Sentíes-Aguilar Eugenia M, Martén-Rodríguez Silvana, Huerta-Ramos Guillermo, Díaz-Infante Sergio, López-Segoviano Gabriel, Aguirre-Jaimes Armando, Quesada-Avendaño Mauricio, Cortés-Flores Jorge, Arizmendi María Del Coro
Laboratorio Nacional de Análisis y Síntesis Ecológica, Escuela Nacional de Estudios Superiores Universidad Nacional Autónoma de México (UNAM) Morelia Michoacán Mexico.
Posgrado en Ciencias Biológicas Universidad Nacional Autónoma de México Morelia Michoacán Mexico.
Ecol Evol. 2024 Oct 24;14(10):e70469. doi: 10.1002/ece3.70469. eCollection 2024 Oct.
Tropical mountain ecosystems harbor diverse biological communities, making them valuable models for exploring the factors that shape ecological interactions along environmental gradients. We investigated the spatial and temporal drivers of plant-hummingbird interaction networks across three forest types (pine-oak, fir, and subalpine) along a tropical high mountain gradient in western Mexico (2400 to 3700 m.a.s.l.). We measured species abundance, diversity, morphology, and interaction frequencies. Plant diversity metrics significantly declined in the highest elevation subalpine forest, whereas hummingbird diversity remained consistent across elevations. Interaction networks were similarly nested across elevations, but they were more specialized in the subalpine forest, where lower plant species richness and higher floral abundance led to greater resource partitioning among hummingbirds. Plant-hummingbird networks were larger and less specialized during the dry season, driven by greater species diversity and abundance. Species turnover explained network variation along the elevational gradient, while interaction rewiring and the arrival of migratory hummingbirds explained changes between seasons. Phenological overlap was the most important driver of the observed variation in interaction frequencies across elevations and seasons. Flower abundance had a minor influence on interaction frequencies at low- and mid-elevation networks, and hummingbird abundance was significant for dry- and rainy-season networks. Morphological matching was significant in the low-elevation forest and in the dry season. Plant phylogenetic relatedness had negligible effects on interaction patterns, but hummingbird phylogeny influenced feeding preferences in high-elevation and rainy-season networks. Our findings highlight the role of species turnover, interaction rewiring, and phenological overlap in structuring plant-hummingbird networks, with specific effects of abundance, morphology, and phylogeny varying with elevation and season. High-elevation ecosystems play a crucial role as reservoirs of floral resources for both resident and migratory hummingbirds during resource-scarce periods, emphasizing their importance in maintaining biodiversity in tropical mountain gradients.
热带山地生态系统拥有多样的生物群落，使其成为探索沿环境梯度塑造生态相互作用的因素的宝贵模型。我们沿着墨西哥西部的热带高山梯度（海拔2400至3700米），研究了三种森林类型（松栎林、冷杉林和亚高山林）中植物与蜂鸟相互作用网络的时空驱动因素。我们测量了物种丰富度、多样性、形态以及相互作用频率。植物多样性指标在海拔最高的亚高山森林中显著下降，而蜂鸟多样性在各海拔间保持一致。相互作用网络在各海拔间同样呈嵌套状，但在亚高山森林中更为特化，那里较低的植物物种丰富度和较高的花卉丰度导致蜂鸟之间的资源分配更为精细。植物 - 蜂鸟网络在旱季更大且特化程度更低，这是由更高的物种多样性和丰度驱动的。物种更替解释了沿海拔梯度的网络变化，而相互作用的重新连接以及迁徙蜂鸟的到来解释了季节间的变化。物候重叠是观察到的各海拔和季节间相互作用频率变化的最重要驱动因素。花卉丰度对低海拔和中海拔网络的相互作用频率影响较小，而蜂鸟丰度对旱季和雨季网络有显著影响。形态匹配在低海拔森林和旱季中显著。植物系统发育相关性对相互作用模式的影响可忽略不计，但蜂鸟系统发育影响了高海拔和雨季网络中的取食偏好。我们的研究结果强调了物种更替、相互作用重新连接和物候重叠在构建植物 - 蜂鸟网络中的作用，丰度、形态和系统发育的具体影响随海拔和季节而变化。在资源稀缺时期，高海拔生态系统作为留居和迁徙蜂鸟的花卉资源库发挥着关键作用，凸显了它们在维持热带山地梯度生物多样性方面的重要性。
