Nearshore intertidal flats are dynamic and ever changing ecosystems that supports an exceptional abundance and diversity of life. A number of forces can change the physical features of the intertidal zone over relatively short time periods, including longshore currents, and storm surge. These features, such as sandbars and mudflats, host invertebrates which subsequently provide the food source for wading shorebirds when exposed at low tide. Modeling and mapping this temporally dynamic ecosystem is an essential step to evaluating landscape-scale dynamics of the species that use the ecosystem, as well as any conservation planning methods enacted to protect those species. A pixel based remote sensing approach using Landsat 8 imagery was developed for the northern Brazil along the coast of the states of Pará and Maranhão. Normalized Difference Water Index in conjunction with unsupervised classification was used to map intertidal flat habitat types. Patch and landscape scale features were also mapped and characterized for incorporation into species distribution models.
Results/Conclusions
Approximately 4,100,000 hectares of intertidal flat habitat was delineated along the Pará-Maranhão coast. 75,000 hectares fell within the 12 federal extractive reserves, representing 14% of the area within those extractive reserves. Over 28400 distinct patches were identified, ranging in size from 0.27 to 24 hectares. The methods developed were effective at characterizing the intertidal flat habitat composition, which will be used to further evaluate both the suitability of the habitat for overwintering migratory shorebirds and the gaps between existing management strategies and shorebird habitat.