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Mapeador Temático Landsat: Detección de Desplazamientos en la Composición de Comunidades en Arrecifes de Coral
Author(s) -
Dustan Phillip,
Dobson Eric,
Nelson George
Publication year - 2001
Publication title -
conservation biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.2
H-Index - 222
eISSN - 1523-1739
pISSN - 0888-8892
DOI - 10.1046/j.1523-1739.2001.015004892.x
Subject(s) - thematic mapper , reef , coral reef , coral , remote sensing , brightness , geography , environmental science , ecology , satellite imagery , physical geography , oceanography , geology , biology , physics , optics
We assembled a time series of 20 Landsat thematic mapper images from 1982 to 1996 for Key Largo, Florida, to ascertain whether satellite imagery can detect temporal changes in coral reef communities. Selected reef and control areas were examined for changes in brightness, spectral reflectance, band ratios, spatial texture, and temporal texture ( pixel‐to‐pixel change over time). We compared the data to known changes in the reef ecosystem of Carysfort Reef and terrestrial sample sites. Changes in image brightness and spectral‐band ratios were suggestive of shifts from coral‐ to algal‐dominated community structure, but the trends were not statistically significant. The spatial heterogeneity of the reef community decreased in the early 1980s at scales consistent with known ecological changes to the coral community on Carysfort Reef. An analysis of pixel‐scale variation through time, termed temporal texture, revealed that the shallow reef areas are the most variable in regions of the reef that have experienced significant ecological decline. Thus, the process of reef degradation, which alters both the spatial patterning and variability of pixel brightness, can be identified in unclassified thematic mapper images.