Quantitative fatty acid signature analysis: A new method of estimating predator diets
Quantitative fatty acid signature analysis: A new method of estimating predator diets
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DOI：
10.1890/02-4105
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发表时间：
2004-05-01
影响因子：
6.1
通讯作者：
Blanchard, W
中科院分区：
文献类型：
--
作者：
Iverson, SJ;Field, C;Blanchard, W
生态学的许多领域都需要对捕食者的饮食进行准确估计，但对于许多物种来说，目前的方法并不精确，仅限于最后一餐，而且常常有偏差。脂肪酸的多样性及其在生物体中的模式，加上其生物合成的狭窄限制、单胃动物的消化特性以及许多捕食者体内普遍存在的大量脂质储存库；促使我们建议使用定量脂肪酸特征分析（QFASA）来研究捕食者的饮食。我们提出了一个统计模型，利用脂肪酸特征对个体捕食者饮食中猎物的比例进行定量估计。我们使用 28 个数据库进行了模拟研究；我们使用来自加拿大东部斯科舍大陆架的猎物物种（n = 954 个体）来研究模型的特性并评估模型中区分猎物的可靠性。然后我们进行了实验。灰海豹（Halichoerus grypus，n = 25）和竖琴海豹（Phoca groenlandica，n = 5）评估脂肪酸沉积的定量特征，并开发单个脂肪酸的校准系数以解释捕食者的脂质代谢。然后，我们通过估计其饮食来测试模型和校准系数。实验喂养圈养灰海豹（n = 6，从鲱鱼改为鲭鱼/毛鳞鱼饮食）和水貂套件（Mustela vison，n = 46，从牛奶改为三种补充油饮食之一）。如果使用适当的校准系数，所有实验喂养动物的饮食通常都使用 QFASA 进行了很好的估计，并且与定性和定量预期一致。在最后一个案例中，我们比较了配备 Crittercams 的个体自由放养斑海豹（Phoca vitulina，n = 23）的觅食视频数据，以及 QFASA 使用复杂的生态系统猎物数据库对这些海豹饮食的估计。在数据库中的 28 个猎物物种中，QFASA 估计鳐鱼是所有海豹饮食中的主要猎物物种（平均占饮食的 62%），其次是比目鱼，但也有毛鳞鱼和少量其他物种，尽管海豹之间也存在相当大的个体差异。这些估计与视频数据一致，显示沙枪是主要猎物，其次是比目鱼。我们得出的结论是，QFASA 在与影响生存的生态过程相关的时间尺度上提供了个体饮食的估计，并且可用于研究个体随时间的饮食变化，这将提供其他间接方法很少可能实现的重要机会。我们建议我们提出的 QFASA 模型将适用于广泛的捕食者和生态系统。
Accurate estimates of the diets of predators are required in many areas of ecology, but for many species current methods are imprecise, limited to the last meal, and often biased. The diversity of fatty acids and their patterns in organisms, coupled with the narrow limitations on their biosynthesis, properties of digestion in monogastric animals, and the prevalence of large storage reservoirs of lipid in many predators; led us to propose the use of quantitative fatty acid signature analysis (QFASA) to study predator diets. We present a statistical model that provides quantitative estimates of the proportions of prey specie's in the diets of individual predators using fatty acid signatures. We conducted simulation studies using a database of 28; prey species (n = 954 individuals) from the Scotian Shelf off eastern Canada to investigate properties of the model and to evaluate the reliability with which prey could be distinguished in the model. We then conducted experiments on. grey seals (Halichoerus grypus, n = 25) and harp seals (Phoca groenlandica, n = 5) to assess quantitative characteristics of fatty acid deposition and to develop calibration coefficients for individual fatty acids to account for predator lipid metabolism, We then tested the model and calibration coefficients by estimating the diets of. experimentally fed captive grey seals (n = 6, switched from herring to a mackerel/capelin diet) and mink kits (Mustela vison, n = 46, switched from milk to one of three oil-supplemented diets). The diets of all experimentally fed animals were generally well estimated using QFASA and were consistent with qualitative and quantitative expectations, provided that appropriate calibration coefficients were used. In a final case, we compared video data of foraging by individual free-ranging harbor seals (Phoca vitulina, n = 23) fitted with Crittercams and QFASA estimates of the diet of those same seals using a complex ecosystem-wide prey database. Among the 28 prey species in the database, QFASA estimated sandlance to be the dominant prey species in the diet of all seals (averaging 62% of diet), followed primarily by flounders, but also capelin and minor amounts of other species, although there was also considerable individual variability among seals. These estimates were consistent with video data showing sandlance to be the predominant prey, followed by flatfish. We conclude that QFASA provides estimates of diets for individuals at time scales that are relevant to the ecological.. processes affecting survival, and can be used to study diet variability within individuals over time, which will provide important opportunities rarely possible with other indirect methods. We propose that the QFASA model we have set forth will be applicable to a wide range of predators and ecosystems.