somaye arazi; mohammadhosein irannezhadparizi; Ahad sotoudeh; bahman kiani
Abstract
Background: Landscape of an area consists of uniform parts of that land that have components of patchs, passages and bed of land landscape. Since the density and distribution of vegetation in the landscape of the land of the passage of time is affected by many variables and changes. Variety and uniformity ...
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Background: Landscape of an area consists of uniform parts of that land that have components of patchs, passages and bed of land landscape. Since the density and distribution of vegetation in the landscape of the land of the passage of time is affected by many variables and changes. Variety and uniformity of plants studies the effectiveness of the indicators of richness, diversity and uniformity of vegetation from the structure of the landscape.Materials and Methods: In this study, two variables of size and shape of patchs on the structure of the Adoroshk watershed were selected because these two variables are known as important components in the planning of areas for conservation purposes. For this purpose, first the identification and preparation of the map of the structure of the land address of Adoroshk was performed and then the desired map in Arc GIS 10.3 software with suitable image format and ready to enter FRAGSTATS 4.2 software and then two variables of ratio of environment to area and size The patchs in the structure of Adoroshk land were calculated. Data obtained from identification and counting of vegetation in the area, which were the result of linear transect and plot method, were also entered in SPSS software environment and through Shannon-Wiener, Simpson, Hill, Brillouin and MacArthur Plant diversity was measured using the Margalf, Mann-Henick index of plant richness in each spot of the habitat. The Pilo, Alatalo and Hip indices were also used to measure species uniformity. The correlation between the variables was determined from Pearson correlation.Results and Discussion: In this study, 60 plant species were identified and counted in 338 plots and the findings of this study indicate a significant relationship between the two physical variables of size and shape of habitat spots and richness. The diversity and uniformity of rangeland plant species in the Adoroshk watershed.Conclusion: The priority of paying attention to circular patchs that have a minimum ratio of environment to area in the design and management of Adoroshk watershed was proven during the planning and protection of vegetation.
Mohabat Nadaf; Reza Omidipour
Abstract
Introduction:
Biodiversity includes not only the species number and their abundance but also the differences in the functions of any species, which is measured by the functional diversity indices. On the other hand, land-use change and grazing are two important factors affecting biodiversity and ecosystem ...
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Introduction:
Biodiversity includes not only the species number and their abundance but also the differences in the functions of any species, which is measured by the functional diversity indices. On the other hand, land-use change and grazing are two important factors affecting biodiversity and ecosystem services. This study was carried out to investigate the effects of grazing and forestation on functional diversity indices at Cheshmeh Delav in the western part of Northern Khorasan Province, Iran.
Material and methods:
To measure the functional diversity, the single-trait indices (community-weighted mean; CWM) and also the multiple-trait indices (functional richness, functional evenness, functional divergence, functional dispersion, Rao quadratic diversity) were used and measured by the "FD" statistical package in "R.3.3.1" software. The one-way analysis of variance (ANOVA) followed by Duncan’s test was used to compare the mean diversity.
Results and discussion:
The results showed that grazing and forestation have different effects on functional diversity indices. Based on the results, functional richness, Rao index, CWM of height and therophyte had a significant difference in the studied areas. The highest values of functional richness, Rao and CWM of the height index were related to grazing areas. Therefore, the low levels of disturbance factors such as grazing are necessary to reduce competition between plants and an increase in ecosystem function. As CWM of height was the highest at grazing sites, there was a positive relationship between functional richness and CWM. On the other hand, the maximum value of the CWM of therophyte life form was observed in the ungrazing – forestation site due to environmental adverse conditions such as high competition (due to lack of grazing) and disturbance (forestation).
Conclusion:
Using functional diversity indices as an index of biodiversity that considers not only species abundance, but also functional traits was an effective mean in the study of the effects of different factors on biodiversity and the function of different ecosystems.
Farhad Nouri Najafi; Hadi Veisi; Reza Mirzaee
Volume 16, Issue 1 , April 2018, , Pages 207-224
Abstract
Introduction: Recently, land use change is one of the main possible causes in losing biodiversity and ecosystem services. Dams as main human-made structures in order to save surface water play an important role in this regards. Due to the rapid increasing of dam construction over last 40 years in Iran, ...
