Journal of Marine Science and Technology

Journal of Marine Science and Technology

Monitoring changes in the integrity of mangroves of the Hara Biosphere Reserve in the face of rainfall changes and drought occurrence

Document Type : Original Manuscript

Authors
Davood Mafi-Gholami 1
Abolfazl Jaafari 2
1 Department of Forest Sciences, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran.
2 Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran.(AREEO), Tehran, Iran
10.22113/jmst.2022.223331.2359
Abstract
Abstract
Examining long-term changes in the integrity or fragmentation trends of mangroves due to climate change can lead to a more precise understanding of structural changes in mangroves and their connection to the impacts of climate change. This study investigates the changes in the integrity status of the Hara Biosphere Reserve mangroves in Qeshm in response to variations in rainfall and drought over a 31-year period (1986-2017). For this purpose, a 31-year time series of satellite images and rainfall data were used, and values for the Number of Patches (NP) and Largest Patch Index (LPI) metrics, as well as SPI values, were prepared over the period. The results of changes in the number of patches and the largest patch index of mangroves during periods of wet years (before 1998) and drought years (after 1998) showed that with the increase in SPI values (positive values) before 1998, the number of patches and the largest patch index decreased, while in the period after 1998, with negative SPI values, the number of patches and the largest patch index increased. In fact, the results indicated an increase in the extent of core areas and large vegetative patches (increased structural integrity) of the reserve during the wet period and the reverse trend during the drought period. Based on landscape ecology principles, the increase in the number of patches and the largest patch index (due to the reduction in the total area of vegetation) in the period after 1998 indicates the degradation of this habitat in recent years. The results of this study can be used to assess the vulnerability of these habitats to the impacts of climate change.
1. INTRODUCTION:
Analyzing changes in mangroves and examining their relationship with drought can provide valuable information about the adverse effects of climate change on mangroves. Specifically, investigating long-term changes in the integrity or fragmentation trends of mangroves in response to climatic changes can lead to a more precise understanding of the structural changes in mangroves and their connection to climate change impacts. The results can serve as a decision-support tool, playing a crucial role in developing climate change adaptation programs for these habitats (Reddy et al., 2018). In fact, examining the relationship between changes in mangrove integrity over time can play a significant role in identifying sensitive and vulnerable
habitats and enhancing the effectiveness and success of restoration programs, thereby increasing their adaptability and resilience to multiple environmental hazards (Hauser et al., 2017). Therefore, the aim of this study is to investigate changes in the integrity (fragmentation) status of the Hara Biosphere Reserve mangroves in Qeshm in response to variations in rainfall and drought over a 31-year period (1986-2017). For this purpose, a 31-year time series of satellite images and rainfall data were utilized.
2. MATERIALS AND METHODS
In this study, the relationship between drought occurrence and changes in mangrove integrity was investigated by calculating annual SPI values. For this purpose, a 31-year dataset (1986 to 2017) of monthly rainfall from the Khomir synoptic station, located near the Hara Biosphere Reserve, was used. After performing geometric and radiometric corrections on the 31-year time series (1986-2017) of Landsat images, the time series of mangrove extent maps for the Hara Biosphere Reserve was prepared. Then, the time series of changes in the integrity or fragmentation of the Hara Biosphere Reserve mangroves was prepared using two landscape metrics: The Number of Patches (NP) and the Largest Patch Index (LPI). These metrics are the best indicators of changes in the degree of fragmentation of these ecosystems. Finally, the relationship between changes in landscape metrics and the severity of drought over the 31-year period was analyzed, and the changes in metric values before and after 1998 (the change point in drought occurrence trends in southern Iran) were examined.
3. RESULTS
