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A presentation on the impact new technologies have had on bat monitoring.
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Integration of Radar, Acoustic and Night Vision
Monitoring of Bats at Wind Power Projects
Integration of Radar, Acoustic and Night Vision
Monitoring of Bats at Wind Power Projects
David E. StephensonNatural Resource Solutions Inc.
CanWEA 2006
David E. StephensonNatural Resource Solutions Inc.
CanWEA 2006
OverviewOverview
• Introduction• Challenges of Bat Monitoring• Overview of Approaches
– Acoustic Monitoring– Night Vision Monitoring– Radar Monitoring
• Lessons Learned
IntroductionIntroduction
• Increasing emphasis on bat studies for wind power projects
• Combination of uncertainties and high incidence of mortality at some sites
• Number of guidance documents/protocols being developed
• Wide range of approaches used to study bats
• Talk focuses on techniques used by NRSI at 10 wind power facilities in southern and central Ontario
Challenges of Bat MonitoringChallenges of Bat Monitoring
• Generally little local information about bats• Misconceptions about bats• Seasonal/spatial changes in species & behaviours• Bat activity and weather• Nocturnal activities
• Wide range of approaches being used, widespread
modification of devices
Acoustic MonitoringAcoustic Monitoring
• One of the most common techniques is use of ultrasonic detection devices
• Rely on detecting high frequency ‘calls’ & translating them into audible sounds
• Devices that are tuned to a specific frequency versus broadband devices that can record calls for subsequent analysis
Acoustic MonitoringAcoustic Monitoring
• Range of devices• Accurate species
identification from calls• Susceptible to interference
and distortion• Challenge of detecting
‘calls’ at turbine blade height
• Storage of recorded calls can be problematic (straight recording of 8hrs = 4GB, time expansion calls could yield >10,000 call files per night)
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
1 2 3 4 5 6 7
Monitoring Station
Passes/hr
Hoary Bat
Red Bat
Little Brown Bat
Night Vision MonitoringNight Vision Monitoring
• Relies on low-light enhancing devices• Commercially available devices (Generation
2+) • Storage medium challenges (full 8 hr night
approx. 60GB)• Limited field of vision• Ability to detect bats varies
Night Vision MonitoringNight Vision Monitoring
Generation 2+(with Infrared)Generation 2+
Radar MonitoringRadar Monitoring
Nexrad Radar• Effective range for bird/bat monitoring less than full
range• Use both base reflectivity as well as base velocity• Less effective for local investigations, low density
flights, low altitude investigations• Various anomalies can occur
Radar MonitoringRadar Monitoring
Marine Surveillance Radar
• Devices and methods vary, some off-the-shelf, others modified (esp. antennae or array)
• Use in poor weather can be variable• Clutter is a challenge • Use of CTM allows for 3D flight
trajectory analysis (direction, altitude, speed & changes)
• Remember safety – working with radar is like using a microwave with the door open!
0
2
4
6
8
10
12North
1020
3040
50
60
70
80
East
100
110
120
130
140150
160170
South190
200210
220
230
240
250
260
West
280
290
300
310
320330
340350
Radar MonitoringRadar Monitoring
Marine Surveillance Radar• Target analysis is complex (e.g.
10,000 targets per night is not uncommon)
• Difficult to tell bats from birds• Range of device can be >100km
but ability to discriminate targets is affected
• Passes/hour versus passes/m3/hour
Bearing to Bat Target
0
2
4
6
8
10North
1020
3040
50
60
70
80
East
100
110
120
130
140150
160170
South190
200210
220
230
240
250
260
West
280
290
300
310
320330
340350
Flight Direction of Bat Targets
Radar MonitoringRadar Monitoring
Marine Surveillance Radar• Bat activity density (passes/m3/hour)
0
0.0005
0.001
0.0015
0.002
0.0025
<40 40 -60
60 -80
80 -100
100 -120
120 -140
140 -160
160 -180
180 -200
>200
Altitude (m agl)
Passes/m3/hr
Station 1
Station 2
Station 3
Staton 4
Station 5
Lessons LearnedLessons Learned
• Improved results with integrated use of devices/techniques• Time expansion acoustic ‘call’ identification• 3 dimensional radar flight analysis• Bat monitoring is very data-heavy (tera-bytes of data)• Data collection & analysis are time consuming • Keep the biologist in the process
Booth # 624www.nrsi.on.c
a
Booth # 624www.nrsi.on.c
a
Who isSecuring
Your Project?
Who isSecuring
Your Project?