Chauvin K McManus, Asner G P, Martin R E, Kress W J, Wright S J, Field C B
Earth System Science, Stanford University, Stanford, USA.
Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA.
Oecologia. 2018 Mar;186(3):765-782. doi: 10.1007/s00442-017-4043-9. Epub 2018 Jan 4.
Trade-offs among plant functional traits indicate diversity in plant strategies of growth and survival. The leaf economics spectrum (LES) reflects a trade-off between short-term carbon gain and long-term leaf persistence. A related trade-off, between foliar growth and anti-herbivore defense, occurs among plants growing in contrasting resource regimes, but it is unclear whether this trade-off is maintained within plant communities, where resource gradients are minimized. The LES and the growth-defense trade-off involve related traits, but the extent to which these trade-off dimensions are correlated is poorly understood. We assessed the relationship between leaf economic and anti-herbivore defense traits among sunlit foliage of 345 canopy trees in 83 species on Barro Colorado Island, Panama. We quantified ten traits related to resource allocation and defense, and identified patterns of trait co-variation using multivariate ordination. We tested whether traits and ordination axes were correlated with patterns of phylogenetic relatedness, juvenile demographic trade-offs, or topo-edaphic variation. Two independent axes described ~ 60% of the variation among canopy trees. Axis 1 revealed a trade-off between leaf nutritional and structural investment, consistent with the LES. Physical defense traits were largely oriented along this axis. Axis 2 revealed a trade-off between investments in phenolic defenses versus other foliar defenses, which we term the leaf defense spectrum. Phylogenetic relationships and topo-edaphic variation largely did not explain trait co-variation. Our results suggest that some trade-offs among the growth and defense traits of outer-canopy trees may be captured by the LES, while others may occur along additional resource allocation dimensions.
植物功能性状之间的权衡表明了植物生长和生存策略的多样性。叶经济谱（LES）反映了短期碳获取与长期叶片持久性之间的权衡。在资源状况不同的植物之间，存在着叶片生长与抗食草动物防御之间的相关权衡，但尚不清楚在资源梯度最小化的植物群落中这种权衡是否依然存在。LES和生长 - 防御权衡涉及相关性状，但这些权衡维度之间的相关程度却鲜为人知。我们评估了巴拿马巴罗科罗拉多岛上83个物种的345棵冠层树木的受光叶片中叶经济性状与抗食草动物防御性状之间的关系。我们量化了与资源分配和防御相关的十个性状，并使用多元排序确定了性状协变模式。我们测试了性状和排序轴是否与系统发育相关性模式、幼年种群统计学权衡或地形 - 土壤变化相关。两个独立的轴描述了冠层树木间约60%的变异。轴1揭示了叶片营养和结构投资之间的权衡，这与LES一致。物理防御性状在很大程度上沿此轴分布。轴2揭示了酚类防御投资与其他叶片防御投资之间的权衡，我们将其称为叶防御谱。系统发育关系和地形 - 土壤变化在很大程度上无法解释性状协变。我们的结果表明，冠层外层树木生长和防御性状之间的一些权衡可能由LES体现，而其他权衡可能发生在额外的资源分配维度上。