The results showed that from 1986 to 1998, the SPI values increased (positive SPI values indicating a wet period), and then, over the 19-year period following 1998, the SPI values decreased and consistently exhibited negative values (drought period). Analysis of the obtained results indicated that the values of the NP and LPI metrics in the Hara Biosphere Reserve fluctuated over the 31-year period (1986-2017). Specifically, the changes in the largest patch area in the Hara Biosphere Reserve showed an increase during the pre-1998 period (wet period) and a gradual decrease thereafter until the end of the 31-year period. The results demonstrated that the trend of changes in the LP over the 31-year period (1986-2017) was opposite to the trend in the largest patch area. The LPI value gradually decreased from 1986 to 1998 (wet period) and then increased until the end of the 31-year period (drought period). The NP decreased during the 12-year period (1986-1998), with the number of patches in the reserve being 1281 in 1986 and 911 in 1998. As the results show, the number of patches in the reserve increased during the period following 1998 (drought period), reaching 1639 by the end of the 31-year period.
4. CONCLUSION
The study showed that between 1986 and 1998 (wet period), as the number of patches in the reserve decreased, the area of the largest patch increased. This increase in the largest patch area, along with a decrease in the number of patches, indicates an increase in the reserve's integrity through the expansion of core areas and large vegetative patches in this habitat during the pre-1998 period (wet period). This increase in integrity could have a significant impact on the distribution and higher diversity of animal species dependent on mangroves (Li et al., 2013). Conversely, an increase in the number of patches, a decrease in the size of large patches, and the presence of gaps between patches disrupt biological exchanges and biodiversity at the habitat level, as well as reduce gene flow among subpopulations within the patches (Li et al., 2013). These changes were observed in the mangroves of the reserve during the drought period after 1998.
The study by Mafi-Gholami et al. (2017) showed that the area of mangroves in the Hara Biosphere Reserve decreased during the long-term drought period after 1998. The results of this study also indicated that alongside an increase in the number of patches (increased fragmentation of large vegetative patches) during the post-1998 period, the largest patch index in this habitat increased. Since the largest patch index is derived from the ratio of the largest patch area to the total habitat area, the increase in the largest patch index results from the decrease in the total habitat area during the long-term drought period post-1998. According to landscape ecology principles, an increase in the number of patches along with a decrease in the size of large patches and the total area of an ecosystem over time indicates degradation (Riitters et al., 2002). The decrease in area and the increase in the number of patches in the Hara Biosphere Reserve also indicate the degradation of this habitat during the recent long-term drought periods.
REFERENCES
Hauser, L.T., Vu, G.N., Nguyen, B.A., Dade, E., Nguyen, H.M., Nguyen, T.T.Q., Le, T.Q., Vu, L.H., Tong, A.T.H. and Pham, H.V., 2017. Uncovering the spatio-temporal dynamics of land cover change and fragmentation of mangroves in the Ca Mau peninsula, Vietnam using multi-temporal SPOT satellite imagery (2004–2013). Applied Geography, 86, pp.197-207. DOI: 10.1016/j.apgeog.2017.06.019
Li, M.S., Mao, L.J., Shen, W.J., Liu, S.Q. and Wei, A.S., 2013. Change and fragmentation trends of Zhanjiang mangrove forests in southern China using multi-temporal Landsat imagery (1977–2010). Estuarine, Coastal and Shelf Science, 130, pp.111-120. DOI: 10.1016/j.ecss.2013.03.023
Mafi-Gholami, D., Mahmoudi, B., and Zenner, E. K., 2017. An analysis of the relationship between drought events and mangrove changes along the northern coasts of the Persian Gulf and Oman Sea. Estuarine, Coastal and Shelf Science, 199, 141-151. DOI: 10.1016/j.ecss.2017.10.008
Reddy, C.S., Saranya, K.R.L., Pasha, S.V., Satish, K.V., Jha, C.S., Diwakar, P.G., Dadhwal, V.K., Rao, P.V.N. and Murthy, Y.K., 2018. Assessment and monitoring of deforestation and forest fragmentation in South Asia since the 1930s. Global and Planetary Change, 161, pp.132-148. DOI: 10.1016/j.gloplacha.2017.10.007
Riitters, K.H., Wickham, J.D., O'neill, R.V., Jones, K.B., Smith, E.R., Coulston, J.W., Wade, T.G. and Smith, J.H., 2002. Fragmentation of continental United States forests. Ecosystems, 5, pp.0815-0822. DOI: 10.1007/s10021-002-0209-2
 
