Back when electronic games were new, one very popular game was called "Space Invaders." It was pretty simple: You just had to fight off aliens who were trying to land on the Moon. And battling those simple digital aliens was a piece of cake.
Scientists at the Agricultural Research Service (ARS) are playing their own version of "Space Invaders." But when they play, the invaders aren't little creatures that beep when you zap them.Instead, the invaders are all kinds of plants—like grass.
They might be flowers.
Some of these plants are newcomers to North America. Those newcomers are called "exotic" plants, even though they aren't really very glamorous. Lots of times they're just clumps of grass, like this cheatgrass, which has made itself at home on western rangelands in the United States.
They're so comfortable here that they're pushing out plants that have been here all along—the ones we call "native" plants.
And sometimes it's native plants who are doing the pushing. For example, juniper trees are natives. But the dry, windy rangelands where they grow best are changing. There are more wildfires. Temperatures are getting warmer.
These changes mean that juniper trees can now grow in more places and crowd out rangeland grasses that cows like to eat. A cow has to be pretty hungry before it starts munching on a juniper tree.
ARS scientists are trying to figure out how they can turn back these invaders. Sometimes they'll study a new plant to see if it is sturdy enough to keep the invasive plants from taking over.
Sometimes they may study an insect to see if it has the appetite to literally "eat away" the problem plant.
It's not as quick as a game of "Space Invaders." These studies can take years and years. But ARS scientists like to win—and even though it might take them awhile, they'll make sure they outscore the aliens!