rselectie

R-selection (often written as r-selection or r-strategy) is an ecological and life-history concept describing a reproductive strategy that emphasizes high rates of population growth. Species adopting an r-strategy tend to produce many offspring with relatively little parental investment, aiming to exploit temporarily favorable conditions and colonize new or disturbed habitats. The symbol r refers to the intrinsic rate of increase in population growth, and r-selection contrasts with K-selection, which emphasizes maintaining populations near environmental carrying capacity.

Typical traits associated with r-selected species include small body size, short generation times, early maturity, high fecundity, little or no parental care, and a tendency for population sizes to fluctuate widely. Offspring often experience high mortality, but the large numbers increase the chance that some will survive when conditions improve. Such strategies are common in unstable or unpredictable environments where resources can be abundant for short periods but unpredictable.

The concept originated in the 1960s as part of life-history theory and was formalized by ecologists such as MacArthur and Levins, and later refined by Pianka. R-selection is now understood as a spectrum rather than a strict dichotomy; many species display a mix of r- and K-like traits depending on context and life stage. Critics argue that r/K selection oversimplifies variation in life histories and that contemporary models use continuous trait axes and density-dependent factors.

Examples of r-selected organisms include many insects, annual plants, weedy species, and some small vertebrates in disturbed habitats. Understanding r-selection helps explain how species respond to environmental fluctuations and habitat disturbance.