Within a population of apex predators, differences among individuals can influence both their ecological impact and their vulnerability to threatening processes. Our field studies on a large monitor lizard (Varanus panoptes) in the Australian wet–dry tropics show that diets shift seasonally and depend upon a lizard’s sex and body size. Individuals that had previously been recorded to consume frogs were most at risk following biological invasion by toxic cane toads (Rhinella marina), as were individuals with broad diets during the wet season. As a result, mortality of those individual predators likely reduced predation pressure on other taxa (invertebrates and reptiles) that were frequently consumed by the same lizards that ate frogs, but with less benefit for taxa (e.g., rodents) that were consumed by non‐anuran‐eating individuals within the predator population. In particular, individuals killed by cane toads often had consumed agamid lizards, a group whose abundance has been reported to increase due to toad‐induced mortality of V. panoptes. To understand the vulnerability of apex predators, or the ecological consequences of their extirpation, we need to incorporate the role of variation among individuals in critical ecological traits.

中文翻译：

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饮食特征在人口内部的变化：对脆弱的基石捕食者的脆弱性和影响的影响

在先头天敌的种群中，个体之间的差异会影响他们的生态影响和对威胁过程的脆弱性。我们在澳大利亚干湿热带地区对大型监控蜥蜴（Varanus panoptes）进行的野外研究表明，饮食会季节性变化，并取决于蜥蜴的性别和体型。在被有毒的甘蔗蟾蜍生物入侵之后，先前被记录为食用青蛙的个体受到的威胁最大（Rhinella marina），以及在雨季饮食丰富的人。结果，这些个体捕食者的死亡可能减轻了其他与食用青蛙的蜥蜴共同食用的其他类群（无脊椎动物和爬行动物）的捕食压力，但对非食用类群食用的类群（例如啮齿类动物）的收益较小。捕食者群体中的厌食个体。尤其是，被甘蔗蟾蜍杀死的人经常食用蜥蜴蜥蜴，据报道，蜥蜴蜥蜴的种群数量由于蟾蜍诱导的弧菌死亡而增加。为了了解先头天敌的脆弱性或他们灭绝的生态后果，我们需要将个体间的变异作用纳入重要的生态特征中。