Threshold responses of birds to agricultural intensification in Mediterranean olive groves

Olive groves are the most representative crop of the Mediterranean basin. This agroforestry system is undergoing a strong transformation in recent decades as a result of the agricultural intensification process prevailing in the Northern Hemisphere.

Here, we examined the existence of synchronous responses in bird abundance across a gradient of decreasing agricultural intensification in Spanish olive groves. Our study system comprised 25 sites, each consisting of a pair of farms: one with intensive management and the other one with extensive management of the herbaceous cover. We explored whether bird abundances exhibit non-linear threshold responses to ant abundance and tree density at a local (field) scale, plant diversity (both herbaceous and woody plants) at a local (farm) scale, and to proportion of natural habitat at a landscape scale using Threshold Indicator Taxa ANalysis (TITAN).