Comparing Actual and Potential Productions of Rangeland Ecosystems of Kohgiluyeh and Boyer-Ahmad Province in Different Rangeland Conditions

Spatiotemporal changes of net primary production (NPP) is one of the essential indicators in determining rangeland ecosystem condition. Therefore, the aim of current research was to map and monitor the actual and potential NPP of rangeland ecosystems in Kohgiluyeh and Boyer-Ahmad province, using CASA and Miami models, MODIS and field data from ۲۰۰۹ to ۲۰۱۸. The accuracy of the produced NPP maps was assessed in ۲۵۳ sampling sites located in different vegetation types with good, fair and poor rangeland conditions, using linear regression. Results showed that the difference between actual and potential NPP was greater than ۵۶ gr C/m۲/month, which can be a sign of human impacts and interferences in the rangeland ecosystems of the region. The highest and lowest relationships between modeled and field productions were observed in the Astragalus spp. - Bromus tomentellus vegetation type with good rangeland condition (R۲=۰.۸۴) and Astragalus sieberi- Stipa capensis vegetation type with poor rangeland condition (R۲=۲۸), respectively. The present research findings indicated the importance of drought conditions, vegetation type and rangeland condition in estimating the actual and potential NPP and the difference of these productions can be used as an index to determine and monitor the condition of rangeland ecosystems.

Keywords:

Vegetation type , Net primary production , CASA model , Miami model , Remote sensing , Drought , تیپ گیاهی , تولید خالص اولیه , مدل کسا , مدل میامی , سنجش از دور , خشکسالی