Impact of fine‐scale edaphic heterogeneity on tree species assembly in a central African rainforest
QUESTIONS: Soil properties have been shown to partially explain tree species distribution in tropical forests. Locally, species turnover across space can result not only from edaphic heterogeneities but also from limited seed dispersal. To characterize the contribution of each process, contact areas...
Saved in:
Published in | Journal of vegetation science Vol. 26; no. 1; pp. 134 - 144 |
---|---|
Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Opulus Press
2015
Blackwell Publishing Ltd |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | QUESTIONS: Soil properties have been shown to partially explain tree species distribution in tropical forests. Locally, species turnover across space can result not only from edaphic heterogeneities but also from limited seed dispersal. To characterize the contribution of each process, contact areas between contrasted soil types offer ideal settings. In the present study, we aimed to test species and species assemblage responses to a sharp edaphic discontinuity in a tropical forest tree community. LOCATION: Yoko forest reserve (6975 ha), Democratic Republic of the Congo. METHODS: We set up four 500–600‐m long parallel transects crossing two contrasted edaphic habitats, one lying on clayey soil and the other on sandy soil. The canopy and subcanopy trees were identified and geo‐referenced along the transects over a width of 50 m and 5 m, respectively, and soil samples were collected every 50 m to characterize each habitat. RESULTS: Correspondence analyses indicated a clear differentiation of tree communities between sandy and clayey soils. Using a torus‐translation method combined with Chi‐squared non‐parametric tests, we observed that ca. 40% and 18% of the species represented by at least 12 individuals displayed significant density differences according to habitat in the canopy and subcanopy, respectively, although very few species displayed significant differences in their relative abundance. Nevertheless, whole community tests of differentiation (in species relative abundances) between soil types were significant in both strata, even after removing individual species or families displaying a significant habitat preference. CONCLUSION: While only a minority of species displayed a clear habitat preference, we still observed a community‐wide impact of the edaphic discontinuity on species assemblages at a local scale. Our results provide further evidence for the major contribution of environmental heterogeneity in maintaining biodiversity in tropical forests. |
---|---|
Bibliography: | http://dx.doi.org/10.1111/jvs.12209 ArticleID:JVS12209 Belgian Fund for Scientific Research istex:15A5AD7F19C7CCA1626C236D67095EDEE4286CA2 Belgian Commission Universitaire au Développement (CUD) ark:/67375/WNG-6WWVG8X0-F Belgian Fund for Training to Research in Industry and Agriculture (FRIA) Appendix S1. Subplot values of all environmental variables. Appendix S2. Subplot density of each canopy species used in the CA and CCA. Appendix S3. Subplot density of each subcanopy species used in the CA and CCA. Appendix S4. R code for computing S, s and D statistics. Appendix S5. List of all canopy and subcanopy individuals used in the R code (Appendix S4). Appendix S6. PCA performed on environmental variables. Appendix S7. Summary of stem densities and floristic diversity data on each edaphic habitat, for the canopy and subcanopy strata. Appendix S8. Ordination of the subplots (CA) after removing the highly dominant species Scorodophloeus zenkeri (a) or the Fabaceae (b) in the canopy. Appendix S9. Densities and relative abundances of each testable family of the canopy and subcanopy on each soil type, and significance of the S and s tests. Appendix S10. CCA performed on canopy and subcanopy species densities and environmental data. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1100-9233 1654-1103 |
DOI: | 10.1111/jvs.12209 |