علوم زیستی دریا
Davood Mafi-Gholami; Abolfazl Jaafari
Abstract
This study investigates changes in the integration status of mangroves of Hara Biosphere Reserve in the face of changes of rainfall and drought occurrences over a 31-year period (1986-2017). For this purpose, the 31-year time series of satellite images and precipitation data were used and the values ...
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This study investigates changes in the integration status of mangroves of Hara Biosphere Reserve in the face of changes of rainfall and drought occurrences over a 31-year period (1986-2017). For this purpose, the 31-year time series of satellite images and precipitation data were used and the values of the number of patches (NP) and the largest patch index (LPI) as well as the SPI valueswere obtained during the period. The results of the change in the number of patches and the largest patch index with the change in the pre1998 (wet period) and post-1998 (dry period) showed that with increasing SPI values (positive values) in the pre-1998 period (wet season), the number of patches and the index of largest patch decreased and in the post-1998 (drought period) the negative SPI values increased the number of patches and the index of the largest In fact, the results showed an increase in the size of the main cores and large vegetative patches (increased structural integrity) of the Reservoir during the wet season and its reverse trend during the drought period. According to the principles of landscape ecology, an increase in the number of patches and in the index value of the largest patch (due to a decrease in the total area of the habitat) in the post-1998 period indicates the destruction of this habitat in recent years. The results of this study are of value to assess the vulnerability of these habitats to the consequences of climate change.
علوم زیستی دریا
Davood Mafi-Gholami; Akram Nouri Kamari
Abstract
Generally, determination of degree of coastal area environmental sensitivity is a prerequisite for assessing vulnerability of sensitive ecosystems in these areas, especially mangroves, and plays an important role in the efficiency and success of their recovery and sustainable management programs. Therefore, ...
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Generally, determination of degree of coastal area environmental sensitivity is a prerequisite for assessing vulnerability of sensitive ecosystems in these areas, especially mangroves, and plays an important role in the efficiency and success of their recovery and sustainable management programs. Therefore, the aim of this study was also to determine the degree and prioritization of environmental sensitivity of mangroves of Hormozgan province. To this end, using set of criteria developed by the Marine Environment Bureau and review of studies on sensitivity of mangroves, a list of the most important criteria and sub-criteria for the sensitivity of these ecosystems was provided and the relative weight of the criteria was calculated by analyzing the opinions of experts through the implementation of the FAHP method. The results showed that according to expert's opinion, among the nine criteria for determining the degree of sensitivity of mangroves, vegetation cover and recreational significance criteria obtained the highest and lowest relative weight among the considered criteria, respectively (with relative weights equal to 0.23 and 0.03, respectively). The results also showed that the vegetation cover, wildlife and food network criteria with relative weights of 0.23, 0.17 and 0.13, were the most important sensitivity criteria of mangroves in the final rankings. The results of this study by prioritizing the environmental sensitivity criteria of mangroves of Hormozgan province, provides essential information for assessing the vulnerability of these habitats.
علوم غیرزیستی دریا
Davood Mafi-Gholami; Abolfazl Jaafari
Abstract
In general, fishing activities are considered as one of the most important environmental disturbances in increasing the vulnerability of the mangrove ecosystems due to their destructive effects on the process of sedimentation and wave currents, decreasing biodiversity, and introducing oil pollutants ...
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In general, fishing activities are considered as one of the most important environmental disturbances in increasing the vulnerability of the mangrove ecosystems due to their destructive effects on the process of sedimentation and wave currents, decreasing biodiversity, and introducing oil pollutants into these ecosystems. Therefore, investigating and mapping the intensity of fishing activities in mangrove habitats are of great needs in conducting the vulnerability assessment and providing managerial solutions and empowerment of these ecosystems to minimize and compensate the damages caused by environmental hazards. The aim of this study was to investigate, determine, and delineate and the intensity of fishing activities in the mangrove habitats of the Hormozgan province. To this end, the map of intensity of fishing activities was prepared in Khamir, Qeshm, Tiab, Sirik and Jask habitats through mapping the mangrove habitats, drawing 598 cell networks of 4 × 4 km in the coastal waters and the available geospatial data, and number of vessels in the fishing ports of the Hormozgan province. The results showed that in terms of the geographic distribution and the number of vessels in the fishing ports of the Hormozgan province, the intensity of the fishing activities in the mangrove habitats is ranked as follows: Khamir habitat> Qeshm habitat> Tiab habitat> Jask habitat> Sirik habitat. The results of this study can be used as a prerequisite for assessing the vulnerability of the mangroves of Iran.
علوم غیرزیستی دریا
Davood Mafi-Gholami; Akram Nouri Kamari
Abstract
In general, the analysis of the changes in the area of mangroves and its relationship with changes in the surface water flow into the coastal environment can provide valuable information on the adverse effects of climate change on these ecosystems. Therefore, in this study, the relationship between changes ...
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In general, the analysis of the changes in the area of mangroves and its relationship with changes in the surface water flow into the coastal environment can provide valuable information on the adverse effects of climate change on these ecosystems. Therefore, in this study, the relationship between changes in surface water flows into the coastal environment (occurrence of hydrological drought) and changes in the areas of mangroves in Khamir, Tiab and Jask habitats were investigated in a 30-year period (1986-2016). The results of this study showed that with the occurrence of severe and extreme hydrological droughts in the period after 1998 in the southern coasts of Iran, areas of Khamir, Tiab and Jask habitats also reduced in this period compared to the wet period before 1998. High correlation between hydrological drought occurrence and changes in mangroves areas in different habitats also indicate the adverse effect of reducing the fresh water entering the coastal environment on the areas of mangroves. The results of studies on mangroves in other parts of the world have also shown that reducing rainfall and fresh water inputs to the coastal areas reduce the areas or decrease the progression rates of mangroves. The results of this study by providing accurate information on mangroves responses to consequences of climate change can play an important role in the efficiency and success of adaptation programs to climate change and the conservation and development of mangrove forests in Iran.