Nondispersal

Nondispersal is a pattern or trait in which individuals or propagules remain near their place of origin, resulting in limited or absent dispersal from the natal site. In ecological terms, nondispersal reduces gene flow between populations and increases local relatedness. It contrasts with dispersal, where individuals move away from their birthplace for breeding, for resource acquisition, or to escape competition or in response to environmental conditions.

In plants, nondispersal often occurs when seeds or fruits are released but fall near the parent plant (barochory or autochorous dispersal) or when fruits are adapted to minimize dispersal. In animals, nondispersal can arise from philopatry, home-range fidelity, or breeding-site fidelity, causing populations to form strong local structure.

Ecological and evolutionary consequences include greater genetic differentiation among populations, stronger effects of genetic drift in small populations, and in some cases local adaptation. Nondispersal can increase the risk of inbreeding if mate choice is limited within a small, isolated area, though some species mitigate it via multiyear breeding, polyandry, or social structure.

Factors that influence nondispersal include life history traits, habitat stability, and density-dependent processes. Fragmentation and habitat loss often exacerbate the effects of nondispersal by reducing connectivity.

Researchers study nondispersal using genetic markers to estimate gene flow, direct tracking of individuals with tagging or telemetry, and observational data on movement patterns. Understanding nondispersal has implications for conservation, as low dispersal can hinder range shifts in response to climate change and increase vulnerability to local extinction.