题型：阅读理解 题类： 难易度：普通
四川省成都东部新区养马高级中学2023-2024学年高二下学期期中考试考试英语试题
I traveled to Hawaii several months ago, in part to cover a story on invasive plants and animals and their impact on the state. As I worked on this story, I kept thinking about the fact that some plants and animals become uncontrollably invasive when they're brought into a new ecosystem, while others don't. For example, over the past two hundred years or so, there have been approximately 20, 000 non-native plant species either intentionally or accidentally brought into Hawaii alone. But only a small part of those plants — 200 species or so — have become invasive, threatening the environment, the economy, or human health.
An example from Hawaii's forests: the invasive plant strawberry guava thrives as it gives off a chemical that prevents all other plants from growing nearby, and it also absorbs more water than native species. What makes these particular species so successful? Most of the reasons involve how a particular species interacts with its new environment. First, invasive species may be highly adaptable to a variety of climates. Second, they are usually quite fecund (多产的), which ensures that they can multiply rapidly. Third, they are usually threatening when it comes to resources like nutrients and space, easily crowding out their native counterparts (对应的物种). And finally, invasive species thrive when there are no natural enemies or pests in their new space.
How can we eradicate invasive species once they're in place? Unfortunately, it's nearly impossible to do that — conservationists would have to notice that the species is a problem before its population has established and grown to an uncontrollable size. Instead, most conservationists battling invasive species aim for control in key ecological pockets.
It is a constant battle, though, and humans are always playing catch-up. If you're thinking of planting unusual plants in your garden or keeping a foreign pet, perhaps reconsider and go for a native one. You never know when they might escape and tip over an ecosystem.
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