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Rarity patterns of woody plant species are associated with life form and diversification rates in Pacific islands forests
Author(s) -
Ibanez Thomas,
Ainsworth Alison,
Gross Jacob,
Price Jonathan P.,
Webb Edward L.,
Hart Patrick J.
Publication year - 2021
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1687
Subject(s) - biology , ecology , biological dispersal , shrub , species richness , seed dispersal , phylogenetic tree , abundance (ecology) , relative species abundance , population , biochemistry , demography , sociology , gene
Premise Rarity is a complex and central concept in ecology and conservation biology. Yet, it is still poorly understood why some species are rare and others common. Here, we aimed to understand the drivers of species rarity patterns in woody plant communities. Methods We analyzed the local abundance and landscape frequency of 121 woody plant species across 238 plots on American Samoa and Hawaiian islands. We first assessed whether taxonomy, life form (shrub, small tree, large tree), and dispersal syndrome (dispersed by animals or by other means) are associated with the rarity of species. We then analyzed phylogenetic patterns in plant rarity and tested whether rarity patterns are associated with species evolutionary distinctiveness and the number of species within genera and families. Results Large trees were less abundant but more frequent than shrub species. Animal‐dispersed species tended to be less abundant than species dispersed by other means, while species frequency was not associated with dispersal syndromes. Relative frequency in Hawai′i exhibited a more robust phylogenetic signal than did abundance. Both evolutionary distinctiveness and taxa species richness were significantly associated with the frequency of shrub species in Hawai′i. Conclusions Life form appears consistently associated with the rarity of species. High diversification rate is probably a key factor explaining landscape‐scale rarity of native species on isolated archipelagos like Hawai′i. At the landscape scale, rarity appears to be inversely associated with evolutionary distinctiveness, but at the local scale, species abundance may be not associated with evolutionary distinctiveness.