Hassan Ghelichnia; Hosein Arzani; Mohammad Akbarzadeh; Mahdi Farahpour; Mojgan sadat Azimi
Volume 19, Issue 2 , September 2012, , Pages 203-220
Abstract
Rangeland assessment and recognizing changes in vegetation, yield and their affecting factors are of important issues for planning and optimum utilization management. Firstly in 2000, main habitats of Mazandaran province were determined and then a site was selected in each reference area for collecting ...
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Rangeland assessment and recognizing changes in vegetation, yield and their affecting factors are of important issues for planning and optimum utilization management. Firstly in 2000, main habitats of Mazandaran province were determined and then a site was selected in each reference area for collecting statistical data. Vegetative factors (vegetation cover and yield) were measured in 10 sites along six transects of 200 meter length in sixty plots of one square meter. According to the results, maximum average percentage of vegetation cover (50.22) and maximum yield (417.87) were recorded for 2003. Minimum average percentage of vegetation cover (47.38) was obtained in 2001 and average yields of 391.46 and 391.63 were obtained in 2001 and 2002, respectively. Consequently, a relationship was found between vegetation cover percentage and yield with precipitation. Most of the sites in which average rainfall especially in late winter and spring of 2003 was more than that of the other years, higher average of canopy cover percentage and yield were recorded in the mentioned year. Also, livestock grazing management was effective on amount of yield and vegetation cover. The sites located in highlands showed a better condition due to the cool Mediterranean climate and higher precipitation and proper grazing management in rangelands. The condition of class I and class II species of these sites was better than that of downstream rangelands. In the sites located in lower regions with a cold semi-arid climate especially in sagebrush lands, range condition was lower than that of the highlands due to semi-arid climatic conditions and the use of rangeland in Spring and Autumn. Class III species were dominant in these sites. Precipitation affected all vegetative forms and for perennial grasses vegetation cover percentage and yield were affected. Since cushion plants were not considered in yield calculation, the increment of vegetation cover percentage had no effect on yield. Annual plants also affected the yield due to increased spring rainfall in some sites.
Hosein Arzani; Mahdi Abedi
Volume 13, Issue 2 , February 2006, , Pages 145-161
Abstract
Rangeland as a dynamic ecosystem changes by accruing abundance and if cross the rangeland health threshold may be disturbed. By determination rangeland health attributes, we could judge about management practices effects. In this research for determination three attributes (soil and site stability, hydrologic ...
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Rangeland as a dynamic ecosystem changes by accruing abundance and if cross the rangeland health threshold may be disturbed. By determination rangeland health attributes, we could judge about management practices effects. In this research for determination three attributes (soil and site stability, hydrologic function and biotic integrity) , seventeen indicators used include rill, water flow pattern, pedestals and terracettes, bare ground, gullies, wind scour and depositional area, litter movement, soil resistance to erosion, soil surface loss or degradation, plant composition, soil compaction, plant functional/structural groups, plant mortality, litter amount, annual production, invasive plant and reproductive capability. This method was conducted in six steps. to test this new concept in arid and semi arid zone , thus by using vegetation and soil studies in Orazan (Taleghan) region and Zarand Saveh, selected five treatment included: three grazing intensity and two cultured area and then modified indicators table categorized under three ecosystem attributes in five classes. Because of grazing and cultured treatment rangeland health attributes reduced and showed significant differences by references area. Most treatment crossed the rangeland health threshold. By increasing grazing intensity stractural plant characterestics and soil characteristic beetwin plants disturbed.inreliced cultivated area soil stability and hydrologic function attributes modified but plants health attribute in comperation with references area have a little change. Results showed that soil surface resistance decrease and water flow pattern degradation are the most important causes in rangeland health decrease.