Evaluation and prediction of land use changes in Arak and surrounding villages using hybrid cellular automata-Markov chain model

In the current research, land use changes and spatial development trends of Arak metropolis and surrounding villages were evaluated and predicted. Land use in three time periods 1990 (Landsat satellite), 2006 (Ester satellite) and 2023 AD (Sentinel satellite) was prepared using support vector machine classification and the amount of changes in each land use was calculated. Then, the land use changes and spatial expansion of Arak metropolis and the surrounding villages were predicted using Markov chain-cellular automata model for the horizon of 2040 AD. The results show the high dynamics of land use changes, especially built land use, at the regional level. This is due to the large spatial development of the metropolis of Arak, which has had a profound effect on the peri-urban area. Calculations showed that during the years 1990 to 2006, the built-up area with an increase of about 4104.3 hectares has reached 8391.8 hectares. During the period from 2006 to 2023, a total of 3516.7 hectares has been added to the mentioned land use area. In this regard, a large percentage of agricultural lands in the region have been changed to built-up use. The results of the Markov chain-cellular automata model showed that until 2040, the greatest amount of spatial dynamics will be between built-agricultural uses. It is predicted that up to 2571 hectares of agricultural land in the region will be converted into built-up land by 2040. In this regard, many constructions will take place in Arak-Qom axis and Arak-Shazand axis. In the area of Pirasher, North Arak, the built-up development will be in the form of spatial development of villages and expansion of villas.

In the 21st century, more than half of the world's population lives in cities, which has caused two major and interconnected "population" and "environmental" crises to occur. As a result, valuable lands outside the city have been swallowed up by buildings and their belongings (Yarahmadi, 1378: 9). Despite being aware of the adverse effects caused by the physical development of the city on the natural environment, one should also accept the fact that the phenomenon of urban development is inevitable. Although urban growth can meet a part of this need, development often happens in the suburbs, where the development of irrational land uses leads to the loss of quality natural resources and the destruction of sensitive ecosystems. In order to control and guide such developments, specifying the dimensions of the desired development, choosing the correct location of the land, and applying protection policies in line with social and economic goals, requires precise and scientific planning (Rasouli, 2011: 127). Therefore, irregular urban development has destructive effects on cities and their surrounding environment, including the heterogeneity of natural landscapes and the destruction of agricultural lands. Although scientific findings have proven that this model is not effective for urban development, it is still the dominant model of urban development (Batisani and Yarnal, 2009). In general, it should be acknowledged that what is criticized today as the negative aspects of the city and urban development is mainly not the nature of the city, but rather the unbalanced and exogenous process of the city, which is often the result of physical growth and development of cities exceeding infrastructure development. The services and services required, or the priority of scale over performance and the superiority of quantity over quality. (Pourmohammadi and Jam Kasri, 1390: 31-54). In our time, the uneven physical development of cities has created one of the most important issues in land use. This development is actually the continuation of the expansion of the city around it; Because around big cities, there are areas that always go through the period of transition from rural to urban exploitations (Shakoui, 2012: 213). In this way, the protection of rural spaces and settlements and preventing their transformation into residential spaces, villas, roads, industrial facilities, etc., along with maintaining their ecological and productive capacity, as well as the sustainable management of agricultural and garden lands, is becoming more and more difficult and changing their use. Despite the need of cities and villages for green spaces, especially around big cities, it is happening explosively and continuously. With industrialization and urbanization, the world economy is developing rapidly, but rural areas are shrinking. This issue has received serious attention in many countries (Liu and Li, 2017; Jai et al., 2021). In the process of urban-rural transformation, farmers strongly want to improve their living conditions. The occupation of agricultural lands due to new residential constructions has increased sharply, which has led to the widespread evacuation of rural residential lands (Tan and Lee, 2013). In addition, the migration of rural people to the city has intensified rural evacuation (Gay et al., 2019; Hu et al., 2016). The spatial changes of the surrounding villages have caused traditional agriculture to change from an indigenous-rural society to an urban-rural society (Liu and Wang, 2018). Behind these spatial developments, the evolution of human-land relations, industrial-agricultural relations, and urban-rural relations has caused the reorganization of rural social, economic and spatial structures (Wang et al., 2015), so that at the micro level, Many cities are gradually separated and show significant spatial differences (Gu et al., 2019). In this process, the spatial developments of the surrounding villages have also changed.