تغييرات گروه هاي عملكردي گياهان در اثر آتش سوزي در مراتع نيمه استپي استان چهارمحال و بختياري

Variation of Plant Functional Groups in Relation to Fire in Semi- Steppe Rangelands o f Chaharmahal Va Bakhtiari Province

زﻣﯿﻨﻪ و ﻫﺪف: درك ﭼﮕﻮﻧﮕﯽ ﭘﺎﺳﺦ ﮔﯿﺎﻫﺎن ﺑﻪ آﺗﺶ ﺳﻮزي ﺑﺮاي ﭘﯿﺶ ﺑﯿﻨﯽ وﯾﮋﮔﯽ ﻫﺎ و ﭘﺮاﮐﻨﺶ ﺑﺴﯿﺎري از زﯾﺴﺖ ﺑﻮم ﻫﺎ ﺿﺮوري اﺳﺖ. ﻫﺪف اﯾﻦ ﺗﺤﻘﯿﻖ ﺷﻨﺎﺳﺎﯾﯽ، ﻃﺒﻘﻪ ﺑﻨﺪي و ﺗﺠﺰﯾﻪ و ﺗﺤﻠﯿﻞ ﺻﻔﺎت ﻋﻤﻠﮑﺮدي ﮔﯿﺎﻫﺎن اﺳﺖ ﮐﻪ ﺑﺘﻮاﻧﻨﺪ ﺑﻪ ﻋﻨﻮان وﺳﯿﻠﻪ اي ﺑﺮاي ﺷﻨﺎﺳﺎﯾﯽ ﺗﻐﯿﯿﺮات ﺟﻮاﻣﻊ ﮔﯿﺎﻫﯽ در اﺛﺮ آﺗﺶ ﺳﻮزي در ﻓﻮاﺻﻞ زﻣﺎﻧﯽ ﻣﺨﺘﻠﻒ ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﮔﯿﺮﻧﺪ. روش ﺑﺮرﺳﯽ: ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ در ﻣﻨﻄﻘﻪ ﮐﺮﺳﻨﮏ در ﺷﻬﺮﺳﺘﺎن ﺑﻦ و در اﺳﺘﺎن ﭼﻬﺎرﻣﺤﺎل و ﺑﺨﺘﯿﺎري اﻧﺠﺎم ﯾﺎﻓﺘﻪ اﺳﺖ. ﺗﻌﺪاد 6 ﺳﺎﯾﺖ ﺑﺎ ﺳﺎﺑﻘﻪ آﺗﺶ ﺳﻮزي ﯾﮏ ﺳﺎﻟﻪ و ﭘﻨﺞ ﺳﺎﻟﻪ اﻧﺘﺨﺎب و ﻧﻤﻮﻧﻪ ﺑﺮداري ﺑﻪ روش ﺗﺼﺎدﻓﯽ ﻃﺒﻘﻪﺑﻨﺪي ﺷﺪه اﻧﺠﺎم ﯾﺎﻓﺖ. در ﻫﺮ ﭘﻼت ﭘﺲ از ﺷﻨﺎﺳﺎﯾﯽ ﮔﻮﻧﻪ ﻫﺎي ﻣﻮﺟﻮد، درﺻﺪ ﭘﻮﺷﺶ ﻫﺮﯾﮏ از ﮔﻮﻧﻪ ﻫﺎ ﺗﺨﻤﯿﻦ زده ﺷﺪ و ﺻﻔﺎت ﮔﯿﺎﻫﯽ اﻧﺪازه ﮔﯿﺮي ﺷﺪﻧﺪ. ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺻﻔﺎت ﮔﯿﺎﻫﯽ ﻫﻤﭽﻮن ارﺗﻔﺎع ﮔﯿﺎه، ﺗﻮﻟﯿﺪ، ﺷﺎﺧﺺ ﺳﻄﺢ ﺑﺮگ SLA، ﻣﺴﺎﺣﺖ و وزن ﺧﺸﮏ ﺑﺮگ، درﺻﺪ ﺗﺮﮐﯿﺐ ﮔﻮﻧﻪ ﻫﺎي ﮔﻨﺪﻣﯽ، ﻋﻠﻔﯽ و ﺑﻮﺗﻪ اي، درﺻﺪ ﺗﺮﮐﯿﺐ ﮔﯿﺎﻫﺎن ﺑﺎ ﺧﻮﺷﺨﻮراﮐﯽ ﮐﻼس II و III، درﺻﺪ ﺗﺮﮐﯿﺐ ﮔﻮﻧﻪ ﻫﺎي ﺑﺎ اﺷﮑﺎل زﯾﺴﺘﯽ ﻫﻤﯽ ﮐﺮﯾﭙﺘﻮﻓﯿﺖ و ﮐﺎﻣﻔﯿﺖ در دو ﻣﻨﻄﻘﻪ آﺗﺶ ﺳﻮزي و ﺷﺎﻫﺪ اﺧﺘﻼف ﻣﻌﻨﯽ داري داﺷﺘﻨﺪ )0/05≤ Sig(. ﻃﺒﻖ ﻧﺘﺎﯾﺞ ﺗﺤﻠﯿﻞ ﻣﻮﻟﻔﻪﻫﺎي اﺻﻠﯽ، ﺗﺄﺛﯿﺮﭘﺬﯾﺮﺗﺮﯾﻦ ﺻﻔﺎت ﺑﻪ ﺗﺮﺗﯿﺐ ﻋﺒﺎرت از ﺷﺎﺧﺺ ﺳﻄﺢ ﺑﺮگ SLA، ﺧﻮﺷﺨﻮراﮐﯽ ﮐﻼس II، ﻃﻮل ﺑﺮگ، درﺻﺪ ﺗﺮﮐﯿﺐ ﻫﻤﯽ ﮐﺮﯾﭙﺘﻮﻓﯿﺖ، درﺻﺪ ﺗﺮﮐﯿﺐ ﭘﻬﻦ ﺑﺮﮔﺎن ﻋﻠﻔﯽ و ﻣﺴﺎﺣﺖ ﺑﺮگ ﺑﻮدﻧﺪ ﮐﻪ ارﺗﺒﺎط ﻣﺴﺘﻘﯿﻤﯽ ﺑﺎ آﺗﺶ ﺳﻮزي ﭘﻨﺞ ﺳﺎﻟﻪ و آﺗﺶ ﺳﻮزي ﯾﮏ ﺳﺎﻟﻪ داﺷﺘﻨﺪ. ﺑﺤﺚ و ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﺑﻨﺎﺑﺮاﯾﻦ ﻣﯽ ﺗﻮان ﻧﺘﯿﺠﻪ ﮔﯿﺮي ﻧﻤﻮد ﮐﻪ ﺻﻔﺎت ﮔﯿﺎﻫﯽ ﻧﻘﺶ ﻣﻬﻤﯽ در ﺗﻌﯿﯿﻦ ﭘﺎﺳﺦ ﮔﻮﻧﻪ ﻫﺎي ﮔﯿﺎﻫﯽ ﺑﻪ آﺷﻔﺘﮕﯽ ﻫﺎي ﻣﺤﯿﻄﯽ دارﻧﺪ و از اﯾﻦ رو ﻣﯽ ﺗﻮاﻧﻨﺪ ﺑﺮ ﺳﯿﺮ ﺗﻮاﻟﯽ ﺛﺎﻧﻮﯾﻪ ﻣﺮﺗﻊ ﻧﯿﻤﻪ اﺳﺘﭙﯽ ﭘﺲ از آﺗﺶ ﺳﻮزي ﺗﺄﺛﯿﺮﮔﺬار ﺑﺎﺷﻨﺪ.

Background and Objective: Understanding of how plants respond to a fire is essential to predict the characteristics and distribution of many ecosystems. This research is aimed at identifying, classifying and analyzing plant functional traits that can be used as a means for determining changes in plant communities through the fire at various time intervals. Method: The present study was conducted in the Karsanak region in Chaharmahal Va Bakhtiari province. Six sites with one and five years after the last fire were selected. A stratified random sampling was used. In each plot, after identifying the existing species, the percentage of the cover of each species was estimated and the plant characteristics were measured. Findings: The results showed that vegetative traits such as plant height, production, SLA leaf area index, leaf area and leaf dry weight, composition of Gramineae species, herbaceous plants and shrub, the percentage of plants with class of II and III palatability, percentage of species composition with form of Hemicryptophyte and chamaephyte had a significant difference in fire and control areas. According to Principal Component Analysis, the most effective of trait were SLA leaf area index, palatability of class II, the leaf length, Hemicryptophytes, forbs and long of the leaf which had a direct relationship with five-year fire and one year fire. Discussion and Conclusion: Therefore, it can be concluded that plant traits play an important role in determining the response of plant species to environmental disturbances and hence can influence the process of the post-fire rangeland secondary sequence