Banca de QUALIFICAÇÃO: TAMIRIS PEREIRA LIMA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : TAMIRIS PEREIRA LIMA
DATE: 11/09/2025
TIME: 08:30
LOCAL: Google Meet (https://meet.google.com/zn j-osan-qxw)
TITLE:

Resource partitioning and trophic niche differentiation of migratory shorebirds in the semiarid equatorial coast of the Northeast Atlantic in South America

KEY WORDS:

Benthic macroinvertebrates; Coexistence; Ecology; Foraging Behavior; Migratory birds ; Occupancy models ; Stable isotopes.

PAGES: 54
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUMMARY:

This dissertation investigates habitat use patterns and diet of migratory shorebirds during the nonbreeding season at Banco dos Cajuais, one of the most important stopover and feeding sites along the northeastern Brazilian coast. The approach integrates occupancy models with stable isotope analyses, allowing the assessment of both spatial distribution and trophic ecology of these species. In the first chapter, we evaluated the static occupancy of five shorebird species (Limnodromus griseus, Calidris canutus, Charadrius semipalmatus, Calidris pusilla, and Arenaria interpres) across an extensive tidal flat, testing differences among the upper, middle, and lower intertidal zones. By applying static occupancy models that account for imperfect detection, it was possible to identify distinct patterns among species. While L. griseus showed a higher probability of occurrence associated with the lower intertidal zone, reflecting its dependence on mudflats exposed at low tide for foraging, the other four species exhibited broader distributions across the intertidal strata—although C. canutus also showed preference for the lower stratum, and C. pusilla tended to use the upper stratum. In addition, occupancy for some species increased with environmental variables such as higher benthic invertebrate richness. The second chapter addressed diet and trophic niche overlap using stable isotope analysis of carbon (δ¹³C) and nitrogen (δ¹⁵N). A total of 114 samples were analyzed, including bird blood tissue (n=91) and potential prey (n=23), covering different groups of benthic macroinvertebrates. Results indicated trophic segregation among species, with A. interpres showing the widest niche breadth and higher δ¹³C and δ¹⁵N values, suggesting a more generalist and diverse diet. Conversely, C. pusilla and L. griseus displayed narrower niches, reflecting feeding specialization and greater dependence on specific prey. Beyond trophic segregation, partial niche overlap was also observed, suggesting that migratory shorebirds rely on resource partitioning mechanisms that promote coexistence in other dimensions (such as spatial and temporal, explored in Chapter 1). Taken together, the two chapters demonstrate that shorebirds use Banco dos Cajuais in differentiated ways—both spatiotemporally and through distinct food resource selection—reflecting diverse ecological strategies that enable coexistence in a shared environment. At the same time, the results highlight the ecological and conservation relevance of the region, which remains a strategic site along the West Atlantic Flyway, providing consistent and diverse resources to migratory bird populations during their stay in the Southern Hemisphere

COMMITTEE MEMBERS:
Presidente - 1439088 - MAURO PICHORIM
Externo à Instituição - LEANDRO NOLÉ EDUARDO
Externo à Instituição - RODRIGO LIMA MASSARA