evaluation of development scenarios of the ecological connectivity in ahvaz city in order to improve of the ecosystem services and biodiversity stage

introduction ecosystem services are the benefits that human derives from the ecosystems. these are servicessuch as goods and products (e.g., fresh water, fuel), regulation of natural processes (e.g., climate, flooding, erosion), and nonmaterial benefits (e.g., recreation, aesthetic enjoyment). many cities are located in the important ecological areas. currently 29 out of the 825 ecological zones of ecological areas are under urban development inthe world so that more than one-third of the areashavebeen human constructed. it is predicted that by 2030, 15 other ecological areas of 118 vertebrate species specific and rare, at least the about 5% of the total area, will be built. on the other hand, the reflections have led to the phenomenon of urbanization in the world in terms of environmental considerations.the two look quite the opposite in such a way that they are as a challenge for the ecosystem or an opportunity. on the one hand, this phenomenon eliminates natural ecosystems or at least makes it apart. it promotes non-native species, changes and reduces ecosystem and eventually disrupts normal diet.  the urbanization can create some social and economic opportunities, connection of people and nature, unique environmental areas and increase ecosystem services based on the principles of sustainable planning and design. in the convention of biological diversity (cbd), three roles havebeen definedfor cities: 1-maintaining ecosystem goods and services in towns and cities 2-protecting biological diversity in cities and towns and promoting sustainable planning and design at various scales to maximize self-reliance of these areas 3- promoting effective policy to create a livable, not only for humans, but plants and animals in man-made environments. accordingly, it can be said that urban biodiversity points to all communities, plants, animals and microorganisms that live in and around the city. howard achieved this goal outside of the cities and new cities. while today's computing ecosystem services and biodiversity studies are in different scales of global, national, regional, urban-rural, and even at the district levels, block design and spatial resolution has had an important role in maintaining and improving the ecological balance.to achieve a sustainable level, we consider the performance of public services, urban management. to develop patterns that emerged from the concept of sustainable development, the new urbanism, pedestrian areas and tod are examples of it.the concept of ecological cities and villages were discussed as a tool to achieve sustainable development in three areas: as a tool to open the original settlement structure, increased density around the center, restoration of the natural environment and agricultural landscapes in the spaces. city network: a new model for open collaborative development in the surrounding areas that leads to the formation of the city's network and metropolitan area network. the spatial pattern, the area between the green and blue urban centers will be assigned to the matrix. in conjunction with landscape architecture and planning development ecosystem. the tools, designed by james corner and charles vadhaym landscape architecture in urban scale in the united states and in europe krysynzexpanded major role. studies of ecosystem services and biodiversity in cities are considered in the past two decades. the importance of this issue in urban planning has been observed inthe world major cities, including frankfurt.the studies have been conducted in the three-phase investigation, representation, and control of the land to be annexed to the application process.a recent evaluation of policies, particularly in the area of ​​urban green spaces, green corridors, green belts and important results in maintaining and even improving the ecosystem of valuable resources and the conservation of biodiversity are represented in urban and land use planning reform measures.as one of the most important urban green space to urban habitats, it provides humans with unique perspective to a variety of flora and fauna, as well as direct access to nature. keeping in touch with nature citizens is a basic need and a criterion for quality of life. ecosystem services and biodiversity are high quality urban green areas, environmental benefits, economic, and psychological offers. studying the process of planning and development and the spread of the best practices based on the minimization of ecosystem services and urban development can be realized as two seemingly contradictory trends and competitor. thus, an optimal choice is to provide policy development, conservation of ecosystems and biodiversity in general elections. this research answers to three important questions.  first, what type of services does ecosystems, general in cities and specifically in urban management, have and what types of the strategieshavebeen used to maintain and improve these services? second, what are the main criteria and methods of analysisof planning and design of urban development in terms of ecosystem services and biodiversity considerations? third, what kinds of processes in the ecological integrity of space are seen in the city of ahvaz and what is the priority of strategic choice to increase the connectivity of the areas?   materials andmethods there are two basic types of metrics at the patch level: (1) indices of the spatial character and context of individual patches, and (2) measures of the deviation from class and landscape norms; that is, how much the computed value of each metric for a patch deviates from the class and landscape means. the deviation statistics are useful in identifying patches with extreme values on each metric. there are two basic types of metrics at the class level: (1) indices of the amount and spatial configuration of the class, and (2) distribution statistics that provide first- and second-order statistical summaries of the patch metrics for the focal class. like class metrics, there are two basic types of metrics at the landscape level. landscapes are composed of elements–the spatial components that make up the landscape. a convenient and popular model toconceptualizeand represent the elements in a categorical map pattern (or patch mosaic) is known as the patch-corridor-matrix model. under this model, three major landscape elements are typically recognized, and the extent and configuration of these elements defines the pattern of the landscape. while individual patches possess relatively few fundamental spatial characteristics (e.g., size, perimeter, and shape), collections of patches may have a variety of aggregate properties, depending on whether the aggregation is over a single class (patch type) or multiple