endemism

Endemism is the ecological and biogeographical pattern in which species, subspecies, or higher taxonomic groups are restricted to a particular geographic area and do not naturally occur elsewhere. Endemism can apply to a single location (microendemism), a region (local or regional endemism), or more broadly to a biogeographic realm. Endemic taxa may be highly restricted and vulnerable to extinction, or they may represent stable, long-standing lineages with a confined distribution.

There are several recognized forms of endemism. True or geographic endemism refers to a taxon found only in a specific place. Neoendemism describes recently evolved taxa whose distribution remains limited, while paleoendemism refers to ancient lineages that persist only in a restricted area after widespread decline. These concepts help distinguish how evolutionary history and geography shape current patterns of restricted distribution.

Causes of endemism include geographic isolation (islands, mountain blocks, plateaus), climatic stability, and unique habitats that promote speciation or survival of relict lineages. Isolation limits gene flow and dispersal, while historical events such as climate fluctuations and geological changes can contract broad distributions. Human activities—habitat destruction, climate change, and introduction of competitors or predators—can exacerbate endemism by shrinking ranges and increasing extinction risk.

Examples of renowned endemism include Madagascar’s flora and fauna, New Zealand’s biota, Hawaii’s insects and plants, and the Cape Floristic Region of South Africa. Islands and isolated mountain systems often harbor high endemism. Endemism is a key consideration in conservation planning, as highly localized species are typically more vulnerable to habitat loss and environmental change.