Banca de QUALIFICAÇÃO: ISABEL GONZALVES VELASCO

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: ISABEL GONZALVES VELASCO
DATA : 22/10/2026
LOCAL: VIDEOCONFERÊNCIA
TÍTULO:

Environmental and temporal drivers of tadpole assemblage diversity in a semi-arid landscape in northeastern Brazil

PALAVRAS-CHAVES:

Caatinga. Functional diversity. Anuran larvae. Species richness. Biotic filtering.

PÁGINAS: 20
RESUMO:

In arid and semi-arid regions, the short and unpredictable hydroperiod of freshwater habitats imposes strong constraints on amphibian reproduction.Yet, the relative roles of hydroperiod, water chemistry and predators in structuring tadpole assemblages remain poorly understood in the Caatinga, one of the most threatened and least studied semi-arid biomes in northeastern Brazil. In this study, we investigate how physicochemical properties, habitat heterogeneity and predator diversity of lentic water bodies affect variation in richness, composition and functional diversity of tadpole assemblages acrossa semi-arid Caatinga landscape. We predicted that pond hydroperiod would be the primary driver of assemblage diversity, with water chemistry and predators playing secondary roles. We sampled24permanent and temporary ponds monthly from July 2024 to July 2026, recording tadpoles, potential invertebrate predators, and a set of environmental variables (pH, dissolved oxygen, salinity, conductivity, turbidity, canopy openness, hydroperiod and a habitat heterogeneity index). NMDS was used to summarize tadpole diversity data in each pond. Relationships between variation in tadpole assemblage composition and diversity and environmental predictorswere tested using PERMANOVA, multiple linear regression and Generalized Linear Mixed Models.Tadpole functional richness and evenness were analyzed with AICc-based model selection and redundancy analysis. We recorded 2872 tadpoles belonging to 19 species, distributed in six families. Assemblage composition differed significantly along the hydroperiod gradient, and long-duration temporary ponds supported higher species richness than permanent ponds. Tadpole richness was positively associated with the biomass of predatorsand negatively associated with pH.Functional richness declinedwith increasing pH and functional evenness declined with increasing pond volume and predator biomass. Species richness and tadpole abundance showed a strong seasonal pattern, peaking during the rainy season and tracking recent rainfall. Our results show that temporal variation in water availability, local physicochemical conditions and predator-mediated filtering jointly structure tadpole assemblages in this semi-arid landscape. Because tadpole assemblages responded consistently to hydroperiod, pH and predator biomass, standardized tadpole sampling emerges as a practical and cost-effective protocol for monitoring anuran diversity in the Caatinga, complementing more expensive adult surveys. Given that both natural ponds on rocky outcrops and artificial ponds within pastures supported diverse assemblages, monitoring and conservation programs should not be restricted to protected natural habitats but should also consider human-modified ponds on private farmlands as functionally relevant components of the pond network.

MEMBROS DA BANCA:
Externa à Instituição - CAMILA CHIAMENTI BOTH
Interna - ***.728.884-** - PAULA BRAGA GOMES - UFRPE
Interno - 1551332 - PAULO SERGIO MARTINS DE CARVALHO
Presidente - 3091544 - PEDRO IVO SIMOES