While researching a topic, a student has taken the following notes:
- A nonnative species that causes environmental or economic harm when introduced to an ecosystem is considered invasive.
- Leafy spurge is an invasive species of flowering plant that crowds out livestock forage and native plants.
- It was first introduced to the US accidentally through contaminated seed.
- Water hyacinth is an invasive species of aquatic plant that blocks sunlight and reduces oxygen levels in bodies of water.
- It was first introduced to the US as an ornamental plant.