A new study published in the most recent issue of the journal Ecology and Evolution shows that plant species native to the Great Basin are generally adapted to local conditions, a fact that could be a key to the success of future wildland restorations.
The study, authored by twelve researchers spanning 7 federal, state, and nonprofit agencies and organizations, compiled evidence and data from over 327 previously published experiments spanning 75 years and covering over 100 species of Great Basin native plants.
Local Plants Outperform Distant Seed Sources
They found strong evidence that a process called local adaptation has occurred for many species. This means that populations of the same species from different locations or environments can have different traits, and these differences are often related to the home environment of each population and large enough to affect how well plants grow when planted outside of their adapted environment. This pattern is reflected in important measures of plant success, such as survival, and important characteristics such as leaf size, flower structure, and flowering date.
“If you’ve driven for hours through the Great Basin, you may notice some species that seem to occur everywhere, ” said Owen Baughman, a restoration scientist with the Nature Conservancy and lead author of the study. “The truth is, there is a lot of variation that we can’t easily see across this large and complex region. A native bluegrass or lupine from southern Idaho has different adaptations than populations of the same species from western Nevada, or from eastern Oregon. A good analogy is dog breeds; one population of bluegrass might be a Doberman, and the other a Chihuahua.”
Over 90% of the experiments examined showed that plants differed from population to population and over 80% found that this variation was linked to conditions in their home environment, such as temperature and precipitation, which indicates widespread local adaptation.
The findings of widespread variation and local adaptation in this new research are not new to science, and their implications for vegetation restoration are already well known across the globe. However, they are somewhat at odds with the traditional restoration approach most commonly used in the Great Basin, where habitat loss from large wildfires and invasive species creates the need for hundreds of thousands of acres of restoration each year. Over the last few decades, state and federal agencies have spent billions of dollars attempting to restore native species to damaged range and wildlands using an approach in which one or a few “workhorse” varieties for each native species are expected to perform well throughout entire regions. This new study suggests that such an approach is likely overlooking important adaptations that could improve success.
“I understand why people want to find just a few seed sources to plant all over the West. It certainly simplifies seed farming, storage, and planning. But, if that simplification means plants don’t grow, that defeats the purpose of wildland seedings,” says Beth Leger, Professor at the University of Nevada, Reno.
Habitat Restoration With Local Seed More Likely to Succeed
Despite great efforts, native restoration in the Great Basin is very often unsuccessful, especially in warmer and drier parts of the region. The findings of this study strongly support shifting to an approach that generates and preserves diverse and wild varieties of native species, then matches them to their adapted environments, similar to long-used strategies in forest regeneration and silviculture.
The researchers found that when plants were moved beyond the environmental region where they are adapted, climate may constrain their success. For example, in a subset of 27 experiments examined, two thirds showed higher local plant survival and 90% revealed greater flowering and reproduction for local plants compared to plants sourced from a distant location.
“It’s now clear that across the Great Basin, local plants have a home turf advantage over seeds from another area, even of the same species,” notes Tom Kaye, Executive Director of the Institute for Applied Ecology, and one of the authors of the study. “Planting the right seed in the right place just makes sense, and it saves money because habitat restorations are more likely to succeed.”
Fortunately, recent research on a handful of the species most important for restoration in the Great Basin has extensively examined natural trait variation to produce maps of “seed zones” that define where it is appropriate to transfer seeds from a particular location while keeping within its adapted environment. The findings of this new and ongoing research show that such variation within species is likely the norm for the many other plant species native to the region, which number in the thousands.
In addition to having practical implications for restoration, the study is the largest yet to examine within-species variation for an entire community within a single region, uncovering which plant traits are adapting to the unique Great Basin environment, and which environmental conditions are responsible for these adaptations. An improved understanding of how and why plants evolve to their surroundings is important knowledge as environments are rapidly changing due to increased disturbance, invasive species, and a changing climate.
“We’ve known for decades that local adaptation is common in nature, and we know in theory that an understanding of local adaptation should inform how we manage and restore natural resources,” says Matt Forister, professor at the University of Nevada, Reno. “However, it takes decades of studies and ultimately a review paper of this kind to bring the issue into sufficient focus, for one particular region, so that knowledge can improve management on the ground.”
The authors of the study include researchers from the Department of Biology at the University of Nevada Reno, Institute for Applied Ecology, Washington State University, and USDA Forest Service.
FOR MORE INFORMATION
Original scholarly publication: Strong patterns of intraspecific variation and local adaptation in Great Basin plants revealed through a review of 75 years of experiments
Rocky Mountain Research Station, USDA Forest Service, Boise, Idaho
Department of Biology, University of Nevada, Reno, Nevada
Institute for Applied Ecology, Corvallis, Oregon
Deschutes National Forest, USDA Forest Service Pacific Northwest Region, Bend, Oregon
Washington State University, Pullman, Washington
Pacific Northwest Research Station, USDA Forest Service, Corvallis, Oregon