrad C.;Wilf, Peter
古生态学研究增强了我们对生物对气候变化的反应的理解，因为它们认为时间尺度无法通过实验室或生态学研究获得。从6000万年前到5100万年前，全球气温逐渐变暖，达到过去6500万年来最高的持续温度。叠加在这种逐渐变暖的是一个短暂的高温和pCO（2）（大气中二氧化碳的分压;古新世-始新世热最大值55.8 Ma）和随后的短期冷却事件（类似于54 Ma）。美国怀俄明州大角盆地的高分辨率大陆化石记录跨越了这段时间，因此特别适合于研究温度变化对陆地生态系统中两个主要群体（植物和昆虫食草动物）的长期影响。我们采样的被子植物化石叶片上的昆虫损害在9个良好的日期地点，年龄范围从52.7至59马。共调查了107种植物的9071片叶片，共鉴定出71种取食危害类型。损害丰富度，频率和组成进行了分析，对散装植物区系和个别主机种。总体而言，有一个很强的正相关性之间的变化，在损害丰富度和估计温度的变化，损害频率和温度的弱正相关性，并没有显着的相关性为花的多样性。因此，虫害丰富度似乎是更敏感的过去的气候变化比植物多样性，虽然我们的样本中的植物多样性只有6至25双子叶植物物种。密切跟踪的丰富的食草动物的损害，一个假定的代理实际的昆虫食草动物的丰富性，无论是升温和降温在一个细分的，延长的时间间隔具有深远的意义，解释昆虫和植物-昆虫协会的进化背景下，深时间。我们的研究结果还表明，增加昆虫植食性很可能是人为变暖的净长期影响。
Paleoecological studies enhance our understanding of biotic response to climate change because they consider timescales not accessible through laboratory or ecological studies. From 60 to 51 million years ago (Ma), global temperatures gradually warmed to the greatest sustained highs of the last 65 million years. Superimposed on this gradual warming is a transient spike of high temperature and pCO(2) (partial pressure of carbon dioxide in the atmosphere; the Paleocene-Eocene Thermal Maximum 55.8 Ma) and a subsequent short-term cooling event (similar to 54 Ma). The highly resolved continental fossil record of the Bighorn Basin, Wyoming, USA, spans this interval and is therefore uniquely suited to examine the long-term effects of temperature change on the two dominant groups in terrestrial ecosystems, plants and insect herbivores. We sampled insect damage on fossil angiosperm leaves at nine well-dated localities that range in age from 52.7 to 59 Ma. A total of 9071 leaves belonging to 107 species were examined for the presence or absence of 71 insect-feeding damage types. Damage richness, frequency, and composition were analyzed on the bulk floras and individual host species. Overall, there was a strong positive correlation between changes in damage richness and changes in estimated temperature, a weak positive relationship for damage frequency and temperature, and no significant correlation for floral diversity. Thus, insect damage richness appears to be more sensitive to past climate change than to plant diversity, although plant diversity in our samples only ranges from 6 to 25 dicot species. The close tracking of the richness of herbivore damage, a presumed proxy for actual insect herbivore richness, to both warming and cooling over a finely divided, extended time interval has profound importance for interpreting the evolution of insects and plant-insect associations in the context of deep time. Our results also indicate that increased insect herbivory is likely to be a net long-term effect of anthropogenic warming.