Bonin Michaël, Dussault Christian, Taillon Joëlle, Lecomte Nicolas, Côté Steeve D
Caribou Ungava Centre d'études nordiques Université Laval Québec QC Canada.
Direction de l'expertise sur la faune terrestre, l'herpétofaune et l'avifaune Ministère des Forêts, de la Faune et des Parcs Québec QC Canada.
Ecol Evol. 2020 May 27;10(13):6664-6676. doi: 10.1002/ece3.6397. eCollection 2020 Jul.
Accurate estimates of animal diet composition are essential to untangle complex interactions in food webs. Biomarkers and molecular tools are increasingly used to estimate diet, sometimes alongside traditional dietary tracing methods. Yet only a few empirical studies have compared the outcomes and potential gains of using a combination of these methods, especially using free-ranging animals with distinct foraging preferences.We used stable isotopes, morphological, and molecular analyses to investigate the diet of free-ranging consumers with two distinct diet types, that is, carnivore and omnivore. By combining the three analytical methods to assess the diet of consumers during the same period, we aimed to identify the limits of each method and to assess the potential benefits of their combined use to derive diet estimates.Our results showed that the different methods led to a consistent diet description for carnivores, which have a relatively simple diet mixture, but their outcomes somewhat differed for omnivore, which have a more complex diet. Still, the combined use of morphological and molecular analyses enhanced the diversity of food sources detected compared to the use of a single method independently of diet types. Precision of diet estimates derived from stable isotope analyses was improved by the addition of priors obtained from morphological and molecular diet analyses of the same population.Although we used free-ranging animals without a known diet, our empirical testing of three of the most widely used methods of diet determination highlights the limits of relying over a single approach, especially in systems with few or no a priori information about the foraging habits of consumers. The choice of an appropriate approach of diet description should be a key step when planning dietary studies of free-ranging populations. We recommend using more than one dietary determination methods especially for species with complex diet mixtures.
准确估计动物的饮食组成对于理清食物网中的复杂相互作用至关重要。生物标志物和分子工具越来越多地用于估计饮食，有时会与传统的饮食追踪方法一起使用。然而，只有少数实证研究比较了使用这些方法组合的结果和潜在收益，特别是对具有不同觅食偏好的自由放养动物的研究。我们使用稳定同位素、形态学和分子分析来研究具有两种不同饮食类型（即食肉动物和杂食动物）的自由放养消费者的饮食。通过结合这三种分析方法来评估同一时期消费者的饮食，我们旨在确定每种方法的局限性，并评估其联合使用以得出饮食估计值的潜在益处。我们的结果表明，不同的方法对食肉动物的饮食描述是一致的，它们的饮食结构相对简单，但对杂食动物的结果有所不同，杂食动物的饮食更为复杂。尽管如此，与单独使用单一方法相比，形态学和分子分析的联合使用增加了检测到的食物来源的多样性，而与饮食类型无关。通过添加从同一群体的形态学和分子饮食分析中获得的先验信息，稳定同位素分析得出的饮食估计精度得到了提高。虽然我们使用的是饮食未知的自由放养动物，但我们对三种最广泛使用的饮食测定方法的实证测试突出了依赖单一方法的局限性，特别是在对消费者觅食习惯几乎没有或没有先验信息的系统中。在规划对自由放养种群的饮食研究时，选择合适的饮食描述方法应该是关键步骤。我们建议使用多种饮食测定方法，特别是对于饮食结构复杂的物种。
