Body size and lean mass of brown bears across and within four diverse ecosystems
Body size and lean mass of brown bears across and within four diverse ecosystems
复制标题
DOI：
10.1111/jzo.12536
复制
发表时间：
2018-05-01
影响因子：
2
通讯作者：
Cambier, T.
中科院分区：
文献类型：
--
作者：
Hilderbrand, G. V.;Gustine, D. D.;Cambier, T.
棕熊（Ursus arctos）种群的体型差异主要是营养资源的可用性和质量的函数，而种群内的可塑性反映了利用的生态位宽度和种群弹性的含义。我们评估了阿拉斯加四个研究区域的成年雌性和雄性棕熊的头骨大小、体长和瘦体重，这些研究区域在气候、主要食物资源、人口密度和收获制度方面存在差异。在8-14岁时，所有人群和性别都达到了完整的身体框架尺寸，这一点可以通过颅骨大小和体长的渐近来证明。男性和女性的瘦体重在他们的一生中都在持续增加。种群间在所有形态指标上均存在差异，在鲑鱼丰富的生态系统中，熊一般体型较大。在所有人群中，成年人的体型差异很大，女性的瘦体重大约相差2倍，而男性的瘦体重相差3到4倍。种群间和种群内的高水平种内变异表明存在多种生活史策略和与资源分配、风险耐受或厌恶以及竞争相关的生态位变异。此外，这种水平的变异表明在给定的生态系统和物种范围内适应变化的广泛潜力。
Variation in body size across populations of brown bears (Ursus arctos) is largely a function of the availability and quality of nutritional resources while plasticity within populations reflects utilized niche width with implications for population resiliency. We assessed skull size, body length, and lean mass of adult female and male brown bears in four Alaskan study areas that differed in climate, primary food resources, population density, and harvest regime. Full body-frame size, as evidenced by asymptotic skull size and body length, was achieved by 8-14years of age across populations and sexes. Lean body mass of both sexes continued to increase throughout their life. Differences between populations existed for all morphological measures in both sexes, bears in ecosystems with abundant salmon were generally larger. Within all populations, broad variation was seen in body size measures of adults with females displaying roughly a 2-fold difference in lean mass and males showing a 3- to 4-fold difference. The high level of intraspecific variation seen across and within populations suggests the presence of multiple life-history strategies and niche variation relative to resource partitioning, risk tolerance or aversion, and competition. Furthermore, this level of variation indicates broad potential to adapt to changes within a given ecosystem and across the species' range.