Partição de nicho acústico das aves insetívoras de sub-bosque da reserva biológica do Gurupi

Abstract

Birds represent a very diverse group, consisting of different trophic guilds (e.g., insectivores, frugivores, nectarivores, omnivores), which exploit different food resources and occupy varied micro-habitats. These insectivorous birds play a fundamental role in ecosystems as bioindicators of environmental health. However, they are susceptible to the negative effects of habitat disturbance and fragmentation. Passive acoustic monitoring, using autonomous recorders, is a non-invasive and effective tool that allows the study of these birds, offering a practical and low-cost solution to assess aspects of the acoustic interaction of a community over time. Thus, this work had the general objective of characterizing the spectral and temporal acoustic interaction of insectivorous birds in the understory of the Gurupi Biological Reserve. Two autonomous recorders were installed to record the vocalizations of the species. The recorders were programmed to record 1 minute of audio every 4 minutes, 24 hours a day, and were checked at intervals of approximately two months for replacement of the batteries and memory card. The identification and cataloging of the vocalizations was done using the RFCx-ARBIMON platform, and the acoustic niche boundary measurements of the species were obtained by measuring acoustic variables using Raven Pro 1.5 software. Eleven species of insectivorous understory birds belonging to four families were identified. Of these, one species is endemic to the Belém Center of Endemism (CEB). The results show that the temporal and spectral characteristics of bird songs influence how they occupy the sound space, for example, Cercomacra cineracens and Myrmotherula menetriesii sing at the same time and at different frequencies, other species such as Formicivora grisea and Formicarius analis sing at the same time and frequency range between 1600 and 2000 Hz. This behavior may be related to competition, which may generate selective pressure for species to develop characteristics that minimize interference between them. These results are crucial for understanding the vocal communication of insectivorous birds, providing relevant information for conservation and future studies. It is concluded that with the use of autonomous recorders it was possible to identify the detections of bird vocalizations recorded in a collection of passive audio recordings and to determine the sound parameters of insectivorous understory bird species recorded in the Gurupi Biological Reserve.