Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, Mexico.
Red de Interacciones Multitróficas, Instituto de Ecología, A.C., Xalapa, Veracruz, Mexico.
PLoS One. 2015 Mar 31;10(3):e0121275. doi: 10.1371/journal.pone.0121275. eCollection 2015.
Despite increasing knowledge about the effects of habitat loss on pollinators in natural landscapes, information is very limited regarding the underlying mechanisms of forest fragmentation affecting plant-pollinator interactions in such landscapes. Here, we used a network approach to describe the effects of forest fragmentation on the patterns of interactions involving the understory dominant palm Astrocaryum mexicanum (Arecaceae) and its floral visitors (including both effective and non-effective pollinators) at the individual level in a Mexican tropical rainforest landscape. Specifically, we asked: (i) Does fragment size affect the structure of individual-based plant-pollinator networks? (ii) Does the core of highly interacting visitor species change along the fragmentation size gradient? (iii) Does forest fragment size influence the abundance of effective pollinators of A. mexicanum? We found that fragment size did not affect the topological structure of the individual-based palm-pollinator network. Furthermore, while the composition of peripheral non-effective pollinators changed depending on fragment size, effective core generalist species of pollinators remained stable. We also observed that both abundance and variance of effective pollinators of male and female flowers of A. mexicanum increased with forest fragment size. These findings indicate that the presence of effective pollinators in the core of all forest fragments could keep the network structure stable along the gradient of forest fragmentation. In addition, pollination of A. mexicanum could be more effective in larger fragments, since the greater abundance of pollinators in these fragments may increase the amount of pollen and diversity of pollen donors between flowers of individual plants. Given the prevalence of fragmentation in tropical ecosystems, our results indicate that the current patterns of land use will have consequences on the underlying mechanisms of pollination in remnant forests.
尽管人们对自然景观中栖息地丧失对传粉者的影响有了更多的了解，但关于森林破碎化影响此类景观中植物-传粉者相互作用的潜在机制的信息却非常有限。在这里，我们使用网络方法来描述森林破碎化对个体水平下墨西哥热带雨林景观中底层优势棕榈树 Astrocaryum mexicanum（棕榈科）及其花访客（包括有效和非有效传粉者）相互作用模式的影响。具体来说，我们提出了以下三个问题：（i）碎片大小会影响基于个体的植物-传粉者网络的结构吗？（ii）高度相互作用的访客物种核心是否会随着破碎化大小梯度而变化？（iii）森林碎片大小会影响 A. mexicanum 的有效传粉者的丰度吗？我们发现，碎片大小不会影响基于个体的棕榈-传粉者网络的拓扑结构。此外，虽然外围非有效传粉者的组成随碎片大小而变化，但有效核心的一般传粉者物种保持稳定。我们还观察到，A. mexicanum 雌雄花的有效传粉者的丰度和方差都随森林碎片大小的增加而增加。这些发现表明，在所有森林碎片的核心中存在有效传粉者，可以使网络结构在森林破碎化梯度上保持稳定。此外，由于这些碎片中传粉者的丰度增加，可能会增加花粉量和个体植物花朵之间花粉供体的多样性，因此 A. mexicanum 的传粉可能在较大的碎片中更有效。鉴于热带生态系统中普遍存在的破碎化，我们的研究结果表明，目前的土地利用模式将对残余森林中授粉的潜在机制产生影响。
