Theme GRAD - Vegetation communities and environmental gradients

Context

Environmental gradients are good tools to infer the organization and the dynamics of vegetation communities. The gradients can be structured in space (stress gradients, disturbance gradients) and/or over time (ecological successions). They cause variations in taxonomic and functional plant diversity at both interspecific and intraspecific levels.

Scientific objective

The main objective of the theme is to create synergies between different geographical projects (the Alps, the Andes, Central Africa, and the Mediterranean basin) using the same method (studies along environmental gradients) to discuss ecological concepts in vegetation ecology.

Approach

In geographic terms, the project in the tropical high Andes examines the role played by interactions between plants in community organization along gradients of environmental stress (aridity, temperature). In the Mediterranean basin, we study the dynamics of vegetation communities under the effects of a disturbance gradient (road infrastructure). A recent project focused on determining how the growth of aerial and subterraneous plant organs is modified along elevation gradients in the Alps (France) and in a tropical context (Mexico), respectively. Also in the Alps, our aim is to identify the microclimatic drivers of root growth (intra- and inter-annual) in montane and subalpine forests. In Central Africa, we examine the influence of climatic, soil and disturbance gradients on plant species composition and on the functional diversity of wooded communities.

Expected results

Results obtained on interactions between plants are – and will continue to be – used to review and refine existing ecological theories such as the stress-gradient hypothesis, especially by accounting for the effects of herbivory and fine variations in the 3D architecture of interacting plants. With respect to ecological successions, we expect variations in the functional strategies of plants, especially intraspecific variations in ecophysiological and architectural traits along gradients. We also expect high responsiveness of plant communities to variations in the frequency of disturbances in systems driven by high levels of anthropogenic pressure (pastures, tropical forests, and road infrastructure). Finally, improved knowledge on the drivers of tree growth along elevation gradients will make it possible to develop growth models based on the assumption that tree growth depends on meristem activity rather than on photosynthetic activity.

Scientific projects

Acronym Title Duration
DISCO-WEEDAssemblage des communautés adventices : entre processus écologiques et perturbations 2016 - 2019
BIO-THAWModeling BIOdiversity and land use interactions under changing glacial water availability in Tropical High Andean Wetlands2013 - 2017
TAFERApport des traits végétaux pour la compréhension et la visualisation des trajectoires successionnelles des communautés végétales de talus d’infrastructures linéaires de transport 2013 - 2016

Major publications

All publications
  • Mao Z., Wang Y., Jourdan C., Cécillon L., Rey H., Saint-André L., Stokes A., 2015. Characterizing above- and belowground carbon partitioning in forest trees along an altitudinal gradient using area-based indicators. Arctic, Antarctic and Alpine Research, 47: 59–69. [Editor link]
  • Prieto I., Roumet C., Cardinael R., Kim J., Maeght J.L., Mao Z., Portillo N., Thammahacksa C, Dupraz C, Jourdan C, Pierret A, Roupsard O, Stokes A, 2015. Root community traits along a land use gradient: evidence of a community-level economics spectrum. Journal of Ecology, 103(2): 361-373. [Editor link]
  • Munoz F., Anthelme F. & Raevel V., 2014. Procesos ecológicos a múltiples escalas que afectan a las dinámicas de comunidades de plantas en los humedales altoandinos de Bolivia. Ecología en Bolivia, 49(3): 104-120.
  • Anthelme F., Buendia B., Mazoyer C. & Dangles O., 2012. Unexpected mechanisms sustain the stress gradient hypothesis in a tropical alpine environment. Journal of Vegetation Science, 23: 62-72. [Editor link]