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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A plasticidade ac?stica de uma popula??o de Boto - Cinza, Sotalia Guianensis (Van Ban?d?n, 1864) (Cetacea, Delphinidae), na regi?o Nordeste do Brasil

Martins, Dalila Teles Le?o 20 November 2014 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-01T21:51:31Z No. of bitstreams: 1 DalilaTelesLeaoMartins_TESE.pdf: 918692 bytes, checksum: b31e0bfa27adc90d4f8669b343f994ad (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2016-03-03T15:29:58Z (GMT) No. of bitstreams: 1 DalilaTelesLeaoMartins_TESE.pdf: 918692 bytes, checksum: b31e0bfa27adc90d4f8669b343f994ad (MD5) / Made available in DSpace on 2016-03-03T15:29:58Z (GMT). No. of bitstreams: 1 DalilaTelesLeaoMartins_TESE.pdf: 918692 bytes, checksum: b31e0bfa27adc90d4f8669b343f994ad (MD5) Previous issue date: 2014-11-20 / As caracter?sticas do ambiente podem modificar a ac?stica de uma esp?cie devido o habitat, per?odo do dia e ano. Por isso, esse estudo investigou as rela??es entre esta??es do ano, mar?, ciclo di?rio da mar?, per?odos do dia e diferentes habitat e as emiss?es sonoras de S. guianensis. As grava??es sonoras ocorreram na Enseada do Curral e Complexo Lagunar de Guara?ras (CLG) no munic?pio de Tibau do Sul/RN. Assobios s?o emitidos com diminui??o da frequ?ncia durante a esta??o chuvosa e a mar? de siz?gia; enquanto, estalidos sofrem aumento. ? durante o ciclo di?rio de mar? vazante que assobios, estalidos e gritos apresentam aumento dos par?metros de frequ?ncia. Essas modifica??es podem estar relacionadas com a turbidez e disponibilidade de presas. Percebeu-se que a noite ocorre aumento consider?vel da ocorr?ncia de assobios e estalidos provavelmente devido a pouca luminosidade. Al?m disso, a redu??o dos par?metros de frequ?ncias dos assobios e estalidos durante a noite permite que o som viaje dist?ncias maiores j? que a vis?o fica limitada; entretanto, o aumento da frequ?ncia m?nima seria para precisar a captura das presas em si. A baixa ocorr?ncia dos gritos pode estar relacionada ao tamanho pequeno do grupo no local. As mudan?as ac?sticas a noite pode ser influenciada em parte pelos n?veis de ilumina??o como pela disponibilidade de presas que ? maior nesse per?odo. No CLG, as frequ?ncias dos assobios s?o maiores que na Enseada, assim como a frequ?ncia inicial dos estalidos o que possibilita uma precis?o. Entretanto, a frequ?ncia central dos estalidos diminuiu e esse fato pode estar ligado ao rastreamento da ?rea. V?rios fatores podem estar associados a essas modifica??es como ru?dos de fundo, propriedades do fundo, entre outros. Esse estudo suporta a hip?tese de que S. guianensis apresenta uma plasticidade ac?stica de acordo com as condi??es do local onde a esp?cie est? inserida e se adapta as mudan?as ambientais. / The environmental characteristics can modify the acoustics of a species due to habitat, time of day and year. Therefore, this study investigated the relationships between seasons, tide, daily cycle of tides, times of day and different habitat and noise emission of S. guianensis. Sound recordings occurred in the Curral?s Cove and Lagoon Complex of Guara?ras (CLG) in the municipality of Tibau do Sul/RN. Whistles are emitted with lower frequency during rainy season and spring tide while clicks are higher; whistles, clicks and calls have higher frequency during ebb tide. These modifications can be related with turbidity and prey availability. The whistles and clicks occurrence are higher at night probably because luminosity is lower. Furthermore, the whistles and clicks frequency reduction overnight allows the sound to travel longer distance and helps the view which is limited; but the minimum frequency increase was needed to catch the prey. The low occurrence of calls could be related to the small group size. The acoustic changes at night may be partly influenced by light levels as prey availability that is larger in this period. Whistle frequencies and click initial frequency are higher in CLG than Curral?s cove that permitted good precision. However, click central frequency is lower and may be connected to tracking the area. Several factors may be associated with such modifications as background noise, bottom and others. This study supports the hypothesis that S. guianensis presents an acoustic plasticity according to the local conditions where the species is embedded and adapts to the environmental changes.

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