Temporal and spatial changes in land use and ecosystem service value based on SDGs' reports: a case study of Dianchi Lake Basin, China

Understanding the impact of land use and ecosystem services on sustainable development goals is a key to achieving sustainable development goals (SDGs). Taking Dianchi Lake Basin as the research area, land use data from five periods, 2001, 2005, 2010, 2015, and 2019, were analyzed using the dynamic equivalent method to determine ecosystem service value (ESV) and hot spot analysis method to explore temporal and spatial changes in ESV in Dianchi Lake Basin. Three sustainable development goals, SDG15.1.1, SDG15.2, and SDG15.3.1, were selected to quantitatively analyze the impact of land use change in Dianchi Lake Basin. The results showed that (1) in the 20-year study period, the main land use types in Dianchi Lake Basin were forest land, cultivated land, construction land, and water area. In the land transfer, the largest amount of land transferred out is cultivated land, accounting for 35.50% of the total transferred out amount. It is transferred to construction land, resulting in significant expansion of construction land, nearly twice as much. (2) The SDG15.1.1 index of three forest land types in Dianchi Lake Basin showed a downward trend, and the total forest land decreased from 45.36 to 41.80%, with a cumulative decrease of 3.56%, of which 2.35% was caused by the transformation from open forest land to other land types. For watershed SDG15.2 and SDG15.3.1 indicators, all were degraded, but the degradation of high forest (SDG15.2) was the most obvious. (3) From 2001 to 2019, the total ESV in Dianchi Lake Basin initially decreased and then increased before decreasing again, with an overall decrease of 3.687 billion yuan. The ESV in the study area was high in the middle and low in the periphery, and the water area dominated by Dianchi Lake was the highest value area. (4) From 2005 to 2019, the spatial displacement relationship between cold and hot spots dominated by Dianchi Lake was corresponding and obvious, during which the ESV fluctuated violently. This study provides a basis for the sustainable development and ecological construction in typical urbanized watershed.