Transcript Bird Species Richness

Effects of Urban Noise on Bird Diversity
Pedro Garcia, Madhusudan Katti, Jenny Phillips
Department of Biology, California State University, Fresno
[email protected] • [email protected] • [email protected]
SINGING THROUGH THE URBAN NOISE
RESULTS
Many studies have shown that products of urban development, such
as anthropogenic noise, have an impact on the behavior of animals,
especially birds. The sensory drive concept suggests that environmental
conditions, such as ambient sound, influence the evolution of vocal
behavior. In the Central Valley of California, recent studies have shown
that house finches and white-crowned sparrows tend to change their
songs in noisy areas. Urbanization and associated vehicular traffic
present the biggest modern source of noise, and thus a novel context in
which to study the effects of noise on bird diversity.
*
Richness
p = 0.0338
p = 0.0517
p = 0.9518
*
This study examines how urban noise affects bird richness and
abundance in the Fresno-Clovis Metropolitan Area (FCMA). The insights
gained into how the urban environment affects biodiversity and animal
behavior can help us better manage cities in ways that promote
biodiversity.
p = 0.0855
Moderate
None
 Noise level has a significant effect
on bird species richness at the site
(ANOVA, F2, 236 = 3.28 ; p = 0.0392).
We hypothesize that noisier urban areas will have fewer bird species
(lower bird species richness) and perhaps fewer individual birds (lower
abundance) overall.
 Site with extreme noise levels had
significantly fewer species than those
with moderate or no noise
METHODS
post-hoc Tukey-Kramer HSD
Bird counts and noise data were taken concurrently by volunteers in
the Fresno Bird Count, a citizen science project that uses point counts to
census birds on a 460km2 grid across the FCMA, during spring breeding
season (April-May) since 2008, and winter (January) since 2011.
This analysis focuses on the following variables:
 Noise: estimated subjectively at the same time as the 5 minute point
count; ranked as none, moderate, or extreme. These levels were
validated with measurements taken with a noise meter during the
2012 count.
 Bird Species Richness: cumulative count of all bird species per site
for the years 2008-2012
 Abundance: average; total number of birds per site divided by
number of years the site was surveyed.
Level
None
Moderate
None
- Level
Extreme
Extreme
Moderate
p-Value
0.0338
0.0517
0.9518
Abundance
Extreme
p = 0.3348
Extreme
p = 0.4524
Moderate
None
 Noise level does not have a significant effect on total bird
abundance at the site. (ANOVA, F2,236 = 2.44 ;p = 0.0898).
DISCUSSION
Our results support the hypothesis that anthropogenic
noise in urban areas is correlated with reduced bird species
richness.
More so, urban areas with extreme noise levels had fewer
species than areas with moderate noise (p = 0.0517) and
significantly fewer species when compared to areas with no
noise (p=.0338).
The overall abundance of birds is not influenced by noise levels
(p = 0.0898), suggesting factors other than noise (such as food
availability) play a bigger role in urban bird populations.
*
Although there was a similar trend in the effect of noise on the
species richness of only passerines, the differences were not
significant. Considering that past research has shown the
significant effects that noise has on song development and
formation, we expect that a larger sample size for each survey
year would give more sound results.
A combination of vector data and rasterized satellite imagery data was
used to generate the FCMA boundary layer.
Future research will focus on:
 Species level analyses to assess which ones are likely more
vulnerable to anthropogenic noise.
 Using precise background noise recordings (dB) for each site
to improve the resolution of the noise map.
 Using Kriging models for interpolating distribution patterns
of different bird groups in relation to noise.
ArcGIS 10.0 was used to construct a GIS model to analyze species
occurrence against the acoustic soundscapes faced by urban birds.
SITE LOCATIONS
Richness
p = 0.7823
p = 0.2863 p = 0.3221
Extreme Moderate
None
 Noise level does not have a
significant effect on passerine
richness at the site.
(ANOVA, F2, 211= 2.44;
p = 0.1856).
 We predict that a larger
sample size for each survey
would strengthen the trend.
 An Inverse Distance Weighted (IDW) interpolation
model was used to create a noise map of the FCMA.
Observed noise values (none, moderate, extreme) for each
survey site (n=239) were used to create a large gradient
of noise values ranging from no noise (value = 1) to
extreme noise (value = 3).
Future research will use similar interpolation models to
predict distribution of bird species in relation to noise.
ACKNOWLEDGMENTS
We are grateful to all the volunteers of the Fresno Bird Count for all of their hard work for the last five years. We would also like to
thank Sonia Mendoza, Steven Jones, and Seth Reid for their work on the project, the Division of Graduate Studies at CSU, Fresno for
financial support to P. Garcia, and the National Science Foundation and U.S. Forest Service (Award #0949036) for supporting the
ULTRA-FACES project. Photos: M. Katti
REFERENCES
City of Clovis. City boundary shapefile <http://www.ci.clovis.ca.us>
City of Fresno. City boundary shapefile <http://www.fresno.gov>
Earth Explorer. Landsat 5 TM <http://www.earthexplorer.usgs.gov>
Reid, S. 2011. Ecological & Social drivers of tree species diversity &
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Rosenzweig, M.L. 2003. Reconciliation Ecology and the Future of
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Slabbekoorn, H. and E. A. P. Ripmeester 2008. Birdsong and
Anthropogenic Noise: Implications and Applications for Conservation.
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Schleder, B. 2010. Residential irrigation as a driver of urban bird
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