The study of habitats properties and response pattern of (Chaerophyllum macropodum Boiss. ) to environmental factors by using Canonical Correspondence Analysis (CCA) and Generalized Additive Model in rangelands of Mazandaran province

Knowing the ecological characteristics of plant species and their response to environmental factors provides the necessary information for managing vegetation and improving  of rangelands. Due to the importance of the  Chaerophyllum macropodum and its role in soil protection and forage production, we conducted a study of the ecological needs and determining the ecological factors affecting in plant cover and the response of the species to changes in ecological factors, using the Canonical Correspondence Analysis method ( CCA) and Generalized Additive Models (GAM) in Mazandaran province. The results of conventional comparative analysis showed that environmental factors such as altitude, aspect, phosphorous, organic carbon, organic material, pH, Ec, %sand, saturated moisture percentage and lime  of soil, respectively with the expression of 5.9, 5.6, 2, 2, 1.8, 1.7, 1.7, 1.6 and 1.3 percent of the variance in plant composition had an important role in the changes of plant cover in the studied habitats. The response of the species to the amount of phosphorus and potassium follows the monotonic decrease model. The response of species to the percentage of silt, sand, organic material, organic carbon,nitrogen,line and aspect  follows the bell model (Unimodal) and the optimal growth limit For each of these factors, it is 20%, 55%, 5%, 35,0.45 and north and westnorth slopes. The study of the response of the species  to environmental and soil factors provided valuable information to determine the ecological needs of this species, which can be taken into consideration in the operation of rangelands improvement in similar areas.