Data from: Forest structure provides the income for reproductive success in a southern population of Canada lynx

Understanding intrinsic and extrinsic drivers of reproductive success is central to advancing animal ecology and characterizing critical habitat. Unfortunately, much of the work examining drivers of reproductive success is biased toward particular groups of organisms (e.g., colonial birds, large herbivores, capital breeders). Long-lived mammalian carnivores that are of conservation concern, solitary, and territorial present an excellent situation to examine intrinsic and extrinsic drivers of reproductive success, yet they have received little attention. Here, we used a Canada lynx (Lynx canadensis) dataset, from the southern periphery of their range, to determine if reproductive success in a solitary carnivore was consistent with capital or income breeding. We radio-marked and monitored 36 female Canada lynx for 98 lynx years. We evaluated how maternal characteristics and indices of food supply (via forest structure) in core areas influenced variation in body condition and reproductive success. We characterized body condition as mass/length and reproductive success as whether a female produced a litter of kittens for a given breeding season. Consistent with life-history theory, we documented a positive effect of maternal age on body condition and reproductive success. In contrast to predictions of capital breeding, we observed no effect of pre-pregnancy body condition on reproductive success in Canada lynx. However, we demonstrated statistical effects of forest structure on reproductive success in Canada lynx, consistent with predictions of income breeding. The forest characteristics that defined high success included (1) abundant and connected mature forest and (2) intermediate amounts of small-diameter regenerating forest. These attributes are consistent with providing abundant, temporally stable, and accessible prey resources (i.e., snowshoe hares; Lepus americanus) for lynx and reinforce the bottom-up mechanisms influencing Canada lynx populations. Collectively, our results suggest that lynx on the southern range periphery exhibit an income breeding strategy and that forest structure supplies the income important for successful reproduction. More broadly, our insights advance the understanding of carnivore ecology and serve as an important example on integrating long-term field studies with ecological theory to advance landscape management.探究繁殖成功率的内在与外在驱动因子，是推动动物生态学研究发展、精准表征关键栖息地的核心任务。然而当前绝大多数针对繁殖成功率驱动因子的研究，均偏向于特定生物类群（例如集群鸟类、大型草食动物、资本繁育者（capital breeders））。作为受保育关注的长寿食肉目哺乳动物，独居且具有领地性的类群本是探究繁殖成功率内在与外在驱动因子的理想研究对象，但相关研究却极为匮乏。本研究依托分布范围南部边缘的加拿大猞猁（Lynx canadensis）数据集，旨在探究独居肉食动物的繁殖策略是否符合资本繁育或收入繁育（income breeding）模式。我们对36只雌性加拿大猞猁进行了无线电标记与追踪监测，累计监测时长达98个猞猁年。我们评估了母本特征以及核心区域内基于森林结构表征的食物供应指数，对体况与繁殖成功率变异的调控作用。我们将体况定义为体重与体长的比值，将繁殖成功率定义为雌性在特定繁殖季是否产下一窝幼崽。与生活史理论（life-history theory）的预期一致，我们观测到母本年龄对体况与繁殖成功率具有显著正向影响。与资本繁育的理论预测相悖，我们未观察到孕前体况对加拿大猞猁繁殖成功率的影响。但我们证实，森林结构对加拿大猞猁的繁殖成功率具有统计学显著性影响，这与收入繁育的理论预测相符。与高繁殖成功率相关的森林特征包括：（1）丰富且连通的成熟林，以及（2）中等占比的小径级更新林。这些特征可为猞猁提供充足、时空稳定且易于获取的猎物资源（即雪兔（Lepus americanus）），验证了调控加拿大猞猁种群的自下而上调控机制。综上，本研究结果表明，栖息于其分布范围南部边缘的猞猁采取收入繁育策略，而森林结构为其成功繁殖提供了关键的资源支撑。从更广泛的层面来看，本研究增进了我们对肉食动物生态学的理解，同时也为整合长期野外研究与生态学理论以推进景观管理提供了重要范例。