What Makes a Plant Invasive?
Researchers are also working to discover why some non-natives become invasive while others don’t. According to one theory, some probably succeed because they aren’t held in check by the predators and parasites that controlled their numbers in their original lands. And because they’re not under attack, they may be able to redirect energy they would have invested in producing the toxic chemicals or spines to growth and reproduction. Native plants, by contrast, cannot lower their defenses or they will be attacked by the pests that evolved along with them. Two major studies found the best predictor was whether a plant was known to be invasive in another part of the world. Recent work has found that species that share some or all of the following characteristics are most likely to be invasive: • They produce many small seeds and begin reproducing within their first few years. • Their seeds are dispersed by animals. • They can reproduce both by seed and vegetative growth. • They have long fl
