“Schwartz’s Ecological Rule”—A Look through the Decades

Academician S.S. Schwartz, whose 100th birthday was celebrated by ecologists in 2019 and who can rightfully be called the herald of population-ecological thinking, formulated a pattern: “specialized species are always better adapted than specialized intraspecific forms.” Polish academician K. Petrusevich (1979) proposed to elevate this pattern to the rank of “Schwartz’s ecological rule.” Numerous studies of warm-blooded animals (mainly mammals) in mountainous regions and regions of the Far North fully confirm this rule, which is essential for modern ideas about the ecological mechanisms of evolution. At the same time, it is not applicable to cold-blooded animals (fish, amphibians), and therefore it is advisable to consider this pattern from a general biological point of view as an empirical generalization.