Monitoring of the Uçá crab (Ucides cordatus) in the lagamar paranaense, Brazil

Abstract

Monitoring mangroves is a strategy to assess their conservation status. In Brazil, it is part of the National Action Plan for the Conservation of Endangered Species and of Socioeconomic Importance of the Mangrove Ecosystem (PAN Manguezal). In this study, the protocol for monitoring the density and population structure of the uçá crab proposed by ICMBio (Chico Mendes Institute for Biodiversity Conservation) was implemented in three protected areas in Guaraqueçaba, located in the region of the lagamar paranaense. Subsequently, these areas were compared with mangroves under anthropogenic influence, located near the industrial port complex of the city of Paranaguá. Population densities were higher in the preserved mangroves. The immediate extractive potential, calculated based on the conversion of the burrow opening into the estimated size of the crab's carapace width, was also higher in protected areas. Among the variables measured, the level of flooding (r = -0.50; p < 0.001), relative density (r = -0.30; p < 0.001) and dominance (r = -0.34; p < 0.001) of Rhizophora mangle, as well as dominance (r = 0.38; p < 0.001) of Laguncularia racemosa were significantly correlated with crab densities. Thus, marked differences were observed in the mangrove under anthropogenic influence, evidencing the sensitivity of the methodology to environmental stressors. The continuity and expansion of this type of study will allow for more in-depth assessments and monitoring of the availability of the uçá crab, an extremely important resource in Brazilian mangroves.