Essential buffer zones between land and water in estuaries, salt marshes are disappearing rapidly, and those that remain are often in poor health. Traditional methods to monitor salt marsh health, ironically, often exacerbate the problem, as trudging through remote areas to dig up dirt and cut down plants contributes to marshes' demise. But a team of UC Davis researchers may be on to a better way. Minghua Zhang of the land, air and water department, along with colleagues Eric Sanderson and Susan Ustin, of the same department, and Eliska Rejmankova, of environmental studies, asked recently whether remote-sensing techniques, such as measuring the amount of light reflected off marsh plants, could give the same results as standard invasive sampling techniques. They looked at salt marshes at three sites along the Petaluma River near the entrance into San Pablo Bay, Calif., which represented a range of soil and salt conditions. They mapped more than 300 small plots of land, digging up soil samples and cutting down all plant life to analyze in labs on campus. They then compared their results from the field to data taken using spectrometers -- devices that read the amount of light being reflected by the marsh -- held about three feet above the plant level. Their results are intriguing: they could, with accuracy up to 85 percent, predict what types of plants were in a marsh, and how many; both of these factors are indicators of the health of the marsh. More work still needs to be done in correlating what is on the ground with what can be determined from above, but Zhang is confident that data such as this will lead to the ability to determine the composition of a salt marsh -- and thus its health -- using satellite images. Zhang and her colleagues published their results this summer in the journal Ecological Applications.