The effects of precipitation variability on the canopy cover of forage species in arid rangelands, Iran
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ORIGINAL PAPER
The effects of precipitation variability on the canopy cover of forage species in arid rangelands, Iran Hamed Joneidi 1,2 & Nahid Azizi 1 & Khaled Osati 1,2 & Isa Bandak 3 Received: 3 September 2019 / Accepted: 20 August 2020 # The Author(s) 2020
Abstract This research was conducted to monitor changes in canopy cover of typical species during a 10-year period in the part of arid rangelands, to find out the relationship between two important climate variables (precipitation and temperature) and canopy cover changes. For that reason, canopy cover percentages of six dominant perennials and all annual plant species combined were measured during a 10-year period at phenological maturity of plant in thirty 2 m × 2 m plots which were placed along two 250-m transect lines. The results demonstrated that the maximum canopy cover for water year 2006–2007 (wet year) and the minimum value for water year 2012–2013 (drought) were 15 and 5.5%, respectively. The canopy cover was modeled by linear regression in which precipitation and temperature variables were considered independent variables. April precipitation explained 65% of changes in the canopy cover percentage of Artemisia sieberi at 95% confidence level (RRMSE = 0.26 and MAE = 0.49). The best simple linear regression models for estimating canopy cover percentages of Stipa barbata and Zygophyllum eurypterum corresponded to cumulative 4-month precipitation from March to June and March precipitation respectively, representing 77% (at 99% confidence level) and 67% (at 95% confidence level) of changes correspondingly. Considering the dominance of A. sieberi, S. barbata, and Z. eurypterum in floristic composition of the study area, it can be concluded that most changes in canopy cover of the studied rangeland are predicted by variability of precipitation during growing seasons. Keywords Canopy cover . Climate variability . Precipitation . Linear regression
Introduction Sustainable exploitation of rangelands in arid regions needs the knowledge of variation in vegetation cover and the effective Responsible Editor: Amjad Kallel * Hamed Joneidi [email protected] Nahid Azizi [email protected]; [email protected] Khaled Osati [email protected] Isa Bandak [email protected] 1
Faculty of Natural Resources, University of Kurdistan, Sanandaj, Iran
2
Kurdistan Studies Institute, University of Kurdistan, Sanandaj, Iran
3
University of Tehran, Tehran, Iran
factors influencing it (Walter 1979; Abdolahi et. al. 2012; Abdolahi et al. 2011a, b). Successive measurements over several years are necessary to achieve such data which is valuable for rational exploitation planning of rangelands at national level (Arzani 1997). Contrary to the temperature regime and soil properties, which undergo little fluctuations, the productivity of the rangelands is much more affected by the characteristics of the rains, in particular their quantities (Akbarzadeh and Mirhaji 2007). Not just the amount of rain but the changes in the frequency of it is critical (Damizadeh et al. 2001)
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