Biodiversity inventories were carried out in the Picardie region (in the north of France) on poplar plantations of various ages and situations. These inventories referred to three biological components: (i) ground-beetles, (ii) birds, (iii) vegetation. For the ground-beetle study, sorne of the poplar stands could be compared with other border environments: cereal fields or broadleaved forests. The results showed that the specific richness ofthe poplar stands in the Picardie region varied according to sites but were overall high for the three components. The ground-beetle specific richness was very variable according to the studied sites, the highest being found on alluvial sites. The populations of ground-beetles seem to be structured according to soil moisture, vegetation coyer and, to a lesser extent, soil pH. Differences were rare1y significant. The comparisons carried out in 2003 with border environments indicated that specific richness in poplar stands is higher than in broadleaved forest and equivalent to that in cereal fields. The Shannon index and Equitability index (species distribution) were higher for poplar plantations and broadleaved forest. Ground-beetle populations in cereal fields were very unbalanced. The poplar stands seem able to accommodate species of open environments and forest species in balanced proportions. For bird communities, poplar stands located on alluvial sites had higher specific richness and diversity than those located on the plateaux. Specific richness and diversity decreased with the age and canopy c1osure. The avifauna was primarily made up of ubiquitous species of c10sed forest environments. Species of open forest environments are more frequent in young poplar plantations without understorey. It seems there is no specific avifauna for poplar stands, except for Oriolus oriolus, which was very frequently observed. Plant communities, in spite of the homogeneity of overstorey, were well diversified. The variety of sites, soils and previous vegetation could explain this diversity. This high specific richness could be due to suitable conditions (water and nutrient availability) of alluvial soils on which poplars are cultivated. The plant communities were structured by number and type of tendings (disks or mowing). The resulting disruptions tend to support the specific diversity, but, on the other hand, reduce the "phytosociological coherence" of the communities. The increase in available resources (light, water, nitrogen) benefited the cultivated poplars, but also sometimes the heliophilous social species (for example Rubus spp on plateaux) that compete strongly with other species.