Synthesis of Noise Effects on Wildlife Populations

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Synthesis of Noise Effects on Wildlife Populations

• Paul Kaseloo
• Department of Biology
• Virginia State University

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Purpose

• To create a review and literature database that
  could be used to review the effects of noise
  (particularly road noise) on wildlife
• Covers animals (invertebrate and vertebrate)
  greatest amount of information deals with birds
  and mammals

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Background

• It has been estimated (in part based on the
  estimates of the effects on birds) that 20 of
  the land area of the United States is
  ecologically affected by public roads
• (Forman, 2000 Cons. Biol. 1431-35)

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Questions

• What is known about the response of birds to road
  noise?
• What are the implications of these findings?
• What future work could be considered to answer
  outstanding questions?

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Effect Distance

• The distance from the road up to the point where
  reduced density was recorded

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Early work

• Avoidance (i.e. reduced breeding density) by at
  least two grassland species (lapwing and
  black-tailed godwit)
• Rural road (Effect distance 500-600 m) with 50
  vehicles/day
• Highway (Effect distance 1600-1800 m) with
  54,000 vehicles/day
• (van der Zande et al., 1980 Biol. Cons.
  18299-321)

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Woodland birds

• A study of 43 bird species (in deciduous and
  coniferous forests) found reduced breeding
  densities of 26 species (60) with effect
  distances that increase with the amount of
  traffic
• 401500 m at 10,000 vehicles/day
• 70-2800 m at 60,000 vehicles/day
• (Reijnen et al., 1995 J. Appl. Ecol.
  32187-202)

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Woodland birds (cont)

• In a multi-year study 17 of 23 species studied
  showed a decrease in breeding density near the
  road in at least one year (40-52,000
  vehicles/day)
• This effect was reduced (only 4 species) in years
  with high population density

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Woodland birds

• High overall population levels will lead to
  underestimation of the quality of the habitat
  (i.e. would not see the effect in years of high
  density)
• (Reijnen and Foppen, 1995 J. Appl. Ecol.
  32481-491)

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(Reijnen et al., 1997 Biodiv. Cons. 6567-581)
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Grassland Birds

• Similar to the earlier study 7 of 12 species
  studied showed a reduction in breeding density
  adjacent to roads
• The effect distances varied with species and
  increased with traffic density

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Grassland birds (cont)

• Effect distances ranged between
• 20-1700 m at 5,000 vehicles/day
• 65-3530 m at 50,000 vehicles/day
• (Reijnen et al., 1996 Biol. Cons. 75255-260)

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Grassland Birds (cont)

• Five years of data on birds (mainly based on two
  species - bobolinks and meadowlarks) near Boston
  found
• Effect distances
• 3,000-8,000 vehicles/day none
• 8,000-15,000 vehicles/day 400 m
  (breeding only)
• 15,000-30,000 vehicles/day 700 m
• 30,000 vehicles/day 1200 m
• (Forman et al., 2002 Environ. Manage.
  29782-800)

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Previous Recommendations

• Sound levels above about 50 dB(A)
• Estimate effect distances of about 1000 m
• (Reijnen et al., 1997 Biodiv. Cons.
  6567-581)

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Other Possible Causes

• Visual disturbance
• Air pollution
• Microclimatic effects
• Road kill
• Increased attraction of predators
• Unlikely to have an effect at the distances
  reported

• (Forman et al., 2002 Environ. Manage.
  29782-800)

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Other Considerations

• Not all species appear sensitive
• (e.g. Study in Spain estimated 15 of breeding
  bird species sensitive, although total density
  did not differ at different levels of traffic)
• (Peris and Pescador, 2004 Appl. Acoustics
  65357-366)
• Some species become more common near roads
  (ecotonal environment)
• (Michael et al., 1976 Proc. 1st Nat. Symp.
  Environ. Conc.) (Ferris, 1979 J. Wildl.
  Manage. 43421-427)
• (Adams and Geis, 1981 FHWA/RD-81/067)

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Other Considerations

• Some species breed well even in noisy
  environments (e.g. California gnatcatchers)
• (Awbrey et al., 1995 Inter-noise 65971-974)

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Other Considerations

• Rights-of-way have been shown to provide breeding
  habitat for some species (e.g. pheasants, ducks,
  passerines) particularly in areas of
  disturbance such as agricultural areas
• (Warner and Joselyn, 1986 J. Wildl. Manage.
  50525-532)
• (Oetting and Cassel, 1971 J. Wildl. Manage.
  35774-781)
• (Voorhees and Cassel, 1980 J. Wildl. Manage.
  44155-163)
• (Laursen, 1981 Biol. Cons. 2059-68)
• (Warner, 1992 Biol. Cons. 591-7)

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Mechanisms

• It has been found that higher-pitched frequencies
  in bird songs may make species less susceptible
  to noise effects from roads implying masking as a
  causative mechanism
• (Rheindt 2003 J. für Ornith. 144295-306)

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Mechanisms

• Birds in noisier urban environments also
  increased amplitude of songs when background
  noise increased
• (Brumm, 2004 J. Anim. Ecol. 73434-440)

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Important Questions

• Is noise alone sufficient to cause the effect
  seen?
• It has been established that it is not the
  presence of a road, but the level of traffic that
  influences the densities of birds, presumably due
  to noise because of the distances involved
• Will mitigation of noise alone be sufficient to
  change the response?

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(Reijnen et al., 1997 Biodiv. Cons. 6567-581)
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Future Research

• Can noise (as opposed to noise with associated
  traffic) cause the same effect? (i.e. can
  mitigation of noise be expected to reduce the
  effect zone)
• Will reduction in noise lead to a return of
  affected species? (How long until this response
  is seen?)

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Future Research

• What are the proximate effects of noise on birds?
• Masking of vocalization?
• Physiological changes?
• Locomotor activity?
• Behavioral patterns?

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Future Research

• Can we see areas where noise mitigation (for
  other purposes) has altered species composition
  compared to areas without mitigation?

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Acknowledgements

• Undergraduate research assistant Katherine Tyson
• Paul Garrett _at_ FHWA for support and advice
• Funded through FHWA cooperative agreement
  DTFH61-03-H-00123

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Questions?