Understanding specifics in generalist diets of carnivorans by analyzing stable carbon isotope values in Pleistocene mammals of Florida
Understanding specifics in generalist diets of carnivorans by analyzing stable carbon isotope values in Pleistocene mammals of Florida
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通过分析佛罗里达州更新世哺乳动物的稳定碳同位素值，了解食肉动物的通才饮食细节
DOI：
10.1666/13055
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
L. Desantis
中科院分区：
文献类型：
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作者：
Robert S. Feranec;L. Desantis
在古代生态系统中，通常很难从更高的营养水平确定物种的特定饮食，这反过来又阻碍了我们对这些系统的营养关系和能量流动的理解。为了更好地了解更高营养水平分类群的生态学，我们利用牙釉质稳定碳同位素值分析，推断了佛罗里达州两个更新世地区Leisey Shell Pit 1A （LSP 1A）和Inglis 1A的edwardii和Smilodon gracilis的饮食偏好。分析的目的是：(1)确定这些食肉动物是专门针对特定的猎物类型，还是维持广泛的饮食；(2)确定碳同位素值是否支持先前关于这些物种生态的建议；(3)通过高营养水平的碳同位素分析，确定古代食物网的生态细节。结果表明，食肉动物的碳同位素值分布在疑似猎物的碳同位素值中，表明在研究地点捕获了不同的猎物。利用稳定同位素分析（SIAR）对各食肉动物的猎物组成进行了建模。模拟的饮食表明，每一种被研究的食肉动物都有一个多面手的饮食；然而，这些分类群如何实现饮食的一般化存在差异。在英格利斯1A冰川地区，尽管这两种食肉动物都表现出对放牧猎物的偏好，但edwardii和S. gracilis的样本个体显示出相似的同位素值和模拟的膳食猎物比例。在这些物种之间观察到的相似的同位素值和计算出的猎物比例可能意味着更大的种间食物竞争。在间冰期LSP 1A位置，C. edwardii的值与Inglis 1A观测到的值相似。相比之下，细叶蝉的数据显示出对浏览猎物的偏好。此外，其有限的碳同位素值范围表明，薄叶蝉可能集中在一个特定的栖息地觅食。在较高营养水平的物种之间的稳定碳同位素值的检查表明，古代食物网的一些复杂性可以被识别。
Abstract Within ancient ecosystems, it is generally difficult to determine the specific diets of species from higher trophic levels, which in turn hinders our understanding of trophic relationships and energy flow through these systems. To better understand the ecology of taxa at higher trophic levels, we used analysis of tooth enamel stable carbon isotope values to infer the dietary preferences of Canis edwardii and Smilodon gracilis from the Leisey Shell Pit 1A (LSP 1A) and Inglis 1A, two Pleistocene localities in Florida. The goals of the analyses were to (1) determine whether these carnivorans specialized in particular prey types or maintained a generalist diet; (2) ascertain whether carbon isotope values support what was previously suggested about the ecology of these species; and (3) establish what ecological details of ancient food webs can be discovered by carbon isotope analyses at higher trophic levels. Results show that the sampled carnivoran carbon isotope values are distributed among suspected prey isotope values, suggesting that varied prey were taken at the study localities. Prey compositions were modeled for each carnivoran species by using Stable Isotope Analysis in R (SIAR). The modeled diets indicate that each studied carnivoran had a generalist diet; however, there are differences in how these taxa achieved dietary generalization. At the glacial Inglis 1A locality, sampled individuals of C. edwardii and S. gracilis show similar isotope values and modeled dietary prey proportions, although both carnivorans do show a preference for grazing prey species. The similar isotopic values, and calculated prey proportions, observed between these species may imply greater interspecific competition for food. At the interglacial LSP 1A locality, C. edwardii shows values similar to those observed at Inglis 1A. In contrast, the data for S. gracilis shows a preference for consuming browsing prey species. Further, its restricted range of carbon isotope values suggests that S. gracilis may have concentrated its feeding within a particular habitat. Examination of stable carbon isotope values among species at higher trophic levels reveals that some intricacies of ancient food webs can be discerned.