ACOUSTIC POLLUTION HOW HUMAN ACTIVITIES DISRUPT WILDLIFE COMMUNICATION

Transcription

1 ACOUSTIC POLLUTION HOW HUMAN ACTIVITIES DISRUPT WILDLIFE COMMUNICATION Emily Hockman M.S. Candidate Department of Forestry, Wildlife, and Fisheries 12:20 pm Wednesday, April 13 th Room 160 Plant Biotech Building INTRODUCTION OUTLINE Background on sound properties Communication responses of animals to anthropogenic sound Unique properties of acoustic pollution in the oceans and effects on marine mammals Where do we go from here? 1

2 SOUND PROPERTIES What is sound? Density, pressure, and temperature Amplitude (db) and frequency (Hz and khz) #1: Attenuation of sound increases as frequency increases #2: Speed of sound is proportional to temperature of the medium #3: Sound waves can converge to either cancel or amplify others BACKGROUND ON ACOUSTIC POLLUTION Anthropogenic sound generation Transportation Army/Navy Research Commercial Birds Lombard effect when noises have the same frequency (Brumm 2004) Songbirds increase amplitude and frequency in urban areas (Slabbekoorn and Peet 2003) Amphibians Airplane fly-overs and motorcycles altered multi-species chorus (Sun 2005) Increase in pitch of calls with higher ambient noise (Parris 2009) Mammals Humpbacks lengthen song duration during LFA sonar (Miller 2000) California ground squirrels increased anti-predator vocalizations near wind turbines (Rabin et al 2006, Slabbekoorn and Ripmeester 2008) Fish Increase release of stress hormones Masking of acoustic communication (Sabbekorn et al 2010) So what? BACKGROUND ON ACOUSTIC POLLUTION SPECIES FREQUENCY SOURCE LEVEL Baleen Whales (Hz) db at 1m S. Right Whale Mating behavior N. Right Whale < 400 Gray Community structure Humpback Energy expenditure Toothed Whales (khz) Increase in predation Sperm whale Beluga * Killer whale * Bottlenose dolphin * #1: Attenuation of sound increases Narwhal as frequency * increases #2: Speed of sound is proportional to Harbor temperature porpoise * of the medium #3: Sound waves from can converge to either cancel or amplify others Seals/Sirens (khz) Bearded Seal California sea lion <1 8 Harp seal Slabbekoorn et al 2010 Walrus Dugong 1 8 low 2

3 SHIPPING Main overall source of man-made noise in the marine environment (Richardson 1995) >80% of global freight transport Supertankers-: lower frequencies (< 10 Hz) heard km away Icebreaking Frequencies <100 Hz have increased 15dB since 1950 Baleen whale communication Modern ships louder, higher frequencies Beaked whales and other cetaceans COMMERCIAL ACTIVITIES Air guns Single or multiple airgun array db at Hz Directionality Oil and gas rigs Installation vs operation Location Manned vs un-manned Off-shore wind turbines Dredging Low and high frequencies up to 50 km (Richardson et al 1995) NAVY SONAR SOund Navigation And Ranging Active vs passive Sub-hunting and onboard systems Sounds Low, Mid and High-Frequency Up to 235 db, low attenuation (NRDC) Avoidance by beaked whales and other species (Tyack et. al 2011, Parsons et al 2008) Litigation How loud is too loud? (Tyack et al 2011) NRDC vs the NAVY 3

4 NAVY SONAR Beachings What s normal? Bahamas, March beaked whales of 4 species Acoustically-induced hemorrhages Cuvier s Beaked Whales disappeared Mid-frequency SONAR exercise Canary Islands beaked whales on different islands Decompression sickness Mid-frequency SONAR exercise Associated with low, mid, and highfrequency noises RESEARCH Climate change Acoustic thermometry 221 db 57 Hz 16,000 km Whale-watching boats Geophysical surveys Airgun arrays SOLUTIONS More research! What s out there? Replication Improve techniques Warning systems Automated detection bouys Listens for up calls Tells ships >65 feet to slow down SONAR Avoid known breeding/feeding grounds Low Frequency Active SONAR? What db range? Sanctuaries 4

5 REFERENCES Brumm, H The impact of environmental noise on song amplitude in a territorial bird. Journal of Animal Ecology 73(3): Kaseloo, Paul A Synthesis of noise effects on wildlife populations. IN: Proceedings of the 2005 international conference on ecology and transportation, eds. Irwin DL, Garrett P, McDermott KP. Center for transportation and the environment, North Carolina State University, Raleigh, NC Miller, P. J. O., N. Biassoni, et al Whale songs lengthen in response to sonar. Nature 405(6789): National Research Council Marine Mammals and Low-Frequnecy Sound Progress Since National Academy Press, Washington D. C. Tyack, Peter L., W. M. X. Zimmer, D. Moretti, B. L. Southall, D. E. Claridge, J. W. Durban, C. W. Clark, A. D Amico, N. DiMarzio, S. Jarvis, E. McCarthy, R. Morrissey, J. Ward, and I. L. Boyd Beaked whales respond to simulated and actual navy sonar. PLoS ONE 6(3). Parris, K. M., M. Velik-Lord, et al Frogs call at a higher pitch in traffic noise. Ecology and Society 14(1): Parsons, E. C. M., S. J. Dolman, et al Navy sonar and cetaceans: Just how much does the gun need to smoke before we act? Marine Pollution Bulletin 56(7): Richardson, W. J., C. R. J. Greene, C. I Malme, and D. H. Thompson Marine Mammals and Noise. San Diego, California, Academic Press, Inc. Sun, J. W. C. and P. M. Narins Anthropogenic sounds differentially affect amphibian call rate. Biological Conservation 121(3): Slabbekoorn, H., and N. Bouton A noisy spring: the impact of globally rising underwater sounds levels on fish. Trends in Ecology and Evolution 25: Slabbekoorn, H. and M. Peet Ecology: Birds sing at a higher pitch in urban noise. Nature 424(6946): Slabbekoorn, H. and E. A. Ripmeester Birdsong and anthropogenic noise: implications and applications for conservation. Molecular Ecology 17(1):