Reflectance properties and physiological responses of Bulrush in Wetland Park to heavy metal contamination

摘要

Wetland park ecosystems of Yangtze River Delta are located in highly populated areas and subject to high levels ofcontamination. Monitoring of wetlands to assess degrees of pollution damage requires periodic retrieval of informationover large areas, which can be effectively accomplished by remote sensing technologies. The biophysical principles ofremote sensing of vegetation under stress need to be understood in order to correctly interpret the information obtained atthe scale of canopies. To determine the potential to remotely characterize and monitor pollution, plants of Bulrush, a major component ofwetland park communities in Yangtze River Delta, were treated with two metals to study their sensitivity to pollutantsand how this impacted their reflectance characteristics. Several growth and physiological parameters, as well as theirreflectance were measured. Significant differences between treatments were found in at least some of the measuredparameters in pollutants. Reflectance was sensitive to early stress levels only for cadmium. Pollutants that differ in theirway of action also had different plant reflectance signatures. The high degree of correlation between spectral reflectanceand plant stress by heavy metal contamination showed the potential of using remote sensing to assess the type and degreeof pollution damage.