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Clumps of Heliconia Inflorescences as Ecological Islands
Author(s) -
Seifert Richard P.
Publication year - 1975
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1934708
Subject(s) - ecology , species richness , insular biogeography , biology , species evenness , mainland , habitat , gamma diversity , biogeography , alpha diversity
Previous theoretical and field studies have identified quantifiable relationships between migration, extinction, island size, and distance to mainland with species richness on islands. Some of these relationship hold for insects living in spatially and temporally separated Heliconia inflorescences. Analysis of 45 clumps of Heliconia wagneriana and 77 clumps of Heliconia imbricata using MacArthur and Wilson's (1967) island biogeography theory indicates that area—species richness curves are more similar to those of true islands than to those of mainland areas. Other island relationships such as distance influences could not be found. It is postulated that beta diversity (the diversity due to the number of habitats available) is more important in increasing species richness of animals in Heliconia clumps than is alpha diversity (the diversity due to the number of species using a given resource). The reduction of evenness as area size increases indicates that increasing ecological island size increases populations of common insects more rapidly than new species can invade these ecological islands.