Plant species, functional assemblages and partitioning of diversity in a Mediterranean agricultural mosaic landscape

Abstract

Agricultural landscapes represent mosaics of different habitats that can harbour high plant diversity where plant traits and trait syndromes can be used for predicting either plant responses to agricultural intensification or plant functional effects on other organisms. Understanding the spatial components of diversity within an agricultural mosaic can help to select the appropriate spatial scale for conserving species and ecological functions such as the provisioning of resources for pollinators. We hypothesize that trait syndromes aimed at provisioning resources for pollinators are positively related to non-crop habitats and negatively related to increasing agricultural intensification. We sampled plant species in 140 patches distributed among seven habitats (abandoned fields, boundaries, roadverges, and edges and inner alfalfa and cereal fields) that were classified into three levels of agricultural intensification: Low, Medium and High. We examined differences in species and functional assemblages, splitting response and effect traits, across various habitats and levels of agricultural intensification. Species richness and functional diversity of response and effect traits were partitioned along spatial scales. Both species and functional assemblages changed across habitats and with different levels of agricultural intensification. Non-cropped habitats and low levels of agricultural intensification promoted trait syndromes with trait-overdispersion mainly linked to the provisioning of resources for pollinators. The species turnover did not imply a functional turnover. Our study shows that traits are determined by agricultural intensification, and no further details on field position and habitat variability are needed to promote vegetation types with trait syndromes able to support pollinating insects.