Mongolia's transition from a centralized socialist economy to a market economy since 1990 has led to enormous changes in the country's socio-economic and environmental conditions. The livestock privatization was one of the most significant reforms in a country that promotes herders to increase their herd size to improve their livelihood. Although rangeland is under state authority by law, its strict control on rangeland management disappeared, and the herding system of Mongolia turned into de facto open access. There are differing opinions as per conflicts between private livestock versus public rangelands, and the pastoral livestock sector of Mongolia is a classic case of "tragedy of commons." Thus, Mongolia was faced with the dilemma of increasing the number of livestock and the need to manage natural resources properly. As livestock is the primary livelihood of rural households and provides most of the foodstuffs for Mongolia, an increase in livestock number is supported. However, a massive increase in livestock number creates high pressure on the rangeland and leads to rangeland degradation caused by overgrazing and other problems in the long run.Rangeland degradation caused by overgrazing is one of the most significant environmental challenges that Mongolia is facing. According to the recent statistics, livestock numbers have tripled within the last two decades, which has put pressure on the rangelands, exceeding the rangeland carrying capacity by more than 30 million heads. Although the number of livestock has reached its highest record, the livestock number-based inequality is high within the herder households. Herders with less than 200 livestock, which is below the subsistence level, take up more than 50 percent of the total herder households.The main reason for the increase in livestock number is a lack of Government policy on rangeland management and markets to regulate its natural expansion. Because privatization of the livestock took place before the appropriate livestock support services could be introduced, that would have replaced the former negdel service and state procurement system.The objective of this study was 'to obtain insights into the relationship between poverty and sustainability of rangeland use under different arrangements for community-based rangeland management systems in different agro-ecological regions of Mongolia.' The objective is achieved by answering four research questions throughout the five separate chapters.Chapter 2 analyzed herders' behavior using game theory to characterize which type of game is being 'played' in the Mongolian livestock sector and provides better insight into the dynamics of the pastures' carrying capacity. The game estimation results suggest a so-called non-coordination game for steppe regions and a chicken's game for the Gobi region. Increasing herders' payoffs from the herding business would also be significant in the Gobi region by taking a more market-based approach. It has shown that when we allow the carrying capacity to be dynamic by letting it depend on weather conditions, the cycle of animal losses and increases can be explained better.Chapter 3 described the current institutional arrangements of rangeland management in Mongolia and the stakeholders participating in this area. The government of Mongolia and donor organizations supported and strengthened the institutions involved in rangeland management. This chapter analyzed the approaches of the donor organizations such as the World Bank, UNDP, and SDC. Since 2006, the territory based PUG approach have been promoted by the Administration of Land Affairs, Geodesy and Cartography. The nested PUG system vision is comprehensively organized throughout Mongolia and takes the lead in rangeland and livestock management and improvement.Chapter 4 deals with the specification of rangeland management in the Gobi region where it needs to have a long-distance move to seek better grazing areas or areas with less dzud and drought and have high pasture yields and adequate water supply. The case study presents general conditions in the Gobi region and introduction of PUG approach. The institutional arrangement of rangeland management in Gobi region needs a specific policy to regulate large mobile communities within and across soum and aimag territory.Chapter 5 analyzed the performance of the newly introduced institutional arrangement for community-based rangeland management in Mongolia. In recent years, community-based rangeland management approaches such as PUGs have been introduced in selected regions of Mongolia to explore appropriate mechanisms for countering rangeland degradation. The results show that the current select institutional arrangements have significant impacts on rangeland quality. A well-defined rangeland boundary is key to supporting rangeland quality, which is in line with the current government policy to introduce this scheme within the framework of an annual land management planning scheme. Inequality in herd sizes within a PUG negatively affects rangeland quality; the impact of group size resembles an inverted U-shaped relationship. Intermediate group sizes have the highest monitoring effort on rangeland management and lead to the best outcomes in rangeland quality.Chapter 6 investigates the comparative advantage of selected livestock-oriented products using the revealed comparative advantage index to show export opportunities for different types of livestock-oriented products. The study results illustrate that there are possibilities to develop export-oriented livestock production in Mongolia in various stages. The export of livestock-oriented products, combined with other policies, is a way to substantially reduce the animal number to sustainable levels, reduce overgrazing pressure, and increase export income. Long-term policy on meat and other livestock-oriented products should provide a legal framework of rangeland use to secure Mongolia's livestock sector's sustainable development.In general, many herders do not have enough animals to sustain themselves traditionally. Therefore, herders need to combine subsistence livestock-keeping with various other jobs to become more market-oriented herders to increase their income, health, and maintain the rangeland. The key innovation of the community-based rangeland management in Mongolia is herders' entire organization on a territorial basis, which is necessary to transfer the leadership role in pasture management from local governments to the herders themselves. However, pasture user groups cannot perform these management functions on their own. They need support and collaboration from soum and aimag governments to allocate pasture use rights and must assist with enforcing the rules that are agreed upon within and among PUG. Moreover, this system would be best introduced in conjunction with alternative income generation activities and economic support to compensate for losses associated with limiting herd sizes. The government of Mongolia aims to ensure the sustainable livestock sector, to secure herder households' livelihoods, and improve economic opportunities within the sector. One of their significant policy is to increase resilience to climate change by addressing overgrazing and balancing the livestock numbers with the rangelands' carrying capacity. For instance, an increase in meat exports would support decreasing livestock numbers to a level that would balance the carrying capacity. However, promoting exports will need to be combined with appropriate rangeland management policies, such as a user fee (pasture tax), to control the overgrazing problem. Possible policies that would support the export of meat and other products of animal origin in this context are developing a meat export industry and strategic animal breeding, reintroducing a livestock tax, supporting the growth of more productive animals.The research on this thesis contributes to the literature by i) adding a new country case to the World rangeland management study where still have nomadic pastoral livestock, ii) testing the interrelation between poverty and rangeland use, iii) analyzing the adoption of CBNRM approach in Mongolia's condition within the theoretical framework of sustainable governance of common-pool resources, and, iv) systematically analyzing the characteristics of pastoral livestock and its linkage to the market system.