نوع مقاله : مقاله پژوهشی

نویسندگان

گروه علوم جنگل، دانشکده منابع طبیعی و علوم زمین، دانشگاه شهرکرد، شهرکرد، ایران

چکیده

سابقه و هدف:
اکوسیستم‌های مختلف ساحلی، به ویژه مانگروها، تقریبا به‌صورت دائمی و همزمان، در معرض تنش‌ها وآشفتگی‌های چندگانه محیطی (ژئولوژیک، فیزیکی، شیمیایی و بیولوژیک) قرار می‌گیرند و از نظر ویژگی‌های‌شان در طول زمان و مکان، متنوع هستند. نتیجه مستقیم وقوع این تنش‌ها و آشفتگی‌ها، کاهش وسعت و سلامتی مانگروها و به دنبال آن تشدید گرمایش جهانی و سایر تغییرات اقلیمی، کاهش کیفیت آب‌های ساحلی، کاهش تنوع زیستی و تخریب زیستگاه‌های ساحلی است. با توجه به این پیامدهای نامطلوب ناشی از کاهش وسعت مانگروها، اولویت‌بندی اقدامات مدیریتی و فراهم آوردن زیرساخت‌های مطلوب برای جلوگیری یا کاهش گستره این اکوسیستم‌ها ضروری است. دست‌یابی به این هدف در گرو آگاهی و اطلاعات کافی و دقیق درباره روند تغییرات ایجاد‌شده در مانگروها در طول زمان است که می‌تواند نقش مهمی در کارایی و موفقیت برنامه‌های احیا و توسعه آنها داشته باشد. بنابراین هدف این پژوهش بررسی تغییرات ایجاد‌شده در گستره مانگروهای استان هرمزگان در یک دوره زمانی 30 ساله است.
مواد و روش‌ها:
در این پژوهش برای بررسی تغییرات گستره مانگروها در طول زمان، از تصاویر ماهواره لندست مربوط به مقاطع زمانی 1986، 2000 و 2016 استفاده شد. پیش‌پردازش‌های لازم بر روی تصاویر با استفاده از نرم‌افزار Idrisi انجام گرفت و پس از استخراج نقشه‌های پوشش گیاهی مانگرو در مقاطع زمانی ذکر‌شده، تغییرات گستره مانگروهای زون‌های رویشگاهی خمیر، قشم، تیاب، سیریک و جاسک در نرم‌افزار ArcGIS تجزیه و تحلیل‌ شد و مقادیر متوسط تغییرات وسعت رویشگاه‌ها در دو دوره زمانی قبل و بعد از سال 2000 و نیز تمام دوره 30 ساله محاسبه و بررسی شد.
نتایج و بحث:
نتایج این پژوهش نشان داد که در میان زون‌های رویشگاهی مورد بررسی (خمیر، قشم، تیاب، سیریک و جاسک)، زون رویشگاهی خمیر بیشترین مقدار متوسط کاهش وسعت (64/4- هکتار در سال) و زون رویشگاهی سیریک بیشترین مقدار متوسط افزایش وسعت (5/23 هکتار در سال) را در دوره 30 ساله داشتند. نتایج همچنین نشان داد که در دوره زمانی 2000 تا 2016، زون‌های رویشگاهی سیریک و قشم به ترتیب بیشترین مقدار متوسط افزایش و کاهش وسعت را در میان زون‌های مورد بررسی داشتند (به ترتیب با مقادیر متوسط تغییرات وسعت برابر با 47/32 و 38/21- هکتار در سال). تجزیه‌و‌تحلیل تغییرات وسعت مانگروها در رویشگاه‌های مختلف نشان داد که به رغم کاهش وسعت کلیه رویشگاه‌های مانگرو استان هرمزگان در دوره زمانی پس از سال 2000، رویشگاه سیریک دارای افزایش قابل‌توجه وسعت در این دوره زمانی نسبت به دوره پیش از سال 2000 بود که دلیل آن جنگل‌کاری با گونه‌های حرا و چندل در پهنه‌های گلی این رویشگاه در سال‌های اخیر بوده است.
نتیجه‌گیری:
نتایج بررسی تغییرات گستره مانگروهای استان هرمزگان نشان داد که روند تغییرات گستره مانگروهای استان هرمزگان در طول دوره 30 ساله از سواحل خلیج فارس به دریای عمان به‌صورت افزایشی بوده است که نشان‌دهنده تاثیر عوامل مختلف محیطی بر نحوه تغییرات وسعت مانگروهای استان در طی زمان است. در نهایت می‌توان گفت نتایج حاصل از این پژوهش می‌تواند با فراهم آوردن اطلاعات به‌روز و دقیق در زمینه تغییرات وسعت رویشگاهی استان هرمزگان به برنامه‌ریزی‌های اثربخش برای انجام اقدامات حفاظتی و احیای مانگروهای استان کمک قابل‌توجهی کند.

