Fences are ubiquitous in many landscapes. Along with walls, roads, and railways, fences act as a linear barrier to movement for wildlife worldwide and can lead to reductions in gene flow, access to resources and even mortality. Fences are especially problematic for migratory species, who are more likely to encounter multiple fence barriers as they travel long distances and therefore more threatened by decreased connectivity.
The removal of portions of fence line could restore connectivity for migrating animals. Despite the negative impacts they present to wildlife, fences are costly to remove. Targeted removal of fences that restore the largest amount of connectivity could have the greatest impact on wildlife while keeping costs within manageable limits.
Schwandner, I.A., Morrison, T.A., Hopcraft, J.G.C., Wall, J., Hughey, L., Boone, R.B., Ogutu, J.O., Jakes, A.F., Kifugo, S.C., Limo, C. and Ndambuki Mwiu, S. 2025. Predicting the impact of targeted fence removal on connectivity in a migratory ecosystem. Ecological Applications, 35(1): e3094.
In a new study, researchers used spatial data to determine where to remove fences to restore connectivity for one migratory species, the white bearded wildebeest that inhabit the Greater Masai Mara Ecosystem in Kenya. Despite their high mobility, they are poor at jumping fences. To determine how fence removal could restore connectivity for wildebeests, researchers used wildebeest movement data pre-fencing, movement data during fencing, and fine-scale fencing records to simulate how targeted fence removal could lead to connectivity gains for the wildebeest.
The results show that just 15-140 km of fence removal could improve connectivity for the wildebeest by 39-54%. Researchers balanced the cost of fence removal and connectivity gains while evaluating three possible corridor locations, finding that one corridor was preferable above the rest. Compared to the other two corridors, their pick intersected fewer parcels of land and terminated in a sparsely fenced area. Researchers also found that even narrow corridors (500 m-1km) could provide substantial connectivity gains (>40% increase in connectivity).
In sum, targeted fence removal can provide substantial connectivity gains for wildebeests in this ecosystem, while still balancing cost. This study provides an example of how human landscape modification can be balanced to maintain connectivity for wildlife. With the necessary data in hand, this approach could be applied to other landscapes, like western North America where fences disrupt connectivity for animals traversing the Yellowstone to Yukon corridor.
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