Data from: Experimental evidence of human recreational disturbance effects on bird-territory establishment

The worldwide increase in human outdoor activities raises concerns for wildlife. Human disturbances, even at low levels, are likely to impact species during sensitive periods of the annual cycle. However, experimental studies during the putative sensitive period of territory establishment of birds which not only investigate low disturbance levels, but which also exclude the effect of habitat modification (e.g. walking trails) are lacking. Here, we experimentally disturbed birds in forest plots by walking through twice a day during territory establishment. Later we compared the breeding bird community of experimentally disturbed plots with that of undisturbed control plots. We discovered that the number of territories (−15.0%) and species richness (−15.2%) in disturbed plots were substantially reduced compared with control plots. Species most affected included those sensitive to human presence (assessed by flight-initiation distances), open-cup nesters and above-ground foragers. Long-distance migrants, however, were unaffected due to their arrival after experimental disturbance took place. These findings highlight how territory establishment is a sensitive period for birds, when even low levels of human recreation may be perceived as threatening, and alter settlement decisions. This can have important implications for the conservation of species, which might go unnoticed when focusing only on already established birds.

全球人类户外活动规模的持续增长，引发了野生动物保护领域的广泛担忧。即便是低强度的人类干扰，也有可能在鸟类年度生活周期的敏感阶段对其种群产生影响。然而，目前尚缺乏针对鸟类领地建立这一推定敏感阶段、同时排除栖息地改造（如步行步道）影响的低强度人类干扰实验研究。本研究于森林样地中开展实验：在鸟类领地建立期内，每日往返穿行两次以对鸟类施加干扰。后续将受实验干扰样地与未受干扰的对照样地的繁殖鸟类群落进行对比分析。研究结果显示，相较于对照样地，受干扰样地的领地数量（下降15.0%）与物种丰富度（下降15.2%）均出现显著下降。受影响最为显著的类群包括对人类活动敏感的物种（通过起飞距离（flight-initiation distances）进行评估）、开放式杯状筑巢鸟类以及地面以上觅食者。但长距离迁徙鸟类未受影响，因其抵达时间晚于实验干扰实施阶段。上述研究结果表明，领地建立期是鸟类的关键敏感阶段：即便低强度的人类休闲活动也可能被鸟类视作威胁，并改变其定居决策。这一结论对物种保护工作具有重要启示：若仅关注已完成定居的鸟类，这类干扰带来的影响可能被忽视。