On May 20, Professor YANG Jun from the Department of Earth System Science of Tsinghua University accepted an interview from Beijing TV Station and expressed his opinions on the changes in Beijing's biodiversity over the years. He talked about investigating the urban area of Beijing while working on his doctoral dissertation in 2002. A total of 78 tree species were found in more than 200 plots within the fourth ring road. In 2017, he and his students conducted another investigation on Beijing city. 230 tree species were observed in 180 plots set up in the fifth ring road, an increase of nearly three times. In 2020, his team made a public science project, and discovered about 300 tree species from photos of Beijing trees which was taken and submitted using the WeChat applet by everyone. Changes in diversity of these tree species reflect the increase in biodiversity in Beijing.

In addition, Professor YANG Jun also talked about the increasing phenomenon in bird diversity based on the changes in the data on bird species in Beijing and his personal experience of getting in touch with birds. Professor YANG Jun pointed out that the continuous improvement of Beijing's ecological environment has a great relation with the increase of biodiversity. He suggested that the monitoring and evaluation of the ecological environment need to be strengthened in the future, and annual monitoring indicators for biodiversity can be added to the ecological environment communique. These indicators can reflect the current status and sustainability of biodiversity.