Continuous exposure to humans causes wildlife to either habituate or sensitize. Although increased tolerance may play an important role in coexistence with humans, the mechanisms and fitness outcomes of long-term changes of tolerance are not fully understood because only a few studies have assessed individual- and population-level responses over many years. We developed a novel predictive framework to study habituation and sensitization to humans and applied it to yellow-bellied marmots (Marmota flaviventer) in areas of high and low human disturbance. We focused on two antipredator behaviors—time allocation to vigilance during foraging to quantify baseline vigilance levels and flight initiation distance (FID)—to quantify subsequent responsiveness to threat. We used the rate of body mass gain during the active season as a fitness outcome. Assessing 15 years’ population and individual-level responses to human disturbances, marmots in highly disturbed colonies allocated more time to vigilance, but this did not change over time. FID decreased on average when they were approached more and also tended to decrease in highly disturbed colonies and over 15 years. Yet, there was individuality in FIDs; marmots that fled at greater distances became sensitized with repeated approaches. Additionally, the marmots in highly disturbed colonies gained less body mass over time compared to conspecifics in less disturbed colonies. These results suggested that, although marmots habituated to humans, long-term human disturbance has negative fitness consequences. Our framework should help wildlife managers evaluate the comprehensive impact of human activities on wildlife.

中文翻译：

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习惯化还是敏感化？黄腹土拨鼠对人类干扰的长期反应

持续接触人类会导致野生动物习惯化或敏感化。尽管增加的耐受性可能在与人类共存中发挥重要作用，但耐受性长期变化的机制和健康结果尚不完全清楚，因为多年来只有少数研究评估了个体和群体水平的反应。我们开发了一种新的预测框架来研究人类的习惯化和敏感性，并将其应用于人类干扰高和低的地区的黄腹旱獭（Marmota flaviventer）。我们专注于两种反捕食者行为——觅食期间的警戒时间分配，以量化基线警戒水平和飞行起始距离（FID）——以量化随后对威胁的响应。我们使用活跃季节的体重增加率作为健身结果。评估 15 年来人口和个体对人类干扰的反应，在高度干扰的群体中的土拨鼠分配了更多的时间来保持警惕，但这并没有随着时间的推移而改变。当它们被更多地接近时，FID 平均下降，并且在高度干扰的菌落中和超过 15 年时也趋于下降。然而，FID 有个性。在更远距离逃跑的土拨鼠因反复接近而变得敏感。此外，与受干扰较少的群体中的同种动物相比，高度受干扰的群体中的土拨鼠随着时间的推移获得较少的体重。这些结果表明，虽然土拨鼠习惯于人类，但长期的人类干扰会对健康产生负面影响。我们的框架应该帮助野生动物管理者评估人类活动对野生动物的综合影响。