Road effects on tawny owl abundance and population trend

Urbanization and its inherent road network are one of the major movements that impulse landscape and biodiversity change, and its effects have yet to be fully understood. Few works focus on the effect of this urbanization on abundance and population trend of a certain species, as this study does, using the tawny owl (Strix aluco) as our case study. Although the tawny owl is not threatened at European or global scale, it is often found roadkilled. We studied the effects of different road types on tawny owl abundance in southern Portugal, from 2005 to 2016. In woodlands far from roads, we found high tawny owl abundance, a stable population trend, and low variation in site occupancy. On the contrary, main roads disrupted habitat quality for tawny owls— limiting their abundance and site occupancy and leading to a negative population trend due to disturbance and/or mortality. Secondary roads did not severely disrupt habitat quality, allowing initial occupation and relatively high densities, yet they may act as ecological traps, revealing instability in occupation along the breeding season and a negative population trend. Tawny owl individuals may settle near secondary roads while waiting for a vacant space in woodlands far from roads (the prime high-quality habitats). To avoid the negative effects of roads on tawny owl populations, mitigation efforts should be applied to both main and secondary roads.LIFE LINES (Linear Infrastructure Networks with Ecological Solutions, LIFE14 NAT/PT/001081)(LIFE EU); Popconnect (PTDC/AAGMAA/ 0372/2014) (FCT

Data on mesopredator species

Data on the ranks attributed to the species of mesopredators in terms of their abundance near eagle owl nest sites, their percentage in the diet of eagle owls, and their biomass ratio with the eagle owl

Data for eagle owl nest sites

Data for eagle owl nest sites with: 1) the abundance of the main prey (rabbits); 2) the abundance of mesopredators (owls and raptors); 3) the percentage in the diet of main prey groups and mesopredator