Action

Use nets to keep primates out of fruit trees

How is the evidence assessed?
  • Effectiveness
    40%
  • Certainty
    30%
  • Harms
    20%

Source countries

Key messages

  • One controlled, replicated, before-and-after study in Indonesia found that areas where nets were used to protect crop trees, crop-raiding by orangutans was reduced.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A controlled, replicated, before-and-after trial in 2007-2009 in an agro-forest system in Batang Serangan region, north Sumatra, Indonesia found that in areas where farmers used tree nets, crop-raiding by orangutans Pongo abelii was reduced. In areas where farmers used no mitigation technique, the frequency of crop-raiding events did not change. Crop yield increased from 69 kg to 176 kg (61% increase) after trials on farms where farmers used tree nets (n=10 farms) and decreased from 64 kg to 47 kg (27% decrease) on farms where no mitigation technique was trialled (n=15 farms). In addition, interviews with 50 farmers (of which 50% participated in the trials) showed that attitudes towards orangutan management had changed after the study. The proportion of farmers who wanted orangutans removed from their farms decreased from 58% before the study to 28% after the study. However, all farmers stopped using nets as a mitigation technique five months after the study. Barrier nets of 5 x 5 cm2 mesh stitching nylon rope were placed to partially or entirely cover the canopy of 14 separate jengkol Archidendron pauciflorum trees.

    Study and other actions tested
Please cite as:

Junker, J., Kühl, H.S., Orth, L., Smith, R.K., Petrovan, S.O. & Sutherland, W.J. (2019) Primate conservation. Pages 439-491 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

Primate Conservation

This Action forms part of the Action Synopsis:

Primate Conservation
Primate Conservation

Primate Conservation - Published 2017

Primate Synopsis

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 17

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust