# Simulating Ecological Functions of Vegetation Using a Dynamic Vegetation Model
## 4 Discussion
The distribution of precipitation in the LP is consistent with that in China, decreasing from southeast to northwest and generally tending to be warm and dry. Climatic zones migrate southward, resulting in corresponding changes in the vegetation zones. Under the SSP119 and SSP585 scenarios, the decline of SC caused by the vegetation in the western region (Figure 5(b2,b3)) is caused by the decrease in precipitation and an uneven seasonal distribution in this area. Every year, the months of July, August, and September are prone to heavy rain, aggravating the soil erosion in the region. Therefore, vegetation managementin this region should be strengthened. For example, such measures could include planting suitable vegetation with a scientific approach (e.g., _Halaxylon ammonodrris_, sea-buckthorn, and other plants to enhance soil conservation ability) [48], implementing technical measures to make full use of the precipitation resources, and enhancing people's awareness of ecological protection [49]. The WC of the LP shows a high in the southeast and low in the northwest pattern, with the WC being highest in the western region (Figure S2(c1,c2)) owing to the high rainfall. Rainfall and evapotranspiration are important parameters for quantifying water production [50]. Precipitation minus evapotranspiration includes the soil moisture and possible runoff, and a drop in the WC indicates a possible water shortage. The western part of the LP has a high altitude and sufficient evapotranspiration. Compared with 2001-2020, the WC of the western part of the LP will decrease during 2081-2100 (Figure 5(c2,c3)). As a result, the amount of water resources in the high elevations of the west will decline and face the risk of water shortages. The trade-offs and synergies among the CS, WC, and SC of the LP were determined by the climatic conditions of the region, including temperature and rainfall [51]. Changes in the carbon and water fluxes and the structure of the vegetation simulated by the dynamic vegetation model can capture the transformation of the relationship between ecological functions at the same site (Figures S3 and 6). To promote the sustainable management of regional ecosystems, we should consider the relationship between ecological functions, minimize trade-offs, and increase synergies. [PERSON] et al. [52] showed that multiple ecosystem services can be gained by adjusting the ratios of forest, shrub, and grass vegetation simultaneously. The development of mixed forest can improve CS and SC. Strengthening natural grass protection, sustainable grazing, and reducing human disturbance can reduce the vulnerability of the ecological environment. The current research methods for the study of ecological functions do not consider certain dynamic information on vegetation. However, the dynamic vegetation model can capture the dynamic changes in the carbon and water flux and the structure of the vegetation, especially under scenarios of future climate change. Combined with the equation for calculating the ecological functions of vegetation, the dynamic evolution of the ecological functions under climate change is accurately described, which provides a reference for the research of related subject. Therefore, studying the dynamic response of ecological functions of vegetation to climate change based on the LPJ-GUESS model can be used to carry out similar research in other regions of the world and obtain corresponding results. The LPJ-GUESS model has many vegetation parameters, so it is difficult to calibrate all the parameters. Therefore, this study only calibrated 21 sensitive parameters based on existing studies [34]. In future research, the simulation accuracy of the model needs to be further improved.