A acústica como dimensão de comunidades ecológicas e instrumento para o monitoramento da biodiversidade
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Data
2019-12-02
Autores
Sugai, Larissa Sayuri Moreira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A natureza é ruidosa. Passarinhos gorjeiam enquanto o vento silva ao pentear os campos com abelhas e seus zunzuns rondando flores. Desatentos, deixamos de notar uma incrível quantidade de elementos retumbando em nosso entorno. No entanto, cada som parte de uma fonte, deixando uma pista sobre a situação na qual foi produzido. Podemos identificar a espécie de passarinho pelo seu canto, e, quem sabe, revelar a passagem de uma espécie migratória. A imagem de um campo nos é desperta ao escutar o vento soprando por gramíneas, que ressoaria diferente se soprasse por uma floresta. Por conseguinte, podemos registrar a atividade acústica dos organismos e descrever as dinâmicas de ecossistemas através de um conjunto de técnicas oferecidas pelo monitoramento acústico passivo. Além disto, os diversos sons emitidos por animais são produzidos sobretudo para fins reprodutivos e territoriais. Sua produção possui elevado custo energético e influencia se a performance de um organismo resultará em saldo positivo para a perpetuação de seus descendentes. Diante disso, alguns percalços no caminho entre a emissão e a recepção desses sons podem adulterar suas características e inviabilizar seu reconhecimento. Por serem ondas mecânicas, a vegetação pode refratar e absorver elementos dos sons emitidos por animais. Ou ainda, em grandes agregações, como os coros por aves no amanhecer e por anuros e invertebrados ao ocaso, os diversos sons podem gerar interferências. Em ambos os casos, a degradação sonora pode comprometer o sucesso reprodutivo das espécies. Contrariamente, uma outra perspectiva prevê que esses percalços não seriam tão custosos assim, e que na verdade os sons emitidos intermediam interações entre diferentes espécies podendo influenciar a distribuição dos organismos. Isto posto, tive como objetivos nesta tese i) sumarizar aplicações do monitoramento acústico em ecologia e conservação e ii) investigar a organização de comunidades de anuros no Pantanal sul-matogrossense a partir de seus aspectos acústicos e de uma alta precisão temporal para representar as comunidades. Para tal, começo com um prólogo que traça um paralelo entre o conjunto de gravações acústicas obtidos atualmente à “cápsulas do tempo” que no futuro, podem se tornar registros únicos do passado dos ecossistemas. Em sequência, os dois primeiros capítulos buscam sintetizar aplicações e tendências bibliográficas sobre monitoramento acústico passivo em ambientes terrestres, sendo o primeiro capítulo uma revisão sistemática da literatura. No segundo capítulo, resumo os desenhos amostrais utilizados e apresento diretrizes para otimizar a amostragem. A segunda parte da tese é destinada a investigação da organização de comunidades de anuros através de monitoramento acústico. No capítulo 3, caracterizo as comunidades a partir de atributos das vocalizações dos anuros e investigo se o espaço acústico estaria arranjado de forma a minimizar potenciais interferências na comunicação. Em geral, as comunidades foram constituídas por espécies acusticamente similares, e aquelas comunidades contendo espécies mais distintas filogeneticamente apresentaram maior similaridade acústica. Esses resultados sugerem que, sob uma perspectiva acústica, a as comunidades podem estar organizadas em função do uso de informação a partir dos sinais acústicos umas das outras. No capítulo 4, analiso as comunidades de anuros a partir de um recorte temporal bastante preciso, onde variações dentro do período de atividade diária das espécies são consideradas. As comunidades apresentaram a maior parte das espécies ativas no começo do período noturno, com conseguinte decaimento ao longo da noite. Essa variação em curto prazo é maior em locais cujo ambiente é estruturalmente mais complexo, sugerindo contundentes dinâmicas temporais de curto prazo associadas a periodicidade e ao ambiente. Isso implica que essas dinâmicas podem modular interações entre espécies e, por consequência, refletir na estruturação das comunidades. Por fim, espero que essa tese possa estimular o uso do monitoramento acústico em pesquisas ecológicas, e apresentar novas perspectivas, a partir da acústica, sobre o funcionamento de comunidade ecológicas.
