Modeling and management of migratory shorebird habitat in northern Brazil using remote sensing

Migratory shorebirds utilize the intertidal zone as key foraging habitat throughout the Western Americas Flyway, from stopover locations like Delaware Bay in the United States, to overwintering locations like the Gulf Coast, Bahia Lomas in Chile, and the states of Pará and Maranhão on the northern coast of Brazil. Northern Brazil serves as a critical stopover and overwintering location for a number of migratory shorebirds. Characterizing, modeling, and managing the intertidal habitat in northern Brazil is critical for conserving this ecosystem crucial to the Western Americas Flyway. In Chapter 1, intertidal habitat is characterized by evaluating the relationship between the remote sensing metrics of Landsat 8 optical reflectance, Sentinel 1 radar backscatter, and intertidal sediment conditions in northern Brazil and Bahia Lomas, Chile. Consistent patterns are found within each site, indicating that remote sensing effectively characterizes sediment, but the patterns are unique to each location, and distinct from previous research. In Chapter 2, remote sensing, landscape, and climatic metrics are utilized in Maxent distribution models of eight shorebird species of conservation interest. Resulting models effectively distinguished between presence and absence validation data, even though some models did not have high values of internal model function. Remote sensing metrics contributed significantly to model performance, with models' responses reflecting the relationships between remote sensing and sediment size determined in Chapter 1 and known ecology of each shorebird species. Landscape metrics also contributed significantly, though interpreting how the metric response related to shorebird ecology was less clear. Climatic variables contributed significantly, but their relevance to the underlying biological processes was suspect, considering the equatorial nature of northern Brazil. Finally, in Chapter 3, the models developed in Chapter 2 were applied to a case study of three different conservation prioritization strategies: umbrella species, flagship species, and biodiversity. Semipalmated sandpipers were used as the umbrella species, red knots as the flagship, and areas with high shorebird species richness as biodiversity. The umbrella approach cast the widest net, and protected very species rich habitat, the biodiversity protected similarly rich habitat, but under a much narrower range, and the flagship species protected the least species rich areas, though with greater species richness than the landscape or areas currently protected. Both umbrella and biodiversity approaches did not cover a significant portion of the rarer, red knot habitat. A final hybrid approach, using both biodiversity and flagship species approaches, was proposed to protect both species diversity, and the rarer species of concern. Three areas outside of current protections were identified as potential hot spots for conservation prioritization using the different management regimes, Baía do Cumã, and Baía de São José, and an area west of Extractive Reserve Cururupu.Ph.D.Includes bibliographical reference