The DNA survey and analysis, led by researchers at the University of Illinois at Urbana-Champaign, will be posted online this week ahead of regular publication by the Proceedings of the National Academy of Sciences.
"White spruce (Picea glauca) is a dominant species in the boreal forests of North America," said Lynn L. Anderson, lead author and doctoral student. "In the face of global warming, we need to study how plant and animal populations have responded to climate change in the past, to better predict what will happen in the future."
In their study, the researchers analyzed chloroplast DNA from 24 spruce forests in Alaska and Canada. Because chloroplast DNA contains genes inherited from only one parent, there is no confusing genetic recombination to take into account.
"We found a significant pattern in the geographic distribution of the chloroplast DNA haplotypes (groups of individuals with similar sequences of base pairs of genetic material) that differentiates into two regions," Anderson said.
The chloroplast DNA, the researchers write, "offers compelling evidence that white spruce survived the last glacial maximum and probably some of the previous glacial episodes in Alaska. This survival must have been facilitated by the existence of favorable microhabitats … and by adaptations of these trees to harsh climate."
The DNA data help resolve an old controversy over the manner in which trees had migrated in response to past climate change, said Feng Sheng Hu, an ecologist at Illinois and corresponding author of the paper.
"One view is that trees were restricted to areas south of the continental ice sheets covering North America, and then migrated extremely rapidly as the climate grew warmer," Hu said. "The other view is that there was a refuge in the ice-free areas north of the ice sheets, and spruce trees expanded within those areas as the climate warmed. It now seems clear that a glacial refuge existed, and the trees advanced from at least two directions."
Based on the data, it also appears likely that the migration rate was lower than previously thought.
"Our results suggest that estimated rates of tree migration from fossil pollen records are too high and that the ability of trees to keep pace with global warming is more limited than previously thought," said Hu, who has studied plant responses to climate change for 15 years. "Additional analysis of fossil pollen in sediments, as well as DNA data from living trees, could help pin down the actual rate of tree movement over time."
The researchers' findings also illustrate the great resilience of white spruce – and perhaps other tree species – to climate change, and have important implications for the future.
For example, isolated populations of trees might persist in locally suitable habitats for long periods after regional climatic conditions have become unfavorable as a result of rapid global warming. This resilience might reduce the probability of species extinction and allow time for efforts at biodiversity conservation.
Or maybe not.
"Our study looked at the past, before humans had made any significant impact on climate," said Hu. "In the future, both human and natural disturbances will likely interact with climate change to reduce resilience and trigger larger ecological shifts."
The study "illustrates the power of using genetic techniques to answer paleoecological questions relevant to global change," said co-author Ken N. Paige, who has studied the genetic structure and dynamics of plant and animal populations for more than 20 years. "It's likely that more new insights can be gained by studying other plant and animal species with this approach."
James E. Kloeppel | EurekAlert!
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
24.05.2017 | Physics and Astronomy
24.05.2017 | Physics and Astronomy
24.05.2017 | Event News