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Introduction: Recently, land use change is one of the main possible causes in losing biodiversity and ecosystem services. Dams as main human-made structures in order to save surface water play an important role in this regards. Due to the rapid increasing of dam construction over last 40 years in Iran, the contradiction between dam productivity and the loss of ecosystem services has become an issue of increasing concern. The aim of this study was to investigate the effect of Sahand Dam construction on land use, land use changes and ecosystem services. Materials and methods: In this study three Landsat satellite images were used to track land use changes over a period of 28 years (1989, 2006 and 2017). First, these images were used for geometric, atmospheric and topographic correction. The maximum possibility of different land uses and cover were determined using supervised classification method and their accuracy checked again by field inspection. The user authenticity and Kappa coefficient calculated and resulted in value of 63 and 79 percent respectively. The value of ecosystem services and changes in land uses carried out using aerial photographs and satellite imagery between 1989 and 2017 throughout 49400 ha of areas around Sahand dam in East Azarbaijan province. Results and discussion: Results showed that the total area for rangeland decreased significantly between years 1989 and 2017 while there has been a noticeable increasing in cropping land. In general, the share of area under rangeland decreased by 56% over period 1989-2017. The total area for rainfed and irrigated cropping areas increased by 38 and 32 percent respectively indicating significant changes in this area. In regards to ecosystem services value, land uses changes from rangeland to crop land led to a 35900000 dollars annually loss in ecosystem services value (10.6 $ per hectare per year). Conclusions: To conclude, although dam construction and shifting from natural land toward crop land may be profitable but due to depletion of the ecosystem capacities to deliver ecosystem services, long-term losses may exceed short-term gains. Land use and policy making should aim at balancing society needs and preferences, while considering long-term negative effects of dams and ecosystem service losses. Therefore, providing a land management roadmap for future economic development programs is receiving a great priority. It will be beneficial if natural ecosystems are preserved and used adequately.
Majid Ramezani Mehrian; Shahrzad Faryadi
Volume 12, Issue 2 , July 2014
Abstract
Connectivity is one of the most important characteristics of urban green network and its necessary to enhance efficiency of landscape and biodiversity. Hence, urban green space designers need a tool to analyze and optimize the connectivity of green networks. Concepts of graph theory can be used to simulate ...
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Connectivity is one of the most important characteristics of urban green network and its necessary to enhance efficiency of landscape and biodiversity. Hence, urban green space designers need a tool to analyze and optimize the connectivity of green networks. Concepts of graph theory can be used to simulate and analyze of green networks and develop a plan prepared for improving efficiency and biodiversity. In this paper, potential corridors were determined for connecting the main green patches of district 1 of Tehran using shortest path analysis. Then, using network analysis and principles existed in graph theory and gravity model, an optimized plan was developed for urban green space network of this area. Results indicated that network analysis provided high efficiency in modeling, analyzing and optimizing of the urban green space network. Therefore, in order to cover the deficiencies in urban green space development plans, an appropriate method for increasing network continuity and enhancing the efficiency green space was presented.
Einollah RouhiMoghaddam,; Seyed Mohsen Hosseini,; Ezzatollah Ebrahimi; Ahmad Rahmani; Masoud Tabari
Volume 8, Issue 3 , April 2011
Abstract
The regeneration structure and biodiversity of trees and shrub species in the understory of pure and mixed oak plantations were investigated at Chamestan Forest and Rangeland research station. Planted species included oak (as the main species) and maple and nettle trees (as associated species ). These ...
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The regeneration structure and biodiversity of trees and shrub species in the understory of pure and mixed oak plantations were investigated at Chamestan Forest and Rangeland research station. Planted species included oak (as the main species) and maple and nettle trees (as associated species ). These species were planted in 1995 on the basis of a split plot design with two mixtures (oak-maple and oak-nettle tree) and four mixing rates (including oak rate: 40 %, 50 %, 60 % and 70 %). All the seedlings and saplings of woody plants were divided into two height classes including 15-200 cm and more than 200 cm. In the biodiversity study, the Berger-Parker dominance index, Fisher alpha diversity index, Margalef richness index and Equitability J evenness index were used. The results showed that the abundance and diversity of regenerated species in the understory of mixed plantations of oak-nettle tree was greater than in a pure stand of oak and a mixed oak-maple stand. Crown cover and litter layer depth showed a negative significant effect on their abundance and richness. The presence of primary forest species in the understories of mixed plantationa showed the usage of these plantations in the development of succession in natural forests.
