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Latitudinal gradients in climatic‐niche evolution accelerate trait evolution at high latitudes
Author(s) -
Lawson Adam M.,
Weir Jason T.
Publication year - 2014
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/ele.12346
Subject(s) - niche , latitude , ecology , ecological niche , biology , trait , ecological speciation , tropics , reproductive isolation , parallel evolution , ecological selection , selection (genetic algorithm) , evolutionary biology , geography , population , genetic variation , phylogenetic tree , habitat , gene flow , biochemistry , demography , geodesy , artificial intelligence , sociology , computer science , gene , programming language
Despite the importance of divergent selection to the speed of evolution, it remains poorly understood if divergent selection is more prevalent in the tropics (where species richness is highest), or at high latitudes (where paleoclimate change has been most intense). We tested whether the rate of climatic‐niche evolution – one proxy for divergent selection – varies with latitude for 111 pairs of bird species. Using Brownian motion and Ornsetin–Ulhenbeck models, we show that evolutionary rates along two important axes of the climatic‐niche – temperature and seasonality – have been faster at higher latitudes. We then tested whether divergence of the climatic‐niche was associated with evolution in traits important in ecological differentiation (body mass) and reproductive isolation (song), and found that climatic divergence is associated with faster rates in both measures. These results highlight the importance of climate‐mediated divergent selection pressures in driving evolutionary divergence and reproductive isolation at high latitudes.