Document Type : Research Paper
Authors
1 PhD Candidate of Rangeland Science, Shahrekord University- Expert, Department of Kurdistan Natural Resources, Iran
2 Associate Professor, Associate Professor, Faculty of Natural Resource and Earth Sciences, Shahrekord University, Iran
3 Assisstant Professor, Department of Range and Watershed Management, Kurdistan University, Iran
4 دانشیار، گروه مرتع و آبخیزداری، دانشکده منابع طبیعی و علوم زمین، دانشگاه شهرکرد، ایران
Abstract
The present study was conducted to investigate the differences between several remote sensing indices, four different plot sizes and two different sampling methods to estimate the percentage of plant cover and production in three plant communities in 2013. Ground sampling was performed in three communities with different dominant vegetation in two forms of six and three quadrats. Four different dimensions of the quadrats were used nested to estimate production and coverage percentage. Sampling was performed in each community within 30 pixels along three transects with different heights (sampling method and testing were performed according to the researcher opinion). Dominant plant density was measured by counting the bases per plot, plant cover percentage as an estimate and production in the form of double sampling in relation to cover percentage. The results showed that with increasing plot area, the degree of correlation of plant indexes of Landsat image and their significance in relation to production and percentage of plant cover will increase. But this increase in community 2 is more dramatic in most respects with predominantly shrubs. As in this community, most of the studied indicators in 3 × 3 plot have a correlation and a reliable model, and in the three sizes of 1×1, 2×1 and 2×2 plots, the resulting models are not valid enough and have high RMSE. In community one with dominant broadleaf plants, only the model obtained in 1×1 plot and in community two with dominant plants, the model obtained in 1×1 and 1×2 plots are not statistically valid, although sometimes they have a significant correlation. The results of two different models are statistically different in communites 1 and 3 and there was no significant difference between them in community 2. According to the results of the study of indicators in terms of correlation and model validity, the two indicators NDVI and CTVI can be used in community 1, NDVI and TSAVI1 in community 2 and NDVI, NRVI and TSAVI1 in community 3 recommended for estimating production and percentage of plant cover using satellite images.
Keywords
)