Knowledge gaps and future research needs for assessing the non-market benefits of Nature-Based Solutions and Nature-Based Solution-like strategies

Environmental benefits of re-using excavated soil flows: The case of Luxembourg

The management of soil excavated during construction can lead to substantial environmental impact, especially in Luxembourg, where high per capita soil waste and limited landfill capacity intensify the challenge. This study employs an ad hoc spatially resolved model to assess the environmental impacts of current excavated soil management practices in Luxembourg from a life cycle perspective. It compares these impacts with alternative scenarios, where excavated soil is reproposed as substrate for nature-based solution (NbS) projects rather than backfilled. This model enables the design of prospective environmental impact reduction scenarios, highlighting that most alternative management practices -particularly those involving transportation distances under 50 km- can significantly reduce environmental impacts, mitigate landfill use and decrease the overall environmental footprint by ~18 % to ~92 % depending on the impact indicator. Findings support circular economy strategies for excavated soil recovery in Luxembourg, such as the development of green spaces and recreational areas.

Spatial and temporal patterns of supply and demand risk for ecosystem services in the Weihe River Main Stream, NW China

The rapid development of society and economy in the post-industrial era has exacerbated the spatial matching contradiction between the demand of humans and the supply of the natural environment, while ecosystem service (ES) as a bridge linking nature and society, identifying and assessing its supply-demand risk, was beneficial to ecosystem management and promoted regional high-quality development. Based on the data of multi-source remote sensing and statistics, the supply and demand levels of four ESs, which contain food supply, carbon storage, soil conservation, and water yield in the main stem of the Weihe River in 2000, 2010, and 2020, were quantitatively measured. The spatial and temporal analysis of the supply, demand, and supply-demand ratio of each service was carried out using spatial mapping. The spatio-temporal pattern of the supply-demand risk was recognized by the method of spatial overlay, which means overlaying the supply and demand for material quality, ratio, trend, and the degree of trade-off coordination together between each service. The results showed that (1) the demand for water yield decreased slightly while the demand for food and the supply of carbon storage remained stable. In addition, the supply and demand of other services showed an upward trend. (2) The spatial distribution of the supply-demand ratio of each service shows "high in the south and low in the north" and "high in the east and low in the west," among which the supply-demand ratio of carbon storage is decreasing. (3) The overall supply-demand risk of soil conservation in the study area is low with characteristics of small range and high degree, the risk distribution characteristics of the other services are high in the east and low in the west, and the risk is high in the city center and low around. Otherwise, the supply-demand risk of food supply showed a downward trend, the risk of carbon storage showed an upward trend, the risk of soil conservation remained stable, and the risk of water yield showed a significant downward trend. Based on static supply-demand risk identification, this study assesses supply-demand risk over two periods and analyzes the trend of supply-demand risk changes over time. It clarifies the extent and direction of supply-demand risk shifts, as well as provides improved theoretical support for ecosystem service management.

Assessing the environmental and social co-benefits and disbenefits of natural risk management measures

Risk management measures (RMM) participate in the sustainability of cities and communities through the protection of these socio-eco-environmental systems against threatening events, and by ensuring system recovery. They include structural measures that are grey or green/blue solutions, or hybrid solutions combining the two former types. These measures can provide environmental and social co-benefits (e.g., improved biodiversity, recreational services) and disbenefits (e.g., the development of unwanted flora, concentrations of pollutants). The aim of this article is to provide an approach to assess and compare RMMs by considering these different dimensions. An application to three natural hazards - floods, coastal floods and wildfires - is proposed. The approach takes the form of a procedure to assess the co-benefits/disbenefits of the various RMMs and some technical specifications. It allows comparing the performances of one RMM against another and collectively discussing the choice of RMMs that takes into account a wide range of dimensions. The approach is based on the formulation of eight sustainability criteria and thirty-one indicators. The results were graphically displayed as several types of diagram: one radar chart per RMM, compiling all the indicators; one radar chart by type of risk studied (flood, wildfire and coastal flooding) based on averages of indicators per criterion; a table of the global score assigned to each RMM calculated with an arithmetic mean or a weighted mean. The approach relies on an interdisciplinary research team and involves end-users in a focus group for the validation step. This approach constitutes a transparent base for decision-making processes in the context of sustainable spatial planning against natural risks.