The NoAClim project explores how Scandinavian forests might respond to climate change.
Scandinavia supports many different ecosystems, ranging from arctic and alpine tundra in the far north and at high elevations, to rich deciduous forests of oak, elm, lime, and beech in the south. The vast boreal forests of pine, spruce and birch that cover much of central and northern Scandinavia are, with their associated forestry and forest-based industries, one of the most important land-based economic sectors, providing much income and employment through activities such as industry, bioenergy and tourism.
Forests are not static like other ecosystems. They vary in space and time in response to environmental changes. This long-term temporal variation has been elucidated by detailed studies of pollen grains preserved in lake sediments or peats. These natural archives, if carefully sampled in the field and analysed in the laboratory, show the changing abundances of different pollen types (e.g. birch, oak, pine, grasses and heather) with depth, thereby providing a record of ‘vegetation’s fourth dimension’ over time.
Over 300 pollen studies in Scandinavia demonstrate major changes in the distribution, composition and extent of forest trees, primarily in response to climate changes at millennial or centennial scales after the last glaciation (ca. 11,700 years ago) and, in the last 4,000-5,000 years, to changes in human impact, land use and soil. Few major terrestrial ecosystems in Scandinavia (or elsewhere) have existed for more than 10,000 years and most are considerably younger, some developing only within the last few centuries. Future ecosystems are inevitably uncertain and historically contingent. Given the richness of ecosystem responses in the last 11,700 years, many future responses, outcomes and surprises are possible.
More questions than answers
A key question for future forest management, and hence adaptation strategies, is what will happen to Scandinavia’s extensive forests under future climate change? Will some tree species be lost due to an inability to cope with or adapt to a particular climate? Which forest systems will increase or decrease? Which regions will lose or gain forest cover? In planning for future conservation and management of these economically valuable resources, such questions are critical and obvious – so why have they not been addressed before?
As our American colleagues Jack Williams (Madison, Wisconsin, USA) and Steve Jackson (Tucson, Arizona, USA) have asked, how do you study an ecosystem no ecologist has ever seen? This is an extremely critical question for scientists trying to reconstruct or predict ecosystem responses in times beyond modern ecological observations. Pollen analysts (palaeoecologists) look to the past and global-change ecologists look to the future, but both rely solely on our understanding of modern ecosystems and ecological processes as a basis for reconstruction and prediction.
Palaeoecologists apply the concept that “the present is the key to the past” whereas global-change ecologists project this forward and use “the present is the key to the future”. But the present is only one ‘time slice’ in the past 11,700 years since the last ice age. Are today’s ecosystems and climate representative of tree and ecosystem-climate relationships under past or future climate change? Are they robust to climate conditions beyond modern states?
To address the questions above, we need information on:
- Estimates of past, present, and future climate at the appropriate spatial scale for Scandinavia, derived from computer-based simulation models of regional climate;
- Quantitative measures of how similar (analogous) past and future climates are to the modern climate;
- Pollen-analytical data from Scandinavia about the past composition and extent of Scandinavia’s forests and quantitative measures of how analogous these past pollen assemblages are to modern pollen assemblages;
- Numerical estimates of key environmental parameters (so-called ‘realised niches’) of major tree pollen types today and at different times in the past 11,700 years to test the assumption that ecological responses have not changed over time;
- Predictions using these tree parameters and future climate forecasts of the distribution and abundances of major Scandinavian trees and forest ecosystems in 100-250 years’ time; and
- Predictions, other independent scientific data, and expert knowledge for robust scenario-planning for Scandinavian forests in the future to provide an informed basis for management and adaptation strategies.
NoAClim
The Norwegian Research Council-funded NoAClim (No-analogue climates and ecological responses in the past and future) project co-ordinated by John Birks at the Ecological and Environmental Change Research Group, Department of Biology, University of Bergen, is currently compiling the information needed to answer these key questions about Scandinavian forest responses in the past and the future. It is a three-year project that started on 1 January 2014, running until 31 December 2016, with an extension for Birks and PA Cathy Jenks to 31 December 2018. The major research players in NoAClim are Joe Chipperfield (postdoc fellow in Bergen), Paul Valdes (climate-model simulations, University of Bristol), Anne Bjune (pollen-analytical data, Bergen), and Jack Williams (climate and statistical advice, Madison), along with collaborators in Helsinki (Finland), Göttingen (Germany), Oxford (UK) and Bergen (Norway).
One of the novel features of the NoAClim research approach is an implicit consideration of the many uncertainties inherent in the various data sources – pollen counts, datings, climate-model simulations, spatial patterns of sites, and interpolation and down-scaling procedures. Using state-of-the-art Bayesian modelling approaches, Joe Chipperfield mainly concentrates on estimating realised niches and the associated uncertainties of major trees today and in the past. Preliminary results suggest that these trees may have wider-realised tolerances than we see from their current distribution patterns. These results bode well for the future of Scandinavian forests, contrasting with predictions of rapid and extensive declines in the extent and abundance of certain trees. These dire predictions are based solely on present day distributions and climate without consideration of past behaviour, and the changing realised niche of these trees under past climates different from those of today.
The American science journalist Douglas Fox wrote in Science in 2007 that in North America ‘fossil pollen and climate models suggest a messy world in 2100, as surviving species reshuffle into entirely new combinations, creating ‘no-analogue ecosystems’. The fossil pollen records and climate simulations in NoAClim suggest, to paraphrase Fox, that Scandinavia was a messy world over the last 11,700 years as trees spread, expanded and declined and formed different combinations and abundances in response to the diverse and bewilderingly complex combinations of climate variables such as temperature, precipitation, seasonality, continentality, length of growing season, extremes and so on.
About the author
|
NoAClim is showing how the many pollen-analytical records collected in Scandinavia in the last 100 years provide a ‘long-term ecological observatory’ to help understand ‘the biotic effects of future environmental change’. Lessons from the past, as are currently being deciphered in NoAClim from pollen records and computer climate-model simulations via data-analytical and modelling techniques, have much to tell us about what we may expect about future responses to Scandinavian forests in our rapidly changing world. Scandinavia is an appropriate area for such research, not only because of its extensive forests, but also because it is the birthplace of pollen analysis. This technique was first presented to a scientific audience in Christiana (now Oslo) in 1916 by the Swedish geologist Lennart von Post.
Professor John Birks
Group Leader
NoAClim Project
+47 5558 3350
john.birks@uib.no
http://www.uib.no/en/rg/EECRG/56799/noaclim
The post Scandinavian forest response appeared first on Horizon 2020 Projects.
Project Category:
- Special Reports