Biodiversity, the variety of life on Earth, supports countless species within intricate ecosystems. However, a concerning trend reveals a decline in animal populations, leading to species becoming endangered. Understanding the factors pushing animals towards extinction is important for addressing this global challenge. This issue stems from human activities disrupting natural balances.
Loss of Habitat
Transformation, fragmentation, and degradation of natural environments cause species endangerment. Human activities like deforestation or agricultural expansion directly remove animal habitats. For instance, approximately 420 million hectares of forest have been lost since 1990 due to conversion for other land uses, with agriculture being a primary driver.
This loss not only reduces available habitat but also isolates remaining populations, making it difficult for animals to find food, mates, and shelter. Urbanization further contributes by converting natural environments into cities and infrastructure, leading to biodiversity loss. Species that require large territories or specific habitat types are particularly susceptible to these changes, as their environments are paved over or fragmented. These disruptions can lead to population declines and even extinction for animals unable to adapt to altered landscapes.
Illegal Wildlife Trade
Illegal capture, hunting, and trafficking drive many species towards extinction. This trade is fueled by demand for products such as ivory, rhino horn, pangolin scales, and exotic pets. For example, an estimated one million pangolins have been poached in the last decade, making them the most trafficked mammals globally.
Illegal wildlife trade reduces population sizes and genetic diversity, increasing species’ vulnerability to diseases and limiting their ability to adapt to environmental changes. The targeting of larger, healthier individuals for trade can also create gender imbalances and slow reproductive rates within populations.
Climate Change Impacts
Global climate shifts significantly affect animal populations by altering environments. Rising temperatures can destabilize ecosystems, forcing animals to migrate outside their usual patterns in search of food and suitable living conditions. Changes in temperature can disrupt the timing of natural events, such as when flowers bloom, which can impact pollinators who rely on these specific cycles. The Earth is now about 1.1°C warmer than it was in the 1800s, with projections indicating further warming.
Altered precipitation patterns and extreme weather events, like droughts, wildfires, and floods, cause habitat destruction and loss of life. For instance, Australia’s 2019-2020 bushfires killed or displaced an estimated three billion animals.
Ocean acidification, caused by increased carbon dioxide absorption, makes it difficult for marine organisms like corals, sea urchins, and shellfish to build and maintain their calcium carbonate shells and skeletons. This can have cascading effects through marine food chains, impacting species that rely on these calcifying organisms for food.
Pollution
Pollution directly harms animals and degrades their environments. Chemical pollution, including pesticides, industrial waste, and “forever chemicals,” can damage nervous systems, impair immunity, and affect reproductive capabilities in wildlife. For example, harbor porpoises have an increased risk of infectious diseases due to accumulated harmful chemicals, raising their disease risk by 41%.
Plastic pollution is another widespread issue, with thousands of seabirds, sea turtles, and marine mammals dying annually from ingesting plastic or becoming entangled in it. Plastic debris can cause internal injuries, block digestive systems, and lead to starvation in animals that mistake it for food.
Light pollution, from artificial light at night, disrupts the natural day-night cycle animals depend on for reproduction, foraging, and protection from predators. This can disorient migrating birds, prevent nocturnal animals from feeding, and alter predator-prey relationships. Noise pollution further impacts wildlife by interfering with communication, navigation, and breeding behaviors, particularly for species sensitive to sound.
Invasive Species and Disease
Introduction of non-native species into new environments threatens native wildlife. These invasive species can outcompete native animals for resources such as food and space, or directly prey upon them. Approximately 42% of threatened or endangered species are at risk due to invasive species.
Invasive plants, for instance, can quickly take over land from native plant species, subsequently reducing native animal populations. Invasive species also carry or introduce new diseases to which native populations may have no natural immunity. Diseases can rapidly decimate vulnerable animal groups, especially those that are isolated or have limited genetic diversity.
Climate change can also exacerbate the spread of invasive species and create environmental conditions that allow them to establish more easily, placing additional pressure on already at-risk native species.