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are estimated by post-processing, and the original diffuse influence matrix is
refined accordingly and converges in a few relaxation steps. The method is
higher-order accurate, computationally efficient, and similar to the diffuse
case in that it includes strict enforcement of energy conservation. The simu-
lations give accurate results compared to exact modal solutions. Sample cal-
culations are presented to show that the mean-square pressure spatial varia-
tion can be tailored using a combination of diffuse and specular surfaces for
the design of acoustic spaces.
THURSDAY MORNING, 18 NOVEMBER 2010 CORAL GARDEN 1, 7:55 A.M. TO 12:00 NOON
Session 4aAB
Animal Bioacoustics: Tropical Animal Bioacoustics
Edmund R. Gerstein, Chair
Leviathan Legacy Inc., 1318 SW 14th St., Boca Raton, FL 33486
Chair’s Introduction—7:55
Invited Papers
8:00
4aAB1. Case studies of bioacoustics research in Brazil. R. S. Sousa-Lima 共Bioacoustics Res. Program, Cornell Lab. of Ornithology;
Inst. Baleia Jubarte, Caravelas, BA, Brazil; Inst. de Ciências Biológicas, Univ. Federal de Minas Gerais, Belo Horizonte, Brazil, RSL32
@cornell.edu兲
Brazilian researchers have a growing interest in animal sounds as more and more exposure is given to this subject in the worldwide
literature and concerns about noise pollution are on the rise. Some case studies focusing on research that I have been involved in, i.e.,
studying manatees 共Trichechus inunguis and T. manatus兲, humpback whales 共Megaptera novaeangliae兲, manned wolves 共Chrysocyon
brachyurus兲, primates 共Callitrix penicillata兲, and fish 共Prochilodus sp. and Leporinus sp.兲, will be presented. Studies of the acoustic
ecology of these species have focused on determining the importance of acoustic communication, vocal identity, and differences in the
acoustic behavior of groups of animals to better understand animal populations in the wild and in urban areas. Such studies help to
support overall conservation efforts and highlight the importance of the potentially negative effects of masking on animal communi-
cation systems in the tropics.
8:20
4aAB2. A comparison of acoustic soundscapes within and among three tropical habitats: Can soundscape heterogeneity be used
as an index of alpha diversity? L. J. May-Collado, T. M. Aide 共Dept. of Biology, Univ. of Puerto Rico, P.O. Box 23360, San Juan, PR
00931, lmaycollado@gmail.com兲, C. Corrada, and R. Alvarez 共Univ. of Puerto Rico, San Juan, PR 00931兲
Rapid biodiversity assessment methods are needed to ensure that adequate policies and management strategies are established to
protect biodiversity. In this study, we evaluate the reliability of a recently developed acoustic index for alpha diversity by determining
the within and among site variations from three permanent automated recording stations located in Sabana Seca 共wetland兲and El Verde
共moist forest兲, Puerto Rico and in La Selva 共wet forest兲, Costa Rica. All stations sampled the soundscape for 1-min every 10-min, 24
h per day throughout the year. For this analysis, we evaluated recordings from the dry season and wet season for each site. The analyzes
were carried out on each individual recording and then mean values were calculated for each month. Independent of the season or time,
La Selva had the highest acoustic diversity and El Verde had the lowest. Both Sabana Seca and El Verde showed a significant increase
in acoustic richness after dusk, reflecting the peak of amphibian activity. This acoustical index is a useful tool for identifying important
areas of biodiversity without relying on individual species identification. Our results indicate that soundscape heterogeneity is a good
indicator of alpha diversity.
Contributed Papers
8:40
4aAB3. The role of the environment on the acoustic radiation patterns
of mating calls of the túngara frog. Ximena E. Bernal 共Dept. of Bio. Sci.,
Texas Tech Univ., Lubbock, TX 79409-3131兲, Rachel A. Page 共Smithsonian
Tropical Res. Inst., MRC 0580-06, Apartado 0843-03092 Panamá,
República de Panamá兲, Michael J. Ryan 共Section of Integrative Biology,
Univ. of Texas at Austin, Austin, TX 78712兲, Theodore F. Argo, IV, and Pre-
ston S. Wilson 共Mech. Eng. Dept. and Appl. Res. Labs., Univ. of Texas at
Austin, Austin, TX 78713-8029兲
The present work is a follow-up to previously reported 关J. Acoust. Soc.
Am. 122, 2981共A兲共2007兲兴 laboratory measurements of both the horizontal
and vertical frequency-dependent directivity of the mating calls of túngara
frogs, Physalaemus pustulosus. Band-limited directivities are significantly
greater than broadband directivities, with a maximum directivity of 20 dB in
the vertical plane for harmonics near 6 kHz. This result is unexpected given
that female frogs, the intended receivers of this call, are on the horizontal
plane rather than on the vertical plane where unintended receivers 共predators
and parasites兲reside. New numerical finite element modeling of the radia-
tion, including the effects of the environment, will be reported. Túngara
frogs only call while partially submerged in water. Modeling results indicate
that the reflecting boundary provided by a finite-sized air-water interface
dominates the radiation, and results in the observed directivity. There is
comparatively little directivity dependence on the nature of the surrounding
terrain, be it acoustically hard or soft, smooth or rough. These modeling re-
sults indicate that the radiation patterns found in laboratory measurements,
although unexpected, are likely to be found in nature too.
2412 2412J. Acoust. Soc. Am., Vol. 128, No. 4, Pt. 2, October 2010 2nd Pan-American/Iberian Meeting on Acoustics