| The quantity and quality of available water resources impose limits on the use of water for agricultural, industrial and domestic consumption. The effects of such limits appear as stresses in agricultural crops and natural ecosystems. This study evaluated the use of various remote sensing techniques to detect stress at three local scales in an agricultural system (individual leaves, tree canopies, and an entire citrus grove), and at regional scale, in natural wetland ecosystems.; The use of multispectral digital imagery is evaluated to identify stressed grapefruit (Citrus paradisi) trees within an experimental grove in southeastern Florida. Salinized irrigation water at four salinity levels and three different fertilization regimes were applied to trees grown on four different rootstock varieties. Spectral reflectance analysis of individual leaves, and multispectral images of single trees and of the whole grove were used to assess stress effects by comparing reflectance in specific spectral bands from trees that received different experimental treatments. A separate citrus grove located in Vero Beach, Florida was used to assess remote sensing methods including airborne laser terrain mapping and leaf area index mapping.; The study of stress effects on a regional scale in cypress ( Taxodium spp.) wetlands uses a database containing quality rankings of over 200 sites in the Northern Tampa Bay Region of Florida to investigate the individual and cumulative effect that regional groundwater use and other external factors have on the wetlands. The wetlands were evaluated by field biologists from the Southwest Florida Water Management District based on a qualitative assessment on a 1 to 5 scale of factors such as hydrology, wetland vegetation and wildlife usage. Landsat imagery was used to assess wetland health throughout the region according to reflectance characteristics of the monitored wetlands. |
