Holoendemismi

Holoendemismi is a term used in biogeography and ecology to describe a pattern of endemism in which species or higher taxa are confined to a large, continuous geographic region rather than to isolated pockets. The word blends holo- “whole” with endemism, signaling a regional-scale distinctiveness.

In practice, holoendemismi denotes endemics whose ranges are extensively distributed within a major biogeographic unit (such as a continent, a major rainforest block, or a mountain system) but are not found outside that unit. This contrasts with microendemism, where species are restricted to very small areas, or with more widespread endemism that spans multiple regions. The concept emphasizes long-term regional isolation and historical stability that maintains a unique lineage across broad swaths of habitat.

Methods used to identify holoendemism include compiling comprehensive distribution data, conducting phylogeographic analyses, and integrating paleoclimate and paleoecological information. Researchers may look for high regional endemism across many taxa, concordant geographic patterns, and deep phylogenetic splits suggesting historical in-situ diversification within the region.

Examples (where discussed) typically reference core blocks of biodiversity within large biogeographic units, such as major forest or montane systems, rather than isolated microhabitats. However, the term is not universally standardized, and some scholars reserve it for particular cases or prefer alternative descriptors such as regional endemism or basin-scale endemism.

Criticism centers on ambiguities in delimiting regions and distinguishing holoendemism from broader regional endemism; as such, the term remains a topic of ongoing methodological debate in biogeography. See also Endemism, Biogeography, Phylogeography.