Search

The water conservation (WC) function of ecosystems is related to regional ecological security and the sustainable development of water resources, and the assessment of WC and its influencing factors is crucial for ecological and water resource management. The Tumen River Basin (TRB) is located in the core of the Northeast Asian ecological network and has been experiencing severe ecological crises and water shortages in recent years due to climate change and human activities. However, these crises have not been fully revealed to the extent that corresponding scientific measures are lacking. This study analyzed the spatial and temporal evolution characteristics and drivers of WC in the TRB from 1990 to 2019 based on the water yield module of the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model. The results showed that: 1) under the combined effect of nature and socioeconomics, the WC depth of the TRB has slowly increased at a rate of 0.11 mm/yr in the past 30 years, with an average WC depth of 36.14 mm. 2) The main driving factor of the spatial variation in WC is precipitation, there is a significant interaction between precipitation and velocity, the interaction between each factor is higher than the contribution of a single factor, and the interactions between factors all have nonlinear enhancement and two-factor enhancement. 3) Among the seven counties and municipalities in the study area, the southern part of Helong City and the southeastern part of Longjing City are extremely important areas for WC (> 75 mm), and they should be regarded as regional water resources and ecological priority protection areas. It is foreseen that under extreme climate conditions in the future, the WC of the watershed is under great potential threat, and protection measures such as afforestation and forestation should begin immediately. Furthermore, the great interannual fluctuations in WC depth may place more stringent requirements on the choice of time scales in the ecosystem service assessment process. [ABSTRACT FROM AUTHOR]

Spartina alterniflora has rapidly and extensively encroached on China's coastline over the past decades. Among the coastal areas invaded by S. alterniflora , at most 93% are mudflats. However, the effect of S. alterniflora invasion on soil organic carbon (SOC) stocks of coastal mudflats has not been systematically studied on a national scale. Here, we quantified the nationwide changes in SOC stocks in coastal mudflats associated with S. alterniflora invasion between 1990 and 2020. We found that S. alterniflora invasion significantly enhanced SOC stocks in coastal China. Nonetheless, the benefit of S. alterniflora invasion of coastal SOC stock may be weakened by continuing human intervention. We found that S. alterniflora invading mudflats added 2.3 Tg SOC stocks to China's coastal blue carbon, while 1.78 Tg SOC stocks were lost mainly due to human activities, resulted in a net SOC stock gain of 0.52 Tg C. These findings overturned the traditionally thought that S. alterniflora invasion would reduce ecosystem services by highlighting that the historical invasion of S. alterniflora has broadly and consistently enhanced blue carbon stock in coastal China. [ABSTRACT FROM AUTHOR]

• Ecosystem service (ES) supply-demand relationships were assessed for a sustainable Northeast China. • Spatial similarity and mismatch between ES supply and demand were evaluated at different scales. • Ecological supply-demand ratios have consistency with the pattern of land cover in Northeast China. • Integrating ESs evaluation into decision-making is necessary for sustainable development. Ecosystem service (ES) supply and demand, as well as their interactions, are vital aspects of ES research in the context of sustainable ecosystem management. In this study, we assessed the supply-demand relationships of four provisioning and regulating services in Northeast China based on the InVEST model and multi-resource data. Then, we examined the spatial similarities and mismatches of selected ESs via correlation analyses and local indicators of spatial association. The results reveal that Northeast China is, in general, self-sufficient in terms of supply and demand for the estimated four ESs. Interactions among ES supplies were similar, whereas those among ES demands and ecological supply-demand ratio varied from case to case. Spatially-aligned supply and demand of water yield, soil conservation, and food provision were evident, whereas spatially-mismatched carbon sequestration supply and demand were dominant in Northeast China. Our study identifies significant high-low or low-high spatial mismatches for four ESs. Locations for these mismatches suggested that these areas should be prioritized for socio-ecological management. Balance between ES supply and demand recognized in this study could support comprehensive decision-making for sustainable spatial management of ecosystems in Northeast China. [ABSTRACT FROM AUTHOR]