12 research outputs found
Global change, soil biodiversity, and nitrogen cycling in terrestrial ecosystems: three case studies.
The relative contribution of different soil organism groups to nutrient cycling has been quantified for a number of ecosystems. Some functions, particularly within the N-cycle, are carried out by very specific organisms. Others, including those of decomposition and nutrient release from organic inputs are, however, mediated by a diverse group of bacteria, protozoa, fungi and invertebrate animals. Many authors have hypothesized that there is a high degree of equivalence and flexibility in function within this decomposer community and thence a substantial extent of redundancy in species richness and resilience in functional capacity. Three case studies are presented to examine the relationship between soil biodiversity and nitrogen cycling under global change in ecosystem types from three latitudes, i.e. tundra, temperate grassland and tropical rainforest. In all three ecosystems evidence exists for the potential impact of global change factors (temperature change, COP enrichment, land-use-change) on the composition and diversity of the soil community as well as on various aspects of the nitrogen and other cycles. There is, however, very little unequivocal evidence of direct causal linkage between species richness and nutrient cycling efficiency. Most of the changes detected are shifts in the influence of major functional groups of the soil biota (e.g. between microflora and fauna in decomposition). There seem to be few data, however, from which to judge the significance of changes in diversity within functional groups. Nonetheless the soil biota are hypothesized to be a sensitive link between plant detritus and the availability of nutrients to plant uptake. Any factors affecting the quantity or quality of plant detritus is likely to change this link. Rigorous experimentation on the relationships between soil species richness and the regulation or resilience of nutrient cycles under global change thus remains a high priority
Suivi ecologique des micro-meiofaunes des sediments marins en zone littorale en Guadeloupe
SIGLECNRS RP 185 (1703) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Examen de fractions granulometriques de la matiere organique en tant que source d'azote mineral Effet de l'activite rhizospherique
SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : RP 185 (2860) / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc