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Good practice Imported

Canopy Bridges in Playa Hermosa, Guanacaste — Rope Crossings Linked to a Near-Doubling of a Costa Rican Howler Monkey Population

Costa Rica · Playa Hermosa · See the Costa Rica profile

Evidence: Observational / pre–post Top 76% 33/100 · Ask Evidence Copilot about this practice

After a University of Costa Rica primatologist found a howler monkey electrocuted crossing a canopy gap, her team strung rope bridges over roads and power lines in Playa Hermosa; cameras recorded 76 crossings within months, and the local howler population nearly doubled by 2021.

76
Recorded howler-monkey bridge crossings (within months of installation)
nearly doubled
Local howler population change (2015-2021)
~1,000
National electrocution deaths (howler monkeys) (2018-2019)

Details

Maturity
Established
Promoter
University of Costa Rica (research team led by Inés Azofeifa Rojas)
Period
2015-2021
Keywords
road and powerline ecology, primate conservation, wildlife crossings, community science

Context

Costa Rica's mantled howler monkeys move almost entirely through the forest canopy; roads and power lines force them onto wires or the ground, where they are electrocuted or hit by vehicles. University of Costa Rica primatologist Ines Azofeifa Rojas began installing canopy bridges in Playa Hermosa, Guanacaste in 2015.

Activities

Two-line rope bridges (mesh cylinder plus guide rope) were installed at roughly 20 identified crossing hotspots and monitored with monthly censuses and camera traps over six years.

Results

Camera traps recorded 76 separate howler crossings within months of installation, and the local howler population nearly doubled between 2015 and 2021. Secondary users (squirrels, kinkajous, opossums) were also recorded.

Conclusions

The project fed into Costa Rica's August 2026 national law requiring wildlife-crossing measures on new road/infrastructure projects, though implementing regulation is not due for up to two more years.

Implementation
Indicative cost
Low (< €50k)
Time to results
Medium (1–3 years)
Staffing & skills
University of Costa Rica research team, community volunteers

Conditions for success

  • identification of collision hotspots via prior mortality data
  • sustained multi-year camera-trap monitoring

Commonly funded by

National / regional programmes

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Data sources

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