When Roads Become Walls: The Struggle of the Mongolian Gazelle

For migratory wildlife, the open steppe is becoming an obstacle course. A recent study focusing on 62 Mongolian gazelles has illuminated exactly how human-made structures—specifically fences and roads—disrupt their natural movements. By analysing behaviour at both fine and broad scales, researchers discovered that fences act as major blockades to these iconic ungulates.

When confronted with a fence, gazelles rarely cross immediately. Instead, they exhibit 'tracing' behaviour, walking alongside the barrier for extraordinary distances. The study recorded an average tracing distance of 40.2 kilometres, with one determined individual travelling 211.6 kilometres before finding a way across or turning away. This significant energy expenditure highlights the severity of the habitat fragmentation.

Surprisingly, paved roads often provoked a similar reaction. High traffic volumes turned these open strips of tarmac into semi-permeable barriers, causing the gazelles to display 'bouncing behaviour'—moving back and forth—much like they do at physical fences. Identifying these long-distance tracing patterns is crucial for conservation. It allows planners to pinpoint exactly where barrier effects are strongest, guiding the design of smarter, more permeable infrastructure to protect the steppe ecosystem.