Field margins as ecological corridors: Uncovering connectivity in agricultural landscapes using high-resolution tracking data and translocation experiments

Ecological corridors are key for reducing habitat fragmentation, yet their designation often relies on structural connectivity analysis based on expert opinion, land uses and species occurrence rather than actual movement analysis, limiting our understanding of their effectiveness. This study aims to explore and experimentally test how different habitats facilitate or impede species movement in an intensive agricultural landscape designated as ecological corridors. Using a cutting-edge tracking system (ATLAS), we monitored the movement of 68 white-spectacled bulbuls (Pycnonotus xanthopygos) at high resolution (4 or 8-s intervals) and explored fine-scale habitat selection through integrated step selection analysis, focusing on movement segments while excluding static periods. To validate our observational findings, we conducted a translocation experiment with 64 bulbuls across three habitat treatments: natural, arable fields and arable fields intersected by a main paved road. We compared return time, number of stops, the movement straightness of return flights across treatments and the habitat selection during these flights. Bulbuls avoided arable fields, which significantly impeded their movement through the agricultural landscape. This was further confirmed in the translocation experiment, where bulbuls from the ‘arable field’ treatment took the longest to return, made the most stops and followed the most tortuous paths. Bulbuls demonstrated a strong preference for vegetative features, such as narrow field margins, which comprised only 2.2% of the study area, underscoring their importance as movement corridors. The translocation experiment reinforced this result, with bulbuls consistently selecting field margins regardless of their treatment group. Additionally, bulbuls from the ‘natural’ treatment returned the fastest and followed the most direct paths. Synthesis and applications. Our study demonstrates that field margins can play a major role in maintaining connectivity and enhancing ecological corridor functionality in intensive agricultural landscapes, even for habitat generalist species like the bulbul. The use of high-resolution movement data enabled fine-scale habitat analysis, revealing the key role of these vegetative features in facilitating movement. Conservation efforts should prioritize maintaining these small-scale elements to enhance corridor effectiveness in agricultural landscapes.