Carbon storage (CS) is closely linked to the global challenge of climate change. Land use/cover (LULC) change is the main factor driving changes in CS, and evaluating the impact of LULC changes on CS is important for carbon balance. Taking Jiangsu Province as an example, we used the Integrated Valuation of Ecosystem Services and Trade-offs model to analyze the spatiotemporal changes in CS during 2000–2015. Then we coupled it with the patch-generating land use simulation model to simulate and predict LULC and CS in 2050 under four different development plans. The results showed that LULC change in Jiangsu Province was manifested mainly as transformation of cropland to construction land (3,485 km²) and cropland to water body (470 km²). The high value area for CS was concentrated mainly in forest land, water body and grassland, whereas the low value area was concentrated mainly in construction land. During 2000–2015, CS decreased by 0.23 Tg, and during 2015–2050, CS was predicted to decrease by 0.16, 1.69, 0.02, and 0.10 Tg under the baseline, fast, slow and harmonious development scenarios. The conversion of a large amount of cropland to construction land was the main cause of CS loss. In all scenarios, the carbon loss was the largest in southern Jiangsu and lowest in central Jiangsu. It is necessary to balance the conflict between economic development and ecological protection during the process of urbanization. This study can provide an important reference for decision makers during the formulation of regional development models and ecological management strategies.

The existence of alternative stable states and hysteresis underpinned by positive feedback mechanisms explains why it is often difficult to restore submerged macrophytes in shallow lakes. It is especially difficult to restore water quality of turbid tropical lakes. It has been speculated that transplanting macrophytes tolerant of high turbidity may help the system escape from the turbid state, but systematic assessments are so far largely lacking. Here we conducted a mesocosm transplanting experiment in a shallow lake of subtropical China to mimic macrophyte restoration. We transplanted three common native turbidity-tolerant submerged macrophyte species in shallow-water mesocosms and monitored water quality within one growing season. Our experiment demonstrated that following artificial recolonization, the submerged macrophytes could indeed persist in turbid shallow water. However, the persistence of submerged macrophytes cannot significantly improve water quality, and cannot reverse the ecosystem state of tropical shallow lakes within one growing season. Our results thus provide useful implications to the current lake restoration practices. In real-world situations, it may not be realistic to anticipate rapid restoration through macrophyte transplantation only. Monitoring the long-term effects of macrophyte transplantation is imperative for lake restoration. Our work highlights the need to harness the nuanced hidden complexity for tropical lake restoration and calls for attention to alternative stable states among practitioners of lake management.