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THE CONTROL OF POPULATION‐DENSITY THROUGH SOCIAL BEHAVIOUR: A HYPOTHESIS
Author(s) -
WynneEdwards V. C.
Publication year - 1959
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1959.tb02400.x
Subject(s) - population density , competition (biology) , population , index (typography) , density dependence , emigration , food supply , position (finance) , economics , ecology , biology , geography , demography , agricultural economics , sociology , computer science , archaeology , world wide web , finance
Summary. Any given species of animal generally occurs at a higher population‐density where food is more plentiful, and vice versa ; quantitative evidence points to a rather close correlation between the two. Such density differences arise from the activities of the animals themselves, and this implies that population‐density is subject to effective internal control, i.e., it is self‐regulating. A theory is put forward that, for each species, population‐densities are limited at a safe level, which will protect the food‐supply from long‐term depletion and assure its renewal for the future. Instead of competing directly for food, animals compete for conventional substitutes, e.g. territory or social position, which are capable of imposing a ceiling density at the optimum level, and can prevent it from rising to the starvation level which would endanger future resources. Such limitation by conventional means requires the existence of a social organisation. Forms of social competition supplant direct competition for food; their intensity is density‐dependent and provides the animals with an index of population‐density. This index serves as the “feed‐back” for the machinery of density‐adjustment, which operates, very broadly, through (1) direct movement (emigration/immigration), and (2) varying the birth and survival rates.