Posted by Unknown
On 04:40
A colorful caterpillar feeds on dogwood.
Photograph courtesy Dr. Doug Tallamy
Green invaders are taking over
America. Nope, not invaders from space. Plants. You might not think of
plants as dangerous, but in this case they are threatening nature's
delicate food web.
The invaders are plants from other countries
brought here to make gardens and yards look pretty. Ever since people
started to arrive on America's shores, they've carried along trees,
flowers, and vegetables from other places.
Now there are so
many of those plants, they are crowding out the native plants that have
lived here since before human settlers arrived.
And that's a
problem, says Dr. Doug Tallamy. He's an entomologist (an insect expert)
at the University of Delaware. He explains that almost all the
plant-eating insects in the United States—90% of them—are specialized.
That means they eat only certain plants.
Monarch butterfly
caterpillars, for example, dine on milkweed. If people cut down milkweed
and replace it with another plant, the butterflies will not have the
food source that they need to survive.
But the trouble doesn't
stop there, it goes right across the food web. When insects can't get
the right plants to eat and they die off, then the birds don't have
enough bugs for their meals. Tallamy points out that almost all
migrating birds depend on insects to feed their young.
"We cannot let the plants and
animals around us disappear," says Tallamy. "The way to preserve them is
to give them food to eat. But when we plant non-native plants, we are
clobbering the food web, because then we don't have the insects the
birds need to live."
Fewer of the right plants mean fewer bugs,
and fewer bugs mean fewer birds. And that's bad for the Earth, because
we need a variety of living things to keep the planet healthy and
beautiful.
The good news is, gardeners everywhere are working
hard to protect native plants and get rid of the invaders. Many local
garden centers sell native plants. "Just Google 'native plants' and your
location, and you can find out which plants really belong where you
live," says Tallamy.
Planting the right things makes a real
difference, and fast. He describes planting milkweed in a tiny city
courtyard about the size of a living room one spring. By summertime,
that milkweed patch had produced 50 new monarch butterflies!
Tallamy encourages kids to go out and plant native plants. "Adopt a bird
species in trouble and see if you can't plant some things that will
attract the insects they need," he suggests. "It will happen—insects
move around a lot, and they will find the plants you put out there for
them!"
Earth Day Tip:
Plant a native plant or tree this year!
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