Nahid Azizi; Hamed Joneidi; Khaled Osati
Volume 26, Issue 3 , September 2019, , Pages 717-730
Abstract
This research monitored changes in canopy cover percentage of typical species during a 10-year period in the Ghosheh rangelands to find out the relationship between two important climate variables (precipitation and temperature) and canopy cover changes. Therefore, the canopy cover ...
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This research monitored changes in canopy cover percentage of typical species during a 10-year period in the Ghosheh rangelands to find out the relationship between two important climate variables (precipitation and temperature) and canopy cover changes. Therefore, the canopy cover percentages of six typical species (separately) and annual species (overall) were measured during 10 years at the end of growing season in thirty 2-m2 plots, distributed along two 250–m transect lines. The results demonstrated that the maximum canopy cover percentage 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 percentage modeling was performed based on linear regression method using precipitation and temperature variables. The precipitation of April explained 65% of changes in canopy cover percentage of A. sieberiat 95% confidence level (RRMSE = 0.26 & MAE=0.49). The best simple linear regression model for estimating canopy cover percentage of S. barbata and Z. eurypterum was introduced by total precipitation of March-June and precipitation of March, representing 77% (at 99% confidence level) and 67% (at 95% confidence level) of changes in canopy cover, respectively. Considering the dominant role of A. sieberi, S. barbata and Z. eurypterum in vegetation composition of study areas, it can be concluded that most changes in canopy cover of the studied rangeland are predictable by variabilityofprecipitation during growing seasons.
Ali Taya; Hamid reza Naseri; Jamshid Ghorbani; Maryam Shokri
Volume 16, Issue 4 , January 2010, , Pages 456-467
Abstract
Species richness and biological diversity have been declined throughout the world as a result of human activities. Protected areas are an attempt to conserve the remaining species. Measuring species richness is important for understanding resource condition but heterogeneity in plant distribution make ...
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Species richness and biological diversity have been declined throughout the world as a result of human activities. Protected areas are an attempt to conserve the remaining species. Measuring species richness is important for understanding resource condition but heterogeneity in plant distribution make inventories difficult. Salok National Park with 6000 ha space located in North-west of Esfarayen County, Iran. In this study, species richness was measured by Modified – Whittaker plot for this National Park. For analysis of this richness a regression model as have been used. Totally, 184 plant species was found belonging to 137 geniuses and 40 plant family which Poaceae, Asteraceae, Fabaceae and Lamiaceae families with 28, 26, 19 and 17 plant species, respectively had the most species richness abundant among the others. As a biological spectral and life form, prevailing relations in studied area were HC>TH>GE>CH>PH and herbaceous Forbs>Grass>Bush>Shrub, respectively. The most plant species are perennial totally.