The structure of mutualist interactions is still poorly understood in isolated remnants of montane forests. We tried to answer whether a plant–frugivore network from an isolated remnant could maintain its functional structure, despite the absence of certain species and traits. We hypothesized that a network of frugivore birds and plants from an isolated remnant would be less specialized and modular, and would show higher degree of nestedness than one from a continuous forest area. Functionally distinctive species in the networks were also identified based on analyses of the fourth-corner matrices, which cross plant and bird traits weighted by their interaction frequencies. The structure of studied networks showed a high similarity in which most interactions were performed by small generalist bird species on plant species carrying small unprotected fruits. Both networks showed similar levels of niche partitioning, although specialization and modularity increased in the isolated remnant network. Networks also showed a strong correlation between fruit weights and bird masses reflecting the functional distinctiveness of large frugivorous birds and plants with the heaviest fruits. Several large bird species were recorded in the studied networks although they contributed with a low percentage of interactions. Therefore, networks from isolated forest remnants seem resilient to the reduction of species richness due to the persistence of tolerant bird species and plant species carrying small fruits.

在山地森林的孤立残余中，人们对互惠互动的结构仍然知之甚少。我们试图回答，尽管缺乏某些物种和性状，但来自孤立的残余物的植物-草食动物网络是否可以维持其功能结构。我们假设，一个孤立的残余物组成的节食性鸟类和植物网络的专业性和模块化程度较低，并且与连续森林地区的相比，它们的嵌套度更高。根据第四角矩阵的分析，还确定了网络中功能上独特的物种，该矩阵通过植物和鸟类的性状交互作用频率加权。所研究网络的结构显示出高度相似性，其中大多数互动是由小型通才鸟类在携带小型未保护果实的植物物种上进行的。尽管隔离的剩余网络中的专业化和模块化程度有所提高，但两个网络都显示出类似的细分位置级别。网络还显示出果实重量与鸟类质量之间的密切相关性，反映出大型节食鸟类和具有最重果实的植物的功能独特性。在研究的网络中记录了几种大型鸟类，尽管它们的相互作用百分比较低。因此，由于耐受性鸟类和携带小果实的植物物种的持续存在，来自孤立的森林残余物的网络似乎可以抵抗物种丰富度的降低。尽管隔离的剩余网络中的专业化和模块化程度有所提高，但两个网络都显示出类似的细分位置级别。网络还显示出果实重量与鸟类质量之间的密切相关性，反映出大型节食鸟类和具有最重果实的植物的功能独特性。在研究的网络中记录了几种大型鸟类，尽管它们的相互作用百分比较低。因此，由于耐受性鸟类和携带小果实的植物物种的持续存在，来自孤立的森林残余物的网络似乎可以抵抗物种丰富度的降低。尽管隔离的剩余网络中的专业化和模块化程度有所提高，但两个网络都显示出类似的细分位置水平。网络还显示出果实重量与鸟类质量之间的密切相关性，反映出大型节食鸟类和具有最重果实的植物的功能独特性。在研究的网络中记录了几种大型鸟类，尽管它们的相互作用百分比较低。因此，由于耐受性鸟类和携带小果实的植物物种的持续存在，来自孤立的森林残余物的网络似乎可以抵抗物种丰富度的降低。网络还显示出果实重量与鸟类质量之间的强烈相关性，反映出大型节食鸟类和具有最重果实的植物的功能独特性。在研究的网络中记录了几种大型鸟类，尽管它们的相互作用百分比较低。因此，由于耐受性鸟类和携带小果实的植物物种的持续存在，来自孤立的森林残余物的网络似乎可以抵抗物种丰富度的下降。网络还显示出果实重量与鸟类质量之间的强烈相关性，反映出大型节食鸟类和具有最重果实的植物的功能独特性。在研究的网络中记录了几种大型鸟类，尽管它们的相互作用百分比较低。因此，由于耐受性鸟类和携带小果实的植物物种的持续存在，来自孤立的森林残余物的网络似乎可以抵抗物种丰富度的降低。