کلیدواژه‌ها

عنوان مقاله [English]

Mapping area changes of mangroves using RS and GIS (Case study: mangroves of Hormozgan province)

نویسندگان [English]

  • Davood Mafi Gholami
  • Masoumeh Baharlouii
  • Beytollah Mahmoudii

Department of Forest Science. Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran

چکیده [English]

Introduction:
Different coastal ecosystems, especially mangroves, are exposed permanently and almost simultaneously to multiple environmental stresses and disturbances (geological, physical, chemical and biological) which are varied in terms of their characteristics over time and space. The direct result of these stresses and disturbances is the reduction in area and health of mangroves and the subsequent exacerbation of global warming and other consequences of climate change, reduced coastal water quality, loss of biodiversity and degradation of coastal habitats. Considering the adverse consequences arising from the reduction in mangrove forest area, prioritizing management actions and providing appropriate infrastructure is essential to prevent a decrease in the extent of these ecosystems. Achieving this goal depends on having accurate and sufficient information and knowledge about the process of changes in the extent of mangrove forest habitats over time which can play an important role in the efficiency and success of rehabilitation programmes and the development of these ecosystems. Hence, the aim of this study was to investigate the long-term changes occurred in areas of mangrove forest of Hormozgan Province.
Materials and methods:
In this study, Landsat images from 1986, 2000, and 2016 were used to study changes in the extent of mangroves over time. The necessary pre-processing was doneconducted on images using Idrisi software. After extraction of the mangrove vegetation maps in the aforementioned years, changes in mangroves of the Khamir, Qeshm, Tiab, Sirik and Jask habitats were analyzed in ArcGIS software and the average values of areas of mangroves were calculated for two periods, namely pre- and post- 2000, and during a 30-year period.
Results and discussion:
The accuracy assessment of the classified images showed that the overall accuracy was equal to 92%.  The results also showed that among the zones investigated (Khamir, Ghesh, Tiab, Sirik and Jask), Khamir habitat zone had the highest average annual value of area reduction (equal to -4.64 h/yr) and Sirik habitat zone had the highest average annual value of area expansion (equal to 23.5 h/yr) during the 30-year period. The results also showed that during period of 2000-2016, Sirik and Qeshm zones had the highest average value of expansion and reduction in area, respectively (equal to 32.47 and -21.38 h/yr, respectively). Analysis of mangrove area changes in different habitats showed that, despite the reduction in the extent of all mangroves in the period after 2000, the mangroves of Sirik habitat had significant increase in area in this period compared to the period before 2000 which was due to forestation with Avicenna and Rhizophora in the mud flats of this habitat in recent years.
Conclusions:
The results of the study of changes in the areas of mangroves of Hormozgan Province showed that the trend of change the in area covered by the mangroves of Hormozgan Province over a 30-year period has been increasing from the coasts of the Persian Gulf to the Oman Sea; this indicates the impact of various environmental factors affecting the changes in the extent of the mangroves of the province. Finally it can be said that the results of this study, by providing up-to-date and accurate information about areas changes of mangrove habitat in Hormozgan Province, can help significantly to the planning of effective actions to protection and restoration of these habitats.

کلیدواژه‌ها [English]

  • Coastal ecosystems
  • Satellite images
  • Extent changes

Allen, J.A., Ewel, K.C. and Jack, J., 2001. Patterns of natural and anthropogenic disturbance of the mangroves on the Pacific Island of Kosrae. Wetlands Ecology and Management. 9, 291-301.

Alongi, D.M., 2015. The impact of climate change on mangrove forests. Current Climate Change Reports. 1, 30-39.

Bazrafshan O., Ahmadi, S. and Khurani, A., 2016. Effect of runoff and sediment of watershed on mangroves forest area changes. Environment Erosion Researches. 6(21), 88-102. (In Persian with English abstract).

Binelli, A., Sarkar, S.K., Chatterjee, M., Riva, C., Parolini, M., Bhattacharya, B. and Satpathy, K.K., 2007. Concentration of polybrominated diphenyl ethers (PBDEs) in sediment cores of Sundarban mangrove wetland, northeastern part of Bay of Bengal (India). Marine Pollution Bulletin. 54, 1220-1229.

