WE Web Ecology WE Web Ecol. 1399-1183 Oikos Editorial Office Göttingen, Germany 10.5194/we-6-17-2006 Evolutionary changes in correlations among functional traits in <i>Ceanothus</i> in response to Mediterranean conditions Pugnaire F. I. 1 Chapin III F. S. 2 Hardig T. M. 3 Estación Experimental de Zonas Áridas, CSIC, Almería, Spain Inst. of Arctic Biology, Univ. of Alaska, Fairbanks, 99775, USA Dept. of Biology, Univ. of Montevallo, Montevallo, 35115-6000, USA 08 06 2006 6 1 17 26 Copyright: © 2006 F. I. Pugnaire et al. 2006 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://we.copernicus.org/articles/6/17/2006/we-6-17-2006.html The full text article is available as a PDF file from https://we.copernicus.org/articles/6/17/2006/we-6-17-2006.pdf

<i>Ceanothus</i> is a widely speciated genus with two sections that differ markedly in size, patterns of biomass allocation and reproductive strategies. On greenhouse-grown seedlings we tested whether divergence occurred in single traits or in suites of traits, and whether taxonomic affinity or the ability to fix nitrogen (N) influenced the relationships among functional traits. Species of the subgenus <i>Cerastes</i> differed from species in the subgenus <i>Ceanothus</i> in the following characteristics: reproduction by seed rather than primarily resprouting, high rates of photosynthesis and high stomatal conductance, thick leaves, low root allocation, and high leaf allocation. Correlations of traits across the entire genus showed positive correlations among traits that maximize photosynthesis and tradeoffs between root allocation and carbon gain patterns frequently observed in other broad taxonomic comparisons. Trait correlations differed between the two subgenera (divergence in allocation-photosynthesis tradeoffs in <i>Ceanothus</i> and divergence of growth-related traits in <i>Cerastes</i>). Similarly, N-fixers, which were distributed broadly between the two subgenera, differed in trait correlations (primarily among traits related to photosynthesis) from non-fixers (primarily among traits related to growth and allocation). These results indicate that 1) divergence in genus <i>Ceanothus</i> was associated with changes in entire suite of traits, rather than independent changes in individual traits and 2) evolution occurring under different environmental or nutritional circumstances alters the suites of traits exhibited by plants.