October 4, 2025

What Is An Invasive Species

Q: What is the difference between a native and an invasive species?

A native species naturally occurs in a specific ecosystem, whereas an invasive species is introduced from elsewhere and causes significant environmental or economic harm to that new ecosystem.

Q: How do invasive species get introduced into new environments?

They can be introduced accidentally (e.g., via ship ballast water, contaminated packaging, or hitchhiking on vehicles) or intentionally (e.g., as pets, ornamental plants, agricultural crops, or for pest control) but then escape or spread beyond their intended area.

Q: Are all non-native species considered invasive?

No, a species is only considered invasive if it is non-native AND causes significant ecological, environmental, or economic harm. Many non-native species exist in new environments without causing such problems and are often called 'introduced' or 'exotic' species.

Q: Why are invasive species so harmful to local ecosystems?

Invasive species often lack natural predators or competitors in their new environment, allowing their populations to grow unchecked. They can outcompete native species for food and habitat, prey on native species, introduce diseases, or alter habitats, ultimately leading to population declines of native species and reduced biodiversity.

Learn about invasive species, their characteristics, the harm they cause to ecosystems, and why their control is crucial for environmental health and biodiversity.

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Definition of an Invasive Species

An invasive species is an organism (plant, animal, fungus, or microorganism) that is not native to a particular ecosystem and causes ecological or economic harm, or harm to human health. They are often introduced intentionally or unintentionally by human activities, such as global trade, travel, or habitat alteration.

Key Characteristics of Invasive Species

Invasive species typically possess traits that allow them to thrive in new environments, such as rapid reproduction rates, aggressive competition for resources, broad dietary preferences, high adaptability to diverse conditions, and a lack of natural predators or diseases in their new habitat. These characteristics enable them to outcompete native species effectively.

Ecological and Economic Harm

Invasive species can displace native populations, reduce biodiversity, alter habitats, disrupt food webs, and introduce diseases, leading to ecosystem imbalance. Economically, they can damage agriculture, forestry, fisheries, infrastructure (e.g., by clogging pipes), and tourism. For example, the emerald ash borer has decimated ash tree populations across North America.

Importance of Control and Prevention

Controlling and preventing the spread of invasive species is crucial for maintaining ecosystem health, protecting native biodiversity, and safeguarding economic resources. Management strategies include public education, careful inspection of goods, early detection, rapid response to new incursions, and long-term control measures such as biological, chemical, or mechanical removal efforts.

Frequently Asked Questions

What is the difference between a native and an invasive species?

How do invasive species get introduced into new environments?

Are all non-native species considered invasive?

Why are invasive species so harmful to local ecosystems?