Vineyard modernization drives changes in bird and mammal occurrence in vineyard plots in dry farmland

Abstract

The fast intensification of agriculture affects many systems. In recent decades, traditional vineyards have been rapidly converted to trellis vineyards in Spain (the country with the largest vineyard surface worldwide) in an attempt to reduce harvesting costs and increase vine productivity. The implications of this modernization of vineyards on farmland biodiversity are still largely unknown. We studied 52 vineyards (26 traditional and 26 trellis) from June to September in south-western Spain, aiming to describe the effect of the modernization of goblet-shape traditional vineyards on vine structure and their management, as well as its effect on species' occurrence in vineyard plots. We applied hierarchical occurrence models to assess the occurrence probability of 10 bird species and two mammal species in traditional and trellis vineyard plots. Vineyard modernization involved taller vines (connected by metallic guide wires and poles by rows), greater distance between vine rows, bigger plot sizes, the systematic implementation of irrigation, and an application of fertilizers through the watering system (fertirrigation) in a third of studied vineyards. Other agrochemical treatments seemed to be equally used in both vineyard types. Due to the use of herbicides and frequent tilling, both types of vineyards showed low natural vegetation groundcover. Vineyard modernization had clear effects on fauna biodiversity in vineyard plots, with a higher occurrence in trellis vineyards of some species (rufous-tailed scrub-robin, European goldfinch, red-legged partridge, and house sparrow) and a higher occurrence of other species (European rabbit and European greenfinch) in traditional ones. Thus, vineyard modernization can drive a change in the community of birds and mammals that inhabit them. In addition, vineyard use by some species (particularly ground-dwelling ones) was strongly determined by the presence of arable land adjacent to the vineyard. These species may therefore use vineyards during summer because they provide water and/or better cover than harvested crops. Animals attracted to vineyards for water could be exposed to toxic doses of nitrates that are routinely applied through the watering system in a third of these. To maximize benefits for biodiversity, it would be advisable to manage modernization schemes in order to maintain landscape heterogeneity, with vineyards of both types combined with other agricultural systems, as well as higher proportions of natural vegetation surface cover.