Open AccessToward a theory for diversity gradients: the abundance–adaptation hypothesis
Author(s) -
Weiser Michael D.,
Michaletz Sean T.,
Buzzard Vanessa,
Deng Ye,
He Zhili,
Shen Lina,
Enquist Brian J.,
Waide Robert B.,
Zhou Jizhong,
Kaspari Michael
Publication year - 2018
Publication title -
ecography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.973
H-Index - 128
eISSN - 1600-0587
pISSN - 0906-7590
DOI - 10.1111/ecog.02314
Subject(s) - biology , ecology , abundance (ecology) , taxon , adaptation (eye) , habitat , clade , invertebrate , niche , temperate climate , relative species abundance , niche differentiation , ecological niche , phylogenetics , biochemistry , neuroscience , gene
The abundance–adaptation hypothesis argues that taxa with more individuals and faster generation times will have more evolutionary ‘experiments’ allowing expansion into, and diversification within, novel habitats. Thus, as older taxa have produced more individuals over time, and smaller taxa have higher population sizes and faster generation times, the Latitudinal Diversity Gradients (LDGs) of these clades should show shallower slopes. We describe the LDGs for archaea, bacteria, fungi, invertebrates and trees from six North American forests. For three focal groups – bacteria, ants, and trees – older taxa had shallower LDG slopes than the more recent, terminal taxa. Across 12 orders of magnitude of body mass, LDG slopes were steeper in larger taxa. The slopes of LDGs vary systematically with body size and clade age, underscoring the non‐canonical nature of LDGs. The steepest LDG slopes were found for the largest organisms while the smallest, from bacteria to small litter‐soil invertebrates, have shallower‐ to zero‐slope LDGs. If tropical niche conservatism is the failure of clades to adapt to, and diversify in temperate habitats, then the steep LDGs of chordates and plants likely arise from the decreased ability of clades with large individuals to adapt to the multiple challenges of extra‐tropical life.