Drivers – ecosystems
Results in stage one will be used for the design of stage two. Three to six locations will be selected based on cumulative driver pressure. We will analyze how driver pressure influences ecosystem condition and transitions.
Some examples of ecosystem states and properties relevant for TUNDRA:
Vegetation transitions are a natural part of ecosystem dynamics, and can take several directions, depending on the underlying ecosystem processes. Grazing-induced transitions from moss to graminoid dominated tundra have been documented where the intensity of grazing herbivores increases (e.g. Zimov 1995*, Van der Waal 2004**). On the other hand increasing temperature and precipitation in the Arctic have resulted in increased shrubbiness of typical tundra vegetation (e.g. ACIA 2004***, Sturm et al. 2001****), and movement of the treeline towards higher altitudes and latitudes (e.g. Tømmervik et al. 2004). Such ecosystem transitions may have consequences for the trophic structure and dynamics of the system, as the species composition of plants and animals change.
*Zimov, Sergey A., V. I. Chuprynin, A. P. Oreshko, F. S. Chapin III, J. F. Reynolds, M. C. Chapin. 1995. Steppe-Tundra Transition: A Herbivore-Driven Biome Shift at the end of the Pleistocene. American Naturalist, Vol. 14, No. 5, 765-794.
**Van der Wal, R., R. W. Brooker. 2004. Mosses mediate grazer impacts on grass abundance in arctic ecoystems. Functional Ecology Vol. 18, 77-86.
***Impacts of a Warming Arctic: Arctic Climate Impact Assessment. 2004. Cambridge University Press
****Sturm, M., C. Racine, K. Tape. 2001. Increasing shrub abundance in the Arctic. Nature, 411: 456-457
*****Tømmervik, H., B. Johansen, I. Tombre, D. Thannheiser, K. A. Høgda, E. Gaare, F. E. Wielgolaski. Vegetation Changes in the Nordic Mountain Birch Forest: The Influence of Grazing and Climate Change. Arctic, Antarctic and Alpine Research, Vol. 36, No. 3, 323-332.
Cyclic population fluctuations of small herbivores are essential for the integrity of many tundra food webs, and often in synchrony with specialized predators, such as the lemming – arctic fox relation (Elton 1924*). This integrity is threatened in some tundra ecosystems as the cyclicity flattens out and the frequency of population peak years decline (Ims and Fuglei 2005**). Hence, the degree of cyclicity of tundra herbivores can be used a an indicator of other properties in the same system.
*Elton C. 1924. Periodic fluctuation in the number of animals: Their causes and effects. British Journal of Experimental Biology 2: 119-163.
**Ims, Rolf A., E. Fuglei. 2005. Trophic Interaction Cycles in Tundra Ecosystems and the Impact of Climate Change. 2005. Bioscience Vol. 55, No. 4, 311-322.
Henttonen, H., H. Wallgren. 2001. Rodent dynamics and communities in the birch forest zone of northern Fennoscandia in Nordic Mountain Birch Ecosystems 2001. Ch 22, pp 262-278.
SEFALO; The Swedish, Finnish, Norwegian Arctic Fox Project
Primary productivity is and ecosystem property that strongly affects ecosystems and resource-dependent communities. Both climate change and economic development are factors that impact on primary productivity and large areas and time spans. Thus, monitoring these changes is important for understanding the implications for ecosystem management, ecosystem properties and ecosystem services.
Ecosystems – ecosystem services – resource dependency
The concept of ecosystem services is dualistic. Tundra people depend on ecosystems to fulfill a wide variety of needs, including local economic development and cultural identity. At the same time, these activities often contribute to ecosystem change. Resource dependency is at the core of this relationship because people who depend strongly on resources are more likely t be seriously affected by ecosystem change. The millennium ecosystem assessment divided services into four categories (see figure). We only focus on those services relevant to resource dependent communities. Resource dependency is often measured economically, and is related to the size and type of businesses. However, people are also socially dependent on resources through their i) attachment to an occupation, ii) employability in other sectors and iii) mobility and attachment to place and iv) family situation. The level of environmental dependency could also be influenced by the degree of specialization and time spent harvesting the resource.
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