Responses of birds to vineyard abandonment in Slovakia

Vineyards are semi-natural, human-modified ecosystems where the extent of natural elements is determined primarily by the type of management and by the abandonment rate. In this study, we analyzed bird assemblages in 40 vineyard plots in six wine-growing regions of Slovakia. We examined bird communities on managed and abandoned vineyards to identify possible patterns. Environmental and spatial predictors of species richness and abundance were analyzed using partial redundancy analysis (pRDA) and a generalized additive model (GAM). Bird communities were influenced by both environmental and spatial factors. As expected, elevation explained most of the variation in bird assemblages. Tree coverage was found to be more important than the vineyard abandonment rate in explaining the observed variability. Only a portion of the variance in the species data reported by pRDA was accounted for by the difference in vineyard abandonment degree. Our results show that the species richness of all birds was positively correlated to vegetation density (captured by NDVI). Herb and shrub cover had less effect on bird species richness than tree cover and the presence of traditional agricultural vineyard landscapes. However, shrub density emerged as a key explanatory factor for the abundance of habitat specialists. Our study shows that, depending on whether the goal is to promote the diversity and abundance of farmland or non-farmland bird species, different conservation biology approaches should be used. Increasing the landscape diversity and avoiding large vineyard abandonment are necessary if we are to stem the decline of valuable farmland species.