ZoBell Vanessa M, Furnas Brett J
Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, CA, United States of America.
Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, United States of America.
PeerJ. 2017 Sep 15;5:e3761. doi: 10.7717/peerj.3761. eCollection 2017.
Oceanic islands are among the most endemically biodiverse ecosystems in the world. They have been adversely impacted by human expansion, which affects regional biodiversity by altering the natural habitats of vulnerable, indigenous species. Birds represent a valuable indicator species of environmental change due to their ability to adapt quickly. Investigating the relationship between environmental change, abundance, and behaviors of birds can help us better anticipate potential impacts to island ecosystems. In addition, we can understand the population trends and restricted ranges of native avifauna, identify the regions needing protection, and assess habitat vulnerability linked to anthropogenic activities. In Mo'orea, French Polynesia, we studied nine passerine bird species using automated acoustic recording devices placed in agricultural, forested, and mixed habitats. Based on call counts per unit time and occupancy modeling, we found evidence that three non-native species preferred agricultural areas and low-canopy cover over dense forested areas. Furthermore, native bird detectability and possibly abundance was significantly lower than non-native birds. Using hierarchical cluster analysis to support inferences regarding behavioral differences, we found that native bird calling activity was negatively associated with non-native bird calling activity. Altogether, these results suggest native bird populations are at risk in all of the habitats studied, but forests serve as a potential refuge.
海洋岛屿是世界上特有生物多样性最为丰富的生态系统之一。它们受到人类扩张的不利影响，人类扩张通过改变脆弱的本土物种的自然栖息地来影响区域生物多样性。鸟类由于其快速适应的能力，是环境变化的重要指示物种。研究环境变化、鸟类数量和行为之间的关系有助于我们更好地预测对岛屿生态系统的潜在影响。此外，我们可以了解本地鸟类的种群趋势和分布范围限制，确定需要保护的区域，并评估与人为活动相关的栖息地脆弱性。在法属波利尼西亚的莫雷阿岛，我们使用放置在农业、森林和混合栖息地的自动声学记录设备研究了九种雀形目鸟类。基于单位时间内的叫声计数和占有率模型，我们发现有证据表明三种非本土物种更喜欢农业区域和低树冠覆盖区域，而不是茂密的森林区域。此外，本土鸟类的可探测性以及可能的数量明显低于非本土鸟类。使用层次聚类分析来支持关于行为差异的推断，我们发现本土鸟类的鸣叫活动与非本土鸟类的鸣叫活动呈负相关。总之，这些结果表明在所研究的所有栖息地中，本土鸟类种群都面临风险，但森林可能是一个潜在的避难所。
