Marques Thiago S, Lara Neliton R F, Bassetti Luis A B, Piña Carlos I, Camargo Plínio B, Verdade Luciano M
a Laboratório de Ecologia Isotópica, Centro de Energia Nuclear na Agricultura , Universidade de São Paulo , Piracicaba , Brazil.
Isotopes Environ Health Stud. 2013;49(3):325-35. doi: 10.1080/10256016.2013.835309.
Strategies to minimise intraspecific competition are common in wild animals. For example, individuals may exploit food resources at different levels of the food chain. Analyses of stable isotopes are particularly useful for confirming variations in an intraspecific niche because the chemical composition of animals tends to reflect both the food consumed and the habitats occupied by the species. However, studies using this methodology to investigate neotropical crocodilians are scarce. This study aimed to verify the existence of ontogenetic and sexual niche variation in broad-snouted caiman in a silvicultural landscape in Brazil through the use of carbon and nitrogen stable isotopes. The isotopic ratios of carbon and nitrogen were determined in claw samples collected from 24 juveniles, 8 adults, and 16 hatchlings of C. latirostris. We identified a discrete ontogenetic variation in the isotopic niche and sexual difference only for juveniles. These results may indicate differences in the exploitation resources and a consequent reduction in competition between age classes.
在野生动物中，将种内竞争降至最低的策略很常见。例如，个体可能会利用食物链不同层次的食物资源。稳定同位素分析对于确认种内生态位的变化特别有用，因为动物的化学成分往往既反映了所消耗的食物，也反映了该物种所占据的栖息地。然而，利用这种方法研究新热带区鳄鱼的研究很少。本研究旨在通过使用碳和氮稳定同位素，验证巴西一个造林景观中宽吻凯门鳄的个体发育和性别生态位变异的存在。从24只宽吻凯门鳄幼体、8只成体和16只幼鳄采集的爪样本中测定了碳和氮的同位素比率。我们仅在幼体中发现了同位素生态位的离散个体发育变异和性别差异。这些结果可能表明在资源利用上存在差异，从而减少了不同年龄组之间的竞争。
