Changing circumstances : implications for trophic dynamics and species conservation in the Fennoscandian tundra

• Main Author: Henden, John-André
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universitetet i Tromsø 2009
• Subjects: VDP::Matematikk og naturvitenskap: 400::Zoologiske og botaniske fag: 480; climate change; conservation; cyclic prey dynamics; intraguild competition; non-stationary small rodent dynamics; population synchrony; predator-prey dynamics; matrix model; stochasticity; stochastic growth rate; viability; Vulpes lagopus; VDP::Matematikk og naturvitenskap: 400::Zoologiske og botaniske fag: 480::Økologi: 488; VDP::Mathematics and natural science: 400::Zoology and botany: 480::Ecology: 488; Arctic; Arctic Fox; Climate change; Fennoscandian; Tundra
• Online Access: https://hdl.handle.net/10037/2585

Papers number 1,2 and 3 of the thesis are not available in Munin due to publishers' restrictions. 1.Rolf A. Ims, John-André Henden, Siw T. Killengreen.: "Collapsing population cycles." Trends in Ecology & Evolution; 23(2): 79-86 (Science Direct). Available at http://dx.doi.org/10.1016/j.tree.2007.10.010 2.John-André Henden, Rolf A. Ims, Nigel G. Yoccoz.: "Nonstationary spatio-temporal small rodent dynamics: evidence from long-term Norwegian fox bounty data." Journal of Animal Ecology; 78(3): 636-645 (Wiley). Available at http://dx.doi.org/10.1111/j.1365-2656.2008.01510.x 3.John-André Henden , Bård-Jørgen Bårdsen, Nigel G. Yoccoz, Rolf A. Ims.: " Impacts of differential prey dynamics on the potential recovery of endangered arctic fox populations." Journal of Applied Ecology Journal of Applied Ecology; 45(4): 1086-1093 (Wiley). Available at http://dx.doi.org/10.1111/j.1365-2664.2008.01515.x A special case of population fluctuation is multi-annual population cycles. While such population cycles exist in several ecosystems, they are more prominent in northern (e.g.tundra) ecosystems, especially among key stone herbivore species. These herbivores providean important ecosystem function in the sense of pulsed flows of resources (i.e. for predators) and disturbances (i.e. for vegetation) throughout the ecosystem. However, the circumstances on the tundra are changing. For instance, large scale collapse of population cycles of many herbivors has been reported, as well as northward expansion of novel predators (e.g. red fox). These changes, heavily connected to climate changes, are capable of disrupting the function and structure of such systems. Overall this thesis aims to outline and evaluate the recent dramatic changes in multi-annual population cycles of many herbivores and the possible implications of such changes on the trophic dynamics and species conservation in the Fennoscandinavian tundra ecosystem. First I show that the recent collapse of multi-annual population cyclles are now a widespread phenomenon, ...