Assessment of Biological and Environmental Phenology at a Landscape Level from 30 Years of Fixed-Date Repeat Photography in Northern Sweden
A 30-year series (1978–2007) of photographic records were analysed to determine changes in lake ice cover, local (low elevation) and montane (high elevation) snow cover and phenological stages of mountain birch (Betula pubescens ssp. czerepanovii) at the Abisko Scientific Research Station, Sweden. In most cases, the photographic-derived data showed no significant difference in phenophase score from manually observed field records from the same period, demonstrating the accuracy and potential of using weekly repeat photography as a quicker, cheaper and more adaptable tool to remotely study phenology in both biological and physical systems. Overall, increases in ambient temperatures coupled with decreases in winter ice and snow cover, and earlier occurrence of birch foliage, signal a reduction in the length of winter, a shift towards earlier springs and an increase in the length of available growing season in the Swedish sub-arctic.
KeywordsLake ice Phenophase Mountain birch Snow cover Swedish sub-arctic
This project was developed under the auspices of SCANNET (www.SCANNET.nu), through collaboration with the IPY ‘Back-to-the-future’ project and INTERACT (FP7 Infrastructure fund). The first author offers thanks to the Abisko Scientific Research Station for providing access to their photographic archives and phenological/meteorological data, and especially to Annika Kristoffersson for her technical assistance whilst in Abisko. Further thanks go to Nils Åke Andersson for providing translations and supporting information for birch phenological records, and to the Natural Environment Research Council for providing the travel grant to conduct this study.
- Aerts, R., J.H.C. Cornelissen, and E. Dorrepaal. 2006. Plant performance in a warmer world: General responses of plants from cold, northern biomes and the importance of winter and spring events. Plant Ecology 182: 65–77.Google Scholar
- Blenckner, T., M. Jarvinen, and G.A. Weyhenmeyer. 2004. Atmospheric circulation and its impact on ice phenology in Scandinavia. Boreal Environment Research 9: 371–380.Google Scholar
- Callaghan, T.V., F. Bergholm, T.R. Christensen, C. Jonasson, U. Kokfelt, and M. Johansson. 2010. A new climate era in the sub-Arctic: Accelerating climate changes and multiple impacts. Geophysical Research Letters 37.Google Scholar
- Callaghan, T.V., T.R. Christensen, and E.J. Jantze. 2011. Plant and vegetation dynamics on Disko Island, West Greenland: Snapshots separated by over 40 years. Ambio. doi: 10.1007/s13280-011-0169-x.
- Christiansen, H.H. 2001. Snow-cover depth, distribution and duration data from northeast Greenland obtained by continuous automatic digital photography. In Annals of Glaciology, ed. K. Hutter, vol. 32. Cambridge: International Glaciological Society.Google Scholar
- Kudo, G., U. Nordenhall, and U. Molau. 1999. Effects of snowmelt timing on leaf traits, leaf production, and shoot growth of alpine plants: Comparisons along a snowmelt gradient in Northern Sweden. Ecoscience 6: 439–450.Google Scholar
- Magurran, A.E., S.R. Baillie, S.T. Buckland, J. Dick, D.A. Elston, E.M. Scott, R.I. Smith, P.J. Somerfield, et al. 2010. Long-term datasets in biodiversity research and monitoring: Assessing change in ecological communities through time. Trends in Ecology & Evolution 25: 574–582.CrossRefGoogle Scholar
- Myking, T., and O.M. Heide. 1995. Dormancy releases and chilling requirements of buds of latitudinal ecotypes of Betula pendula and B. pubescens. Tree Physiology 15: 697–704.Google Scholar
- Partanen, J., and E. Beuker. 1999. Effects of photoperiod and thermal time on the growth rhythm of Pinus sylvestris seedlings. Scandinavian Journal of Forest Research 14: 487–497.Google Scholar
- Shutova, E., F.E. Wielgolaski, S.R. Karlsen, O. Makarova, N. Berlina, T. Filimonova, E. Haraldsson, P.E. Aspholm, et al. 2006. Growing seasons of Nordic mountain birch in northernmost Europe as indicated by long-term field studies and analyses of satellite images. International Journal of Biometeorology 51: 155–166.CrossRefGoogle Scholar
- Sokratov, S.A., and R.G. Barry. 2002. Intraseasonal variation in the thermoinsulation effect of snow cover on soil temperatures and energy balance. Journal of Geophysical Research-Atmospheres 107: 6.Google Scholar
- Tenow, O., H. Bylund, and B. Holmgren. 2001. Impact on mountain birch forests in the past and the future of outbreaks of two geometrid insects. In Nordic Mountain birch ecosystems, ed. F.E. Wielgolaski, New York: Parthenon Publishing.Google Scholar