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Mangroves occupy geomorphologically active estuarine settings but many studies have focused on short-term. Static views fail to capture the wholeness of these systems and could lead to failed conservation policies or management guidelines. These wetlands are of critical interest to resource managers because of their productivity, economic, and ecological roles. This paper describes the structural, temporal dynamics of forests at the Cananéia-Iguape Coastal System, located along the south coast of São Paulo State (Brazil), between latitudes 24°40’S and 25°20’S where three mangrove species occur in within different depositional facies: Rhizophora mangle (Rhizophoraceae); Laguncularia racemosa (Combretaceae); Avicennia schaueriana (Acanthaceae/Avicenniaceae). Monitoring was done in January/2001, November/2002, May/2003, November/2003, May/2004, November/2004, July/2008, January/2009, July/2009 and January/2010. In each of 15 plots in total, all plants were identified, and tree diameter and average height were recorded. Mean tree diameter, basal area dominance, and stem density were assessed. The forest’s succession revealed three distinct stages of development with increasing diameter and mean height: 1. colonization; 2. young; and 3. mature. Where tidal energy dominates, the initial and young stages were dominated by Laguncularia racemosa (96-100%) and mature stages by Avicennia schaueriana (75-92%). Where fluvial energy dominates, Rhizophora mangle dominated in all stages. Sedimentary and hydrological conditions are essential in defining which typical mangrove forest species will colonize accretion areas and how zonation and succession will be manifested. Monitoring structural characteristics over time helps to understand processes involved the differentiation of the landscape. The analysis of historical satellite images allows the assessment of processes at higher hierarchical levels and the relations between morphogenetic and ecological views.

This paper describes the development of mangrove forests monitored in permanent plots at the Cananéia-Iguape Coastal System. The coastal system is located along the south coast of São Paulo State (Brazil), between latitudes 24°40’S and 25°20’S. In different environmental settings, within two transects (Baguaçu and Sítio Grande) fixed plots were established. New plots were placed when new mangrove stands colonized depositional areas. Plot size varied according to stem density, varying from 2m×2m to 20m×20m, according to methodology proposed by Cintrón and Schaeffer-Novelli (1984). The monitoring was done in January/2001, November/2002, May/2003, November/2003, May/2004 and November/2004. Once field data had been collected, the average height, dnominal (dn: diameter at or close to normal stem form), basal area, basal area dominance, and stem density were assessed. The mangrove forest’s succession revealed patterns of structural development with increasing dn and mean height and decreasing density over time. We identified three stages of mangrove forest development: 1. colonization or initial; 2. young; and 3. mature. In the Baguaçu transect, the initial and young stages were dominated by Laguncularia racemosa (70-100%), and the mature stage by Avicennia schaueriana (80-90%). In contrast, in the Sítio Grande transect Rhizophora mangle dominated in the initial and mature stages (100%) and a mixed forest (R. mangle and L. racemosa) dominated in the young stage. The mangrove forests’ zonation and succession in our study sites seem to be the response of depositional processes.

Wetlands, including mangroves, perform several functions, besides generating products and services, which have a fundamental importance for the human society. It is possible to manage mangrove areas, making use of opportunities for recreation, tourism, fishing, education and research, without the need of a considerable manipulation of the system. Such management can be done for instance while preserving the flow of material and nutrients that sustain ecosystem production and while maintaining control of the quality of the water. The study of physiographic types could be of help in the comprehension of the large variability of structural development, as a result of the response of mangrove plant species to the innumerous abiotic components that interact in this environment. With the aim of improving the understanding of mangrove vegetation structure dynamics and to help the management of the Cananéia region, located in the South coast of the São Paulo State (25°S), data from the 1980’s to present on the structural development of mangrove forests of different physiographic types, were analyzed. The fringe forests studied in the region presented a predominance of Rhizophora mangle and high structural development due to the high inundation frequency, in stable sites, where there are no important sedimentary processes. On the other hand, fringe forests, located in progradation areas with low tidal energy, were dominated by Laguncularia racemesa with low structural development. As a rule, the riverine forests are dominated by R. mangle, with a high structural development in function of the high inundation frequency and a continuous flow of fresh water, this permitting a larger input of nutrients, oxygen and dissipation of noxious substances from the sediment. Riverine forests, located in progradation areas with high river energy, were dominated by R. mangle with low structural development and were associated to the smooth cordgrass Spartina alterniflora. The basin forests were also seen to be dominated by R. mangle, presenting, however, reduced structural development in function of the low inundation frequency, a predominantly sandy sediment and low salinity. However, some areas showed to be well developed due to the structural characteristics of the dominant arboreal mangrove species (Avicennia schaueriana). The results presented here indicate that variations in the quality and intensity of forcing functions are infinite, the structural variability being limited by the plasticity of the species involved and their capacity to adjust themselves to the environment in which they develop. The main objective of management should be limited to the protection of those processes which act upon the system, and the control of the fulfillment of services. Studies of the different physiographic types, dynamics, zonation patterns, and responses to abiotic characteristics are essential to help to define conservation policies for the mangroves in the Cananéia region.

The current paper examines the growth and spatio-temporal variation of mangrove forests in response to depositional processes and different salinity conditions. Data from mangrove vegetation structure collected at permanent plots and satellite images were used. In the northern sector important environmental changes occurred due to an artificial channel producing modifications in salinity. The southern sector is considered the best conserved mangrove area along the coast of São Paulo State, Brazil. Landsat TM5 images from 1997 and 2010 were processed using Geographical Information Systems. Supervised classifications complemented by visual interpretations and ground truth were used to map mangrove areas in both periods. In each permanent plot, all plants were identified and tree diameter, height, and incidence of associated species were recorded. Mean height, basal area dominance, and stem density were also assessed. In the southern sector of the study area, digital image analysis revealed shoreline progradation and mangrove establishment. These sites have demonstrated both vegetation growth and extension. In the northern sector, the satellite image analysis revealed an increase of depositional areas. An important number of associated freshwater plants were observed, inhibiting the establishment of mangrove seedlings or growth of saplings. Despite the high sedimentation rate, which enables mangrove colonization, the low salinity exerts indirect negative influence on mangrove development, considering that it creates good conditions to macrophytes reproduction. Coastal planning requires that the spatial differences be recognized as unique sub-systems due to the hydrodynamic complexity. Both on-theground monitoring of the vegetation structure and space-borne remote sensing are important tools to support coastal zone management.