Resource Competition: When a new species arrives in an ecosystem and competes for the same food sources as another species, it can reduce the availability of resources for the existing species. This can lead to nutrient deficiency, starvation, and decreased fitness, ultimately contributing to population decline and increased vulnerability to extinction.
Predation: New competitors may also pose a predatory threat to existing species, directly reducing their population size. This can occur when the new species preys on the existing species' young, eggs, or adults.
Disease Transmission: The introduction of new species can also lead to the spread of novel diseases and pathogens, to which the existing species may have no immunity. This can cause widespread mortality and population decline, potentially leading to extinction.
Habitat Disruption: The arrival of new competitors may alter or disrupt the existing species' habitat, affecting their ability to access food, shelter, and other essential resources. This can result in population fragmentation, reduction of suitable habitat, and increased vulnerability to other threats.
Ecological Imbalance: The introduction of new species can upset the delicate ecological balance within an ecosystem, disrupting food chains and trophic interactions. This can have cascading effects on other species dependent on the affected species, leading to population declines and increased extinction risk.
Examples:
- The introduction of European rabbits in Australia caused overgrazing of vegetation, leading to habitat degradation and starvation for native species, contributing to the extinction of several marsupials.
- The Nile perch introduction into Lake Victoria in Africa decimated the native cichlid fish species due to intense competition for food resources, resulting in the extinction of hundreds of endemic cichlid species.
- The arrival of invasive feral pigs in Hawaii caused habitat destruction and competition for food with native species, contributing to the extinction of several bird and plant species.
Preventing extinctions caused by competition involves careful assessment and management of introduced species, habitat conservation, and measures to mitigate the impacts of invasive species. Conservation efforts should focus on preserving and restoring habitats, controlling invasive species, and promoting sustainable practices that minimize the introduction of new competitors and safeguard biodiversity.