Departamento de Ecología y Biodiversidad, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile.
Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
Sci Rep. 2019 Nov 4;9(1):15934. doi: 10.1038/s41598-019-52395-z.
Intertidal communities' composition and diversity usually exhibit strong changes in relation to environmental gradients at different biogeographical scales. This study represents the first comprehensive diversity and composition description of polyplacophoran assemblages along the Peruvian Province (SE Pacific, 12°S-39°S), as a model system for ecological latitudinal gradients. A total of 4,775 chitons from 21 species were collected on twelve localities along the Peruvian Province. This sampling allowed us to quantitatively estimate the relative abundance of the species in this assemblage, and to test whether chitons conform to elementary predictions of major biogeographic patterns such as a latitudinal diversity gradient. We found that the species composition supported the division of the province into three ecoregional faunal groups (i.e. Humboldtian, Central Chile, and Araucanian). Though chiton diversity did not follow a clear latitudinal gradient, changes in species composition were dominated by smaller scale variability in salinity and temperature. Body size significantly differed by ecoregions and species, indicating latitudinal size-structure assamblages. In some localities body size ratios differed from a random assemblage, evidencing competition at local scale. Changes in composition between ecoregions influence body size structure, and their overlapping produce vertical size segregation, suggesting that competition coupled with environmental conditions structure these assemblages.
潮间带生物群落的组成和多样性通常与不同生物地理尺度的环境梯度密切相关。本研究代表了对沿秘鲁省（东南太平洋，12°S-39°S）的多板类动物群进行的首次综合多样性和组成描述，作为生态纬度梯度的模型系统。总共从 12 个地点采集了 4,775 个多板类动物，来自 21 个物种。这种采样方法使我们能够定量估计该组合中物种的相对丰度，并检验多板类动物是否符合主要生物地理格局的基本预测，例如纬度多样性梯度。我们发现，物种组成支持将该省划分为三个生态区动物群（即洪堡、智利中部和Araucanian）。尽管多板类动物的多样性没有明显的纬度梯度，但物种组成的变化主要受盐度和温度等较小规模的可变性控制。体型在很大程度上因生态区和物种而异，表明存在纬度体型结构组合。在一些地方，体型比例与随机组合不同，表明在局部尺度上存在竞争。生态区之间的组成变化影响体型结构，它们的重叠产生垂直体型隔离，表明竞争与环境条件共同构成了这些组合。
