Human impacts affect plant stability

Danielle Korby

Researchers have found a new link between human interactions with plants and their ability to consistently reproduce over time. 
 
University of Minnesota researchers found that stability of plant production was only affected by human interactions when they spurred a decline in the number of species.
 
In one of 12 different grassland studies from the school’s Cedar Creek Ecosystem Science Reserve in East Bethel, some plants received more water than others, and researchers found that they grew more consistently from year to year, said Forest Isbell, co-author of the study and associate director at Cedar Creek.
 
Associate ecology, evolution and behavior professor Eric Seabloom said one of the studies showed that plants grew less consistently when nitrogen was added. In the real world, using land for farming would have similar effects to those that the nitrogen had in the study. 
 
Lead researcher Yann Hautier said he started the study in 2013, and it was published earlier this month. 
 
Isbell said researchers analyzed data from Cedar Creek because it’s a well-known site for biodiversity studies, adding that most of the studies they looked at are still 
ongoing. 
 
Plant growth in all 12 of the studies was measured by cutting, drying and weighing plants each year, Isbell said.
 
Many of the Cedar Creek studies lasted more than a few years, which allowed researchers to see significant changes over time, Seabloom said.
 
“As you do experiments over long periods of time, the results start to change and become more interesting,” he said.
 
A change in stability of plant growth helps to ensure consistent carbon dioxide, crop, coal and other resource production, Seabloom said. 
 
One of the reasons researchers chose grasslands was because they make up a large portion of Earth’s plant population and many have been converted into farmland, he said.
 
“Understanding what causes systems to be productive and how variable [they are] is kind of the core of what allows us to live on Earth,” Seabloom said.