CT4HU55H

2764

5 janvier 2021 17:06

5 janvier 2021 17:06

Biodiversity studies that guide agricultural subsidy policy have generally compared farming systems at a single spatial scale: the field. However, diversity patterns vary across spatial scales. Here, we examined the effects of farming system (organic vs. conventional) and position in the field (edge vs. center) on plant species richness in wheat fields at three spatial scales. We quantified a-, b-, and c-diversity at the microscale in 800 plots, at the mesoscale in 40 fields, and at the macroscale in three regions using the additive partitioning approach, and evaluated the relative contribution of b-diversity at each spatial scale to total observed species richness. We found that a-, b-, and c-diversity were higher in organic than conventional fields and higher at the field edge than in the field center at all spatial scales. In both farming systems, b-diversity at the meso- and macroscale explained most of the overall species richness (up to 37% and 25%, respectively), indicating considerable differences in community composition among fields and regions due to environmental heterogeneity. The spatial scale at which b-diversity contributed the most to overall species richness differed between rare and common species. Total richness of rare species (present in 5% of total samples) was mainly explained by differences in community composition at the meso- and macroscale (up to 27% and 48%, respectively), but only in organic fields. Total richness of common species (present in !25% of total samples) was explained by differences in community composition at the micro- and mesoscale (up to 29% and 47%, respectively), i.e., among plots and fields, independent of farming system. Our results show that organic farming made the greatest contribution to total species richness at the meso (among fields) and macro (among regions) scale due to environmental heterogeneity. Hence, agri-environment schemes should exploit this large-scale contribution of b-diversity by tailoring schemes at regional scales to maximize dissimilarity between conservation areas using geographic information systems rather than focusing entirely at the classical local-field scale, which is the current practice.

None

• AB - Modalité bio
• FREDO environnement
• GEO Allemagne
• arable weeds
• biodiversité
• comparaison
• field edge
• gamma diversity
• landscape
• mass effect
• mixed effect models
• organic farming
• spatial scale
• species richness

Ecological Applications

16

2011-2021

10/2006

1 octobre 2006

10.1890/1051-0761(2006)016[2011:BDADSS]2.0.CO;2 Le DOI est une URL unique de référencement d'une publication. Il est donc plus fiable et permanent qu'une URL classique

1051-0761 L’ISSN est un code de 8 chiffres servant à identifier les journaux, revues, magazines, périodiques de toute nature et sur tous supports, papier comme électronique.