Analysis of the conquiological spatial distribution of the beaches of Itanhaém, São Paulo-SP Felipe Ferreira Lucas, Roberto Pereira Borges

Abstract

The study highlights the conchological importance in understanding the diversity and structure of these mollusks. The objective is to analyze the richness and diversity of mollusk shells, as well as to conduct similarity tests between beach fragments to guide future studies in the region. Mollusk shell samples were collected from five beaches in Itanhaém in May 2020. Transects of 500m were established at each location, with randomly sampled 100m² sampling units. Shells were classified based on morphology, and diversity was assessed using the Shannon-Wiener Index and Pielou's evenness. Data analysis was performed using Past 4.03 software, including species composition comparison and similarity analysis between beach fragments. A total of 377 shells were collected on Itanhaém beaches, identifying 14 species. Diversity was highest in Cibratel (H’ = 2.055) and lowest in Loty (H’ = 1.407) and Gaivotas (H’ = 1.19). Intermediate morphodynamics influenced richness. The Loty beach, with rocky outcrops, exhibited lower diversity away from these areas. Bray-Curtis correlation indicated homogeneity among Itanhaém beaches. It is concluded that Cibratel is the most diverse, and the coastal fragments of Itanhaém are homogeneous in terms of species richness and abundance.