Influence of climatic factors and vegetation on population dynamics of Phyllomedusa iheringii

• Grant number: 23/12279-1
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2023
• End date: July 31, 2025
• Field of knowledge: Biological Sciences - Ecology
• Principal Investigator: Denise de Cerqueira Rossa-Feres
• Grantee: Guilherme Castro Franco de Lima
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil

Abstract

Long-term studies on amphibians, especially those on population dynamics, are rare, despite being crucial for establishing effective conservation strategies. Studies in demographic dynamics allow us to understand how biotic and abiotic variables influence the survival on populations. Population size can be estimated through birth, death, migration and emigration rates that may be directly influenced by climatic factors, such as temperature and rainfall, in addition to biotic interactions. Landscape structural descriptors are also important predictors for the distribution and abundance of these animals, constituting the structural matrix where amphibians perform essential activities, such as foraging and reproduction, in addition to providing shelter from predators and providing humid microclimates with milder temperatures. In this study, we propose to analyze the relationship between climatic and structural variations of the vegetation with the population parameters of the tree frog Phyllomedusa iheringii. Population data were obtained using the mark-and-recapture method between 2018 and 2021. Amphibians were individualized by photo-identification and fluorescent subcutaneous implantation. We tagged 256 and recaptured 138 individuals. In addition to the population size, the rates of colonization, survival and population recruitment will be determined using the MARK computational program. The climatic variations will be monthly average temperature, monthly average variations, temperature seasonality, storm seasonality and monthly relative humidity and will be extracted from the WordClim database, three variables will be extracted from the local vegetation structure: percentage of tree cover/ shrubby and herbaceous cover, and presence of melostomataceae. Vegetation structure on a regional scale will be represented by the percentage of forest cover in 50 m polygons. We will test the hypotheses that climatic and structural variations in cultivation influence different periods of P. iheringii population dynamics. For this, we will select the models with the best representation and fit to the data obtained in the MARK computational program. Based on the knowledge about the natural history of this species, we expect to detect the influence of structural tissue variations on survival and habitat occupation, and the influence of temperature on survival rates.