Nature is noisy. Birds chirps while the wind whistle when brushing the fields, with bees buzzing around flowers. Meanwhile, our absence of mind prevents us to notice many elements rumbling on our surroundings. However, each sound has a source that leaves clues about the situation in which it was produced. The songbird can be identified by its song and eventually reveal the passage of a migratory species. The wind blowing through the grass quickly resemble the image of a field that would otherwise sound different if it blew through a forest. Therefore, such acoustic activity of the organisms can be recorded and used to describe ecosystems dynamics through a set of techniques included in passive acoustic monitoring. In addition, sounds emitted by animals are produced mainly for reproductive and territorial purpose. Its production is costly and influences whether the performance of an organisms will lead a positive balance for the perpetuation of its descendants. As such, obstacles on the path between sound emission and reception may distort its characteristics and impair sound recognition. As sound are mechanical waves, vegetation can refract and absorb elements on the acoustic signal, or in large aggregations, such as dawn bird chorus and dusk anuran and invertebrate choruses, an abundance of animal sounds can generate interferences. In both cases, sound degradation may compromise species’ reproductive success. On the contrary, another perspective predicts that such obstacles are not that hard, and that in fact, animals use sounds to mediate interactions between species, even influencing the distribution of those relying in such interactions. Hence, my goals with this thesis were i) to summarize applications of acoustic monitoring in ecology and conservation, and ii) to investigate the structuring of anuran communities in the southwest Pantanal in Brazil using acoustic characteristics and a high temporal precision perspective to determine communities. Thereby, I begin this thesis with a prologue that parallels que set of acoustic recordings being acquired currently to “time capsules” for the humanity. Following up, I devote two chapters to synthesize applications and bibliographic tendencies about passive acoustic monitoring in terrestrial environments. The first chapter is a systematic review of the literature and the second is a synthesis of survey designs used in the reviewed bibliography, with guidelines to optimize acoustic sampling. The next chapters are dedicated to investigating the organization of anuran communities in the Pantanal wetlands, acoustic monitoring was employed. In chapter 3, I address the acoustic dimension to characterize communities, described by anurans’ advertisement calls. We explore the arrangement of such acoustic space and whether its structure may reflect strategies to minimize interference in animal communication. In general, communities were composed by species with similar acoustic characteristics, where those communities composed by more distantly related species showed greater acoustic similarities. These findings suggest that communities may reflect strategies for information use through the acoustic signals of heterospecifics. In chapter 4, I use a fine temporal resolution scale to address species’ diel activity and investigate its consistency within and between communities. Communities had most species are active in early periods of nocturnal activity and short-term species composition decay along the night. Such nocturnal decay in species composition was also associated with communities located at more structurally complex habitats. These findings suggest widespread short-term dynamics across communities associated to diel cycle and environmental structure, which may influence species interaction potential and consequently, the structure of communities. Finally, I hope that this thesis can stimulate ecological research with acoustic monitoring and to open new perspectives with acoustics on the dynamics of ecological communities.
Nature is noisy. Birds chirps while the wind whistle when brushing the fields, with bees buzzing around flowers. Meanwhile, our absence of mind prevents us to notice many elements rumbling on our surroundings. However, each sound has a source that leaves clues about the situation in which it was produced. The songbird can be identified by its song and eventually reveal the passage of a migratory species. The wind blowing through the grass quickly resemble the image of a field that would otherwise sound different if it blew through a forest. Therefore, such acoustic activity of the organisms can be recorded and used to describe ecosystems dynamics through a set of techniques included in passive acoustic monitoring. In addition, sounds emitted by animals are produced mainly for reproductive and territorial purpose. Its production is costly and influences whether the performance of an organisms will lead a positive balance for the perpetuation of its descendants. As such, obstacles on the path between sound emission and reception may distort its characteristics and impair sound recognition. As sound are mechanical waves, vegetation can refract and absorb elements on the acoustic signal, or in large aggregations, such as dawn bird chorus and dusk anuran and invertebrate choruses, an abundance of animal sounds can generate interferences. In both cases, sound degradation may compromise species’ reproductive success. On the contrary, another perspective predicts that such obstacles are not that hard, and that in fact, animals use sounds to mediate interactions between species, even influencing the distribution of those relying in such interactions. Hence, my goals with this thesis were i) to summarize applications of acoustic monitoring in ecology and conservation, and ii) to investigate the structuring of anuran communities in the southwest Pantanal in Brazil using acoustic characteristics and a high temporal precision perspective to determine communities. Thereby, I begin this thesis with a prologue that parallels que set of acoustic recordings being acquired currently to “time capsules” for the humanity. Following up, I devote two chapters to synthesize applications and bibliographic tendencies about passive acoustic monitoring in terrestrial environments. The first chapter is a systematic review of the literature and the second is a synthesis of survey designs used in the reviewed bibliography, with guidelines to optimize acoustic sampling. The next chapters are dedicated to investigating the organization of anuran communities in the Pantanal wetlands, acoustic monitoring was employed. In chapter 3, I address the acoustic dimension to characterize communities, described by anurans’ advertisement calls. We explore the arrangement of such acoustic space and whether its structure may reflect strategies to minimize interference in animal communication. In general, communities were composed by species with similar acoustic characteristics, where those communities composed by more distantly related species showed greater acoustic similarities. These findings suggest that communities may reflect strategies for information use through the acoustic signals of heterospecifics. In chapter 4, I use a fine temporal resolution scale to address species’ diel activity and investigate its consistency within and between communities. Communities had most species are active in early periods of nocturnal activity and short-term species composition decay along the night. Such nocturnal decay in species composition was also associated with communities located at more structurally complex habitats. These findings suggest widespread short-term dynamics across communities associated to diel cycle and environmental structure, which may influence species interaction potential and consequently, the structure of communities. Finally, I hope that this thesis can stimulate ecological research with acoustic monitoring and to open new perspectives with acoustics on the dynamics of ecological communities.
Descrição
Palavras-chave
Montagem de comunidades, Comunicação acústica, Anuros, Pantanal, Ecologia da informação, Community assembly, Acoustic communication, Anura, Ecology of information