What are invasive species?

Prepare for the Maine Fish and Game Officer Test. Study with flashcards and multiple choice questions, each question features hints and explanations. Get ready for your exam!

Invasive species are non-native organisms that can cause harm to local ecosystems, the economy, or human health. They arrive from outside the area and often establish themselves and spread rapidly because they lack natural checks in the new environment. Their traits—such as quick reproduction, broad tolerance, and strong ability to outcompete native species—lead to degraded habitats, reduced biodiversity, and disrupted food webs. This harm can ripple into fisheries, forestry, tourism, and even health concerns if the species carries diseases or creates safety hazards. It’s important to note that not all non-native species become invasive; some may be harmless or beneficial, but invasives are defined by their harmful impacts and their ability to spread. Examples like zebra mussels or milfoil illustrate how introduced species can dramatically alter ecosystems in ways that are costly and difficult to reverse.