Long-term effects of oil pollution in mangrove forests (Baixada Santista, Southeast Brazil) detected using a GIS-based multitemporal analysis of aerial photographs

Authors

  • Luciana Cavalcanti Maia Santos Universidade de São Paulo
  • Marília Cunha-Lignon Universidade de São Paulo
  • Yara Schaeffer-Novelli Universidade de São Paulo
  • Gilberto Cintrón-Molero Universidade de São Paulo

DOI:

https://doi.org/10.1590/S1679-87592012000200006

Keywords:

Coastal wetland, Remote sensing, Impact assessment, Monitoring, Coastal management

Abstract

Oil spills are potential threats to the integrity of highly productive coastal wetlands, such as mangrove forests. In October 1983, a mangrove area of nearly 300 ha located on the southeastern coast of Brazil was impacted by a 3.5 million liter crude oil spill released by a broken pipeline. In order to assess the long-term effects of oil pollution on mangrove vegetation, we carried out a GIS-based multitemporal analysis of aerial photographs of the years 1962, 1994, 2000 and 2003. Photointerpretation, visual classification, class quantification, ground-truth and vegetation structure data were combined to evaluate the oil impact. Before the spill, the mangroves exhibited a homogeneous canopy and well-developed stands. More than ten years after the spill, the mangrove vegetation exhibited three distinct zones reflecting the long-term effects of the oil pollution. The most impacted zone (10.5 ha) presented dead trees, exposed substrate and recovering stands with reduced structural development. We suggest that the distinct impact and recovery zones reflect the spatial variability of oil removal rates in the mangrove forest. This study identifies the multitemporal analysis of aerial photographs as a useful tool for assessing a system's capacity for recovery and monitoring the long-term residual effects of pollutants on vegetation dynamics, thus giving support to mangrove forest management and conservation.

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Published

2012-06-01

Issue

Section

naodefinida

How to Cite

Long-term effects of oil pollution in mangrove forests (Baixada Santista, Southeast Brazil) detected using a GIS-based multitemporal analysis of aerial photographs. (2012). Brazilian Journal of Oceanography, 60(2), 159-170. https://doi.org/10.1590/S1679-87592012000200006