Costa de manguezais de macromaré da Amazônia: cenários morfológicos, mapeamento e quantificação de áreas usando dados de sensores remotos

Abstract

ABSTRACT. According to the World Mangrove Atlas, this ecosystem represents 8% of the world's coastline and one quarter of the tropical coastal zone shoreline, embracing 181,077 km 2 . The aim of this work is to map and to quantify the extension of macrotidal mangroves along the northeastern Pará and northwestern Maranhão coasts, here named as Amazon Macrotidal Mangrove Coast (AMMC). The identification of mangrove areas and their quantification were carried out using Landsat-7 ETM + images acquired in 1999 and 2000 and a geographic information system (GIS). The integration of remote sensing data, geological and oceanographic data allowed the recognition of five geomorphologic sectors, representing a total mangroves area of 7.591 km 2 . This area represents the largest continuous mangrove belt in the world and constitutes 56,6% of mangroves in Brazil. Prioritary measures for Amazon mangrove conservation must be taken and research to enhance understanding of this complex and important ecosystem must be supported and developed.Keywords: mangroves, area estimative, remote sensing, Amazon. RESUMO.De acordo com o Atlas de Manguezais, este ecossistema representa 8% de toda a linha de costa do planeta e um quarto da linha de costa da zona tropical, perfazendo um total de 181.077 km 2 . Este trabalho objetiva quantificar a extensão dos manguezais de macromaré da costa nordeste do Pará e noroeste do Maranhão, aqui denominada de Costa de Manguezais de Macromaré da Amazônia (CMMA). O reconhecimento dasáreas de manguezais e sua quantificação foram realizados a partir da utilização de imagens Landsat-7 ETM + , adquiridas em 1999 e 2000 e de um sistema de informações geográficas (SIG). A integração dos dados de sensores remotos, dados geológicos e oceanográficos permitiu o reconhecimento de cinco setores geomorfológicos, que abrangem uma superfície total de 7.591 km 2 de manguezais.Estaárea representa a maior faixa de manguezais contínuos do planeta e corresponde a 56,6% dos manguezais do Brasil. Medidas prioritárias de conservação dos manguezais da Amazônia devem ser tomadas e pesquisas que busquem a melhor compreensão deste complexo e importante ecossistema devem ser financiadas e desenvolvidas.Palavras-chave: manguezais, estimativa deárea, sensoriamento remoto, Amazônia.

Mangrove vegetation in Amazonia: a review of studies from the coast of Pará and Maranhão States, north Brazil

“…in this region, mangroves can extend more than 40 km landward following the course of numerous small estuaries and bays (souza-Filho, 2005). The area is characterised as macrotidal; tidal amplitude varies between 4 m and 7.5 m (souza-Filho, 2005).…”

“…in Brazil, mangroves occur from the Amapá state in the north to santa Catarina state in the south. The north coast has an area of approximately 8000 km 2 of mangroves (souza-Filho, 2005). Along the coast the states of Pará and Maranhão, mangroves form a continuous belt of about 700000 ha, that is, nearly 85% of all Brazilian mangroves (herz, 1991; lacerda, 1999).…”

Seagrass and Submerged Aquatic Vegetation (VAS) Habitats off the Coast of Brazil: state of knowledge, conservation and main threats

“…It has a wide continental shelf (up to 300 km wide) and is controlled by macrotidal processes (> 4 m, up to 6.3 within estuaries), with wide estuary mouths and short and narrow barriers (SOUZA-FILHO et al, 2009). The region holds the largest mangrove system in the world and the gorge of the largest river in length, water and sediment discharge, the Amazon River (SOUZA-FILHO, 2005). It has a tide-muddominated coast to the west (Amapá-Guyanas) and a tidedominated mangrove coast to the east (Pará-Maranhão) (DOMINGUEZ, 2004).…”

Survival and Growth of Mangrove Tree Seedlings in Different Types of Substrate on the Ajuruteua Peninsula on the Amazon Coast of Brazil

“…Approximately half of this area (6516 km 2 ) is found on the Amazon coast, between the states of Pará and Maranhão [2]. In Pará, the mangroves form an almost continuous tract of forest lining the coast for 300 km, with a total area of 2176.78 km 2 .…”

“…Approximately half of this area (6516 km 2 ) is found on the Amazon coast, between the states of Pará and Maranhão [2]. In Pará, the mangroves form an almost continuous tract of forest lining the coast for 300 km, with a total area of 2176.78 km 2 . The decline of these forests around the world is becoming increasingly evident, however, given the progressive growth of impacts such as the predatory extraction of the lumber produced by these systems [3].…”