Banca de QUALIFICAÇÃO: THIAGO AUGUSTO MENDES PINHEIRO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : THIAGO AUGUSTO MENDES PINHEIRO
DATE: 26/11/2024
TIME: 09:30
LOCAL: Google Meet (https://meet.google.com/vdd-jcub-zrb)
TITLE:

Vocal activity, species richness and the choruses and “non-choruses” of the birds in the Caatinga and Atlantic Forest of Rio Grande do Norte state, Brazil.

KEY WORDS:

Birds; Caatinga; Atlantic Forest; Vocal activity; Species richness; Dawn and Dusk choruses.

PAGES: 67
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

Birds are generally well studied animals, partially due to their exuberant vocal activity at dawn, which is referred to as “morning chorus”. This phenomenon is most studied in temperate regions of the northern hemisphere and generally assess a single bird species. Birds’ vocal activity can be influenced by environmental factors, which can limit vocalizations during adverse conditions. This study aimed to assess how environmental factors influence birds’ vocal activity and species richness, and also identify the occurrence and conspicuity of the bird’s dawn and dusk choruses at the community level. Audio recordings were acquired through the use of autonomous recorders placed in two points in Rio Grande do Norte state (Brazil): one at the rural zone of Currais Novos municipality (Caatinga biome) and the other at the Parque Estadual Dunas de Natal (state park at Natal, Atlantic Forest biome). The recordings were performed during twelve 3-day monthly collections at each site. Audio files were analyzed using spectrograms in Raven Pro 1.6 software, in which all the vocalizations were manually counted and the species identified. We used ten environmental variables which included atmospheric factors and the phenological state of the vegetation to create multiple Generalized Additive Models (GAM) that related the explanatory environmental variables to the two response variables 1) vocal activity (number of vocalizations) and 2) species richness. Heatmaps were made to visualize the distribution of vocal activity throughout two daily periods (dawn/morning and afternoon/dusk) in order to identify peaks of vocal activity at the expected moments (dawn and dusk). A method to establish the beginning and ending of the choruses was tested, and the influence of the environmental factors on the choruses' occurrence or not was also evaluated. To date, the GAM models showed the importance of several environmental factors acting together as predictors of the vocal activity and species richness in the sampled sites. Some factors, such as light condition, had positive effects on the response variables, while others, such as rainfall and wind speed had negative effects. Some of the results are consonant with literature, while others were unexpected and raise hypotheses regarding their occurrence. The dawn and dusk choruses were identified as sporadic phenomena at the community level in both sites and it was not possible to relate their occurrence to the environmental factors studied. However, certain seasonal trends seem to be linked to specific patterns observed so far. It is possible that the detected “community choruses” are not only a result of the environmental factors discussed here, but also have the contribution of important behavioral aspects and stochastic events that act on both in this system.

COMMITTEE MEMBERS:
Externo à Instituição - MARINA SCARPELLI DRUMMOND DE ALMEIDA
Interno - 1439088 - MAURO PICHORIM
Presidente - 1863735 - RENATA SANTORO DE SOUSA LIMA