Krebs Charles J, Boonstra Rudy, Gilbert B Scott, Kenney Alice J, Boutin Stan
Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada.
Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada.
Integr Zool. 2019 Nov;14(6):528-541. doi: 10.1111/1749-4877.12397. Epub 2019 Oct 22.
Long-term monitoring is critical to determine the stability and sustainability of wildlife populations, and if change has occurred, why. We have followed population density changes in the small mammal community in the boreal forest of the southern Yukon for 46 years with density estimates by live trapping on 3-5 unmanipulated grids in spring and autumn. This community consists of 10 species and was responsible for 9% of the energy flow in the herbivore component of this ecosystem from 1986 to 1996, but this increased to 38% from 2003 to 2014. Small mammals, although small in size, are large in the transfer of energy from plants to predators and decomposers. Four species form the bulk of the biomass. There was a shift in the dominant species from the 1970s to the 2000s, with Myodes rutilus increasing in relative abundance by 22% and Peromyscus maniculatus decreasing by 22%. From 2007 to 2018, Myodes comprised 63% of the catch, Peromyscus 20%, and Microtus species 17%. Possible causes of these changes involve climate change, which is increasing primary production in this boreal forest, and an associated increase in the abundance of 3 rodent predators, marten (Martes americana), ermine (Mustela ermine) and coyotes (Canis latrans). Following and understanding these and potential future changes will require long-term monitoring studies on a large scale to measure metapopulation dynamics. The small mammal community in northern Canada is being affected by climate change and cannot remain stable. Changes will be critically dependent on food-web interactions that are species-specific.
长期监测对于确定野生动物种群的稳定性和可持续性至关重要，并且如果发生了变化，还要了解变化的原因。我们对育空地区南部北方森林中小型哺乳动物群落的种群密度变化进行了46年的跟踪，通过在春季和秋季对3至5个未受干扰的网格进行活体诱捕来估计密度。这个群落由10个物种组成，在1986年至1996年期间，该群落占该生态系统食草动物部分能量流动的9%，但在2003年至2014年期间这一比例增加到了38%。小型哺乳动物虽然体型小，但在能量从植物向捕食者和分解者的转移过程中却起着重要作用。有四个物种构成了生物量的主体。从20世纪70年代到21世纪初，优势物种发生了转变，红背䶄的相对丰度增加了22%，而白足鼠的相对丰度减少了22%。从2007年到2018年，红背䶄占捕获量的63%，白足鼠占20%，田鼠属物种占17%。这些变化的可能原因包括气候变化，气候变化正在增加这片北方森林的初级生产力，以及随之而来的三种啮齿动物捕食者——貂（美洲貂）、伶鼬（伶鼬）和郊狼（郊狼）数量的增加。跟踪和了解这些以及未来可能的变化将需要进行大规模的长期监测研究，以测量集合种群动态。加拿大北部的小型哺乳动物群落正受到气候变化的影响，无法保持稳定。变化将严重依赖于具有物种特异性的食物网相互作用。
