INFLUENCE OF THE RAIN PERIOD ON THE DISTRIBUTION AND BIOECOLOGY OF BOLACHA-DA-PRAIA Mellita quinquiesperforata (LESKE, 1778ON A TROPICAL SANDY BEACH (Atena Editora)

Abstract

The beach cookie Mellita quinquiesperforata (LESKE, 1778) occurs on the beaches of the State of Maranhão and was analyzed in the rainy season, for four consecutive years, in six collections between the months of December to May, on a sandy beach of Araçagi, municipality of São José de Ribamar. Five profiles were established perpendicular to the coastline with three collection points in each, in a total of 15 collection points. The profiles were located in three bands, according to the distances from the lowest syzygy tide line. The beach area covered by the profiles was 3,000 m², arranged 100 meters long by 30 meters wide. The results showed that, where M. quinquiesperforata was found, the sediment consisted of fine sand, with moderately selected grains. A total of 483 individuals were sampled at 15 collection points. No significant differences were found that could establish patterns in the distribution of animals between different heights and tidal ranges, indicating that they were all in the lower mesolittoral, in the same sediment facies. The average density found for the species was 5.36 ind/m². In periods of greater or lesser rainfall, significant differences (p< 0.001) were observed for abundance, density, body size and salinity. The average density (for all profiles) in the period of intense rainfall was 1.28 ind/m² and in the period of lower rainfall it was 9.44 indv/m² as for the size of the endoskeleton, there was a significant variation between the periods of high rainfall and low rainfall. rain, and most of the chicks and juveniles were found in the period when it rained little. The rains indicated to be a determining factor for the population structure of M. quinquiesperforata.