Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Arthropods represent most of global biodiversity, with the highest diversity found in tropical rain forests. Nevertheless, we have a very incomplete understanding of how tropical arthropod communities are assembled. 2. We conducted a comprehensive mass sampling of arthropod communities within three major habitat types of lowland Amazonian rain forest, including terra firme clay, white-sand and seasonally flooded forests in Peru and French Guiana. We examined how taxonomic and functional composition (at the family level) differed across these habitat types in the two regions. 3. The overall arthropod community composition exhibited strong turnover among habitats and between regions. In particular, seasonally flooded forest habitats of both regions comprised unique assemblages. Overall, 17.7% (26 of 147) of arthropod families showed significant preferences for a particular habitat type. 4. We present a first reproducible arthropod functional classification among the 147 taxa based on similarity among 21 functional traits describing feeding source, major mouthparts and microhabitats inhabited by each taxon. We identified seven distinct functional groups whose relative abundance contrasted strongly across the three habitats, with sap and leaf feeders showing higher abundances in terra firme clay forest. 5. Our novel arthropod functional classification provides an important complement to link these contrasting patterns of composition to differences in forest functioning across geographical and environmental gradients. This study underlines that both environment and biogeographical processes are responsible for driving arthropod taxonomic composition while environmental filtering is the main driver of the variance in functional composition.
ISSN: 0021-8790

hal-01531619
https://hal.archives-ouvertes.fr/hal-01531619
PRODINRA : 349695
PUBMED : 26346553
DOI : 10.1111/1365-2656.12445

Éditeur(s) : HAL CCSD Wiley
Résumé : 1. Functional traits provide insight into a variety of ecological questions, yet the optimal sampling method to estimate the community-level distribution of plant functional trait values remains a subject of debate, especially in species-rich forests. 2. We present a simulation analysis of the trait distribution of a set of nine completely sampled permanent plots in the lowland rain forests of French Guiana. 3. Increased sampling intensity consistently improved accuracy in estimating community-weighted means and variances of functional trait values, whereas there was substantial variation among functional traits and minor differences among sampling strategies. 4. Thus, investment in intensified sampling yields a greater improvement in the accuracy of estimation than does an equivalent investment in sampling design complication. 5. Notably, 'taxon-free' strategies frequently had greater accuracy than did abundance-based strategies, which had the additional cost of requiring botanical surveys. 6. We conclude that there is no substitute for extensive field sampling to accurately characterize the distribution of functional trait values in species-rich forests.
ISSN: 0269-8463

hal-01536541
https://hal.archives-ouvertes.fr/hal-01536541
PRODINRA : 343202
DOI : 10.1111/1365-2435.12433