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Aggregation pattern of individuals and the outcomes of competition within and between species: Differential equation models
Author(s) -
Kuno Eizi
Publication year - 1988
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/bf02512603
Subject(s) - intraspecific competition , interspecific competition , competition (biology) , crowding , biology , ecology , niche , statistical physics , logistic function , econometrics , statistics , economics , mathematics , physics , neuroscience
Summary The influence of spatial distribution pattern on the outcomes of intra‐ and interspecific competition is studied theoretically. The models developed are the generalized logistic and Volterra equations, where Lloyd 's indices of intra‐ and interspecies mean crowding were incorporated with their assumed linear relationship to mean density in order to express the intensity of crowding which is really effective to the existing individuals. It is shown that while the increasing patchiness of distribution has a pronounced effect of promoting the intraspecific competition and lowering the equilibrium density for individual populations, it generally relaxes the interspecific competition, making it easy for different species sharing the same niche, which would otherwise be incompatible, to coexist stably. These models thus provide a simplest theoretical basis to explain why many insect populations in nature are kept relatively rare in number and why a number of allied species often coexist freely sharing the same resource, against the “competitive exclusion principle” deduced from the original Volterra equations.