Banca de QUALIFICAÇÃO: WILLIAMS OLIVEIRA DA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : WILLIAMS OLIVEIRA DA SILVA
DATE: 26/06/2025
TIME: 08:00
LOCAL: SALA DE REUNIÕES DO DECOL/CB/UFRN
TITLE:

HABITAT USE, CO-OCCURRENCE, AND VOCAL ACTIVITY OF INSECTIVOROUS BIRDS IN DIFFERENT ENVIRONMENTS OF THE BRAZILIAN SEMIARID

KEY WORDS:

Occupancy models; single-season occupancy; conditional occupancy; vocalization patterns; autonomous recorders; passerines; Caatinga

PAGES: 87
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

In scenarios of environmental change, insectivorous birds are among the most affected groups due to their sensitivity to habitat structure alterations, particularly in seasonal ecosystems. Within seasonal environments, the Brazilian semiarid region represents a clear example of a threatened and altered ecosystem. The overarching objective of this thesis was to investigate how environmental factors influence habitat use, co-occurrence, and daily activity patterns of insectivorous birds across distinct landscape units in the Brazilian semiarid. This thesis comprises four chapters. In Chapter 1, we examined the influence of topography and vegetation variables on habitat use by Thamnophilidae species in semideciduous forest fragments of the Brazilian semiarid. Environmental variables were measured at three spatial scales (250-m, 500-m, and 1000-m radius buffers), encompassing land-cover metrics and topography. No single spatial scale predominated exclusively. At the 250-m scale, forest formation influenced occupancy of Sakesphoroides niedeguidonae, Thamnophilus capistratus, and Taraba major, while grassland formation affected only T. major. Canopy height was relevant for T. torquatus, and forest integrity for S. niedeguidonae. At 500 m, slope exerted the greatest effect on Myrmorchilus strigilatus, Herpsilochmus atricapillus, and T. major. At 1000 m, canopy height was a key determinant for M. strigilatus, H. atricapillus, and T. major. Altitude exhibited the broadest influence, correlating with occupancy of M. strigilatus, S. niedeguidonae, T. capistratus, T. torquatus, and T. major. Our results demonstrate that while topographic variables exerted moderate influence, vegetation attributes were essential for habitat use by insectivorous species. In Chapter 2, we investigated how multi-scale environmental variables (microhabitat and landscape) influence habitat selection by insectivorous birds in two protected areas within the Brazilian semiarid. Environmental variables included vegetation structure, land cover, and topography metrics at microhabitat (6-m radius) and landscape scales (250-m, 500-m, 1000-m). Microhabitat variables were critical for habitat selection. Tree richness influenced Formicivora melanogaster and Hemitriccus margaritaceiventer, while litter depth was associated with F. melanogaster and T. major. Canopy cover exclusively affected F. melanogaster. Massapê soil was determinant for T. capistratus, Sittasomus griseicapillus, and Lepidocolaptes angustirostris, and altitude correlated with Todirostrum cinereum and Cantorchilus longirostris. Our findings underscore that habitat selection by the studied species is strongly linked to fine-scale variables, particularly vegetation structure, highlighting their sensitivity to changes in plant complexity. Chapters 3 and 4 are currently under analysis and development. Briefly, Chapter 3 aims to analyze co-occurrence levels among insectivorous species across three semiarid areas. Chapter 4 will describe diel variation patterns in vocal activity of the species studied in preceding chapters.

COMMITTEE MEMBERS:
Interno - 1718346 - EDUARDO MARTINS VENTICINQUE
Presidente - 1439088 - MAURO PICHORIM
Interna - 1914239 - MIRIAM PLAZA PINTO