Download The changing tundra: causes and consequences

The changing tundra: causes and consequences
Jukka Käyhkö
Tim Horstkotte
Sonja Kivinen
Lauri Oksanen
et al.
Preserving arctic-alpine biota in a warmer climate
Abiotic changes
(temperature, snow,
freeze-thaw cycles ...)
Synthesis
Biotic changes
(vole dynamics, moth
dynamics, birch forest
structure & function, food
webs…)
Sámi culture and reindeer
herding practices
(ecology, economy, politics,…)
Social-ecological
system
Eight work packages
• WP1: Predation and the dynamics of arctic-alpine food webs
• WP2: Impact of vertebrate herbivory on tundra vegetation
• WP3: Impact of grazing on the dynamics of rare arctic-alpine plants
• WP4: Moth-reindeer-birch dynamics in northernmost Fennoscandia
• WP5: Large scale impacts of herbivory on vegetation
• WP7: Interaction between vegetation and climate
• WP6: Socio-economy of reindeer herding systems
• WP8: Abiotic processes, spatial information, synthesis and policy
recommendations
The changing tundra
Amplifying feedback
Reducing feedback
Undetermined feedback
Myers-Smith et al. (2011), Environ. Res. Lett. 6
Climate-animal-plant interaction of the tundra ecosystem
•
reduced snow cover period
•
prolonged vegetation period
Herbivory
Above-ground
Trampling
Faeces
Below-ground
Soil microbial community & activity
(mycorrhizae / bacteria)
Acceleration of
nutrient cycling
Change in plant community composition & function
How can the top down impact of herbivores prevent expansion of woody plants?
Top-down impact of summer grazing in the tundra - forest ecotone
Reindeer
Microtines
•
Tall shrubs ( > 30 cm), lichens
•
Dwarf shrubs ( < 30 cm), mosses
•
Largest effect in tundra
•
Largest effect in forest
Shrub expansion more pronounced when herbivores are excluded
reindeer can preserve open tundra by preventing the expansion of shrubs
Olofsson et al. (2009), Glob. Change. Biol. 15: 2681–2693
Wookey et al. (2009), Glob. Change. Biol. 15 : 1153–1172
Top-down impact of summer grazing in the tundra - forest ecotone
Open tundra stores more carbon than birch forest
•
Higher C-storage in tundra habitat than in birch habitat
Hartley et al. 2012. Nature Climate Change, DOI: 10.1038/NCLIMATE1575
Top-down impact of summer grazing in the tundra - forest ecotone
Geometrid moths
-
Dwarf shrub understory
Deschampsia flexuosa
+
Karlsen et al. (2013) Oecologia
Jepsen et al. (2013), Ecosystems 16: 561-575
Importance of birch forests
Oro-arctic tundra
Birch forest
Boreal forest
Photo: C. Olid Garcia
Map: Bernt Johansen, norut
Traditional grazing grounds at particular seasons
•
Spring: browsing on birch leaves
•
Early winter: digging for lichens at dry sites
Historical context of reindeer husbandry in Fennoscandia
Summer pastures
Spring / autumn pastures
Winter pastures
Year-round pastures
Importance of birch forests
Oro-arctic tundra
Birch forest
Boreal forest
Map: Bernt Johansen, norut
•
Aarseth (1989)
1852: Border closures between Norway and Finland-Russia
Traditional migration between coastal summer pastures to inland winter
pastures no longer possible
•
1889: Russia closes border to Sweden
Forced migration due to reduction in pasture availability
Norway
Finland
2 km
Melting season
Albedo
Long wave
radiation
Finland
Norway
•
Albedo on the Finnish side higher during melting period  lower solar energy absorption
•
Fractional snow cover larger on the Finnish side during the melting season
Cohen et al. (2013), Remote Sens. Environ. 135
Spring
Finland
Norway
Albedo diff = Albedo Fin − Albedo Nor
In tundra, heavy winter grazing by reindeer
removes terrestrial lichen mats
Day of the year
Cohen et al. (2013), Remote Sens. Environ. 135
Finland
may enhance growth of birch trees
Tommervik et al. (2009), For .Ecol. Manage. 257
Norway
What is the role of reindeer management in shaping these trajectories?
•
Herding societies accumulate knowledge of the environmental long term trajectories
(e.g. snow cover dynamics, vegetation dynamics…)
Source of resilience, when disturbances create difficult grazing conditions
or other challenges to herd management
What past and present reindeer management practices/policies are
relevant for pasture vegetation structure/composition (i.e. cultural landscape)?
Snow
Surface
Gaup Eira et al. (2012),
Bottom
Cold Reg Sci Tech
.
Transformations of ecosystems
Capacity of indigenous people and to adapt their culture and livelihoods?
contest the legal background and institutions that govern
reindeer husbandry in the Nordic countries
Inadequate, inconsistent policies regarding indigenous livelihoods in the region?
respecting rights existing since “time immemorial”,
e. g. trans-border reindeer husbandry?
Do the scales of environmental processes match with the scales of administrative
processes?
Is there enough “adaptive space” in the Nordic countries to reorganize the
institutional frameworks that govern reindeer husbandry in Sweden, Norway
and Finland?
Potentially: Sápmi could gain a more prominent role and position as a region
Lantto (2010), Citizenship Studies, 14: 543-556
Preserving arctic-alpine biota in a warmer climate
Sustaining the current tundra vegetation
mitigate climate change
maintaining the reindeer-dependent Sámi culture
a potential win-win situation?
Researchers:
• Lauri Oksanen, PI (University of Turku, Finland + Finnmark University College, Norway)
• Jukka Käyhkö (University of Turku, Finland )
• Lars Ericson (Umeå University, Sweden)
• Bruce C. Forbes (University of Lapland, Finland)
• Rolf Anker Ims (University of Tromsø, Norway)
• Bernt Johansen (NORUT-IT, Norway)
• Erkki Korpimäki (University of Turku, Finland)
• Annamari Markkola (University of Oulu, Finland)
• Pekka Niemelä (University of Turku, Finland)
• Tarja Oksanen (University of Turku, Finland)
• Johan Olofsson (Umeå University, Sweden)
• Jouni Pulliainen (Finnish Meteorological Institute, Finland)
• Juha Tuomi (University of Oulu, Finland)
• Tove Aagnes Utsi (Finnmark University College, Norway)
•
+ many more Post Docs & PhD students