Evaluating the Success of Fine Dust Hotspots Control Projects Using Structural and Functional Characteristics of the Habitat in the West Shore of Urmia Lake

Authors

10.22052/deej.2021.10.33.1

Abstract

Introduction: 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 inter- patch 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.

Keywords


  1. 1. Ahmadi, Z., Heshmati, Gh.A. and Abedi, M., 2009. Investigation the improvement operations affection on ecological indexes of rangeland health (Jahan Nama Garden, Golestan province). Journal of Rangeland and Desert Research, 16(1): 55-65.

    2. Barrett-Lennard, E.G., Bathgate, A.D. and Malcolm, C.V., 2003. Saltland pastures in Australia, a practical guide. Department of Agriculture and Food, Western Australia, Perth. Bulletin, 4312, 112p.

    1. Eldridge, D.J. and Delgado-Baquerizo, M., 2018. Grazing reduces the capacity of Landscape Function Analysis to predictregional-scale nutrient availability or decomposition, but not total nutrientpools. Ecological Indicators, 90: 494-501.

    4. Fakhimi, E. and Motamedi, J., 2020. Effect of mining activities on structure and function of rangeland ecosystem using the Landscape Function Analysis (LFA) (Case study: Dareh Zereshk copper mine, Yazd, Iran). Rangeland Science, 10(3): 291-301.

    1. Ghodsi, M., Mesdaghi, M., Heshmati, Gh.A. and Ghanbarian, Gh.A., 2010. Investigation of the dimensions of ecological spots in reference and critical areas in spring and summer (Case study: semi-steppe rangelands of Golestan National Park and adjacent areas). Rangeland Journal, 4 (1): 92-82.

    6. Heshmati, Gh. A., Siroosi, H. and Sheydei Karkaj, E., 2018. The best model to predict functional changes in the grazing gradient of semi-arid ecosystem (Case Study: Gorgan plain). Journal of Rangeland and Desert Research, 24(4): 742-756.

    1. Heshmati, Gh. A., Amirkhani, M., Heidari, Q.A. and Hosseini, S.A., 2007. Qualitative evaluation of rangeland ecosystem capability in Gomishan region of Golestan province using landscape function indicators. Rangeland Journal, 1 (2): 115-103.
    2. Heshmati, Gh. A., Naseri, K.A. and Ghanbarian, Gh. A., 2008. Landscape function analysis, evaluation methods and rangeland monitoring. Mashhad University Jihad Publications, 112 pages.
    3. Jafari, M. and Panahi, F., 2011. Properties and management of soils. University of Tehran Press, 856 pages.
    4. Joybari, S.A, Rezaei, P., Soleimani, P. and Davoodi, H., 1398. Dust and its centers: basics and methods of identifying and establizing, with a special attitude to the Khuzestan plain. Journal of Applied Sedimentology, 7 (14): 149-129.
    5. Khan, M.A. and Weber, D.J., 2008. Ecophysiology of high salinity tolerant plants. Springer, Amsterdamو 407p.
    6. Ludwig, J.A. and Tongway, D.J., 2000. Viewing rangelands as landscape systems. In: Arnalds, O. and Archer, S. (Eds.), Rangeland Desertification. Kluwer Academic Publishers, Dordrecht, 39-52.
    7. Miller, M.E., 2005. The structure and functioning of dryland ecosystems conceptual models to inform long-term ecological monitoring, USGS-BRD Scientific Investigations Report, USGS: 79p.
    8. Motamedi, J., Mofidi Challan, M. and Khodagholi, M., 2019. Assessment of economic, social and environmental effects of Lake Urmia rehabilitation measures from the perspective of local communities. Iranian Journal of Nature, 4 (18): 51-43.

    15. Shahriary, E., Gill, T.E. and Langford, R.P., 2018. Landscape Functionality Analysis of Soil Surface Conditions in an Arid Zone: A Case Study of Lajaneh Piosphere, Iran. Annals of Arid Zone 57(3-4):163 - 170

    1. Sharafatmandrad, M., and Khosravi Mashizi, A., 2019. Efficacy of landscape function analysis to assess differences between grazed and ungrazed rangelands in an arid landscape. Range Management and Agroforestry, 40(2): 196-201.
    2. Sheidai Karkaj, E, Sepehry, A., Barani, H, Motamedi, J. 2017. Soil organic carbon reserve relationship with some soil properties in East Azerbaijan rangelands. Rangeland journal, 11 (2): 125-137.
    3. Tongway, D. and Ludwig, J., 2002. Reversing desertification in Rattan Lal (Ed) Encyclopedia of Soil Science. Marcel Dekker, New Yurok.
    4. Tongway, D.J. and Hindley, N.L., 2004a. Landscape function analysis: a system for monitoring rangeland. African Journal of Range and Forage Science 21(2):109-113.
    5. Tongway, D.J. and Hindley, N.L., 2004b. Landscape function analysis. Procedures for monitoring and assessing landscapes with special reference to minesites and rangelands, GSIRO sustainable ecosystems, Canberra, Australia, 158p.
    6. Tongway, D.J. and Hindly, N.L., 1995. Assessment of soil condition of tropical grasslands manual. CSRIO, Division of Wildlife and Ecology. Canberra, Australia. 72p.
    7. Vargas, R., Pankova, E.S., Balyuk, S.A., Krasilnikov, P.V. and Khasankhanova, G.M., 2018. Handbook for saline soil management. FAO of the United Nations, 144p.
    8. Vice President for Strategic Planning and Supervision, 2008. Instructions for laboratory analysis of soil and water samples. Journal No. 467, National Soil and Water Research Institute, 278 pages.