Concheddaa, G., Durieuxb, L. and Mayauxa, P., 2008. An Object-Based method for mapping and change analysis in mangrove ecosystems, ISPRS Journal of Photogrammetry and Remote Sensing. 63, 578- 589.

Dahdouh-Guebas, F., Jayatissa, L.P., Di Nitto, D., Bosire, J.O., LoSeen, D. and Koedam, N., 2005. How effective were mangroves as a defense against the recent tsunami? Current Biology. 15, 443-447.

Danehkar, A., Hasheni, A., Varasteh, R., Fadakar, S. and Sharifipour, R., 2008. The spatial analysis of environmental sensitivity of coastal areas in Hormozgan province. The department of the environment, Hormozgan province, 180p. (In Persian with English abstract).

Danehkar, A., Mahmoudi, B. and Hashemi, A., 2007. Management Plan and development of mangrove forests in the Hormozgan province, Department of Natural Resources, Hormozgan province, 200 p. (In Persian with English abstract).

Duke, N.C., Meynecke, J.O., Dittmann, S., Ellison, A.M., Anger, K., Berger, U. and Dahdouh-Guebas, F., 2007. A world without mangroves? Science. 317, 41-42.

Eggert, H. and Olsson, B., 2009. Valuing multi-attribute marine water quality. Marine Policy. 33, 201-206.

Ellison, J.C. and Zouh, I., 2012. Vulnerability to climate change of mangroves: assessment from Cameroon, central Africa. Biology. 1, 617-638.

Eslami-Andargoli, L., Dale, P.E.R., Sipe, N. and Chaseling, J., 2009. Mangrove expansion and rainfall patterns in Moreton Bay, southeast Queensland, Australia. Estuarine, Coastal and Shelf Science. 85, 292-298.

FAO., 2016. State of the world’s forests (SOFO) in 2016. Forests and agriculture: land use challenges and opportunities. FAO, 125P.

Giri, C., 2016. Observation and monitoring of mangrove forests using remote sensing: 0pportunities and challenges. Remote Sensing. 8(9), 783-788.

Giri, C., Ochieng, E., Tieszen, L.L., Zhu, Z., Singh, A., Loveland, T. and Duke, N., 2011. Status and distribution of mangrove forests of the world using earth observation satellite data. Global Ecology and Biogeography. 20, 154-159.

Giri, C., Pengra, B., Zhu, Z., Singh, A. and Tieszen, L.L., 2007. Monitoring mangrove forest dynamics of the Sundarbans in Bangladesh and India using multi-temporal satellite data from 1973 to 2000. Estuarine, Coastal and Shelf Science. 73, 91-100.

Hai-Hoa, N., McAlpine, C., Pullar, D., Johansen, K. and Duke, N.C., 2013. The relationship of spatial–temporal changes in fringe mangrove extent and adjacent land-use: Case study of Kien Giang coast, Vietnam. Ocean and coastal Management. 76, 12–22.

Hajjarian, M., 2006. Check quantitative changes mangrove forest island using aerial photographs and satellite data over a period of forty years. Forestry master's thesis. Department of natural resources, Tehran university, Karaj, 124 p. (In Persian with English abstract).

Halpern, B.S., Selkoe, K.A., Micheli, F. and Kappel, C.V., 2007. Evaluating and ranking the vulnerability of global marine ecosystems to anthropogenic threats. Conservation Biology. 21, 1301-1315.

Held, A., Ticehurst, C., Lymburner, L. and Williams, N., 2003. High resolution mapping of tropical mangrove ecosystems using hyperspectral and radar remote sensing. International Journal of Remote Sensing. 24, 2739-2759.

Khorani, A., Bineiaz, M. and Amiri, H.R., 2016. Mangrove forest area changes due to climatic changes (Case study: forest between the port and the Khamir island). Journal of Aquatic Ecology. 5, 100-111. (In Persian with English abstract).

Koedam, N. and Dahdouh-Guebas, F., 2008. Ecological quality changes precede changes in quantity in mangrove forests. Science. E-Letter, 2 October 2008.

Liu, K., Li, X., Shi, X. and Wang, S.G., 2011. Monitoring mangrove forest changes using remote sensing and GIS data with decision-Tree learning. Wetlands. 28, 336-346.

Mahdavi, A., Zubairy, M. and Namiranian, M., 2003. The trend of qualitative and quantitative changes Qeshm Mangrove forests using aerial photos from 1346 and 1373. Iranian Journal of Natural Resources. 3, 386-377. (In Persian with English abstract).

