Red de Ecoetología, Instituto de Ecología A.C. Xalapa, Veracruz, Mexico.
Centro de Investigaciones Biológicas, Instituto de Ciencias Básicas E Ingeniería, Universidad Autónoma del Estado de Hidalgo, Pachuca, Hidalgo, Mexico.
Oecologia. 2020 Aug;193(4):913-924. doi: 10.1007/s00442-020-04727-4. Epub 2020 Aug 9.
In semi-arid environments, the marked contrast in temperature and precipitation over the year strongly shapes ecological communities. The composition of species and their ecological interactions within a community may vary greatly over time. Although intra-annual variations are often studied, empirical information on how plant-bird relationships are structured within and among years, and how their drivers may change over time are still limited. In this study, we analyzed the temporal dynamics of the structure of plant-hummingbird interaction networks by evaluating changes in species richness, diversity of interactions, modularity, network specialization, nestedness, and β-diversity of interactions throughout four years in a Mexican xeric shrubland landscape. We also evaluated if the relative importance of abundance, phenology, morphology, and nectar sugar content consistently explains the frequency of pairwise interactions between plants and hummingbirds across different years. We found that species richness, diversity of interactions, nestedness, and network specialization did vary within and among years. We also observed that the β-diversity of interactions was high among years and was mostly associated with species turnover (i.e., changes in species composition), with a minor contribution of interaction rewiring (i.e., shifting partner species at different times). Finally, the temporal co-occurrence of hummingbird and plant species among months was the best predictor of the frequency of pairwise interactions, and this pattern was consistent within and among years. Our study underscores the importance of considering the temporal scale to understand how changes in species phenologies, and the resulting temporal co-occurrences influence the structure of interaction networks.
在半干旱环境中，一年中温度和降水的显著差异强烈塑造了生态群落。一个群落中物种的组成及其生态相互作用可能会随时间发生很大变化。尽管已经研究了年内变化，但关于植物-鸟类关系在年内和年际间如何构建以及其驱动因素如何随时间变化的经验信息仍然有限。在这项研究中，我们通过评估物种丰富度、相互作用多样性、模块性、网络专业化、嵌套性和相互作用β多样性在四年内的变化，分析了植物-蜂鸟相互作用网络结构的时间动态。我们还评估了丰度、物候、形态和花蜜糖含量的相对重要性是否一致地解释了植物和蜂鸟之间在不同年份的成对相互作用的频率。我们发现，物种丰富度、相互作用多样性、嵌套性和网络专业化在年内和年际间都有变化。我们还观察到，相互作用的β多样性在年际间较高，主要与物种更替（即物种组成的变化）有关，而与相互作用重新布线（即在不同时间转移伴侣物种）的关系较小。最后，蜂鸟和植物物种在不同月份的时间共现是预测成对相互作用频率的最佳指标，而且这种模式在年内和年际间都是一致的。我们的研究强调了考虑时间尺度的重要性，以了解物种物候变化以及由此产生的时间共现如何影响相互作用网络的结构。
