The unfolding of plant growth form‐defence syndromes along elevation gradients

Abstract

Understanding the functional economics that drives plant investment of resources requires investigating the interface between plant phenotypes and the variation in ecological conditions. While allocation to defence represents a large portion of the carbon budget, this axis is usually neglected in the study of plant economic spectrum. Using a novel geometrical approach, we analysed the co-variation in a comprehensive set of functional traits related to plant growth strategies, as well as chemical defences against herbivores on all 15 Cardamine species present in the Swiss Alps. By extracting geometrical information of the functional space, we observed clustering of plants into three main syndromes. Those different strategies of growth form and defence were also distributed within distinct elevational bands demonstrating an association between the functional space and the ecological conditions. We conclude that plant strategies converge into clear syndromes that trade off abiotic tolerance, growth and defence within each elevation zone.

Plant–herbivore coevolution and plant speciation

“…, Defossez et al. ). To what extent does herbivore pressure contribute to establishing range limits? With regard to Scenario 3, it is important to identify defensive traits and their distribution in range centers and edges.…”

“…, Defossez et al. ). Nonetheless, the role of novel trait evolution (gains or losses in defense) in facilitating population expansion has received remarkably little attention (Farrell ).…”

Mountain building, climate cooling and the richness of cold‐adapted plants in the Northern Hemisphere

“…Plant adaptations to freezing temperatures and short growing seasons include biochemical changes that prevent ice crystals from forming in the cytoplasm, the deployment of proteins and sugars to stabilize cellular membranes when cells become desiccated (Xin & Browse, ), shifts from annual to perennial strategies (Körner, ), as well as additional reproductive investments (Hautier, Randin, Stöcklin, & Guisan, ). Plants further evolved key ecological adaptations in their general morphology, including the evolution of a general lower stature (Körner, ; Pellissier, Pottier, Vittoz, Dubuis, & Guisan, ), tougher leaves (Defossez, Pellissier, & Rasmann, ), more generalist flower shapes (Pellissier et al, ) and a decrease in biomass (Defossez et al, ; Rasmann, Pellissier, Defossez, Jactel, & Kunstler, ). The evolution of ‘trait syndromes’, which represent sets of correlated traits that persist in a given environment, has only occurred in few lineages among vascular plants (Prinzing, ).…”

Tri‐trophic interactions: bridging species, communities and ecosystems

“…Determining the sources of variation will thus require combining environmental manipulations with reciprocal transplant experiments, possibly complemented by genomic approaches to determine the genetic bases for trait variation, patterns of gene expression, as well as manipulations of relevant traits. Third, studies of environmental gradients must move beyond characterising individual food chains (reviewed by Moreira et al ; Defossez et al ; Kergunteuil et al ) to explicitly characterise and compare multiple, co‐occurring tri‐trophic food chains. This approach is analogous to other trait‐based approaches ( sensu McGill et al ), but with a simultaneous focus on plants, herbivores, and natural enemies as well as traits relevant to TTIs (e.g.…”