The nutritional ecology of small mammals

我们研究了鹿鼠和田鼠的生活史在短暂的夏季环境中西南部的阿尔伯塔，在成熟的年龄往往延迟到一年的年龄，雏鸟的生存是可变的，成年人的生存率很高。这些人口容易受到干扰，因为更替率和从下降中恢复的速度很慢。新陈代谢率由环境温度决定，当温度接近零时，新陈代谢率接近最大可持续水平，将繁殖限制在短暂的夏季。在夏季，繁殖没有能量上的限制。我们的食物补充研究已经确定了对雏鸟生长、成熟和春季繁殖开始的营养限制，但对雏鸟或成虫存活没有影响。我们目前的研究调查了鹿、老鼠和田鼠对天然饮食质量变化的人口学反应。鹿鼠是杂食性动物（主要是种子和无脊椎动物，无脊椎动物代表高质量的饮食），毛发样本中氮的稳定同位素被用来确定其饮食质量的季节性和年度差异。田鼠大多是草食性和食谷性的，种子和绿色植被的适口性（以及植物物种的可用性）被用来确定其饮食质量的季节性和年度差异。我们未来的研究将特别集中在人口和人口的反应，小鼠和田鼠针叶树种子生产，植物次生化合物的生物化学，食物储存在改善不好吃的植物物种的质量中的作用，以及比较不同窝田鼠之间的饮食质量。

We study the life histories of deer mice and voles in short-summer environments in southwestern Alberta, where age at maturation is often delayed to one year of age, survival of nestlings is variable, and survival of adults is high. These populations are vulnerable to disturbance because turn-over rates and recovery from declines are slow. Rates of metabolism are dictated by ambient temperatures and approach maximum sustainable as temperatures approach zero, constraining reproduction to a short summer season. There are no energetic constraints on reproduction during the summer. Our food supplementation studies have identified nutritional constraints on nestling growth, maturation, and the initiation of breeding in the spring but no effect on nestling or adult survival. Our current research investigates the demographic responses of deer mice and voles to changes in the quality of natural diets. Deer mice are omnivorous (mostly seeds and invertebrates, with invertebrates representing a high quality diet) and stable isotopes of nitrogen in hair samples are being used to identify seasonal and annual differences in their diet quality. Voles are mostly herbivorous and granivorous and the palatability of seeds and green vegetation (and the availability of plant species) are being used to identify seasonal and annual differences in their diet quality. Our future research will focus specifically on demographic and population responses of mice and voles to conifer seed production, the biochemistry of plant secondary compounds, the role of food storage in improving the quality of unpalatable plant species, and a comparison of diet quality among voles with different litter sizes.