Individual variation in disturbance vulnerability (i.e. the likelihood that disturbance negatively affects an individual's fitness) can affect how disturbance impacts animal populations, as even at low disturbance levels some individuals could be severely affected and die. Individual variation in vulnerability can arise due to different responses to disturbance. We propose a new hypothesis that even when individuals respond similarly to disturbance, time‐limited individuals are more at risk that their condition deteriorates since they have limited ability to extend their foraging time to compensate for disturbance. We investigate this ‘time‐limitation hypothesis' both empirically and mathematically by studying how individuals that differ in their average foraging time (presumably due to differences in foraging efficiency) are affected by disturbance. We used tracking data of 22 wintering Eurasian oystercatchers Haematopus ostralegus to compare time budgets between disturbed and undisturbed tidal periods. In three tidal periods with severe disturbance by transport airplanes, more than a third of the variation in additional flight time and foraging time loss was explained by individual differences. Inefficient individuals that foraged longer in undisturbed tidal periods experienced higher costs in disturbed tidal periods, since they lost more foraging time. We next used an analytical energy balance model to study how time‐limited individuals differed in their maximum disturbance thresholds. Both our theoretical model and empirical study suggest that inefficient individuals in a time‐limited environment may be unable to increase their foraging time to compensate for the effects of disturbance. Consequently, the magnitude of individual variation in time budgets strongly determines what proportion of the population is at risk that their condition deteriorates due to disturbance. Our hypothesis implies that, when assessing disturbance effects on a population, it is not only important to consider individual variation in disturbance responses, but also variation in time budgets that determine the consequences of disturbance.

中文翻译：

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为什么有时间限制的人会使人口更容易受到干扰

干扰脆弱性的个体差异（即干扰对个体适应能力产生负面影响的可能性）可能会影响干扰如何影响动物种群，因为即使在较低干扰水平下，也会严重影响某些个体并使其死亡。脆弱性的个体差异可能是由于对干扰的不同响应而引起的。我们提出了一个新的假设，即使当个体对干扰做出类似反应时，由于时间有限的人延长觅食时间以补偿干扰的能力也有限，因此其处境恶化的风险更大。我们研究了这种“时限假说” 通过研究平均觅食时间不同（大概是由于觅食效率不同）的个体如何受到干扰来从经验和数学上进行研究。我们使用了22个越冬的欧亚蛎cat的跟踪数据骨线虫比较受潮和不受潮的潮汐时间的时间预算。在三个由运输机严重干扰的潮汐时段，额外飞行时间和觅食时间损失的三分之一以上的变化是由个体差异所解释的。在低潮期觅食时间较长的低效率个体在受潮的潮汐期会付出更高的代价，因为他们损失了更多的觅食时间。接下来，我们使用分析型能量平衡模型来研究有时间限制的个体在最大干扰阈值方面的差异。我们的理论模型和实证研究都表明，在时间有限的环境中效率低下的个体可能无法增加觅食时间来补偿干扰的影响。所以，时间预算中个体差异的大小强烈决定着人口中有多少比例的人的生活状况因干扰而恶化。我们的假设意味着，在评估对人群的干扰影响时，不仅重要的是要考虑干扰响应中的个体差异，而且还要考虑确定干扰后果的时间预算中的差异。