Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
In a study of a 15-year-old pasture in Martinique (French West Indies), abundance and organization of microarthropod communities were correlated with the spatial distribution of the earthworm Polypheretima elongata (Megascolecidae). In patches of high earthworm density (133 individuals m-2), microarthropod density was significantly higher (80 000 individuals m-2) than in patches with few earthworms (31 worms m-2 and 49 000 microarthropods m-2). The diversity of microarthropod communities followed a similar pattern, the Shannon index for Collembola communities being, respectively, 3.12 and 1.82 in and outside earthworm patches. These results suggest that mesofauna abundance and diversity might be at least partly determined by the activity of larger invertebrates, as a result of the dramatic effects that the latter group exerts upon soil structure, pore distribution and food resources.
ISSN: 0178-2762

hal-00505427
https://hal.archives-ouvertes.fr/hal-00505427
https://hal.archives-ouvertes.fr/hal-00505427/document
https://hal.archives-ouvertes.fr/hal-00505427/file/Loranger_et_al._1998b.pdf
DOI : 10.1007/s003740050394

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Despite the impact of soil millipedes on litter fragmentation in tropical forests, there have been few studies dealing with factors determining their habitat preference in these ecosystems. In a natural secondary dry forest of Guadeloupe on Leptosol, two complementary studies were carried out in order to test the hypothesis that litter N-content strongly influences millipede distribution. Millipede abundance and species richness were described in the field under two tree species, Bursera simaruba and Pisonia subcordata, and were related to the chemical characteristics of their foliage. In addition, a laboratory experiment was done in order to assess millipede feeding preferences regarding the chemical characteristics of leaves from various species. Millipede abundance and species richness were significantly higher under P. subcordata than under B. simaruba, probably due to the higher N content of P. subcordata leaves. Moreover, millipedes fed preferentially on N-rich leaves. The present study confirms that there was a close correlation between the preferred food, its chemical composition and the local distribution of millipede populations.
ISSN: 0178-2762

hal-00495211
https://hal.archives-ouvertes.fr/hal-00495211
https://hal.archives-ouvertes.fr/hal-00495211/document
https://hal.archives-ouvertes.fr/hal-00495211/file/BFSO-D-08-00133-1.pdf
DOI : 10.1007/s00374-008-0321-3

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
Decomposition processes in tropical semi-evergreen forests are still poorly understood. The influence of soil properties and litter quality on decomposition rate was studied in two semi-evergreen forests of Guadeloupe, a forest plantation and a secondary forest, located on different soils. Leaf litter of four tree species was enclosed in litterbags for a 14-month period. Nonlinear correlations were calculated between mass loss and the concentration of major leaf components (soluble C, N, lignin, cellulose, tannins, total soluble phenols) in order to determine the best predictor of leaf litter decomposition. Soil physico-chemical properties and ratios between some of the above-mentioned litter quality parameters were also examined as mass loss predictors. In addition, non-linear correlations were calculated between mass loss and litter quality parameters, at successive periods. Litter quality was the main determinant of litter decomposition in the studied forests. Several litter quality parameters were correlated with leaf disappearance, varying according to stages of decomposition. Between 1 month and 2.5 months, the mass loss was correlated negatively with the initial phenol content and with initial lignin:N and (lignin+phenol):N ratios. From 2.5 to 5.5 months, the mass loss was correlated negatively with the initial phenol content and positively with the initial cellulose content. At later stages of decomposition (9-14 months), the mass loss was correlated negatively with the initial tannin content. Differences in soil characteristics and fauna did not seem to be enough to affect decomposition.
ISSN: 0178-2762

hal-00499535
https://hal.archives-ouvertes.fr/hal-00499535
https://hal.archives-ouvertes.fr/hal-00499535/document
https://hal.archives-ouvertes.fr/hal-00499535/file/Article_decomposition.pdf
DOI : 10.1007/s00374-002-0467-3

Éditeur(s) : HAL CCSD
Résumé : International audience
Biol fertil soils

hal-00334164
https://hal.archives-ouvertes.fr/hal-00334164
DOI : 10.1007/s00374-008-0321-3

Éditeur(s) : HAL CCSD
Biol fertil soils

hal-00271510
https://hal.archives-ouvertes.fr/hal-00271510
DOI : 10.1007/s00374-007-0199-5

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The importance of secondary tropical forests regarding the maintenance of soil fauna abundance and diversity is poorly known. The aims of this study were (1) to describe soil fauna abundance and diversity and (2) to assess the determinants of soil fauna abundance and diversity in two stands of a tropical semi-evergreen secondary forest. Soil macrofauna and microarthropod abundance and soil macrofauna diversity were described at two sites developed on different soils and with different site histories: (1) a natural secondary stand (natural forest) under two dominant tree species, Pisonia subcordata and Bursera simaruba, and (2) a planted secondary forest (planted forest) under three tree species, B. simaruba, Swietenia macrophylla, and Tabebuia heterophylla. The effects of both soil and main tree species' litter quality were assessed to explain soil fauna abundance and diversity. The abundance of soil macrofauna was significantly higher in the soil under the planted forest, and soil fauna communities were contrasted between the two sites. In the planted forest, a soil-dwelling macrofauna community developed (mainly consisting of the anecic earthworm Polypheretima elongata). In the natural forest, soil macrofauna and microarthropod communities were located at the soil surface. The effect of plant litter quality varied according to each dominant tree species and was superimposed to soil effect. The lowest macrofauna abundance was associated with B. simaruba in the natural forest. T. heterophylla supported a much greater macrofauna community than the two other tree species studied at the same soil, and it appears likely that this is due to the palatability of its leaves compared with the other trees (low lignin, tannins, soluble phenols).
ISSN: 0178-2762

hal-00495371
https://hal.archives-ouvertes.fr/hal-00495371
https://hal.archives-ouvertes.fr/hal-00495371/document
https://hal.archives-ouvertes.fr/hal-00495371/file/Loranger-Merciris_et_al._2007.pdf
DOI : 10.1007/s00374-007-0199-5