The Use of Large - scale Aerial Photography to Inventory and Monitor Arid Rangeland Vegetation

Interpretation of large-scale color infrared and color aerial photography can be a laborand cost-effective means to make inventory of and monitor rangelands while maintaining accuracy. Ground measurements of total vegetation cover, tree, shrub and cacti cover at Organ Pipe Cactus National Monument were taken in 1975 and 1984. Estimates of ground vegetation cover made using large scale (1:1200) color and color infrared aerial photography were compared to these ground measurements. High correlation coefficient values exist between color infrared transparency estimates and ground measurements of total vegetation cover (r = 0.972) and shrub cover (r = 0.891). Correlation coefficients were similarly high when matching color prints against ground measurements of total cover (0-976) and shrub cover (0.858). Estimates from color infrared film transparencies corresponded better with ground measurements for both tree and cactus cover, with r values of 0.685 and 0-812 respectively, than the estimates from color print photographs with r values of 0.501 for tree cover and 0.246 for cactus cover.