Modeling canopy cover and aboveground net primary production using soil factors in rangelands of Ardabil province, Iran

Abstract

<p>Canopy cover (CC) and the aboveground net primary production (ANPP) vary under the influence of various environmental factors. They underscore ecological sustainability under different environment-human interactions. Towards this, the present study aimed to model the CC and ANPP of different plant functional types (PFTs) and their total using the soil attributes in the northwest (Ardabil province) rangelands of Iran. According to ecoregions and plant types and environmental factors, sampling was taken at the peak stage of plant growth from 2016 to 2020 using 1-m2 plots. For each transect, a soil sample was taken and transferred to the soil laboratory and the various attributes were measured. Maps of soil attributes were prepared using the inverse distance weighting (IDW) method. Differences in CC and ANPP of PFTs among soil attributes were analyzed using the paired sample t-test. Linear multiple regression was used for modeling the soil attributes. Total CC and ANPP were prepared in two ways (i.e., regression and PFTs maps summing). The accuracy assessment of the maps was calculated by using the criteria of mean absolute error (MAE), mean deviation error (MDE), and root mean squared error (RMSE). The obtained results were acceptable (value < 7). The difference between the modeled and measured mean values of CC was equal to –0.03% for grasses, –0.01% for forbs, +0.03% for shrubs, 0% for total<sub>regression model</sub>, and +0.06 for total<sub>PFTs maps summing</sub>. Additionally, this difference in terms of the ANPP was equal to 0 kg/ha for grasses, +0.02 kg/ha for forbs, –0.09 kg/ha for shrubs, –0.02 for total<sub>regression model</sub>, and +0.02 kg/ha for total<sub>PFTs maps summing</sub>. The present results are applicable to managing the balance between supply and demand of rangeland products and they can be used from carbon management perspectives.</p>