Biodiversity, or biological diversity, refers to the wide variety of life found on Earth, encompassing all living organisms from microscopic bacteria to large animals and plants. This includes the diversity within species, between species, and of entire ecosystems. This vast array of life forms contributes to the stability and functioning of natural systems. Healthy, diverse ecosystems provide many services that support human well-being, such as clean air and water, food resources, and compounds for medicines. However, this rich web of life faces significant global challenges.
Habitat Loss and Fragmentation
One of the most impactful threats to biodiversity is the destruction and division of natural living spaces. Habitat loss occurs when natural environments are converted for human use, directly removing areas where species live and reproduce. This conversion is driven by activities such as deforestation for agriculture, urban expansion, and natural resource extraction. For example, vast forest areas are cleared for cattle grazing or crop cultivation, displacing or eliminating countless species.
Beyond outright loss, habitats are often broken into smaller, isolated patches, a process known as habitat fragmentation. This division creates barriers, such as roads or developed land, that restrict the movement of animals and plants between remaining natural areas. Such isolation can reduce gene flow within populations, making them less diverse and adaptable to environmental changes or diseases. Fragmented habitats experience increased “edge effects,” where conditions at the boundaries differ from the interior, negatively affecting species that require undisturbed core habitats.
Climate Change
Shifting global climate patterns is another substantial threat, directly affecting species and environments. Rising temperatures, altered precipitation, and more frequent extreme weather events impact ecosystems worldwide. Many species struggle to adapt to these rapid changes, leading to shifts in geographic distributions or disruptions in breeding cycles. Some may migrate to more suitable climates, but physical barriers or the speed of change can prevent successful relocation.
Changes in climate can influence the spread of diseases, as warmer conditions may expand the range of disease-carrying organisms or increase the virulence of pathogens. Marine environments face specific impacts, notably ocean acidification. As oceans absorb increased carbon dioxide from the atmosphere, the water becomes more acidic, making it difficult for many marine organisms, especially those with shells or skeletons like corals and shellfish, to grow and survive. This alteration of ocean chemistry can disrupt marine food webs and reduce biodiversity.
Invasive Species
Organisms introduced to new environments, often by human activities, can become invasive, posing a significant threat to native biodiversity. An invasive species is non-native to an ecosystem and causes harm to the environment, economy, or human health. These introduced species often lack natural predators or competitors in their new location, allowing populations to grow unchecked. They can outcompete native species for limited resources like food, water, and habitat, causing population declines.
Invasive species may prey directly on native wildlife, introduce new diseases, or alter the physical structure of habitats. For example, the lionfish, an invasive predator in the Atlantic, consumes native reef fish, reducing their populations and disrupting the food chain. Invasive plants like kudzu can rapidly spread, smothering native vegetation and changing soil chemistry, degrading the native ecosystem’s ability to support its original inhabitants.