How do invasive species affect the native community structure?

Invasive species can disrupt native community structure by outcompeting native species for resources and altering habitats.

Invasive species, often introduced by human activities, are species that are not native to a specific location and have a tendency to spread, causing damage to the environment, economy, or human health. They can significantly affect the native community structure in several ways.

Firstly, invasive species often outcompete native species for resources such as food, water, and space. They typically have high reproductive rates and can adapt quickly to new environments, giving them an advantage over native species. This can lead to a decrease in the population size of native species, or even their local extinction, thereby reducing biodiversity. For example, the introduction of the brown tree snake to Guam led to the extinction of most of the island's native bird species.

Secondly, invasive species can alter habitats, making them unsuitable for native species. They can change the physical characteristics of an ecosystem, such as the soil composition or water quality. For instance, the invasive plant species, purple loosestrife, can change wetland habitats by altering their hydrology and nutrient cycling, negatively impacting native plant and animal species.

Invasive species can also introduce new diseases or parasites to native species, which may not have the necessary immunity or adaptations to cope. This can lead to significant population declines or even extinctions. The introduction of the chytrid fungus to amphibian populations worldwide is a prime example of this, causing dramatic declines and extinctions in many amphibian species.

Furthermore, invasive species can disrupt the interactions between native species, such as predation, competition, and mutualism. This can lead to changes in the community structure and function. For example, the invasive zebra mussel in North America has disrupted food chains by outcompeting native species for plankton.

In conclusion, invasive species pose a significant threat to native community structures. They can outcompete native species, alter habitats, introduce new diseases, and disrupt species interactions, leading to changes in community structure and function, and a reduction in biodiversity.