Abstract Mixed-species flocking is an important avian social system that supports a large number of species. Current reviews of threats to mixed flocks have only examined two types of anthropogenic pressures: different land use intensity and fragmentation. We highlight the bird trade as another major potential threat for many mixed-species flocking species in Southeast Asia. We examine the potential indirect impact of the bird trade by comparing social networks of flocking data collected over two periods nearly 20 years apart (1997 and 2016) from the same site in Sumatra, Indonesia. We find that the structure of the two networks was significantly correlated. However, of the 90 species observed, 49 had previously been identified as part of the bird trade. These species experienced a significantly greater decrease in network centrality over time compared to the non-traded species, resulting in a loss of structure in the mixed-species flocking network. Simulating further disturbances suggests that flocks may not be resilient to the complete loss of two or more traded species. Our results suggest that trapping is likely to be contributing to the degradation of flocks, and ultimately could lead to the widespread declines in those other species that also rely on mixed-species flocking.

中文翻译：

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鸣禽贸易对混种蜂群的潜在影响

摘要 混种混群是一种重要的鸟类社会系统，支持大量物种。当前对混合鸡群威胁的审查只研究了两种类型的人为压力：不同的土地利用强度和破碎化。我们强调鸟类贸易是东南亚许多混合物种植绒物种的另一个主要潜在威胁。我们通过比较从印度尼西亚苏门答腊岛的同一地点相隔近 20 年（1997 年和 2016 年）两个时期收集的蜂群数据的社交网络，研究了鸟类贸易的潜在间接影响。我们发现两个网络的结构显着相关。然而，在观察到的 90 种物种中，49 种之前已被确定为鸟类贸易的一部分。与非贸易物种相比，随着时间的推移，这些物种的网络中心性显着降低，导致混合物种植绒网络结构的丧失。模拟进一步的干扰表明，鸡群可能无法抵御两个或更多交易物种的完全丧失。我们的结果表明，诱捕可能会导致鸡群退化，并最终可能导致那些也依赖于混合物种植绒的其他物种的普遍减少。