ABSTRACT: Rangeland production is sensitive to climate conditions. In this study, we monitored actual and potential production in the climate zones of Chaharmahal and Bakhtiari province in central Zagros, Iran, from 2000-2016. Net primary production (NPP), light use efficiency (LUE) and rain use efficiency (RUE) were extracted from climatic and MODIS satellite data using the Carnegie-Ames-Stanford approach (CASA) and Miami models. The accuracy of the modeled NPP maps was assessed using regression analysis, based on field data collected at 750 sites under different rangeland conditions. The spatial distribution of NPP and RUE indicated that annual production and photosynthetic efficiency in degraded rangelands with poor and very poor conditions have decreased compared to those of moderate-good classes. The highest relationship between the field and modeled NPP was associated with the Astragalus spp.-Ferula spp. (R² = 0.865, p < 0.001) in the humid and cold climate zone with good rangeland conditions while the lowest was observed in the annual grasses-annual forbs (R² = 0.198, p < 0.001) vegetation type with very poor rangeland conditions within the semi-arid and cold climate zone. Furthermore, the highest and lowest NPP values were observed in the Daphne mucronata-Prangos ferulacea (48.38 g C m^-2 yr^-1) and annual grasses-annual forbs (3.42 g C m^-2 yr^-1) vegetation types with LUE values of 0.13 and 0.02 g C MJ^-1 within the humid and cold and the semi-humid and cold climate zones, respectively. According to these findings, remote sensing-based differences between actual and potential NPP can be used as a valuable tool for identification of human impacts on broad rangeland ecosystems.

中文翻译：

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利用MODIS和气象数据调查伊朗扎格罗斯中部气候区的净初级生产

摘要：牧场的生产对气候条件敏感。在这项研究中，我们监测了2000-2016年伊朗扎格罗斯中部的恰哈马哈尔邦和巴赫蒂亚里省气候区的实际产量和潜在产量。使用卡内基-艾姆斯-斯坦福方法（CASA）和迈阿密模型，从气候和MODIS卫星数据中提取了净初级生产（NPP），光利用效率（LUE）和雨水利用效率（RUE）。基于在不同牧场条件下从750个地点收集的田间数据，使用回归分析评估了建模NPP图的准确性。NPP和RUE的空间分布表明，条件较差和极差的退化草地的年产量和光合效率与中良好等级的相比有所下降。黄芪属。-阿魏属。（R ² = 0.865，p <0.001）在牧场条件良好的潮湿和寒冷气候区，而在草地条件很差的一年生草类-年生前茅（R ² = 0.198，p <0.001）植被类型中观察到的最低值在半干旱和寒冷的气候带内。此外，在达芙妮（Daphne mucronata-Prangos ferulacea）（48.38 g C m ^-2 yr ^-1）和一年生草类-年生前茅（3.42 g C m ^-2 yr ^-1）植被类型中，观察到最高和最低NPP值具有LUE值0.13和0.02 g C MJ ^-1分别位于潮湿和寒冷以及半潮湿和寒冷的气候区。根据这些发现，实际和潜在国家淘汰计划之间基于遥感的差异可以用作确定人类对广阔草原生态系统影响的宝贵工具。