1. Limited Resources: Islands often have unique ecosystems with distinct species, and their environment is typically characterized by limited resources. Invasive species, which often have high adaptability and reproductive rates, can outcompete native species for these limited resources, such as food, water, and habitat.
2. Lack of Natural Predators: Many island species have evolved without natural predators or diseases that control their populations. When invasive species are introduced, they might not have natural predators or competitors on islands, allowing their populations to grow exponentially and disrupt the ecological balance.
3. Small Populations: Island species often exist in relatively small, isolated populations. This can make them particularly susceptible to the impacts of invasive species. Even a small number of invasive individuals can have a disproportionately large effect on a small native population.
4. Habitat Modification: Invasive species can modify and degrade island habitats, altering the ecosystem's structure and composition. This can have detrimental effects on native species that rely on specific habitat conditions for their survival and reproduction.
5. Disease Spread: Some invasive species can carry diseases or parasites that are harmful to native wildlife. These diseases can quickly spread through island populations, causing significant declines and even local extinction of native species.
6. Hybridization: Invasive species can sometimes hybridize with native species, leading to genetic contamination and the loss of unique genetic lineages and adaptations. Hybridization can erode the distinct characteristics of native species and compromise their ecological roles.
7. Competition and Predation: Invasive species often compete directly with native species for food and resources and may also prey on native species. This can disrupt the natural food chains and ecological interactions, causing imbalances and reducing biodiversity.
8. Limited Dispersal: Many island species have limited dispersal capabilities, making it challenging for them to move away from areas where invasive species have established. This can restrict their options for finding suitable habitats and avoiding competition or predation.
These factors combined make island wildlife highly susceptible to the threats posed by invasive species, often resulting in severe ecological impacts and biodiversity loss.