Difference Between Exotic and Invasive Species

Main Difference – Exotic vs Invasive Species

Exotic and invasive species are two types of non-native species. Non-native species can be found in a second ecosystem apart from the ecosystem they evolved from. Non-native species spread by natural process or human activities. Most non-native or indigenous species are harmless. They are called exotic species. When an exotic species becomes harmful to the ecosystem, it is called an invasive species. The main difference between exotic and invasive species is that exotic species is harmless to the ecosystem whereas invasive species is harmful to the ecosystem. Invasive species can be harmful the native habitats, natural areas such as lakes, forests, and rivers, agriculture, economy, and humans.

Key Areas Covered

1. What is an Exotic Species
      – Definition, Examples, Adaptability and Effect
2. What is an Invasive Species
      – Definition, Examples, Adaptability and Effect
3. What are the Similarities Between Exotic and Invasive Species
      – Outline Of Common Features
4. What is the Difference Between Exotic and Invasive Species
      – Comparison of Key Differences

Key Terms: Animals, Ecosystem, Exotic Species, Invasive Species, Native Species, Non-Native Species, Plants

What is an Exotic Species

An exotic species refers to a plant, animal or microorganism species, which is introduced into an area where it does not occur naturally. Plants are introduced into new ecosystems in both agriculture and horticulture. In addition, settlers bring seeds of plants from their homelands due to the economic or medicinal properties of those plants. Most of these exotic plants do not flourish in the wild. But, some plants get adapted to the environmental and climate changes and reproduce to invade the wild areas as well. The Venus flytrap (Dionaea muscipula), purple beautyberry (Callicarpa dichotoma), voodoo lily (Amorphophallus spp.), Sensitive Plant (Mimosa pudica), Cycad (Encephalartos woodii), Flypaper Plant (Pinguicula gigantea), Corpse Flower (Amorphophallus titanum), and Dancing Plant (Desmodium Gyrans) are some examples of exotic plants. Sensitive plant is shown in figure 1.

Figure 1: Sensitive Plant

As mentioned above, exotic species can also include animals. Exotic animals such as cows, pigs, chicken, pigeons, mute swans, cats, dogs, and horses are mostly domesticated. These animals can also become feral. The native plants are endangered by those feral exotic animals.

What is an Invasive Species

An invasive species refers to an exotic species whose introduction causes environmental and economic harm to the ecosystem. This means a significant modifications or disruptions may be caused to the ecosystem by an invasive species. The arrival of the invasive species may occur by natural processes. But, most of these species are introduced to the ecosystems by humans. Invasive species consists of characteristics such as fast growth, rapid reproduction, high dispersal ability, phenotypic plasticity, and ecological competence. Therefore, these species compete with the native species for food and other resources in the introduced ecosystem. They also cause diseases to the native species. Both invasive plants and animals consume native species for food. Kadzu (pueraria montana var. lobata) is an invasive plant in the USA, which covers millions of arches of land. Purple loosestrife (lythrum salicaria), Japanese honeysuckle (lonicera japonica), and English ivy (hedera helix) are other examples of invasive plants. Kudzu is shown in figure 2.

Figure 2: Kudzu

Zebra mussel is an introduced species to the bilge water. Zebra mussels are shown in figure 3.

Figure 3: Zebra Mussels

But these mussels are now colonized and compete for zooplankton with native animals. They also become problematic in lakes and rivers since they clog up the waterways. House mice, feral cats, feral horses, lionfish, Asian carp, Japanese beetle, and cane toads are some examples of invasive animals.

Similarities Between Exotic and Invasive Species

• Exotic and invasive species are two types of non-native species.
• Exotic and invasive species can spread by means of natural processes or human activities.

Difference Between Exotic and Invasive Species

Definition

Exotic Species: An exotic species refers to a plant, animal or microorganism species, which is introduced into an area outside of its native range.

Invasive Species: An invasive species refers to an exotic species whose introduction causes environmental and economic harm to the ecosystem.

Harmfulness

Exotic Species: Exotic species are not harmful to ecosystems.

Invasive Species: Invasive species are harmful to ecosystems.

Characteristics

Exotic Species: Exotic species may require a lot of resources for the growth. 

Invasive Species: Invasive species have a fast growth, rapid reproduction ability, and a high dispersal ability.

Natural Competitors or Enemies

Exotic Species: Exotic species may consist of natural competitors or enemies.

Invasive Species: Invasive species lack natural competitors or enemies.

Effect on Native Organisms

Exotic Species: Exotic species does not have an effect on native species.

Invasive Species: Invasive species may completely replace native species.

Examples

Exotic Species: Venus flytrap, purple beautyberry, voodoo lily, sensitive plant, cows, pigs, chicken, pigeons, mute swans, cats, and dogs are some examples of exotic plants.

Invasive Species: Kudzu, English ivy, feral cats, feral horses, lionfish, Asian carp, Japanese beetle, and cane toads are some examples of invasive species.

Conclusion

Exotic and invasive species are two types of non-native species, which are introduced to ecosystems by natural processes or humans. Most exotic species are domestic, and they do not harm ecosystems. But, invasive species are harmful to the ecosystems. The main difference between exotic and invasive species is their effect on the ecosystem.

Reference:

1. “Introduction of Exotic Species.” NatureWorks, Available here.
2. Carol, Max. “What is an invasive species?” TreeHugger, 12 Sept. 2017, Available here.

Image Courtesy:

1. “Mimosa pudica 003” By H. Zell – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Mexilhão-zebra” By Amy Benson – U.S. Geological Survey (CC0) via Commons Wikimedia
3. “Kudzu” by NatureServe (CC BY 2.0) via Flickr