extirpations

Extirpation refers to the local or regional disappearance of a species from a defined geographic area while the species continues to exist elsewhere. It is used to describe a population or the presence of a species within a particular region, such as a country, watershed, or ecosystem, that has become extinct in that area. Extirpation is contrasted with global extinction, where the species no longer exists anywhere on Earth.

Extirpations result from multiple, interacting pressures. Habitat loss, fragmentation, and degradation reduce available living space and disrupt movement and reproduction. Overexploitation and selective harvesting can erase local populations. Invasive species, disease, pollution, and climate change further threaten small, isolated groups. Because regional populations are often small, stochastic events can trigger local extinction. Recovery depends on habitat suitability, landscape connectivity, and the potential for recolonization from neighboring areas; restoration of habitat and corridors can sometimes facilitate reestablishment.

Geographic and ecological implications are significant. The loss of a population from a region can alter community composition and ecosystem processes, affect genetic diversity, and increase vulnerability to future disturbances. Conservation responses frequently focus on habitat restoration, protection of remaining populations, and, where feasible, reintroduction or augmentation to reverse extirpations. Notable examples include the extirpation of the gray wolf from much of the contiguous United States by the early 20th century, followed by reintroduction in parts of the region, and the historic decline of the American bison from eastern North America, with ongoing restoration in certain areas.