Acoustic Monitoring:

Transforming Primate Conservation Strategies in African Tropical Forest Protected Areas

JOSHUA M. LINDER1, CHRISTOS ASTARAS2, PETER WREGE3, and DAVID W. MACDONALD2. 1Department of Sociology and Anthropology, James Madison University (linderjm@jmu.edu), 2WildCRU, University of Oxford, 3Cornell Lab of Ornithology, Cornell University

Hunting of wild animals to supply a growing commercial

trade in bushmeat is leading to declines of wildlife in many

African tropical forest protected areas. Anti-poaching

patrols have been largely unable to curtail illegal hunting

due, in part, to an inability to properly evaluate the patrol’s

impact on hunting and wildlife abundance and to adjust

patrol activity based on changing hunting patterns.

THE PROBLEM

Develop, test, and provide training for an evidence-based, decision-support

system to help design and assess the efficacy of anti-poaching patrols using

a novel application of passive acoustic monitoring techniques to quantify

spatial and temporal patterns of gun hunting activity.

OUR OBJECTIVE

Each ARU continuously records sounds

(24 hrs/day; 365 days/yr) at a 4 kHz

sampling rate, capable of capturing

gunshots and animal vocalizations.

Acoustic data, in the form of .wav files, are

stored directly to SD flash memory cards in

the ARU, which are changed when

batteries are replaced every 3 months.

185,353 hrs of sound data

were collected

Deployed 12 autonomous recording units (ARUs) in the tropical forest of

Cameroon’s Korup National Park (1,260 km2) for 2 years (June 2013 – May 2015)

This is an ARU. It has a

gunshot detection radius

of 1.2 km and a detection

area of 4.5 km2.

WHAT WE DID & WHERE WE DID IT

1

2

3

Quantified spatio-temporal

patterns of gun hunting by

locating sound signatures of

gunshots in sound files

Scanned sound files and tagged

candidate gunshots using an

automatic detector in RavenPro®

software; experts and hunters

manually screened potential

gunshots to exclude similar

sounds

Determined detection range of

ARUs from an analysis of

controlled gunshots from known

distances to the ARU

Partners and Funding:

GUN HUNTING INTENSITY

& TEMPORAL PATTERNS

1,954 gunshots

recorded in Year 1

Extrapolated to 2,146

annual gunshots (adjusted for days per month

the sensors did not operate)

Hunter success rate = 75%

Primates = ~14% of gun

hunting offtake

4 GUN HUNTING OFFTAKEConcurrent hunter surveys

(weekly offtakes; 30 hunters from 3 villages)

WHY THIS MATTERS

Gun hunting accounts for

77% of the total annual

offtake

1,609 animals shot annually in 54 km2 study area

30 animals shot / km2

>37,000 animals shot annually in all of Korup NP

>5,000 primates killed annually

Annual/seasonal

gun hunting

patterns Year 2: 2,050 gunshots recorded

0.55 shots/day/sensor

Year 1: 1,954 gunshots recorded

0.49 shots/day/sensorXmas/New Years

Daily gun hunting activity

>65% of gun hunting

occurs at night

Weekly gun hunting patterns

Market day

Acoustic monitoring provides unprecedented level of detail on spatial

and temporal patterns of gun hunting, which can be used to:

design, evaluate, and adapt anti-poaching patrols

By using acoustic monitoring to establish a baseline for gun hunting

activity, protected area managers can then assess how different anti-

poaching patrol strategies influence spatio-temporal gun hunting

patterns.

Total detection

area = 54 km2

Therefore…

We are currently testing the efficacy of different anti-

poaching patrol strategies in Korup NP.

Gunshots

Red colobus calls

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