Influência das barracas de praia sobre a população de Ocypode quadrata Fabricius, 1787 (Crustacea, Ocypodidae) em uma praia arenosa no Nordeste Brasileiro

Abstract

In the present work it was evaluated the presence of beach shacks of the Futuro Beach on the population of Ocypode quadrata, and the role of this species as a tool for evaluation of anthropic impact in the sandy beaches of Fortaleza. During one year, two areas were analyzed, one with beach shack and one without it. In each of them, three transects (10m wide) were demarcated, perpendicular to the water line and 10m apart. The transects extended from 5m below the high tide line to the limit of occurrence of burrows. Each transect was divided into continuous squares of 5m x 10m, in which the burrows were counted and measured with a caliper. In the area with the highest degree of impact, it was found a density of 0.0144 burrows/ m2 and average diameter of the burrows of 20.50 mm, while in the area without beach shacks the density was 0.0410 burrows/ m2 and the average diameter of burrows was 29.21 mm. This difference indicates that both facilities and the trampling of its users hinder establishment of the crab, as well as affect the structure of the population. Such vulnerability indicates that this species can be a good indicator of anthropic impacts and can be used as a support tool for environmental monitoring programs in Ceará beaches.