A new study from the University of Wisconsin-Madison reveals how aspen forests maintain the diversity they need to adapt to fluctuating environmental conditions. The experts found that aspen trees change their genetic structure over time as they balance the need to compete for sunlight and defend themselves from pests.
Since Aspen is the most broadly distributed tree species in North America, it serves as a “bellwether species,” or a good indicator of how forests will adapt to anthropogenic climate change and other environmental challenges.
Trees are often faced with competition from other trees for sunlight, and they respond by making growth a priority. But with all of that energy committed to height growth, the trees become more vulnerable to pests.
The new research, which is funded by the National Science Foundation (NSF), demonstrates that evolutionary forces can quickly shape entire forests. The study also shows that exposure to a range of environmental changes promotes the diversity that trees need to overcome various stressors.
“This long-term project provides new insights into the role of forest structure on genetic diversity in aspen groves, and how that affects leaf traits that influence the abundance and distribution of herbivores,” said Colin Orians, a program director in NSF’s Division of Environmental Biology.
According to a report from NSF, the findings are valuable for conservation biologists who want to protect diverse forest ecosystems from the threats of global warming, invasive species, and other environmental changes.
“What this work has done is show how key traits – like growth and defense – can be coupled together and how genetic diversity will allow populations to adapt to new stresses,” said Rick Lindroth, an ecologist at University of Wisconsin–Madison.
The study is published in the journal Proceedings of the National Academy of Sciences.