Edge Effect (page 2)
Although you might not think that plants move, they need to move to reproduce. Some throw their seeds into the air, like the dandelion and the maple tree. Other plants such as burdock (burrs) hitch a ride on animals and people. Some plants have light spores that travel through air or water to a new destination. Some move under the ground, pushing their roots along until they find a good place to pop up and grow. Still others rely on animals to travel from one place to another. The animals eat the seeds, and the seed makes its way through the animal without being digested, emerging as animal scat.
Many weeds are good edge plants. They love the sunshine and are tough, so they don’t mind if people step on them. Native plants can be pickier than these durable weeds, and they may not survive on the forest edge. In the interior of the forest, native plants are at home, and they sometimes grow better than the weeds do.
There’s another reason why there are more weeds on the forest edge. While weeds are very good at growing and reproducing, the forest acts as a barrier to weed seeds. The forest edge plants and trees catch seeds in a giant net of leaves and branches, keeping them from entering the forest interior and forcing them to fall closer to the edge of the forest.
Knowing what you now know about edge effects, do you think that forests act as a filter for other things, like pollution? Why? Maybe you could find a way to investigate!
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