Schreier Amy L, Voss Kristofor A, Bolt Laura M
Department of Biology, Regis University, 3333 Regis Blvd. D-8, Denver, CO, 80221, USA.
The Maderas Rainforest Conservancy, PO Box 55-7519, Miami, FL, USA.
Primates. 2022 Nov;63(6):659-670. doi: 10.1007/s10329-022-01012-1. Epub 2022 Aug 19.
Fragmented forests contain natural edges, including riparian zones, and anthropogenic edges. Edges generally have lower plant density and fewer large trees than forest interior. Riparian edges, however, contain gap-specialist trees yielding leaves with high protein content, providing primates with important resources. We examined mantled howler monkeys' behavioral responses to riparian and anthropogenic edges at La Suerte Biological Research Station (LSBRS), Costa Rica. We predicted the monkeys would spend more time resting and feeding and less time traveling, and be less spatially cohesive, in both anthropogenic and riparian edges compared to forest interior due to lower resource abundance in edges, and in anthropogenic compared to riparian edge due to higher leaf quality in riparian zones. From 2017 to 2020, we collected data across forest zones on activity and spatial cohesion patterns via focal sampling, recording data every 2 min. Howler monkeys were significantly more likely to rest and significantly less likely to travel in both anthropogenic and riparian edges compared to forest interior; however, there were no differences between these edge types. There were significantly more monkeys within a 5-m radius of focal subjects in both anthropogenic and riparian edges compared to forest interior, but no differences between these edge types. While prior research found no differences across zones when only anthropogenic edge and forest interior were compared, results of this study demonstrate that howler monkeys at LSBRS modify their activity patterns in anthropogenic and riparian edge zones compared to forest interior, highlighting the importance of focusing on both natural and anthropogenic edge zones to fully understand primates' behavioral responses in fragmented landscapes.
破碎化森林包含自然边缘，包括河岸带，以及人为边缘。边缘地带的植物密度通常低于森林内部，大树数量也较少。然而，河岸边缘生长着适应林窗环境的树木，其树叶蛋白质含量高，为灵长类动物提供了重要资源。我们在哥斯达黎加的拉苏埃拉生物研究站（LSBRS）研究了鬃毛吼猴对河岸边缘和人为边缘的行为反应。我们预测，由于边缘地带资源丰富度较低，与森林内部相比，吼猴在人为边缘和河岸边缘会花更多时间休息和觅食，花更少时间移动，并且空间凝聚力更低；又因为河岸带树叶质量更高，与河岸边缘相比，吼猴在人为边缘的上述行为表现会更明显。从2017年到2020年，我们通过焦点取样法收集了不同森林区域的活动和空间凝聚力模式数据，每2分钟记录一次。与森林内部相比，吼猴在人为边缘和河岸边缘显著更倾向于休息，显著更少移动；然而，这两种边缘类型之间没有差异。与森林内部相比，在人为边缘和河岸边缘，距离焦点个体5米半径范围内的猴子数量显著更多，但这两种边缘类型之间没有差异。虽然之前的研究发现，仅比较人为边缘和森林内部时，不同区域之间没有差异，但本研究结果表明，与森林内部相比，LSBRS的吼猴在人为边缘和河岸边缘区域会改变其活动模式，这突出了关注自然和人为边缘区域对于全面理解灵长类动物在破碎化景观中行为反应的重要性。
