Banca de QUALIFICAÇÃO: GISELE MARIA NUNES VIEIRA DUBEUX

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : GISELE MARIA NUNES VIEIRA DUBEUX
DATA : 07/11/2025
HORA: 00:00
LOCAL: PARECER
TÍTULO:

Effects of fragmentation and habitat degradation on nutritional indices and environmental stress in forest birds in the northern Atlantic Forest

PALAVRAS-CHAVES:

Body condition, Subcutaneous fat level, Floating asymmetry, Insectivorous birds, Frugivorous birds.

PÁGINAS: 1
RESUMO:

Habitat fragmentation and degradation are listed as some of the main causes of changes in natural
environments in recent decades. These factors reduce the areas of environmental suitability of
species, isolate populations, and affect the availability and quality of food resources. These
environmental changes can cause stress in individuals and affect their diet, impairing their body
condition (BCI), subcutaneous fat levels (SFL), and floating asymmetry (FA) rates. Therefore, we
aimed to evaluate the influence of environmental changes on the nutritional condition and
environmental stress of birds at the Pernambuco Center of Endemism (PCE). We investigated the
current status of BCI, SFL, and FA in bird communities from six partially or fully protected
Atlantic Forest fragments that comprise a gradient of size and conservation status, located in
Alagoas, northeastern Brazil, within the PCE region. The BCI value of each individual was
obtained through simple linear regression using measurements of the right tarsus and its mass.
SFL were verified through visual and/or tactile inspection of individuals, following the six
categories described in the CEMAVE Wild Bird Banding Manual. FA (bilateral variation) was
assessed separately for tarsi and wings. To compare the individual BCI and FA values obtained
and verify whether differences between fragments were significant, both at the population and
community levels, we performed Analyses of Variance (ANOVA) and t-tests. To investigate the
possible influences of landscape variables and climatic factors on BCI in different trophic groups,
we used Generalized Additive Models (GAMs). We found that nutritional condition tends to be
better in larger fragments with better forest structure, and that the spatial configuration of the
fragment shape index (FRAC) and core area ratio (CAI) of the fragments plays a crucial role in
the BCI of frugivorous and insectivorous species. However, FA did not differ significantly
between forest fragments. This study reinforces the hypothesis that birds inhabiting smaller forest
fragments have poorer body condition, evidenced by the tendency for BCI index values to
decrease as fragment size decreases. However, insectivorous birds exhibited a greater range of
variation in BCI, with a tendency toward lower nutritional condition in smaller fragments.
However, individuals with high SFL values, indicating fat accumulation consistent with obesity,
were also found in smaller and intermediate fragments. This suggests rapid fluctuations in energy
reserves in response to critical conditions. On the other hand, frugivorous birds showed no
significant differences in BCI distribution across the fragments evaluated, indicating greater
stability in the nutritional condition of this guild. Despite the nutritional condition observed
between fragments, when evaluating the FA of the bird community, no patterns indicative of 

environmental stress were observed. Although FA constitutes a relevant biomarker in some
contexts, its interpretation must be carried out with caution, since the effects of fragmentation and
environmental stress, although present, tend to be subtle and highly variable between species,
guilds and ecological contexts.

MEMBROS DA BANCA:
Externo(a) à Instituição - JOAO BATISTA DE PINHO
Interno(a) - 1278133 - GUILHERME RAMOS DEMETRIO FERREIRA
Externo(a) à Instituição - LUISA MARIA DIELE VIEGAS COSTA SILVA