Mangroves on Cardoso Island, Cananéia, São Paulo State, Brazil: a historical narrative

ABSTRACT

The Cananéia-Iguape Estuarine-Lagoon System - CIELS is home to nearly 50% of São Paulo’s State mangrove forests and it is considered one of the most preserved estuaries along the Brazilian coast. Many publications exist on CIELS’s structure, function and ecosystem services, particularly focusing on the interconnected ecosystems of Cardoso Island. Here, we present a chronology of the many research projects developed since our lab group first visited the region in 1978. Once the monitoring areas were established (Perequê river, Sitio Grande river and "Cardoso"), sampling protocols were designed for each "workstation", including types of mangrove forests, sample plot's location related to hydroperiod, identification of typical mangrove plant species, and structural and functional characteristics following standardized international methods manuals. The typical mangrove plant species on Cardoso Island are: the red mangrove (Rhizophora mangle L.), the white mangrove (Laguncularia racemosa (L.) Gaertn.f.) and the black mangrove (Avicennia schaueriana Stapf and Leechman). Over time, new experiments were added, such as primary productivity estimation through litterfall production, litterfall decomposition rates of the three typical mangrove plant species in intertidal and infralittoral environments, and respective nutritional declines through the analysis of C/N contents, in addition to the red mangrove propagules dynamics. After several years of studies, the "Transversal Cardoso" ("Cardoso Transect"), extending 340 m from the Trapandé Bay to the adjacent restinga (sandbank vegetation) ecosystem, was selected as a long-term monitoring work platform. Several comparative experiments were developed in this transect, with an emphasis on some of the abiotic variables, structural characteristics and, biological diversity in relation to the dynamics of the mangroves forest. To enhance knowledge for conservation CIELS's mangrove ecosystems, mapping studies were carried out at different hierarchical levels under a systemic view in the context of landscape ecology. More recently, some studies have looked at the importance of mangroves in this coastal segment of the Southeast Region in terms of high soil organic carbon stocks and sequestration rates, belowground biomass and litterfall in the context of climate change. All graduate level studies conducted by our research group have been funded by the National Council for Scientific and Technological Development - CNPq, the Coordination of Superior Level Staff Improvement - CAPES, the São Paulo Research Foundation - FAPESP and Small Grants Fund of the Ramsar Convention.

Keywords:
Brazil; Cananéia; flood gradient studies; mangrove stands