Cornils Jessica S, Hoelzl Franz, Rotter Birgit, Bieber Claudia, Ruf Thomas
Department of Integrative Biology and Evolution, University of Veterinary Medicine, Savoyenstraße 1, 1160 Vienna, Austria.
Front Zool. 2017 Apr 20;14:23. doi: 10.1186/s12983-017-0206-0. eCollection 2017.
Numerous species, especially among rodents, are strongly affected by the availability of pulsed resources. The intermittent production of large seed crops in northern hemisphere tree species (e.g., beech ,oak , pine trees ) are prime examples of these resource pulses. Adult edible dormice are highly dependent on high energy seeds to maximize their reproductive output. For juvenile dormice the energy rich food is important to grow and fatten in a very short time period prior to hibernation. While these erratic, often large-scale synchronized mast events provide overabundant seed availability, a total lack of seed production can be observed in so-called mast failure years. We hypothesized that dormice either switch territories between mast and non-mast years, to maximize energy availability or select habitats in which alternative food sources are also available (e.g., fleshy fruits, cones). To analyze the habitat preferences of edible dormice we performed environmental niche factor analyses (ENFA) for 9 years of capture-recapture data.
As expected, the animals mainly used areas with high canopy closure and vertical stratification, probably to avoid predation. Surprisingly, we found that dormice avoided areas with high beech tree density, but in contrast preferred areas with a relatively high proportion of coniferous trees. Conifer cones and leaves can be an alternative food source for edible dormice and are less variable in availability.
Therefore, we conclude that edible dormice try to avoid areas with large fluctuations in food availability to be able to survive years without mast in their territory.
许多物种,尤其是啮齿动物,会受到脉冲式资源可利用性的强烈影响。北半球树种(如榉树、橡树、松树)间歇性产出的大量种子作物就是这些资源脉冲的典型例子。成年食用睡鼠高度依赖高能种子来最大化其繁殖产出。对于幼年睡鼠来说,富含能量的食物对于它们在冬眠前极短的时间内生长和长胖很重要。虽然这些不稳定的、通常大规模同步的种子大年事件提供了过量的种子,但在所谓的种子歉收年可以观察到完全没有种子产出的情况。我们假设睡鼠要么在种子大年和非种子大年之间切换领地,以最大化能量可利用性,要么选择也有其他食物来源(如肉质果实、球果)的栖息地。为了分析食用睡鼠的栖息地偏好,我们对9年的标记重捕数据进行了环境生态位因子分析(ENFA)。
正如预期的那样,这些动物主要利用树冠郁闭度高和有垂直分层的区域,可能是为了避免被捕食。令人惊讶的是,我们发现睡鼠避开了榉树密度高的区域,但相反,它们更喜欢针叶树比例相对较高的区域。针叶树的球果和叶子可以成为食用睡鼠的替代食物来源,并且其可利用性变化较小。
因此,我们得出结论,食用睡鼠试图避开食物可利用性波动大的区域,以便能够在领地内没有种子大年的年份生存下来。