Exploring the role of transhumance drove roads on the conservation of ant diversity in Mediterranean agroecosystems

Drove roads are a major feature of Mediterranean countries, where this livestock management system has been practiced for centuries. In Spain, many drove roads have become completely or partially abandoned by herders, and transformed for other land uses. Yet, some major drove roads continue to be used for the passage of livestock, and might exert important effects on the conservation of biodiversity and ecosystem functions, particularly in highly transformed agricultural landscapes. In this study, we compare ant taxonomic and functional diversity on a drove road that is still used by transhumant livestock (the Conquense Drove Road) versus an abandoned road (the Murciana Drove Road). Ant species richness per trap and ant richness per sample unit were significantly higher on the used drove road compared to the abandoned drove road. The used drove road also had a positive edge effect on ant species diversity in adjacent croplands (both herbaceous crops and vineyards). Ant functional diversity was also higher on the used drove road. These results draw attention to the role of drove roads as ecologically unique systems and reservoirs of biodiversity, particularly within intensive agricultural landscapes. These effects, however, are largely dependent on maintaining livestock use.