Juliette HEROUET, Thomas DROUET
The main focus of this work is to use the natural variation of stable isotopes to understand element cycling in forest ecosystems. Strontium (Sr) isotopes are used as a proxy for calcium (Ca) and offer a powerful tool to discriminate between atmospheric and mineral weathering sources of Ca in tree nutrition. The origin and fluxes of Ca is examined at several field sites with contrasting nutrient status. The coupling of this isotopic method with the archive properties of tree-rings (dendrochemistry) adds an important piece to the knowledge of the soil acidification story. We are currently testing the use of other isotopic tracers (multi-isotopic approach: Sr-Pb-Nd) to provide data on mineral weathering, atmospheric depositions and anthropogenic sources of nutrients. Such method appears to be a promising way to determine the impact of several tree species on the soil properties and the nutrient biogeochemistry. This work is associated with the development of simple computer model to examine the role of internal fluxes (recycling) and highlight the strategies of nutrient acquisition by trees. Financial support is provided by the Fonds National de la Recherche Scientifique (FNRS, Belgium) through the convention FRFC nr 2.4607.07.
Nicolas DASSONVILLE, Basile HERPIGNY and Pierre MEERTS
Alien invasive plants represent an important dimension of global change. In NW Europe, a number of
3.1. Evolutionary ecology of a zinc hyperaccumulator
Nausicaa NORET and Pierre MEERTS
Thlaspi caerulescens, a Cd-Zn hyperaccumulator, is used as a model species to address fundamental questions on the evolutionary and adaptive significance of heavy metal hyperaccumulation in plants:
3.2. Ecology and evolution of copper/cobalt tolerant plants in Katanga (DR Congo)
In Katanga (DR Congo), natural outcrops of bedrock contaminated with Cu and Co (“copper hills”) are colonized by unique vegetation, consisting of heavy metal tolerant species (cuprophytes). A number of species are endemic of those sites. Plant communities on those sites have an extremely variable species composition, in relation to complex environmental gradients. A number of species have evolved the extraordinary capacity to hyperaccumulate Cu and/or Co.
Our research develops in three directions.
In collaboration with the Herbarium and Library of African Botany of ULB, our laboratory contributes to the elaboration of the Flore d'Afrique Centrale (DR Congo, Rwanda, Burundi), edited by the National Botanical Garden of Belgium. In particular, the complex genus Chlorophytum (Asparagaceae) is being revised, based on herbarium materials and original field observations, in collaboration with the Museum of Natural History of Oslo (molecular phylogeny).