Keywords
Landscape
Climate Change
Satellite Images

Subjects

Allgeier, J.E., Rosemond, A.D., Mehring, A.S. and Layman, C.A., 2010. Synergistic nutrient colimitation across a gradient of ecosystem fragmentation in subtropical mangrove‐dominated wetlands. Limnology and Oceanography, 55(6), pp.2660-2668. DOI: 10.4319/lo.2010.55.6.2660
Da Ponte, E., Roch, M., Leinenkugel, P., Dech, S. and Kuenzer, C., 2017. Paraguay's Atlantic Forest cover loss–Satellite-based change detection and fragmentation analysis between 2003 and 2013. Applied Geography, 79, pp.37-49. DOI: 10.1016/j.apgeog.2016.12.005
Ellison, J.C., 2015. Vulnerability assessment of mangroves to climate change and sea-level rise impacts. Wetlands Ecology and Management, 23, pp.115-137. DOI: https://doi.org/10.1007/s11273-014-9397-8
Ellison, J.C., 2000. How South Pacific mangroves may respond to predicted climate change and sea-level rise. Climate change in the South Pacific: impacts and responses in Australia, New Zealand, and small island states, pp.289-300. DOI: 10.1007/0-306-47981-8_16
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(2), pp.292-298. DOI: 10.1016/j.ecss.2009.08.011
Field, C.D., 1995. Impact of expected climate change on mangroves. In Asia-Pacific Symposium on Mangrove Ecosystems: Proceedings of the International Conference held at The Hong Kong University of Science & Technology, September 1–3, 1993 (pp. 75-81). Springer Netherlands. DOI: 10.1007/978-94-011-0289-6_10
Gilman, E., Ellison, J. and Coleman, R., 2007. Assessment of mangrove response to projected relative sea-level rise and recent historical reconstruction of shoreline position. Environmental monitoring and assessment, 124, pp.105-130. DOI: 10.1007/s10661-006-9212-y
Gilman, E.L., Ellison, J., Duke, N.C. and Field, C., 2008. Threats to mangroves from climate change and adaptation options: a review. Aquatic botany, 89(2), pp.237-250. DOI: 10.1016/j.aquabot.2007.12.009
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(1-2), pp.91-100. DOI: 10.1016/j.ecss.2006.12.019
Hauser, L.T., Vu, G.N., Nguyen, B.A., Dade, E., Nguyen, H.M., Nguyen, T.T.Q., Le, T.Q., Vu, L.H., Tong, A.T.H. and Pham, H.V., 2017. Uncovering the spatio-temporal dynamics of land cover change and fragmentation of mangroves in the Ca Mau peninsula, Vietnam using multi-temporal SPOT satellite imagery (2004–2013). Applied Geography, 86, pp.197-207. DOI: 10.1016/j.apgeog.2017.06.019
Jaafari, S., Sakieh, Y., Shabani, A.A., Danehkar, A. and Nazarisamani, A.A., 2016. Landscape change assessment of reservation areas using remote sensing and landscape metrics (case study: Jajroud reservation, Iran). Environment, development and sustainability, 18, pp.1701-1717. DOI: 10.1007/s10668-015-9712-4
Li, M.S., Mao, L.J., Shen, W.J., Liu, S.Q. and Wei, A.S., 2013. Change and fragmentation trends of Zhanjiang mangrove forests in southern China using multi-temporal Landsat imagery (1977–2010). Estuarine, Coastal and Shelf Science, 130, pp.111-120. DOI: 10.1016/j.ecss.2013.03.023
Mafi-Gholami, D., Feghhi, J., Danehkar, A. and Yarali, N., 2015. Prioritizing stresses and disturbances affecting mangrove forests using Fuzzy Analytic Hierarchy Process (FAHP). Case study: mangrove forests of Hormozgan Province, Iran. Advances in Environmental Sciences, 7(3), pp.442-459. DOI:
Mafi-Gholami, D., Mahmoudi, B., and Zenner, E. K., 2017. An analysis of the relationship between drought events and mangrove changes along the northern coasts of the Persian Gulf and Oman Sea. Estuarine, Coastal and Shelf Science, 199, 141-151. DOI: 10.1016/j.ecss.2017.10.008
Mafi-Gholami, D., Zenner, E.K. and Jaafari, A., 2020. Mangrove regional feedback to sea level rise and drought intensity at the end of the 21st century. Ecological Indicators, 110, p.105972. DOI: 10.1016/j.ecolind.2019.105 972
