Population instability in rural areas is one of the serious challenges of recent decades, the most important reason for which is rural-to-urban migration and population evacuation of villages. People's sense of belonging to a place is formed by the place where they were born and grew up. In fact, this type of relationship with the place affects people in a lasting way and enriches the human identity. From the point of view of environmental psychology, the sense of belonging to a place is at a higher level than the sense of place, which plays a decisive role in order to benefit and continue human presence in the place (Falahat & Nouhi, 21: 2012). Rural settlements, as the smallest and oldest geographical units, have been formed under the influence of various factors such as natural, social, cultural, historical and economic factors in the geographical context and in the form of human-environment relations (Mekaniki & Nik Farjam, 2014: 47). Iran's border areas have always faced many problems due to various threats of neighboring countries. The border villages of Sarbisheh, with a 99 km common border with Afghanistan, are the sample studied in this study. The question of the present study is: How the sense of belonging to a place affects the stability of the population of the border villages of this city? The study results can provide a better understanding of human behavior in different situations, such as the decision to stay or leave a habitat.
 
Method
The present study is descriptive-analytical using survey. Reviewing library and internet references and taking a sample from these references, comprehensive and documented materials related to the research were collected, theoretical foundations related to the subject were reviewed, and the social and physical components of the sense of belonging to a place and appropriate variables were identified. The statistical population of this study includes households living in the border villages of Sarbisheh, i.e. 1394 households. According to Cochran's formula, 253 households were considered as the necessary sample size of the population.
The data of the studied sample were collected by survey and a researcher-made questionnaire with different parts (personal information, social trust, social cohesion and participation, social identity, and access to services and facilities), including 45 items on Likert scale. The answers are scored in five options (very low = 1, low = 2, moderate = 3, high = 4 and very high = 5). In this study, face validity was used. In this way, for the design of the questionnaire, it was attempted to match and relate the questions with the theoretical foundations and objectives of the research. Next, it was modified according to the opinions of the professors in the field of rural planning studies. Cronbach's alpha was used to confirm the reliability of the measurement tool. Descriptive statistics (mean, standard deviation, and coefficient of variation) were used for the data analysis and non-parametric binomial statistical test was used to test the research hypotheses due to the non-normality of the data.
Results: The distribution of the frequency of people's views about the social components affecting the sense of belonging to a place includes social trust, social cohesion and participation, and social identity, from which the following results are obtained:

Social trust: the average opinions of the people studied about the effect of the component of social trust on the sense of belonging to a place and the stability of rural settlements is equal to 3.70, indicating that the effect of the component of social trust on the sense of belonging to a place and stability of rural settlements is high.
Social cohesion and participation: The average opinion of the people studied about the effect of the component of social cohesion and participation on the sense of belonging to a place and the stability of rural settlements is equal to 4.01, indicating that the effect of the component of social cohesion and participation on the stability of rural settlements is high.
Social identity: the average opinions of the people studied about the effect of the component of social identity on the sense of belonging to a place and the stability of rural settlements is equal to 3.68, indicating that the effect of the component of social identity on the stability of rural settlements is high.

The average of the opinions of the people studied about the effect of physical characteristics affecting the sense of belonging to a place and the stability of rural settlements is equal to 2.52, indicating that the effect of physical characteristics on the sense of belonging to a place and stability of rural settlements is less than average.
 
Conclusion
The slow growth and sometimes population evacuation of villages, especially the border villages, is a serious threat to the population and activity, which should be seriously considered by those in charge of land planning and preparation. The study of population changes in the last decade shows the population growth caused by the persistence of the population in the border villages of Sarbisheh. In order to investigate the effect of physical and social components on the stability of rural settlements, due to the non-normality of the data, a binomial non-parametric test was used. The analysis of data obtained from survey showed that all three social components (social trust, social cohesion and participation, and social identity) have a great effect on the sense of belonging to a place and caused the demographic stability of border rural settlements. Also, the results showed the lack of influence of physical components on the sense of belonging to a place in the rural settlements of the border areas. The existing physical infrastructure has not been a factor to strengthen the sense of belonging to a place, and the current sense of belonging to a place is not caused by physical characteristics. However, if the physical infrastructure is strengthened, it can strengthen the sense of belonging to the place and the permanence and stability of the population of remote and border rural settlements. 
In this study, only the effects of social and physical characteristics on the sense of belonging to a place and population stability of border villages were investigated from the perspective of the local community. Family and ethnic cohesion and ties, along with friendly interactions, sympathy and close relationships among villagers, have been among the variables that have led to the strengthening of the sense of belonging to a place among the border villagers of Sarbisheh.