Scenario: Invasive Species Threaten a Local Wetland Ecosystem

A small wetland located near a local park has been home to a diverse range of plant and animal species for many years. Native plants like cattails and water lilies grow in abundance, providing habitat for a variety of animals, including frogs, birds, and insects. The wetland has supported a healthy food web, with native predators controlling populations of smaller animals and insects.

In recent years, however, an invasive species of plant called Japanese knotweed has begun to spread throughout the wetland. This plant grows rapidly and outcompetes the native vegetation, crowding out the cattails and water lilies that many animals depend on. As Japanese knotweed takes over, the habitat for local wildlife shrinks, and the food web becomes unbalanced.

Additionally, an invasive fish species, the northern snakehead, has been introduced into the wetland by anglers. This aggressive predator is known to consume large numbers of small fish, which are an important food source for birds and other animals in the area. The northern snakehead has few natural predators in the wetland, allowing its population to grow unchecked. As a result, local species that rely on these smaller fish for food are struggling to survive.

As these invasive species continue to spread, the wetland’s biodiversity is at risk. The balance of the ecosystem is being disrupted, and native species are being pushed out of their natural habitat. Environmental scientists are now concerned that without intervention, the wetland may undergo irreversible changes, making it much less habitable for the native species that once thrived there.

Multiple Choice Questions

1. Which of the following is most likely a consequence of the spread of Japanese knotweed in the wetland?

   • A) Increased food supply for frogs and birds

   • B) Increased space for native plants to grow

   • C) Reduced habitat for native wildlife

   • D) A balanced food web in the wetland

2. What impact is the northern snakehead having on the wetland ecosystem?

   • A) It provides more food for smaller fish species

   • B) It helps control the population of other invasive species

   • C) It reduces the number of small fish, affecting the food web

   • D) It increases the number of native plants in the area

3. Why is the northern snakehead able to thrive in the wetland?

   • A) It feeds only on plants, leaving other animals unaffected

   • B) It has been introduced to the ecosystem by local birds

   • C) It has no natural predators in the wetland ecosystem

   • D) It has a symbiotic relationship with native fish species

4. What is the main concern of environmental scientists regarding the wetland?

   • A) The wetland is becoming more suitable for invasive species.

   • B) The wetland’s biodiversity is being threatened by invasive species.

   • C) The wetland’s size is increasing, making it less accessible to animals.

   • D) The wetland’s native species are thriving due to fewer predators.

Short Response Questions

1. How do Japanese knotweed and northern snakehead impact the food web in the wetland? Explain the changes they cause.

2. If you were an environmental scientist working on this wetland, what action would you recommend to help restore the biodiversity of the ecosystem? Justify your answer.