كليدواژه :
اراﺿﯽ ﺷﻮر , ﻋﻤﻠﯿﺎت اﺻﻼﺣﯽ , وﯾﮋﮔﯽﻫﺎي روﯾﺸﮕﺎه , ﮔﺮدوﻏﺒﺎر
چكيده فارسي :
ﭘﺪﯾﺪة رﯾﺰﮔﺮد ﺑﻪواﺳﻄﮥ ﺧﺸﮑﺴﺎﻟﯽﻫﺎ و ﻣﺪﯾﺮﯾﺖ ﻧﺎﺻﺤﯿﺢ ﻣﻨﺎﺑﻊ آﺑﯽ و اﺳﺘﻔﺎدة ﺧﺎرج از ﺗـﻮان اﮐﻮﻟﻮژﯾـﮏ اراﺿـﯽ، ﯾﮑـﯽ از ﭼﺎﻟﺶﻫـﺎي ﻣﺤﯿﻂزﯾﺴﺘﯽ اﺳﺖ. در ﺣﺎل ﺣﺎﺿﺮ ﻧﯿﺰ در ﺳﻄﺢ وﺳﯿﻌﯽ از اراﺿﯽ ﺷﻮر ﺣﺎﺷﯿﮥ درﯾﺎﭼﮥ اروﻣﯿﻪ، ﺑﻪواﺳﻄﮥ ﭘﺴﺮوي درﯾﺎﭼﻪ، ﻧﺎﺷﯽ از اﻓـﺖ آب زﯾﺮزﻣﯿﻨﯽ و ﮐﺎﻫﺶ ﺣﺠﻢ ورودي آب، ﮐﺎﻧﻮنﻫﺎي ﺗﻮﻟﯿﺪ رﯾﺰﮔﺮد، اﯾﺠﺎد ﺷﺪه اﺳﺖ. در اﯾﻦ ﺧﺼﻮص ﺑـﺎ اﺳـﺘﻘﺮار 24 ﺗﺮاﻧﺴـﮑﺖ در اﻣﺘﺪاد ﮔﺮادﯾﺎن ﺷﻮري، وﯾﮋﮔﯽﻫﺎي ﺳﺎﺧﺘﺎري و ﻋﻤﻠﮑﺮدي روﯾﺸﮕﺎه، ﺑﻌﺪ از ﮔﺬﺷﺖ ﭘﻨﺞ ﺳﺎل از ﻋﻤﻠﯿﺎت اﺻـﻼﺣﯽ، ﺑـﺮاي ﺑﺮرﺳـﯽ اﺛـﺮ ﻓﻌﺎﻟﯿﺖﻫﺎ و ﯾﺎﻓﺘﻦ ﻣﻮﻓﻖﺗﺮﯾﻦ ﻣﺤﺪودة اﺣﯿﺎﺷﺪه، ﻃﺒﻖ دﺳـﺘﻮراﻟﻌﻤﻞ LFA اﻧـﺪازهﮔﯿﺮي ﺷـﺪ. ﺑﯿﺸـﺘﺮﯾﻦ ﻣﻘـﺪار ﺷـﺎﺧﺺ ﺳـﺎزﻣﺎنﯾﺎﻓﺘﮕﯽ ﭼﺸﻢاﻧﺪاز )0/32(، ﭘﺎﯾﺪاري )44/40(، ﻧﻔﻮذﭘﺬﯾﺮي )24/90( و ﻋﻨﺎﺻﺮ ﻏﺬاﯾﯽ )11/80(، در ﻓﺎﺻﻠﮥ دورﺗﺮ از ﮐﺎﻧﻮن ﺷﻮري ﻣﺸـﺎﻫﺪه ﺷـﺪ. ﮐﻤﺘﺮﯾﻦ ﻣﻘﺪار ﺷﺎﺧﺺﻫﺎي ﻣﺬﮐﻮر ﺑﻪﺗﺮﺗﯿﺐ ﺑﺎ 13/20 ،20/70 ،0/10 و 7/90، ﻣـﺮﺗﺒﻂ ﺑـﺎ ﻓﺎﺻـﻠﮥ ﻧﺰدﯾـﮏ ﺑـﻪ ﮐـﺎﻧﻮن ﺷـﻮري ﻣﯽﺑﺎﺷـﺪ. درﻣﺠﻤﻮع، ﻣﻘﺎدﯾﺮ ﺷﺎﺧﺺﻫﺎ در اﻣﺘﺪاد ﮔﺮادﯾﺎن ﺷﻮرﯾﮋ ﮐﻤﺘﺮ ﻣﯽﺷﻮد. ﺑﻨﺎﺑﺮاﯾﻦ ﻣﻮﻓﻘﯿﺖ ﻋﻠﻤﯿﺎت اﺻﻼﺣﯽ، ﺑـﺎ ﻧﺰدﯾـﮏ ﺷـﺪن ﺑـﻪ ﮐـﺎﻧﻮن ﺷﻮري ﮐﻤﺘﺮ ﻣﯽﺷﻮد؛ ﺑﻪﻋﺒﺎرﺗﯽ، ﻋﻤﻠﯿﺎت اﺻﻼﺣﯽ، اﻧﺘﻈﺎرات ﻣﻮرد ﻧﻈﺮ در ﻧﺎﺣﯿﮥ ﻣﺠﺎور درﯾﺎﭼﻪ را ﮐﻪ ﺑﺎ ﻫﺪف اﻓﺰاﯾﺶ ﭘﻮﺷـﺶ ﮔﯿـﺎﻫﯽ و ﮐﺎﻫﺶ ﻓﻀﺎي ﺑﯿﻦ ﻟﮑﻪاي ﺑﻮده، ﺑﺮآورد ﻧﮑﺮده اﺳﺖ؛ ازاﯾﻦرو ﻗﺮق ﻣﻨﻄﻘﻪ، اﺳﺘﻔﺎده از روشﻫﺎي دﯾﮕﺮ ﮐﺎﻫﺶ ﺳﺮﻋﺖ ﺑـﺎد و دﺳـﺘﮑﺎري ﮐﻤﺘﺮ ﺳﻄﺢ ﺧﺎك ﺗﻮﺻﯿﻪ ﻣﯽﺷﻮد.
