How are invasive species defined?

Invasive species are defined as non-native organisms that spread and cause harm to the environment, economy, or human health. This definition highlights two key aspects: the fact that these species do not belong to the ecosystem in which they are found and their ability to disrupt and negatively impact local ecosystems. Invasive species can outcompete native species for resources, introduce diseases, and alter habitats, often leading to a significant decline in biodiversity. By understanding this definition, it's clear that management and prevention of invasive species are crucial for the protection of native ecosystems and biodiversity. The other options involve concepts related to native species or conservation status but do not accurately capture the essence of what characterizes invasive species.