ecotype

An ecotype is a genetically distinct population within a species that is adapted to a specific local environment. Ecotypes arise when populations experience different selective pressures, leading to heritable differences in traits that improve fitness in their particular habitat. These differences can be morphological, physiological, phenological, or behavioral. If gene flow between populations is limited, divergent selection can produce recognizable locally adapted populations that persist even when raised in a common environment, indicating a genetic basis. Ecotypes are not necessarily discrete subspecies but rather spatially structured populations that show adaptive differentiation along environmental gradients. Some differences may also reflect phenotypic plasticity, in which organisms adjust their traits in response to the environment without genetic change.

Detection and study: ecotypic differentiation is tested with reciprocal transplant or common-garden experiments, which reveal whether local genotypes outperform foreign ones across environments. Genetic and genome-wide association studies can identify alleles associated with local adaptation. Ecotypes can be confused with clines, subspecies, or varieties, but ecotype emphasizes ecological and adaptive differentiation within a species rather than formal taxonomic rank.

Examples: In plants, Arabidopsis thaliana has numerous ecotypes adapted to diverse climates, showing variation in flowering time, drought tolerance, and cold hardiness. In coastal or marine environments, populations may diverge into ecotypes with tolerance to salt spray or wave action. Animal examples include ecotypes of certain fish or birds that exploit different habitats or food resources, though the term is most commonly used in botany and ecology.

Importance: Recognizing ecotypes informs conservation and restoration, where local seed sources are preferred to maintain adaptive traits, and it underpins studies of evolution, speciation, and climate change response. Ecotypic variation illustrates how populations adapt to heterogeneous environments within a species’ range.