Investigation of vegetation changes using Soil Moisture Index in Gavkhouni wetland

Gavkhouni wetland located in the center of Iranchr('39')s Plateau is one of the important habitat for native flora and fauna. The present study aimed to evaluate change trend of vegetation types and Soil Moisture Index in Gavkhouni wetland since recent 16 years. Vegetation types were identified via field visitation during 2011-2017 and the maps were generated in ArcGIS 10.5. SMI is derived using a triangle space concept between the land surface temperature and normalized difference vegetation index from MODIS satellite data during 1380 to 1396. 24 vegetation types were identified in the study area. The highest area of the whole study area was allocated to vegetation type named Salsola tomentosa-Artemisia sieberi (89630 ha). Two vegetation types including Astragalus squarosus- Stipagrostis plumosa and Astragalus squarosus covered the lowest area (158 and 296 ha)in 1390 and 1396 respectively. The results showed that major changes in vegetation types occurred from 1390 including deletion of some dominated species such as Phragmites australis and Aeluropus littoralis in the study area which may be attributed to decreasing soil moisture index. The generated maps of SMI indicated that the area with low level of SMI (0-0.2) have increased while the areas with moderate and high levels of SMI (>0.2) have decrease from 2001 to 2017. In order to investigate plant vegetation changes, monitoring of SMI through satellite imagery can serve as an appropriate alternative to direct sampling and field measurement of soil moisture in wetland areas without available soil moisture records. Furthermore, range managers and natural resources and environmental protection authorities can use our findings as basic information in conservation management of endangered plant species and development of restoration and improvement programs.