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Vertebrate range sizes indicate that mountains may be ‘higher’ in the tropics
Author(s) -
McCain Christy M.
Publication year - 2009
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1111/j.1461-0248.2009.01308.x
Subject(s) - vertebrate , temperate climate , tropics , ecology , range (aeronautics) , latitude , biology , thermoregulation , precipitation , zoology , geography , biochemistry , materials science , geodesy , meteorology , gene , composite material
Abstract In 1967, Daniel Janzen proposed the influential, but largely untested hypothesis, that tropical mountain passes are physiologically higher than temperate mountains. I test his key prediction, the one upon which all the others rely: namely, that elevational range sizes of organisms get larger on mountains at increasing latitudes. My analyses use 170 montane gradients spanning 36.5° S to 48.2° N latitude compiled from over 80 years of research and 16 500 species of rodents, bats, birds, lizards, snakes, salamanders, and frogs. In support of Janzen’s prediction, I find that elevational range size increases with increasing latitude for all vertebrate groups except rodents. I document additional lines of evidence for temperature variability as a plausible mechanism for trends in vertebrate range size, including strong effects of thermoregulation and daily temperature variability, and a weak effect of precipitation.