What if you could close all the roads around the world and let animals roam freely? It may not be realistic to imagine all roads closed all the time. But what would happen if some roads closed some of the time?
That idea was put to test in a recent study at Banff National Park. The Bow Valley Parkway is a secondary road that parallels the TransCanada Highway and currently attracts almost half a million vehicles per year. From 2014-2017, a 17 km stretch of the parkway, which cuts through habitat that supports a diversity of wildlife due to its relatively low elevation, was closed from 10 p.m. to 8 a.m. for almost four months during the spring.
Three methods were used to assess changes in wildlife movement. First, wildlife detections at ten remote cameras along the parkway were compared to detections at 64 cameras elsewhere in the Bow Valley. Second, roadside observation studies along the parkway while it was closed were compared to observations along a permanently open road just west of the parkway. Third, grizzly bear locations (from GPS collars) near the closed parkway were compared to locations in the same region in previous years when the parkway had not been closed.
The remote cameras showed that wolf, deer, and elk use of the parkway dropped the most when the road changed from closed to open, and that wildlife detection rates doubled on the parkway during the temporal closure while detection rates elsewhere remained the same. Road surveys resulted in 112 wildlife detections on the parkway when it was closed, but only 16 detections when it was open, and only 12 detections on the permanently open road to the west. Grizzly bears were more likely to be found near the parkway in the years when it was temporarily closed than in years when it was not.
This provides some of the first empirical evidence that seasonal road closures can be used to restore habitat quality and improve connectivity. They can be particularly effective during spring or fall, when many species are mating or raising young. The results also emphasize the fact that wildlife mostly avoid the people on linear structures, rather than just the linear structures themselves.
Although not every species of wildlife would benefit from seasonal closures, there are many for whom temporarily closed roads would create more linkages in the landscape. Temporal closures can be a powerful tool for managers who must balance the needs of wildlife with socio-economic factors such as tourism, recreation, and resource extraction. They represent an important conservation strategy for restoring multi-species connectivity.