Éditeur(s) : HAL CCSD Wiley
Résumé : The consequences of biodiversity loss for ecosystem services largely depend on the functional identities of extirpated species. However, poor descriptions of spatial patterns of community functional composition across landscapes hamper accurate predictions, particularly in highly diverse tropical regions. Therefore, understanding how community functional composition varies across environmental gradients remains an important challenge. We sampled 15 functional traits in 800 Neotropical tree species across 13 forest plots representative of the broad climatic and soil gradients encompassed by three widespread lowland forest habitats (terra firme forests on clay-rich soils, seasonally flooded forests and white-sand forests) at opposite ends of Amazonia (Peru and French Guiana). We combined univariate and multivariate approaches to test the magnitude and predictability of environmental filtering on community leaf and wood functional composition. Directional shifts in community functional composition correlated with environmental changes across the 13 plots, with denser leaves, stems and roots in forests occurring in environments with limited water and soil-nutrient availability. Critically, these relationships allowed us to accurately predict the functional composition of 61 additional forest plots from environmental data alone.Synthesis. Environmental filtering consistently shapes the functional composition of highly diverse tropical forests at large scales across the terra firme, seasonally flooded and white-sand forests of lowland Amazonia. Environmental factors drive and allow the prediction of variation in community functional composition among habitat types in Amazonian forests.
ISSN: 0022-0477

hal-01204211
https://hal.archives-ouvertes.fr/hal-01204211
DOI : 10.1111/1365-2745.12160
PRODINRA : 259900

Éditeur(s) : HAL CCSD American Arachnological Society
Résumé : To obtain a reliable description of spider communities, robust sampling protocols are crucial. However, it remains unclear if descriptions of spider communities in tropical habitats require both day and night sampling. Here we tested whether sampling both day and night in high and low vegetation strata would lead to better diversity estimates of spider communities than sampling at only one period of the day. We determined spider taxonomic diversity in a network of 12 plots in French Guiana along a vegetation gradient. We found high alpha diversity of spiders as expected for a tropical area at every site. We showed strong differences in spider alpha and beta diversity between high and low vegetation strata, while they were similar between day and night sampling. Our results suggest that collecting spiders at only one period is sufficient to describe the diversity of spider communities across land use types in the neotropics.
ISSN: 0161-8202

hal-01535342
https://hal.archives-ouvertes.fr/hal-01535342
PRODINRA : 346667