مجله بوم شناسی کاربردی
پیاپی 30 (زمستان 1398)

Detecting, predicting and quantifying the trends of landscape pattern change in the forests of Gharasu watershed area are necessary so as to assess the crises or prevent them. To this aim, the land use maps belonging to the years 1987, 2002 and 2018 were classified through the maximum likelihood method, and the forest area changes were estimated. Then, through the Geomod model and the forest change probability map derived from the multi-criteria evaluation method, a forestland map was generated for the year 2041. Moreover, the quantitative characteristics and the spatial distribution of the forested area were evaluated using ten landscape metrics. The results revealed that 2632 hectares had been deforested over the last 31 years; also, it is predicted that 2084.7 more hectares of the forests will be reduced until 2041. The analysis of the landscape metrics also showed that the forest landscape had become more limited and fragmented, as well as becoming less regular and integrated. Through the landscape analysis approach, six of the ten metrics used in this study proved to have a regular trend of change. They include class area, number of patches, patch density, patch area mean, limiting circle and pore size. Thus, it can be concluded that Geomod is a quite successful model in predicting the forest areas for the year 2041.

Following the unbalanced development and overexploitation of the country's watersheds, land fragmentation has become a major concern for the conservation of ecosystem services and land health. For this purpose, the present study was planned to evaluate and compare the landscape connectivity indices of KoozehTopraghi Watershed as one of the ecologically susceptible watersheds located in Ardabil Province. To this end, the landscape connectivity was investigated according to both structural and functional viewpoints, based on the green patches (rangelands and orchard) distributed at 36 sub-watershed areas. The mentioned indices were first calculated using the Fragstats Software and graph theory at each sub-watershed; then, they were standardized according to interval standardization between zero and one in order to consider the scale effect and draw a comparison in the same variation range. Therefore, the landscape connectivity was calculated, classified and mapped for each studied  sub-watershed and the whole watershed. Structural connectivity results showed the high level of landscape connectivity between green patches in all studied sub-watersheds. In addition, the results showed that the landscape connectivity was obtained with the mean and standard deviation of 0.50 ± 0.52, being varied from 0.50 to 0.97. The results also proved that out of the 36 sub-watersheds located in the KoozehTopraghi, only 15 sub-watersheds had natural lands (orchard and rangelands). Also, the sub-watershed 27, with the highest value of landscape connectivity (0.97), had the highest priority.

The Egyptian vulture, Neophron percnopterus, as a globally endangered species, is significantly affected by conflicts with human, leading to the decline of this species population. Availability of food resources is known as one of the most important factors affecting the distribution of the Egyptian vulture. In this study, we employed an ensemble modelling approach to predict the  suitability of the  foraging habitat for the Egyptian vulture based on seven distribution modelling algorithms. According to our results, suitable foraging habitats for this bird accounted for about 4.19% (1021.40 km2) of the study area, of which only approximately 31.92% (326 km2) was covered by the conservation areas. Livestock density (31.82%), the presence of wild ungulates (15.36%), distance to dump sites (14.77%), landcover (12.46%) and elevation (11.85%) made the highest contribution to the ensemble model of this species. Our results indicated that Egyptian vultures mainly rely on dump sites, nomadic areas and livestock farming sites, thereby reflecting the vulture's tendency to livestock carcasses. Thus, it is important to develop effective strategies for proper monitoring and managing human activities in these areas.

Today, there are many factors affecting watersheds, consequently changing natural ecosystems succession. The aim of this study was to investigate the effect of drought events on land use changes at Doiraj Watershed of Ilam Province from 1996 to 2015. For this purpose, Landsat satellite images were used for land use change monitoring and Standardized Precipitation Index (SPI) was applied for drought characterization. The results showed that during the two last decades, the forest and rangeland have been continuously destroyed. However, in the first period (1996-2006), land use changes and land degradation have been more intensive than the second period (2006-2015). Generally, in the past twenty years, about a quarter of the forest land and more than half of the rangeland had been destroyed or changed to become other land uses. Drought monitoring results also showed an extremely wet condition in 1996 and normal and near normal conditions for 2006 and 2015. Therefore, we can conclude that in the first period, in addition to human activities, changes in drought condition as a climatic factor could affected  land use change and land degradation.

One of the primary goals of conservation portfolio selection approaches is to create   a functional landscape or network of sites that can  support all elements of biodiversity and minimize the  environmental risk to critical habitats and species. As human activities, especially roads network development, can be regarded as one of the most important risk elements for the valuable habitats and species of the Chaharmahal & Bakhtiari Province, it is necessary to evaluate the habitat’s condition and ecosystem services for the purpose of  conservation planning,  as well as minimizing the negative impacts of the roads network on the ecosystem services and habitats. So, for this purpose,  first, the habitat quality of Capra aegagrus was modeled using the InVEST module (Integrated Valuation of Environmental Services and Tradeoff). Then, the ecological impacts of roads network were assessed using the spatial landscape index. Finally, the degree of the protected areas was determined and some mitigation measures were introduced.  The results of this study revealed that approximately 45 percent of Ch & B Province, including Tang-e-Syyad national park and and the  Sabzkouh protected area, could be considered as the suitable habitats for the Wild goat. However, about 28 percent of this province is negatively affected by roads network, thereby highlighting the importance of identifying the priority areas for conservation and mitigation measures.

Since the amount of water in the arid and desert regions is limited, the existing water resources utilization methods as well as irrigation methods in these areas are different from other areas. For this purpose, an experiment was conducted as split plot in a completely randomized design with three replications in the Isfahan University of Technology. In this experiment, the amount of irrigation (5 and 10 liters) as the main factor, irrigation method (surface and subsurface irrigation) as the sub-factor, soil amendment (fertilizer 75% and 15% (control) and zeolite 25% and 15%) as the sub-sub factors, and plant height, basal area, relative chlorophyll index and stomata conductance of Melia azedarach as dependent variables were considered. The results showed that the highest height was obtained in 5 liters of subsurface irrigation with 25% zeolite, which was significantly different from the other treatment compounds (P<0.05). A 5-liter surface irrigation treatment with 25% zeolite could be recommended to achieve the maximum stomatal conductance (P<0.05). The 5-liter subsurface irrigation treatments with 15% zeolite and 15% fertilizer had the highest relative chlorophyll content, respectively. Therefore, it could be inferred that using zeolite provided the sufficient and continuous moisture for the plant, resulting in improved plant growth traits.