Mehrabian, A., Naqinezhad, A., Mahiny, A.S., Mostafavi, H., Liaghati, H. and Kouchekzadeh, M., 2009. Vegetation mapping of the Mond protected area of Bushehr province. Journal of Integrative Plant Biology. 51, 251-260.

Murray, M.R., Zisman, S.A., Furley, P.A., Munro, D.M., Gibson, J., Ratter, J., Bridgewater, S., Minty, C.D. and Place, C.J., 2003. The mangroves of Belize part 1. Distribution, composition and classification, Forest Ecology and Management. 174, 265-279.

Nfotabong-Atheull, A., Din, N. and Dahdouh-Guebas, F., 2013. Qualitative and quantitative characterization of mangrove vegetation structure and dynamics in a pre urban setting of Douala (Cameroon): An approach using air-borne imagery. Estuaries and Coasts. 36, 1181-1192.

Nguyen, H.H., McAlpine, C., Pullar, D., Johansen, K. and Duke, N.C., 2013. The relationship of spatial–temporal changes in fringe mangrove extent and adjacent land-use: Case study of Kien Giang coast, Vietnam. Ocean and Coastal Management. 76, 12-22.

Nguyen, T.P., Tong, V.A., Quoi, L.P. and Parnell, K.E., 2016. Mangrove restoration: establishment of a mangrove nursery on acid sulphate soils. Journal of Tropical Forest Science. 275-284.

Proisy, C., Degenne, P., Anthony, E.J., Berger, U., Blanchard, E., Fromard, F. and Lo Seen, D., 2016. A multiscale simulation approach for linking mangrove dynamics to coastal processes using remote sensing observations. Journal of Coastal Research. 75, 810-814.

Sadeghi, A., 2006. Assessment of changes in the density and area of Sirik and Jask mangrove forest habitats in a period of 50 years using aerial photographs. Forestry master's thesis. Department of Natural Resources, Islamic Azad University, science and research branch of Tehran. (In Persian with English abstract).

Salehipour Milani, A. and Lak, R., 2014. Monitoring the extent of mangrove forests in the southern coast of Iran. In proceedings in the 1st international congress of earth sciences, 13th February, Tehran, Iran. pp. 145-157. (Key paper).

Seto, K.C. and Fragkias, M., 2007. Mangrove conversion and aquaculture development in Vietnam: A remote sensing-based approach for evaluating the Ramsar Convention on wetlands. Global Environmental Change. 17, 486-500.

Singh, S.K., Srivastava, P.K., Gupta, M., Thakur, J.K. and Mukherjee, S., 2014. Appraisal of land use/land cover of mangrove forest ecosystem using support vector machine. Environmental Earth Sciences. 71, 2245-2255.

Sirajuddin, F., 2012. The effect of fluctuations in the climate of the area's mangrove forests Iran (Case Study: Guatre Bay). Physical Geography Master's thesis in climatology trends in environmental planning. University of Sistan and Baluchestan. 110 p. (In Persian with English abstract).

Taghizadeh, A., Danehkar, A., Kamrani, E. and Mahmoudi, B., 2010. Mangrove forest communities in Hormozgan province. Journal of Forest of Iran. 1, 25-34.

Tran Thi, V., Tien Thi Xuan, A., Phan Nguyen, H., Dahdouh-Guebas, F. and Koedam, N., 2014. Application of remote sensing and GIS for detection of long-term mangrove shoreline changes in Mui Ca Mau, Vietnam. Biogeosciences. 11, 3781-3795.

Venter, O., Brodeur, N.N., Nemiroff, L., Belland, B., Dolinsek, I.J. and Grant, J.W.A., 2006. Threats to endangered species in Canada. Bioscience. 56, 903-910.

Vo, Q.T., Oppelt, N., Leinenkugel, P. and Kuenzer, C., 2013. Remote sensing in mapping mangrove ecosystems-an object-based approach, Remote Sensing. 5, 183-201.

Walters, B.B., Rönnbäck, P., Kovacs, J.M., Crona, B., Hussain, S.A., Badola, R. and Dahdouh-Guebas, F., 2008. Ethnobiology, socio-economic and management of mangrove forests: a review. Aquatic Botany. 82, 220-236.

Zhang, K., Thapa, B., Ross, M. and Gann, D., 2016. Remote sensing of seasonal changes and disturbances in mangrove forest: a case study from South Florida. Ecosphere. 7(6), 201-209.