Mafi-Gholami, D., Zenner, E.K., Jaafari, A. and Ward, R.D., 2019. Modeling multi-decadal mangrove leaf area index in response to drought along the semi-arid southern coasts of Iran. Science of the Total Environment, 656, pp.1326-1336. DOI: 10.1016/j.scitotenv.2018.11.462
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 & coastal management, 76, pp.12-22. DOI: 10.1016/j.ocecoaman.201 3.01.003
Ojoyi, M.M., Odindi, J., Mutanga, O. and Abdel-Rahman, E.M., 2016. Analysing fragmentation in vulnerable biodiversity hotspots in Tanzania from 1975 to 2012 using remote sensing and fragstats. Nature Conservation, 16, pp.19-37. DOI: 10.3897/natureconservation.16.9312
Reddy, C.S., Jha, C.S. and Dadhwal, V.K., 2013. Assessment and monitoring of long-term forest cover changes in Odisha, India using remote sensing and GIS. Environmental monitoring and assessment, 185, pp.4399-4415. DOI: 10.1007/s10661-012-2877-5
Reddy, C.S., Saranya, K.R.L., Pasha, S.V., Satish, K.V., Jha, C.S., Diwakar, P.G., Dadhwal, V.K., Rao, P.V.N. and Murthy, Y.K., 2018. Assessment and monitoring of deforestation and forest fragmentation in South Asia since the 1930s. Global and Planetary Change, 161, pp.132-148. DOI: 10.1016/j.gloplacha.2017.10.007
Riitters, K.H., Wickham, J.D., O'neill, R.V., Jones, K.B., Smith, E.R., Coulston, J.W., Wade, T.G. and Smith, J.H., 2002. Fragmentation of continental United States forests. Ecosystems, 5, pp.0815-0822. DOI: 10.1007/s10021-002-0209-2
Safiyari, Sh. (2002). Mangrove Forests (Part Two) - Mangrove Forests of Iran. Tehran: Forest Research Institute Publications, 345 p.
Sahana, M., Sajjad, H. and Ahmed, R., 2015. Assessing spatio-temporal health of forest cover using forest canopy density model and forest fragmentation approach in Sundarban reserve forest, India. Modeling Earth Systems and Environment, 1, pp.1-10. DOI: 10.1007/s40808-015-0043-0
Sakieh, Y., Salmanmahiny, A., Jafarnezhad, J., Mehri, A., Kamyab, H. and Galdavi, S., 2015. Evaluating the strategy of decentralized urban land-use planning in a developing region. Land use policy, 48, pp.534-551. DOI: 10.1016/j.landusepol.2015.07.004
Snedaker, S.C., 1995. Mangroves and climate change in the Florida and Caribbean region: scenarios and hypotheses. Hydrobiologia, 295, pp.43-49. DOI: 10.1007/BF00029109
Surati Jaya, I.N., Kusmana, C. and Murtilaksono, K., 2014. Analysis of Tropical Forest Landscape Fragmentation in Batang Toru Watershed, North Sumatra. Journal of Tropical Forest Management/Jurnal Manajemen Hutan Tropika, 20(2). DOI: 10.7226/jtfm.19.2.77
Tran, L.X. and Fischer, A., 2017. Spatiotemporal changes and fragmentation of mangroves and its effects on fish diversity in Ca Mau Province (Vietnam). Journal of Coastal Conservation, 21, pp.355-368. DOI: 10.1007/s11852-017-0513-9
Uezu, A., Metzger, J.P. and Vielliard, J.M., 2005. Effects of structural and functional connectivity and patch size on the abundance of seven Atlantic Forest bird species. Biological conservation, 123(4), pp.507-519. DOI: 10.1016/j.biocon.2005.01.001
Wu, H., Hayes, M.J., Weiss, A. and Hu, Q.I., 2001. An evaluation of the Standardized Precipitation Index, the China‐Z Index and the statistical Z‐Score. International Journal of Climatology: A Journal of the Royal Meteorological Society, 21(6), pp.745-758. DOI: 10.1002/joc.658
Xin, K., Huang, X., Hu, J., Li, C., Yang, X. and Arndt, S.K., 2014. Land use change impacts on heavy metal sedimentation in mangrove wetlands—a case study in Dongzhai Harbor of Hainan, China. Wetlands, 34, pp.1-8. DOI: 10.1007/s13157-013-0472-3.
Journal of Marine Science and Technology
Volume 23, Issue 1
Spring 2024
Pages 84-96

  • Receive Date 13 March 2020
  • Revise Date 23 December 2021
  • Accept Date 08 January 2022
  • Publish Date 20 March 2024