The world’s most critically endangered primate, the Hainan gibbon, has been observed for the first time crossing artificial rope bridges built to connect large gaps in the canopy of its forest habitat. The findings, which suggest that artificial rope bridges may help with conservation efforts, are published in Scientific Reports.
Hainan gibbons are exclusively found in the forests of Hainan Island, China. Within their habitat, they travel above ground from tree to tree and gaps in the forest canopy ― either natural or man-made ― can restrict populations to a specific area, limiting foraging, breeding opportunities and increasing risk of predation.
In 2015, Bosco Pui Lok Chan and colleagues constructed an artificial canopy bridge for Hainan gibbons to support travel between two areas of habitat separated by a 15m wide gully formed by a natural landslide. Mountaineering-grade ropes were tied to sturdy trees with the help of professional tree climbers and motion sensor cameras were installed to monitor wildlife usage.
Hainan gibbons were first photographed crossing the rope bridge 176 days after assembly. Over the 470-day study period, 208 photographs and 53 videos of gibbons using the rope bridge were recorded. Footage captured the gibbons using climbing movements along the rope most often, followed by arm swinging. All nine gibbon group members were recorded using the canopy bridge except the adult male. Larger juveniles did not use the rope bridge often, and were instead regularly recorded leaping across the forest gap with the adult male.
The study highlights the use and value of rope bridges to connect gaps in forest canopies. Although restoring natural forest should be a priority conservation intervention, artificial canopy bridges may be useful short-term solutions, the authors conclude.
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