We assessed the effects of overgrazing by feral sheep on watersheds on Santa Cruz Island, California. Overgrazing had a marked effect on stream flow; flows were much greater in overgrazed than in lightly grazed watersheds early in the rainy season, but the difference vanished later in the season. This pattern can be explained by reduced infiltration and increased surface runoff of rainfall in o...

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An approach to extract watersheds and watercourses, as well as their corresponding valleys and hills, from images with subpixel precision is proposed. The critical points of the terrain are essential as the starting points for the construction of these separatrices. They are extracted efficiently with subpixel precision using an approach based on derivatives of Gaussian filters. The separatrice...

The paper address the problem of retinal image segmentation, and aims at describing a novel segmentation technique, based on the watershed algorithm, able to separate in a clear way blood vessels from background. Automatic accurate analysis and quantitative characterization of diagnostically relevant features of retinal images can help clinicians for diagnosis and follow-up of eye diseases.