Data for: Determinants of resource use in lizard assemblages from the Neotropical semiarid Caatinga

Non-sessile animals could partition the use of resources in different axes, reducing the effects of competition and allowing coexistence. Here, we investigated the spatial and trophic niche dimensions in four lizard assemblages in the Neotropical semiarid Caatinga to investigate the determinants of resource use and the extent which lizards partition their niches. We sampled each lizard assemblage once, for ten days, in the dry season of 2017 and 2018. In two lizard assemblages, we detected non-random niche overlap patterns that were higher or lower than expected by chance. The high niche overlap patterns suggests that either there is intense current competition for available microhabitats or an abundance of microhabitats. The lower niche overlap may be influenced by the presence of species adapted to sandy habitats (psamophilous), suggesting that spatial partitioning detected has historical basis, which is supported by the pPCA results and by the lack of patterns in the realized niche distribution of species across niche space. We detected trophic niche partitioning in three lizard assemblages. In one assemblage, we discovered random spatial and trophic niche overlap patterns, revealing that competition is not a determining factor in the structure of that assemblage. In fact, phylogenetic effects were predominantly the main determinants of resource use in the four studied lizard assemblages. Arid and semiarid habitats cover about one third of land surface of the world. Comparisons between our findings and those from other regions of the world may aid identify general trends in the lizard ecology of dry environments.

非固着动物可通过不同维度对资源进行分化利用，以此缓解种间竞争效应并实现物种共存。本研究以新热带半干旱卡廷加（Caatinga）生物群系中的4个蜥蜴类群为研究对象，对其空间生态位与营养生态位维度展开调查，旨在探明资源利用的决定因素，以及蜥蜴实现生态位分化的程度。我们于2017年与2018年的旱季对每个蜥蜴类群进行了单次为期10天的采样。在其中2个蜥蜴类群中，我们检测到了非随机的生态位重叠模式，其重叠程度高于或低于随机预期水平。高生态位重叠模式表明，当前要么存在针对可用微生境的激烈种间竞争，要么是微生境资源极为丰富。较低的生态位重叠则可能受到嗜沙性（psamophilous）物种（即适应沙质生境的物种）存在的影响，这表明本次检测到的空间生态位分化具有历史演化基础，这一结论得到了系统发育主成分分析（phylogenetic Principal Components Analysis，pPCA）结果的支持，同时也契合了物种在生态位空间中实际生态位分布无明显模式的现象。我们在3个蜥蜴类群中检测到了营养生态位分化现象。在剩余1个蜥蜴类群中，我们发现其空间与营养生态位重叠均呈随机模式，这表明竞争并非该类群群落结构的决定性因素。实际上，在本次研究的4个蜥蜴类群中，系统发育效应均为资源利用模式的主要决定因素。干旱与半干旱生境约占全球陆地总面积的三分之一。将本研究结果与全球其他区域的相关研究结果进行对比，有助于探明干旱环境下蜥蜴生态学的通用规律。