Diversity in the monotony? Habitat traits and management practices shape avian communities in intensive vineyards

Abstract

Spreading of viticulture may pose serious threats to biodiversity and adequate policies targeted at decreasing its impact are urgently required. Current knowledge of viticulture effects on biodiversity is scarce and studies on bird communities in vineyards are even scarcer.We surveyed avian assemblages in Trentino vineyards (North-East Italy) in both breeding and wintering seasons to evaluate the effect of: i) landscape, ii) management and iii) topographic-climatic characteristics on birds and to derive implications for conservation. We calculated four community indexes (species richness, abundance, evenness and conservation index) and modelled their relative variation according to 18 environmental variables belonging to the three above-mentioned groups.Landscape models performed better than the others, except for winter evenness, for which management models were the most supported ones. Generally, models considering the three groups together explained more variation than models from an individual group.Landscape (and agricultural) heterogeneity, extent of marginal habitats, density of traditional elements (hedgerows, tree rows, isolated trees and rural buildings) all had positive effects, whereas vineyard cover had negative impact on the value of the four community indexes.Organic management had no apparent effect on avian communities. We detected a seasonal difference in the effects of environmental characteristics on bird communities, which suggested that local conservation efforts could be tuned according to the seasonal importance of vineyards in different regions.Key measures to promote biodiversity in vineyards include maintaining patches of residual habitats in the vineyard matrix and enhancing heterogeneity. Marginal features appeared particularly important in the homogeneous landscape of intensive vineyards to favour bird communities.