Les recherches sur l'environnement dans le Massif Armoricain

National audienc

Influence of aldicarb kinetics on earthworm activities in experimental microcosms

International audienceThe influence of soil contaminant kinetics on earthworm activity was studied in experimental soil columns with controlled parameters (microcosms). At first, aldicarb kinetics was studied for 75 days. At the same time, activities of Aporrectodea caliginosa were recorded in uncontaminated soil samples. After 15 days, aldicarb disappears and is replaced by aldicarb sulfoxide. One sample of earthworms was set in contact with aldicarb (phase 1), then a second one with aldicarb sulfoxide (phase 2). A disturbance of the activities of earthworms was observed when aldicarb was present but did not seem to exist with aldicarb sulfoxide. -from Author

Biostimulation : perspectives et limites de l'amélioration biologique des sols par stimulation ou introduction d'espèces lombriciennes

Knowledge of the role played by earthworms in the regulation of soil system dates back to the 19th century (Hensen, 1877, Darwin, 1881). However the acquisition of scientific data on the biology and the ecological impact of these animals, is recent. In France, implementation of this knowledge has been restricted to a few cases. Techniques in this area have therefore remained largely empirical. The current trend of innovative research and developpement in the area of biology and environnement lead us to argument the possibility of finding credible techniques allowing the large scale utilization of earthworms for soil improvment. / La prise de conscience du rôle joué par les lombriciens dans les écosystèmes terrestres est ancienne (Hensen, 1877; Darwin, 1881). Pourtant, l'acquisition des connaissnces fondamentales sur la biologie, puis l'écologie de ces espèces animales est récente. L'application en France de ces connaissances pour développer un outil écologique d'amélioration des sols est ponctuelle et anecdotique. La technique, dans ce domaine biologique et environnemental au sens large, nous conduit à débattre et argumenter les possibilités de mise en oeuvre de techniques crédibles pour l'amélioration biologique des sols par stimulation ou introduction d'espèces lombriciennes efficientes

Characterization of the burrow system of the earthworms Lumbricus terrestris and Apporectodea giardi using X-ray computed tomography and image analysis

International audienceThe burrow systems of two earthworm species (Lumbricus terrestris and Aporrectodea giardi) were studied in artificially packed soil columns placed in controlled conditions in the laboratory. At the end of the incubation, which lasted 246 days, the burrow systems were characterized on the undisturbed columns using X-ray computed tomography. This method provided a set of digitized images corresponding to horizontal 3-mm-thick sections. The following parameters were measured using image analysis on each section: number of biopores, their volume, and their individual orientation calculated using an elliptical model of the earthworm channel. The profiles of these parameters through the columns showed that the burrow systems of L. terrestris and A. giardi, which are both anecic species, were very different in terms of total volume, number of burrows, burrow orientation and extension with soil depth. These results led us to conclude that the burrow system of L. terrestris can be considered as a permanent structure whereas that of A. giardi is closer to the burrow system of endogeic species

Developpement economique et culture scientifique technique et industrielle en environnement Impacts economiques de l'environnement, emplois et besoins de competences

Available at INIST (FR), Document Supply Service, under shelf-number : RP 185 (3495) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Ecologie des contraintes : approche evolutive et fonctionnelle Rapport d'activite scientifique 1985-1989 - URA 0696

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : RP 11029 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Biological invasions in the Antarctic: extent, impacts and implications

Alien microbes, fungi, plants and animals occur on most of the sub-Antarctic islands and some parts of the Antarctic continent. These have arrived over approximately the last two centuries, coincident with human activity in the region. Introduction routes have varied, but are largely associated with movement of people and cargo in connection with industrial, national scientific program and tourist operations. The large majority of aliens are European in origin. They have both direct and indirect impacts on the functioning of species-poor Antarctic ecosystems, in particular including substantial loss of local biodiversity and changes to ecosystem processes. With rapid climate change occurring in some parts of Antarctica, elevated numbers of introductions and enhanced success of colonization by aliens are likely, with consequent increases in impacts on ecosystems. Mitigation measures that will substantially reduce the risk of introductions to Antarctica and the sub-Antarctic must focus on reducing propagule loads on humans, and their food, cargo, and transport vessels