挪威旅鼠以其种群周期而知名,这种周期在其高峰时被认为会影响生态系统的其他构成部分。事实上,物理环境(气候也包括在内)在决定啮齿类周期动态中所起作用,在很大程度上仍然是一种猜测。
现在,通过将关于啮齿类密度、鸟类密度和对积雪状态的野外估计等的长期(1970-2007年)观测数据与气象数据结合起来所做的一项研究,研究人员获得了关于旅鼠周期的一幅更为清晰的画面。从该画面可以看出,旅鼠的周期存在一个显著的变化,从人们所熟悉的3-5年的啮齿类周期变为一种非周期性的、基本上为低幅度的状态,这种现象可由冬季气候的年际变化来解释和预测。关于气候对啮齿类动态的影响被传递到生态系统其他部分的假设,有非常可信的证据。(生物谷Bioon.com)
生物谷推荐原始出处:
Nature 456, 93-97 (6 November 2008) | doi:10.1038/nature07442
Linking climate change to lemming cycles
Kyrre L. Kausrud1, Atle Mysterud1, Harald Steen2,7, Jon Olav Vik1, Eivind ?stbye2, Bernard Cazelles3,4, Erik Framstad5, Anne Maria Eikeset1, Ivar Mysterud2, Torstein Solh?y6 & Nils Chr. Stenseth1
1 Centre for Ecological and Evolutionary Synthesis,
2 Department of Biology, University of Oslo, PO Box 1066 Blindern, N-0316 Oslo, Norway
3 CNRS UMR 7625, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris, France
4 IRD GEODES, 32 Avenue Henri Varagnat, 93142 Bondy cedex, France
5 Norwegian Institute for Nature Research, Gaustadalleen 21, N-0349 Oslo, Norway
6 Department of Biology, University of Bergen, Realfagbygget, Allegaten 41, N-5007 Bergen, Norway
7 Present address: Norwegian Polar Institute, N- 9296 Troms?, Norway.
The population cycles of rodents at northern latitudes have puzzled people for centuries1, 2, and their impact is manifest throughout the alpine ecosystem2, 3. Climate change is known to be able to drive animal population dynamics between stable and cyclic phases4, 5, and has been suggested to cause the recent changes in cyclic dynamics of rodents and their predators3, 6, 7, 8, 9. But although predator–rodent interactions are commonly argued to be the cause of the Fennoscandian rodent cycles1, 10, 11, 12, 13, the role of the environment in the modulation of such dynamics is often poorly understood in natural systems8, 9, 14. Hence, quantitative links between climate-driven processes and rodent dynamics have so far been lacking. Here we show that winter weather and snow conditions, together with density dependence in the net population growth rate, account for the observed population dynamics of the rodent community dominated by lemmings (Lemmus lemmus) in an alpine Norwegian core habitat between 1970 and 1997, and predict the observed absence of rodent peak years after 1994. These local rodent dynamics are coherent with alpine bird dynamics both locally and over all of southern Norway, consistent with the influence of large-scale fluctuations in winter conditions. The relationship between commonly available meteorological data and snow conditions indicates that changes in temperature and humidity, and thus conditions in the subnivean space, seem to markedly affect the dynamics of alpine rodents and their linked groups. The pattern of less regular rodent peaks, and corresponding changes in the overall dynamics of the alpine ecosystem, thus seems likely to prevail over a growing area under projected climate change.