چكيده لاتين :
As one of the most serious environmental challenges of Iran during the recent decade, the phenomenon
of fine dust has occurred due to improper and excessive ecologic use of rangeland ecosystems, drought, and mismanagement of water resources. Knowing this phenomenon and being aware of the required strategies to fight
against it play an essential role in reducing the number of dust storms and the way fine dust's hotspots are established.
On the other hand, the hotspots of fine dust have been created in large areas of Urmia Lake's saline lands due to the
regression of the lake made by a decline in groundwater levels and reduced inflow of water into the lake exposing
Western and Eastern Azerbaijan provinces to dust storms. Accordingly, some restoration projects (rangeland seeding)
were carried out in 2014 in large areas of the lake to stabilize the soil of the hotspots' beds. Now, five years after the
implementation of rangeland seeding projects, the question is whether or not the projects have exerted any positive
effect on the structural and functional characteristics of the target habitats? In other words, how have the structural and
functional characteristics of the habitats changed as a result of rangeland seeding operations? Have these changes had
positive or negative effects on the ecosystem? Therefore, to answer these questions, this study was conducted in the
Separghan region in Urmia as a pilot study area and a representative of saline habitats of the western shore of Urmia
Lake. Located at 37° 45' 14"N and 45°14'19", the region was identified as one of the fine dust hotspots in 2014 and
designated as a priority in terms of protective and conservation operations by competent authorities. It was also
introduced as a reference and pilot study area so that the results of the study could be generalized to similar habitats.
Therefore, rangeland seeding operations were carried out in the region at a large scale where livestock grazing was
prohibited.
Material and Methods: 24 transects were established in three ecological areas to measure the structural and
functional characteristics of the habitats. Moreover, the number, length, and width of ecological patches, the
percentage of patches' lengths, and the landscape organization index were calculated for each area by establishing
linear transects in each ecological unit. Finally, eleven indices regarding the soil's surface that are clearly associated
with the soil's level of stability, permeability, and nutrient cycle were valued and categorized for each patch and interpatch
space within the five measured areas using the LFA guidelines.
Results: the study's results indicated that the indices' mean varied along the salinity gradient, being significantly
different in various ecological areas. The highest value of the landscape organization index (0.32) belonged to the first
area (further away from the salinity hotspot), and the lowest values of the index (0.10 and 0.06) belonged to the second
and third areas (closer to the salinity hotspot), respectively. The average values of the stability index were 44.40, 37.01,
and 20.70 in different ecological zones, respectively. Furthermore, the highest values for permeability were found in
the first and second zones as 21.50 and 24.90, respectively, and the lowest index's value (13.20) belonged to the third
zone. Finally, the values of the nutrient cycle were 11.19, 11.80, and 7.90 in the first, second, and third ecological
zones, respectively.
Discussions and Conclusion: it could generally be argued that the values of structural and functional indices decrease
along the salinity gradient. Therefore, the success of rangeland seeding operations would decrease as we get closer to
the salinity hotspot. In other words, rangeland seeding operations have failed to realize the goals set for the first step of
its executive operation to increase vegetation and reduce inter-patch spaces in areas close to the lake. Viewed from
another perspective, it can be concluded that seeding the rangeland with Nitraria schoberi species was hardly
successful and failed to achieve its expected results in terms of controlling the fine dust several years after the
implementation of the project. Therefore, preserving the area and less manipulating the soil's surface is recommended
when rangeland seeding is conducted in such habitats. If prevented from being grazed, indigenous vegetation could be
regenerated through the seed bank and thus help prevent soil surface from wind erosion. The results of this study can
help seed the rangelands prioritized for being protected against the advancement of saline dust hotspots. The areas
prioritized in terms of protection and maintenance of their current situation are those with high structural and
functional indices values. Areas where the inter-patch space is large and the landscape organization index is very low
compared to other places can also be prioritized for restoring projects.
