Research on mountain ecosystem services (MES) under the influence of climate change and human activities has gradually become the focus of academic attention in recent years. Here, this study analyzes the research hotspots and frontiers of this field based on metrics including main research forces, core journals and papers, research hotspots and topics by using the methods of bibliometrics and text mining. The results revealed the following: (1) the number of papers is increasing rapidly in recent years. From 2015 to 2019, 929 papers were published, with an average of 185 papers per year. But the average cited times of those papers is declining, dropped from 6.01 in 2016 to 4.2 in 2019. The USA, UK, and China rank the top three of the number of papers. Univ Maryland, Univ Oxford and Univ Wisconsin have the greatest influence, with an average of more than 77 citations per paper; (2) The most cited journals are PNAS, WETLANDS, ECOLOGY, AND SOCIETY, which are cited 191.54, 53.91, and 40.00 respectively. Most papers were published in OA journals including SUSTAINABILITY, WATER, Forests since 2017. Ten core papers undertaking knowledge transfer in this field have been identified; (3) analysis of the keywords found a new trend of integration of natural science and humanities. In two development stages of 2000-2014 and 2015-2019, the research hotspots mainly focused on mountain water resources, forest resources, land resources and the impact of climate change and human activities, and there are obvious differences and characteristics in different stages. The hotspot worthy of attention in the near future is the assessment of mountain ecosystem services capacity and value. This is the first comprehensive visualization and analysis of the research hotspots and trends of mountain ecosystem services.

Ecological research on the Qinghai-Tibet Plateau (QTP) has become a hotspot in recent years, and a great number of related research papers have been published. Here, a bibliometrics method was utilized to analyze 4315 papers from the Web of Science published from 1990 to 2019, and a comprehensive overview based on metrics, including the publication growth, first author' institutions and countries, research areas, international cooperation, high-impact journals and papers, and research hotspots and topics, is presented. The results revealed the following: (1) The number of published papers has grown exponentially, with China and India being the main research countries. However, China and the USA have the greatest weights in country cooperation. The Chinese Academy of Sciences has a relatively strong influence and plays the leading role in institutional cooperation. Wang Shiping, Zhang Zhenhua, Luo Caiyun, and seven other authors are highly influential. GLOBAL CHANGE BIOLOGY is the scientific journal that has published the greatest number of papers on the subject, and 'Environmental Sciences & Ecology' is the key research area; (2) Grazing, Precipitation, Soil moisture, Aboveground biomass, and Temperature are the top five core keywords. The research hotspots were mainly ecosystem services, biodiversity research, forest protection, and ecological adaptation under the background of climate change; and (3) Both new and old research topics appear in the periods 1990-1999, 2000-2009, 2010-2014, and 2015-2019, but all the periods focused on the impacts of rising temperature on natural elements, such as soil, forests, rivers, and lakes. Many recent also focused on the harmonious coexistence of human beings and nature. On the basis of these findings, some research suggestions and agendas are proposed for future research on the QTP. This is the first visualization and analysis of the hotspots and trends in ecological research on the QTP.