Rivers represent natural edges in forests, serving as transition zones between landscapes. Natural edge effects are important to study to understand how intrinsic habitat variations affect wildlife as well as the impact of human‐induced forest fragmentation. We examined the influence of riparian and anthropogenic edge on mantled howler, white‐faced capuchin, Central American spider monkeys, and vegetation structure at La Suerte Biological Research Station (abbreviated as LSBRS), Costa Rica. We predicted lower monkey encounter rate, tree species richness, and median dbh at both edge types compared to interior and that monkeys would show species‐specific responses to edge based on size and diet. We expected large, folivorous–frugivorous howler monkeys and small, generalist capuchins would be found at increased density in forest edge, while large, frugivorous spider monkeys would be found at decreased density in forest edge. We conducted population and vegetation surveys along interior, riparian, and anthropogenic edge transects at LSBRS and used GLMM to compare vegetation and monkey encounter rate. Tree species richness and median dbh were higher in forest interior than anthropogenic edge zones. Although spider monkey encounter rate did not vary between forest edges and interior, howler monkeys were encountered at highest density in riparian edge, while capuchins were encountered at highest density in anthropogenic edge. Our results indicate that diverse forest edges have varying effects on biota. Vegetation was negatively affected by forest edges, while monkey species showed species‐specific edge preferences. Our findings suggest that riparian zones should be prioritized for conservation in Neotropical forests.

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在河边向下：河岸边缘对零星的哥斯达黎加森林中的三种猴子物种的影响

河流代表森林中的自然边缘，是景观之间的过渡地带。研究自然边缘效应对于了解内在栖息地的变化如何影响野生生物以及人为森林破碎化的影响非常重要。我们在哥斯达黎加的La Suerte生物研究站（简称LSBRS）研究了河岸带和人为边缘对man叫，白面卷尾猴，中美洲蜘蛛猴和植被结构的影响。我们预测，与内部相比，两种边缘类型的猴子的遭遇率，树木物种丰富度和中位数dbh较低，并且猴子会根据大小和饮食对边缘表现出特定物种的反应。我们预计会在森林边缘发现密度较高的大型，食叶食肉性and叫猴子和小型通用卷尾猴，而大型，在森林边缘发现食肉性蜘蛛猴的密度降低。我们在LSBRS沿内部，河岸和人为边缘断面进行了人口和植被调查，并使用GLMM比较了植被和猴子的遭遇率。森林内部的树木物种丰富度和中位数dbh高于人为边缘区域。尽管蜘蛛猴的遭遇率在森林边缘和内部之间没有变化，但在河岸边缘以最高密度遇到how猴，而在人为边缘以高密度遇到卷尾猴。我们的结果表明，不同的森林边缘对生物区系具有不同的影响。植被受到森林边缘的负面影响，而猴子物种则表现出特定物种的边缘偏好。