This blog was written by Anelise Bullard, UF/IFAS CAIP communications intern.
In this blog we will describe how invasive plants outcompete native species for space and resources. There are several concepts that explain why an invasive could outcompete a native. Thanks to Dr. Lindsey Reisinger and her course “Water for the Future”, I learned these concepts and would like to share them with you. Now, let’s take a look at four reasons why invasive species can fare better than natives:
Habitat Modification
Invasive species can change the environment in their introduced range so that native species are no longer adapted to survive there. Water hyacinth (Eichhornia crassipes) is an invasive aquatic plant that grows on the water’s surface in dense, wide mats. This growth blocks sunlight from reaching underwater to submerged aquatic vegetation, like Illinois pondweed (Potamogeton illinoensis).
Enemy Release Hypothesis
When an invasive species are transported from their native range, they leave behind natural predators and parasites that control their population numbers. In a sense, they are “released” from their natural enemies. For example, Air potato leaf beetles (Lilioceris cheni and Lilioceris egena) feed on the leaves and bulbils of the plant. When air potato is introduced to a new habitat outside of its native range, it leaves behind the beetles and is released from its natural enemies. Both species of beetle are being used as biological control for air potato, with Lilioceris cheni already having a stable population in Florida. Adding biological control agents is one way to reintroduce natural enemies for invasive plants.
Novel Weapons
Unlike the enemy release hypothesis where natural enemies are left behind, invasive species can sometimes bring things with them that native species aren’t adapted to defend against. Defense chemicals and co-introduced parasites can be transported with invasive species and present a brand-new enemy to the native community. For example, research suggests that Brazilian peppertree (Schinus terebinthifolius) produces allelopathic compounds that change the chemical makeup of the soil and prevent native plants from growing around it.
Imperfect Natural Selection
Natural selection, coined by Charles Darwin, claims that the individuals with the best traits for a given habitat will survive and reproduce. Like many things in nature, natural selection is not perfect. Individuals of a native species may not have optimally adapted traits for the changes to their habitat, creating an opportunity for invasive species to takeover.
After reading this blog, I hope you have a clearer understanding of how invasive plants can outcompete native species. While there are many more terms and ideas involved in the field, these are a few of the basics that create a foundation for becoming more knowledgeable about invaders. You can always find more resources on our website!
Helpful Resources
- New Air Potato Beetle Available UF/IFAS Blog
- Air Potato Leaf Beetle, Lilioceris cheni UF/IFAS EDIS Document
- Air Potato Beetle, Lilioceris egena, UF/IFAS EDIS Document
- Invasive Plants in Natural Areas: Air Potato (Dioscorea bulbifera) UF/IFAS EDIS Document
- Brazilian Peppertree Florida Department of Agriculture and Consumer Services
Questions or comments can be sent to the UF/IFAS CAIP communications manager at caip@ifas.ufl.edu. Follow UF/IFAS CAIP on Instagram.
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