تأثير تسهيل مكانيكي گونه Astragalus microcephalus Willd. بر شاخص هاي پوشش گياهي در مراتع نيمه استپي زاگرس مركزي

Mechanical facilitate of Astragalus microcephalus on vegetation indices in semi steppe rangelands of Central Zagros

رواﺑﻂ ﻣﺘﻘﺎﺑﻞ ﺑﯿﻦ ﮔﯿﺎﻫﺎن، اﺳـﺘﻘﺮار و ﺑﻘـﺎي آﻧﻬـﺎ را ﺗﺤﺖ ﺗﺄﺛﯿﺮ ﻗﺮار ﻣﯽ دﻫﺪ، در ﻧﺘﯿﺠﻪ آﮔﺎﻫﯽ از ﭼﮕﻮﻧﮕﯽ وﻗﻮع اﯾﻦ رواﺑﻂ ﻣﯽ ﺗﻮاﻧـﺪ ﺑـﺮاي ﺣﻔـﻆ و ﻧﮕﻬـﺪاري ﮔﻮﻧﻪ ﻫﺎي ﻣﺮﺗﻌﯽ و ﻧﯿﺰ اﺻﻼح و ﻣﺪﯾﺮﯾﺖ ﻣﺮاﺗﻊ ﮐﺸﻮر ﻗﺎﺑﻞ اﺳـﺘﻔﺎده ﺑﺎﺷﺪ. اﯾﻦ ﺗﺤﻘﯿﻖ ﺑﺎ ﻫﺪف ﺗﺄﺛﯿﺮ ﮔﻮﻧﻪ ﺑﻮﺗﻪ اي Astragalus microcephalus ﺑﺮ ﺷﺎﺧﺺ ﻫﺎي ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ زﯾﺮاﺷﮑﻮب آن در ﻣﺮاﺗﻊ ﻧﯿﻤﻪ اﺳﺘﭙﯽ ﻣﻨﻄﻘﻪ ﺣﻔﺎﻇﺖ ﺷﺪه ﺗﻨﮓ ﺻﯿﺎد ﺻﻮرت ﮔﺮﻓﺖ. ﺑﺪﯾﻦ ﻣﻨﻈﻮر، درﺻـﺪ ﺗﺎج ﭘﻮﺷﺶ ﮔﯿﺎﻫﺎن زﯾﺮ اﺷﮑﻮب اﯾﻦ ﮔﻮﻧﻪ و ﻓﻀﺎي ﺑﺎز ﻣﺠﺎور آن (ﺷﺎﻫﺪ) در ﻃﻮل ﺗﺮاﻧﺴﮑﺖ ﻫـﺎ ي 100 ﻣﺘـﺮي ﺑـﺎ اﺳﺘﻔﺎده از ﭘﻼتﻫﺎي اﻧﻌﻄﺎف ﭘﺬﯾﺮ اﻧﺪازهﮔﯿﺮي ﺷﺪ. اﻧﺪازه ﭘﻼتﻫﺎ ﻣﺘﻨﺎﺳﺐ ﺑﺎ ﺳﻄﺢ ﺗﺎج ﭘﻮﺷﺶ ﻫﺮ ﯾﮏ از ﭘﺎﯾﻪ ﻫﺎي ﮔﻮن ﺑﺮﺧﻮردي ﺑﻪ ﺗﺮاﻧﺴﮑﺖ ﺑﻮد. ﻧﺘﺎﯾﺞ ﺑﺮرﺳﯽ ﻫﺎ ﻧﺸﺎن داد ﮐﻪ در ﻣﺠﻤﻮع، 30 ﮔﻮﻧﻪ ﮔﯿﺎﻫﯽ در زﯾﺮ اﺷﮑﻮب ﮔﻮﻧـﻪ ﮔﻮن و 33 ﮔﻮﻧﻪ ﮔﯿﺎﻫﯽ در ﻓﻀﺎي ﺑﺎز ﻣﺠﺎور وﺟﻮد داﺷﺘﻪ اﺳﺖ. در زﯾﺮ اﺷﮑﻮب ﮔﻮﻧﻪ A. microcephalus ﮔﻮﻧـﻪ اﻧﺤﺼﺎري از ﺟﻤﻠـﻪ Chaerophyllum macropodum, Onobrychis gaubae, Salvia ceratophila, Stachys pilifera و Artemisia aucheri وﺟﻮد داﺷﺘﻪ اﺳﺖ ﮐﻪ ﺟﺰو ﮔﻮﻧﻪ ﻫﺎي ﮔﯿﺎﻫﯽ ﭼﻨﺪ ﺳﺎﻟﻪ، ﺧﻮﺷـﺨﻮراك و داروﯾـﯽ ﻣﻨﻄﻘﻪ ﺑﻪ ﺷﻤﺎر ﻣﯽ روﻧﺪ. در ﻓﻀﺎي ﺑـﺎز ﻣﺠـﺎور 9 ﮔﻮﻧـﻪ اﻧﺤﺼـﺎري از ﺟﻤﻠـﻪ Hypecum ،Centaurea virgata Roemeria refrecta ،Clypeola aspera ،pendulum و Xeranthemum annum وﺟـﻮد دارد ﮐـﻪ اﮐﺜـﺮاً ﺟـﺰ ﮔﻮﻧﻪ ﻫﺎي ﮔﯿﺎﻫﯽ ﯾﮏ ﺳﺎﻟﻪ و ﻣﻬﺎﺟﻢ ﻣﻨﻄﻘﻪ ﺑﻪ ﺷﻤﺎر ﻣﯽ روﻧﺪ. ﺑﻪ ﻃﻮرﮐﻠﯽ، ﻫﺮﭼﻨﺪ ﺷﺎﺧﺺ ﻫﺎي ﭘﻮﺷﺶ ﮔﯿﺎﻫﯽ (ﺗﻨﻮع و ﻏﻨﺎ، ﮔﺮوﻫﻬﺎي ﮐﺎرﮐﺮدي) زﯾﺮاﺷﮑﻮب ﺑﻪ دﻟﯿﻞ ﭼﺮاي ﻣﺘﻌﺎدل دام در ﻣﻨﻄﻘﻪ ﮐﻤﺘﺮ ﺗﺤﺖ ﺗﺄﺛﯿﺮ ﺷـﺮاﯾﻂ ﺗﺴـﻬﯿﻞ ﻣﮑﺎﻧﯿﮑﯽ ﮔﻮﻧﻪ A.microcephalus ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ وﻟﯽ ﻧﻘﺶ ﺗﺴﻬﯿﻞ اﯾﻦ ﮔﻮﻧﻪ در ﺣﻔﻆ ﮔﻮﻧﻪ ﻫﺎي ﮔﯿﺎﻫﯽ ﺑﺎ ارزش ﻣﻨﻄﻘﻪ ﮐﺎﻣﻼً ﻣﺸﻬﻮد اﺳﺖ.

Interrelationships between plants are affected establishment and survival, as a result, knowledge of how these relationships occur can be used for the maintenance of species and improvement and management of rangelands. This study was conducted to evaluate the effect of Astragalus microcephalus on index vegetation under the canopy in semi-steppe rangeland of protected area in Tange-sayad. For this purpose, percentage of vegetation cover under the canopy of this species and its open space adjacent was measured using a flexible plot along the 100 meters transect. The results showed that 30 species under the canopy of Astragalus microcephalus and 33 plant species in the open space adjacent. In the under canopy of Astragalus microcephalus 6 exclusive species such as Chaerophyllum macropodum, Onobrychis gaubae, Salvia ceratophila, Stachys pilifera and Artemisia aucheri existed that mostly related to perennial, palatable and pharmaceutical plants. In contrast, open space exist 9 exclusive species including Centaurea virgata, Hypecum pendulum, Clypeola aspera, Roemeria refrecta and Xeranthemum annum that mostly related to invasive and annuals species plant. Generally, the vegetation index under canopy of Astragalus microcephalus due to moderate grazing livestock in the region less affected to mechanical facilitating of Astragalus microcephalus but the facilitating role of Astragalus microcephalus in preserving of valuable plant species is highly visible.