بررسي شكل رابطه توليد و غناي گونه اي گياهان در مراتع تنگ چنار استان يزد

The shape of richness-productivity relationships in Tang-e-Chenar rangelands of Yazd province

ﻪ ﻣﻨﻈﻮر درك ﻣﻜﺎﻧﻴﺴﻢ ﺗﻨﻮع زﻳﺴﺘﻲ اﻟﮕﻮﻫﺎي اﻛﻮﻟﻮژﻳﻜﻲ در اﻛﻮﺳﻴﺴﺘﻢ ﻫﺎ و ﭘﺎﻳﻪ اي ﺑﺮاي ﺣﻔﺎﻇﺖ و ﻣﺪﻳﺮﻳﺖ ﺗﻨﻮع زﻳﺴﺘﻲ، ﺗﻮﻟﻴﺪ و ﻏﻨﺎي ﮔﻮﻧﻪ اي ﻃﻲ ﻳﻚ ﺳﺎل در ﻣﺮاﺗﻊ ﺗﻨﮓ ﭼﻨﺎر اﺳﺘﺎن ﻳﺰد اﻧﺪازه ﮔﻴﺮي ﺷﺪ و ﻣﻨﺤﻨﻲ ﭘﺎﺳﺦ ﺧﺼﻮﺻﻴﺖ ﻏﻨﺎي ﮔﻮﻧﻪ ﻫﺎي ﮔﻴﺎﻫﻲ در اﻣﺘﺪاد ﺷﻴﺐ ﺗﻐﻴﻴﺮات ﺗﻮﻟﻴﺪ ﺑﺮرﺳﻲ ﺷﺪ. از آﻧﺎﻟﻴﺰ رﮔﺮﺳﻴﻮن ﺧﻄﻲ و ﻏﻴﺮﺧﻄﻲ ﺟﻬﺖ ﺑﺮرﺳﻲ راﺑﻄﻪ ﺑﻴﻦ ﻏﻨﺎي ﮔﻮﻧﻪ اي ﺑﻪ ﻋﻨﻮان ﻣﺘﻐﻴﺮ واﺑﺴﺘﻪ و ﺗﻮﻟﻴﺪ ﺑﻪ ﻋﻨﻮان ﻣﺘﻐﻴﺮ ﻣﺴﺘﻘﻞ اﺳﺘﻔﺎده ﺷﺪ. ﺗﻌﺪاد 14 ﮔﻮﻧﻪ ﮔﻴﺎﻫﻲ در ﻧﻤﻮﻧﻪ ﺑﺮداري از 30 ﭘﻼت ﻳﻚ ﻣﺘﺮﻣﺮﺑﻌﻲ ﺷﻨﺎﺳﺎﻳﻲ ﺷﺪﻧﺪ. ﻣﻴﺰان ﻣﺘﻮﺳﻂ ﻏﻨﺎي ﮔﻮﻧﻪ اي در ﻫﺮ ﭘﻼت ﺑﺮاﺑﺮ 2/4 ﮔﻮﻧﻪ ﻣﺤﺎﺳﺒﻪ ﺷﺪ. 57 درﺻﺪ ﺗﺮاﻛﻢ ﻧﺴﺒﻲ ﺗﻮﻟﻴﺪ ﺑﻪ ﺑﻮﺗﻪ اي ﻫﺎ، 21/5 درﺻﺪ ﭘﻬﻦ ﺑﺮﮔﺎن ﻋﻠﻔﻲ و 21/5 درﺻﺪ ﺑﻪ ﻋﻠﻒ ﮔﻨﺪﻣﻴﺎن اﺧﺘﺼﺎص ﻳﺎﻓﺖ. ﺑﻴﺸﺘﺮﻳﻦ درﺻﺪ ﺣﻀﻮر در ﭘﻼت ﻫﺎ ﺑﻪ ﮔﻮﻧﻪ ﻫﺎي Artemisiasieberi و Stipahohenackeriana اﺧﺘﺼﺎص ﻳﺎﻓﺖ. ﻛﻞ ﺗﻮﻟﻴﺪ در ﺗﻨﮓ ﭼﻨﺎر ﺣﺪود 278 ﮔﺮم ﺑﺮ ﻣﺘﺮﻣﺮﺑﻊ ﺛﺒﺖ ﺷﺪ ﻛﻪ ﺑﺎﺗﻮﺟﻪ ﺑﻪ ﻣﻘﺎدﻳﺮ ﺗﻮﻟﻴﺪ در ﻧﻈﺮﻳﻪ ﮔﺮاﻳﻢ، اﻧﺘﻈﺎر ﻣﻲ رﻓﺖ ﻛﻪ اﻳﻦ ﺳﺎﻳﺖ در ﺳﻤﺖ ﭼﭗ ﻣﻨﺤﻨﻲ ﻫﺎﻣﭗ ﺑﻚ ﻗﺮار ﮔﻴﺮد و راﺑﻄﻪ ﺧﻄﻲ اﻓﺰاﻳﺸﻲ ﺑﻴﻦ ﺗﻮﻟﻴﺪ و ﻏﻨﺎ در اﻳﻦ ﺳﺎﻳﺖ ﻣﺸﺎﻫﺪه ﺷﻮد اﻣﺎ ﻧﺘﺎﻳﺞ ﻧﺸﺎن داد ﻛﻪ راﺑﻄﻪ رﮔﺮﺳﻴﻮﻧﻲ ﺑﻴﻦ ﻏﻨﺎ و ﺗﻮﻟﻴﺪ ﺑﺮاي ﺗﻤﺎم ﻓﺮم ﻫﺎي روﻳﺸﻲ ﻣﻌﻨﺎدار ﻧﺒﻮده و ﻧﻤﻲ ﺗﻮان ادﻋﺎ ﻛﺮد ﻛﻪ ﺗﻮﻟﻴﺪ ﻣﺘﻐﻴﺮ ﺧﻮﺑﻲ ﺟﻬﺖ ﭘﻴﺶ ﺑﻴﻨﻲ ﻣﺘﻐﻴﺮ ﻏﻨﺎ در ﺳﺎﻳﺖ ﺗﻨﮓ ﭼﻨﺎر اﺳﺖ و ﺷﺎﻳﺪ ﻓﺎﻛﺘﻮرﻫﺎي دﻳﮕﺮي ﻧﻈﻴﺮ ﻋﻨﺎﺻﺮ ﻏﺬاﻳﻲ ﺧﺎك و ﻓﺎﻛﺘﻮرﻫﺎي اﻗﻠﻴﻤﻲ ﻧﻈﻴﺮ دﻣﺎ و ﺑﺎرﻧﺪﮔﻲ ﺑﺮ ﻏﻨﺎي ﮔﻮﻧﻪ اي ﺗﺄﺛﻴﺮ ﺑﻴﺸﺘﺮي از ﻋﺎﻣﻞ ﺗﻮﻟﻴﺪ ﺧﻮاﻫﺪ ﮔﺬاﺷﺖ. ﺑﺎﺗﻮﺟﻪ ﺑﻪ اﻳﻦ ﻧﺘﺎﻳﺞ ﻣﻲ ﺗﻮان ﺑﻴﺎن ﻛﺮد ﻛﻪ ﻓﺮﺿﻴﻪ ﻛﻮﻫﺎﻧﻲ ﺷﻜﻞ ﮔﺮاﻳﻢ در ﻣﻘﻴﺎﺳﻲ ﻓﺮاﺗﺮ از ﻣﺤﻠﻲ ﺑﺎﻳﺴﺘﻲ آزﻣﻮن ﺷﻮد.

In order to understand the biodiversity mechanism of ecological patterns in ecosystems and the basis for conservation and management of biodiversity, the production and species richness was measured during a year in the Tang-e-Chenar rangelands of Yazd province and the response curve of the richness of plant species along the slope of production changes was examined. Analyses of linear and nonlinear regression were used to determine the relationship between richness as dependent variables and productivity as independent variables. Fourteen species were identified in sampling in 30 plots. The average richness was calculated to 2.4 species. According to the results of the relative density in the plot 57% of the shrubs, forbs 21.5% and grasses 21.5 %, respectively. Total production was recorded about 278 g/m2 in Tangechenar that according to production values in theory hump-backed expected that this site is on the left side of the curve hump-backed. In other words, a relationship of increasing linear between production and richness should be seen in site. Relationship between production and richness in each life form was not found all of vegetation forms and have any significant correlation. It cannot be claimed that production is a good variable for predicting the richness in TangeChenar and other factors such as soil nutrients and climatic factors such as temperature and rainfall on the richness will have a greater effect on the factor of production. Based on results it can be concluded that the hump-backed hypothesis should be tested on a scale beyond the local.