a) Research objectives and background
Global warming will likely transform Siberian environments. Early evidence indicates that water and carbon cycles are undergoing rapid change (Ohta et al., 2008; Iijima et al., 2010), with potentially grave impact on Siberian flora and fauna. Human inhabitants, who have adapted to great changes in social structure and environment in the past (Nakada, 2012; Yoshida, 2012), will be forced to adapt again, but to a cascading series of environmental changes whose dimensions are understood only in outline. Local inhabitants depend on agriculture, stockbreeding and on fragile transport, building and water infrastructure. Human survival skills and adaptive capacity to environmental changes depend on unique social structures, history and culture, which have undergone Russian socialistic modernization.
Regional climate in Siberia are based on energy and water exchanges and thus on changes in surface reflectance of snow, ice and vegetation coverage. Such changes should be monitored continuously as long as possible. The Lena River Basin in Eastern Siberia is covered in larch forest but receives little precipitation (Ohta et al., 2001; 2008). The area is an ideal setting in which to study the effects of climate warming, as the forest-permafrost symbiosis (Zhang et al., 2011) is extremely susceptible to abnormal variations in temperature and precipitation.
We have started monitoring of energy and water exchanges between larch forest and the atmosphere since 1998 at Yakutsk, middle part of the Lena River Basin in Eastern Siberia (Ohta et al., 2001). This monitoring revealed that the region suffered from extraordinary high precipitation in late-summer through winter from 2005 to 2008 (Hiyama et al., 2013). This resulted in not only permafrost degradation (Iijima et al., 2010), but also changes in terrestrial ecosystems and hydrological elements in the region (Shiklomanov and Lammers, 2009; Brutsaert and Hiyama, 2012; Zhang et al., 2013).

 

b) Research methods and organization
This research project takes natural and social science perspectives on three aspects of climate-associated environmental change. It is designed to: 1) describe current variation in water and carbon cycles and predict likely variation in the near future; 2) make field observations of the effect of carbon and hydrologic variability in Eastern Siberian landscapes, and identify key exchanges or driving forces; and 3) examine the capability of the multi-ethnic Siberian peoples, and their distinct social economies, to adapt to predicted change in their climate and terrestrial ecosystems. Three research groups are organized (Fig. 1) in order to realize these goals. They are the Siberia bird’s-eye group (Group 1), the Water cycle and ecosystem interaction group (Group 2), and the Human ecology group (Group 3). This project is jointly conducted by Japanese and Russian universities and research institutes.

Two interdisciplinary research achievements, which are foci from FR3 to FR5, are as follows.

 

1) Adaptations of local residents living along the Lena River to seasonal river floods
    Arctic sea ice extent in summer, especially in the Eurasian continent side, has been decreasing partly owing to global warming. As a result, cyclones have been frequently appeared in summer over the region. Such cyclones easily propagate to Siberia (Zhang et al., 2013), and they derive plenty of precipitation in the region. Meteorological data revealed summer precipitation around upper and middle parts of the Lena River Basin became drastically high from 2005 to 2008 as well as in 2012. Consequently around Yakutsk, capital city of the Sakha Republic of the Russian Federation, summer river floods appeared and they derived severe damages to local farmers and cattle-horse pastoralism.
    On the contrary, the Lena River derives spring ice breaking floods every year. Theoretically the spring ice breaking floods become severe in case former winter temperature was low and current spring temperature rise is very gradually. In such case, spring floods derive severe damages to local residents living along the Lena River.
    Using archival sources, remotely sensed data, and numerical simulations, we revealed decadal (and/or historical) changes in spring- and summer-river floods of the Lena River.We found that local residents were damaged from spring ice breaking floods almost every year after 1998. We also investigated local people's perceptions as well as local government's adaptation strategies for such spring- and summer-river floods. Interestingly spring floods have been recognized as benefits except in case they severely damaged to the villages along the Lena River (Takakura, 2013). This is because spring floods derive nutrient rich water to the river sandbanks, on which the farmers cultivate pastures for cattle-horse pastoralism. While on the contrary, in case summer river floods appear, it has been recognized as hazards. This is because it submerges the pasture completely for a long duration in summer, and it made impossible to get hay for cattle-horse.

    We additionally found that increased floods disrupt cold-weather transport via ordinarily frozen rivers and warm-weather transport over land. As result we note that local communities locating very far from the capital city (Yakutsk) are increasingly remote and difficult to access. Consequently, disaster vulnerability has increased in such region and thus their adaptation become more difficult.
    Therefore, migrations of villages were applied as one of the adaptation strategies to prevent spring river floods and the remoteness. Because local peoples prefer to live along the river to do their subsistence activities, those peoples and the government agreed to apply seasonal migrations.
On the other hand, both local peoples and the government have no adaptation ways for the summer river floods.We therefore propose development of information transmission (communications) on river flood (to prevent spring river floods) as well as improvement of distribution network of hay (to adapt summer river floods) as suitable adaptation strategies for their sustainable cattle-horse subsistence activities along the Lena River.

 

2) Adaptations of keepers and/or hunters of reindeers to social-environmental changes
    Interviews with keepers of domestic reindeer revealed that current climate change has not severely damaged their operations. It appears that so far they have been able to successfully adapt to changes in climate, especially in Eastern Siberia. This related to resilient use of microhabitat of the domesticated reindeers around the camping sites. While on the contrary, they were severely impacted by social changes following the collapse of the former Soviet Union. The keepers do not feel air temperature rise (warming) but do feel (remember) heavy rainfall and/or flood events as recent climate change. They fear waterlogging in lower land, especially around flooding plain of small rivers. Additionally, the keepers pointed out increase of carnivore (such like) wolf around their camping sites. They also said recent climate changes affect degradation of reindeer moss in winter, so that birth-rate and weight of reindeers tend to decline.
    We also tracked and documented the migration routes and seasonal behaviours of wild reindeers. In this project, we successively tracked routes of wild reindeers using an ARGOS satellite system. MODIS satellite showed that reindeer have moved along rivers and through zones of better vegetation conditions, while avoiding increasingly common forest fires. Migration distance was very similar to those documented in North America and North Europe. Seasonal behaviours in Siberian wild reindeers were also similar to those in North America and North Europe. The seasonal behaviours are classified into summer breeding season, winter hibernating season, and other migration seasons.
    System dynamics (SD) model was applied in order to diagnose and propose adaptation strategies for keepers of domestic reindeers and/or hunters of wild reindeers to social-environmental changes. In order to keep wild reindeer population, it is better to establish sanctuary in winter hibernating place. And in order to protect reindeer keeping, as one of the very important subsistence activities in Siberia, governmental subsidies should be provided to the keepers of reindeers and to hunters of carnivore.

 

3) Summary
    Human - nature interaction owing to climate change (climate warming and waterlogging) as well as social change (economy-orientation and collapse of the former Soviet Union) has been successfully described. It shows reindeer-related subsistence activities and river flood impacts to the local residents. Adaptation strategies are proposed for both issues.

 Future research issues in this project are to co-design and to co-produce next new trans-disciplinary results with local residents as well as the governments.