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 ([email protected]), 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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