<figure>
 <img src="https://media.eaglewebservices.com/public/2021/4/1618852576892.png" alt="A close-up picture of a grasshopper nymph. USGSBMIL Team" />
 <figcaption>A close-up picture of a grasshopper nymph. USGSBMIL Team</figcaption>
 </figure>By BRIAN GRIMMETT <a href="https://www.kmuw.org/post/climate-change-has-turned-kansas-prairie-junk-food-thats-killing-grasshoppers">Kansas News Service</a>MANHATTAN — Ellen Welti has a Ph.D. in, essentially, grasshoppers.And yet she was still mystified about why the number of grasshoppers in a long-protected and <a href="http://lter.konza.ksu.edu/about-konza">much-studied patch of Kansas prairie</a> was dropping. Steadily. For 25 years.After
 all, the grass that the springy bugs feast on had actually grown more 
robustly as it absorbed mounting levels of carbon dioxide in the 
atmosphere.So why were the grasshoppers faring increasingly worse?“We thought that this is a pretty nice habitat for grasshoppers,” she said.The
 insects dwell on the Konza Long-Term Ecological Research site. Their 
home sat in preserve, shielded from development, from farming, from just
 about everything people do to the planet.“It doesn’t have a lot
 of the pressures we usually associate with insect decline. Like, 
there’s no pesticide spraying,” Welti said. “The size of the habitat is 
not shrinking. It’s the big natural reserve.”And yet the <a href="https://www.pnas.org/content/117/13/7271#xref-corresp-1-1">numbers showed an alarming decline</a> — nearly 2% a year for about a quarter century.“It’s
 like compound interest,” said Michael Kaspari, a research professor at 
the University of Oklahoma who advised Welti on the paper. “You add that
 up over 25 years and we’re talking about a significant decline in one 
of the most important insects on the prairie.”Even this 
treasured research site — part of a worldwide network aimed at studying a
 biological baseline — shares the atmosphere with the rest of the Earth.<figure>
 <img src="https://media.eaglewebservices.com/public/2021/4/1618852648399.png" alt=" Kansas State University undergrad student Victoria Gaa sorts through grass samples taken at the Konza Prairie. Credit Brian Grimmett / Kansas News Service" />
 <figcaption> Kansas State University undergrad student Victoria Gaa sorts through grass samples taken at the Konza Prairie. Credit Brian Grimmett / Kansas News Service</figcaption>
 </figure>Welti and her research team found that all those human-boosted levels
 of carbon dioxide in the air changed the grass. Bigger leaves, sure, 
but all that volume diluted the nutrients grasshoppers need to thrive.Basically, climate change had converted the grasshopper’s staple into insect junk food.“That
 was a surprise for me,” Welti said. “But thinking more about it and 
knowing about grasshoppers and how sensitive they are to these plant 
nutrients, it makes a lot of sense.”A normal amount of 
grasshoppers on the prairie can eat as much grass as a herd of cattle. 
Grasshoppers are a huge part of the tallgrass ecosystem. But they’re 
also limited. They really just eat the grass, so when it changes, it can
 have a huge impact.To figure out just what was going on, Welti 
went back to the Konza research station to take a deeper look. 
Researchers there have tens of thousands of grass samples from the last 
40 years.“Ecology can happen rather slowly,” said Amanda Kuhl, a
 research assistant charged with collecting and cataloguing the samples.
 “Sometimes it can take decades to notice a trend, or tease things 
apart.”In one of the storage rooms at the Konza research 
building on the campus of Kansas State University, brown paper bags full
 of grass and dirt samples fill the walls from the floor to the ceiling.
 And those bags are just some of the samples from last year.“Once
 they get these cleaned up they’ll go back into a drying oven to remove 
all the moisture,” Kuhl said. “I’ll weigh them and that’s how we get our
 biomass numbers.”<figure>
 <img src="https://media.eaglewebservices.com/public/2021/4/1618852681199.png" alt=" A storage room on the Kansas State University campus full of brown paper bags with grass samples from the Konza Prairie. Credit Brian Grimmett / Kansas News Service" />
 <figcaption> A storage room on the Kansas State University campus full of brown paper bags with grass samples from the Konza Prairie. Credit Brian Grimmett / Kansas News Service</figcaption>
 </figure>The facility also has thousands of small envelopes full of ground-up samples. They can be used to run chemical analysis.The
 biomass numbers paired with the chemical analysis led Welti to what was
 causing the grasshopper declines: bigger, but less nutritious grass.“At
 first, it looks like there’s overall more food availability for 
grasshoppers,” she said. “But when we got back the plant chemistry, what
 we could see is that this increase in plant biomass really corresponded
 to decreases in the quality of the biomass.”It’s something known as nutrient dilution.“Every
 bite of those grasses is giving less and less back to all the other 
living things that depend on the plants,” Kaspari said.The 
change is driven by an increase in the amount of carbon dioxide in the 
atmosphere from burning fossil fuels. Every time the plants take in air 
it contains far more carbon than ever before. They can’t get rid of it 
so they stick it in their tissue. That equals bigger plants.The problem is that the amount of other nutrients in the soil, such as nitrogen, potassium and sodium, aren’t really changing.It’s
 like switching out a plate of kale for a plate of iceberg lettuce. The 
plates might have the same amount, but one has a whole lot more of the 
good stuff bodies need.Kaspari said the fact that the problem is rooted in too much carbon dioxide in the atmosphere is particularly daunting.“You
 can remediate habitat destruction,” he said. “You just stop doing it 
and you reforest, or reclaim the grassland. But the answer to nutrient 
dilution is actually reducing the CO2 in the atmosphere.”<figure>
 <img src="https://media.eaglewebservices.com/public/2021/4/1618852711866.png" alt=" Bags full of grasshopper samples taken from the Konza Prairie. Credit Brian Grimmett / Kansas News Service" />
 <figcaption> Bags full of grasshopper samples taken from the Konza Prairie. Credit Brian Grimmett / Kansas News Service</figcaption>
 </figure>Welti said the findings were pretty clear. Where they found large, but less nutritious, grass, they found grasshopper declines.And
 unlike humans, who can use fertilizer to increase nutrients in our food
 or take a multivitamin to supplement any gaps, grasshoppers are stuck 
with what is there naturally.Welti said the findings are about 
more than the bugs. Fewer grasshoppers will lead to fewer birds. Fewer 
birds could lead to more rodents.The decline of one species of grasshopper could strengthen another, potentially leading to swarms that damage crops.And
 the underlying problem, nutrient dilution due to climate change, will 
impact all animals that rely on eating plants. From grasshoppers and 
leaf beetles up to bison and cattle. And eventually humans.“Even
 (at the Konza Prairie),” she said, “climate change can strongly affect 
the community and even lead to insect declines — which is pretty 
depressing.”Brian Grimmett reports on the environment, 
energy and natural resources for KMUW in Wichita and the Kansas News 
Service. You can follow him on Twitter <a href="https://twitter.com/briangrimmett?lang=en">@briangrimmett</a> or email him at grimmett@kmuw.org.

Climate change has turned Kan. prairie into junk food that's killing grasshoppers