classes, and whether the aggregation is within a specified sub-region of a landscape (e.g., the neighborhood of each focal cell) or across the entire landscape. consequently, landscape metrics can be defined at four levels corresponding to a logical hierarchical organization of spatial heterogeneity in patch mosaics. it is important to note that while many metrics have counterparts at several levels; their interpretations may be somewhat different. cell metrics represent the spatial context of local neighborhoods centered on each cell. patch metrics represent the spatial character and context of individual patches. class metrics represent the amount and spatial distribution of a single patch type and are interpreted as fragmentation indices. landscape metrics represent the spatial pattern of the entire landscape mosaic and generally interpreted more broadly as landscape heterogeneity indices because they measure the overall landscape structure. hence, it is important to interpret each metric in a manner appropriate to its level (cell, patch, class, or landscape). aggregation refers to the tendency of patch types to be spatially aggregated; that is,to occur in large, aggregated or “contagious” distributions. this property is also often referred to aslandscape texture. we use the term “aggregation” as an umbrella term to describe several closelyrelated concepts: 1) dispersion, 2) interspersion, 3) subdivision, and 4) isolation. in these exercises, future scenarios are constructed by making different assumptions on the underlying driving forces, and hence on the magnitude of land use change processes. for instance, khajehborjsefidiand colleagues built different land use scenarios by varying the rates of agricultural, river, vacant and urban expansion. less attention has been devoted so far to the effects on ecosystem services of different spatial arrangements of land uses. the effects of spatial patterns on ecological processes represent one of the central themes of landscape ecology. scientists have tried to understand these effects for a broad range of ecosystem services, such as habitat provision, pollination and water purification. according to a recent article, the capacity of a land system to deliver ecosystem services is determined by the kind, magnitude and spatial patterns of land uses. research on land use change and ecosystem services has widely addressed the first two attributes but has disregarded so far the third one, spatial patterns. to the best of our knowledge, none of the studies presented in the literature considered scenarios that differ only in the distribution of land use types, rather than in their relative proportions. the paper presents case-study research aimed at empirically exploring how the implementation of different land use zoning policies can affect the future supplyof ecosystem services. the term ‘land use zoning policy’ is used here to indicate regulations concerning permitted, prohibited or preferred land uses. the design of such policies is often a core issue in spatial planning, and they represent one of the most tangible elements of a plan. the method is based on the generation of future land use scenarios that simulate the implementation of different zoning policies. the scenarios are constructed by holding constant rate of land use change processes but varying their location according to the different policies. the effects of the land use scenarios on selected ecosystem services are then modeled and compared through a set of metrics. the study area is ahvaz (south-western iran), a region diverse in natural resources, but affected by widespread poverty, relatively low performance in development indicators and reliance on the conservation of ecosystem services to support rural livelihoods. the application of the methodology to the case study addresses three more specific questions: what are the effects of different zoning policies on future land uses within the region? how do these affect the conservation of ecosystem services? what are the empirical patterns of trade-offs among ecosystem services associated with the different policies? by answering these questions, the paper aims also at illustrating the potential contribution of the approach to support spatial planning.   results and discussion fragmentation of natural and ecological areas leads to reduction diversity of ecosystems and elimination and extinction of many species. spatial pattern analysis of functional-habitat patches-corridor - matrix components are the basis of landscape ecology. landscape ecologists describe the concept of a corridor connection or continuity of function and structure in terms of space and time effects. residential development along with the development of the ecological environment hasn’t been done. degradation of agricultural land to urban uses hasn’t helped integration. actually, urban development in order to increase economies of agglomeration does not move. despite the reduction of the green matrix during 1991 to 2006, the level of connection and integration has increased slightly. the effect of various scenarios indicated important ecological areas of the matrix green corridor along the river is much more effective than railway corridor that this matter can be considered as a space policy for the management of urban development. corridor little effect on the overall relationship indicates that this is currently located in a highly green matrices are isolated from each other so as a result, it is recommended that the planning of large-scale green space in the city and along the corridors of the linear guide.     conclusion land use policies to increase the level of biodiversity are in the following classified. green space planning with strategic policy that makes these spaces connectedin a set development of parks on the plots larger than one hectare according to climatic conditions; developments of private open spaces and more use of native plants appropriate to the climate; development of blue corridors, especially in regional scales connected to the main blue corridor area (karun river) and development of green and blue corridors in combination; drawing and temporal comparison inthe areas of bio-ecological information continuously; planned urban park with the use of natural patterns in the region, such as the creation of artificial wetlands and coastal water; development of the main areas of ecological corridors, such as river and privacy railroad connection to increase the margin of the inner built areas promotingthe use of semi-natural design of residential settlements such as oil town and etc. integrated development of forested areas, especially in the eastern and western sides of the city and parallel and perpendicular to the river and opposite the city's development; increase in the permeability of the karun river (both in road and in the natural corridors).