The nutritional ecology of small mammals

我们研究了阿尔伯塔西南部短夏环境中的鹿鼠和田鼠的生活史，在那里成熟的年龄通常延迟到一岁，雏鸟的存活率是可变的，成年鼠的存活率很高。这些种群很容易受到干扰，因为更替率和从衰退中恢复的速度很慢。新陈代谢率受环境温度的影响，当温度接近零度时，新陈代谢率达到最大可持续性，这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营养对雏鸟生长、成熟和春季开始繁殖的限制，但对雏鸟或成鸟的存活没有影响。我们目前的研究调查了鹿鼠和田鼠对自然饮食质量变化的人口统计学反应。鹿鼠是杂食性动物（主要是种子和无脊椎动物，无脊椎动物代表着高质量的饮食），头发样本中氮的稳定同位素被用来确定它们饮食质量的季节性和年度差异。田鼠主要是食草和食草动物，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。我们未来的研究重点将集中在小鼠和田鼠对针叶树种子生产的人口统计学和种群反应，植物次生化合物的生物化学，食物储存在改善不美味植物物种质量中的作用，以及不同产仔数田鼠饮食质量的比较。

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.