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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2025

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Abstract

Urban green structures (UGS) play important roles in enhancing urban ecosystems by providing benefits such as mitigating the urban heat island effect, improving air quality, supporting biodiversity, and aiding in stormwater management. Accurately mapping UGS is important for sustainable urban planning and management. Traditional methods of mapping such as manual mapping, aerial photography interpretation and pixel-based classification have limitations in terms of coverage, accuracy, and efficiency. Object-based image analysis (OBIA) has gained prominence due to its ability to incorporate both spectral and spatial information making it particularly effective for classification of high-resolution satellite data. This paper reviews the application of OBIA on satellite images for UGS mapping, focusing on various data sources, popular segmentation methods, and classification techniques, highlighting their respective advantages and limitations. Key segmentation methodologies discussed include multi-resolution segmentation and watershed segmentation. For classification, the review covers machine learning techniques such as random forests, support vector machines, and convolutional neural networks, among others. Several case studies highlight the successful implementation of OBIA in diverse urban environments by demonstrating improvements in classification accuracy and detail. The review also addresses the challenges associated with OBIA, such as dealing with heterogenous urban landscapes, data sources and with OBIA methods itself. Future directions for UGS mapping include the integration of deep learning algorithms, advancements in satellite data technologies, and the development of standardized classification frameworks. By providing a detailed analysis of the current state-of-the-art in object-based UGS mapping, this review aims to guide future research and practical applications in UGS management.

To document

Abstract

Optimised contributions of green infrastructure (GI) to urban ecosystem services are strongly related to its multifunctionality. The challenge, however, is that the concept of multifunctionality still needs to be transformed into an operationalised assessment to evaluate current performance, which is instrumental in supporting spatial planning and policy strategies. Using the case of Stavanger City (Norway), the study conducted a spatial assessment of the multifunctionality of the urban green infrastructure. The study used a comprehensive set of 27 function indicators estimated for each of the 156 spatial units classified by their type, age, size, and biophysical characteristics. Correlation patterns among indicators and how the average and effective multifunctionality related to unit characteristics were analysed using correlation and multivariate approaches. The study demonstrated weak correlations between function indicators but revealed some potential trade-offs and function bundles. Notably, bundles related to tree cover (e.g. C sequestration, stormwater retention) had negative relationships with facilitation measures. There was a large overlap in functions between GI types associated with public green spaces and parks. Moreover, the characteristics of green infrastructure units, like size and age, primarily affected multifunctionality through effects on function indicators. Regarding the city-wide multifunctionality, we found some turnover and subsetting of functions among units, supporting multifunctionality at larger spatial scales. However, the average contributions from different GI types were similar. The study highlights the need to understand correlation patterns among function indicators and function bundles as critical to benefit from synergies and avoid unintentional trade-offs when designing and managing urban green areas.

2024

Abstract

Nature-based solutions (NBS) are an increasingly popular strategy to water resources management, with a growing number of research projects and policy interventions. Development, implementation, and decision on NBS for retention of water, sediments, and nutrients in the landscape often require substantial investment in data acquisition and modeling efforts. SWAT+ provides several new approaches compared to SWAT in terms of i) enhanced catchment configuration with more spatial objects, ii) improved representation of the connectivity between man-made hydrologic systems and the catchment stream network, and iii) new algorithms to implement complex rule-based management actions. These advantages make SWAT+ very suitable for simulating catchment processes in relation to NBS and for developing catchment-based tools for optimizing the type, location, and design of NBS. To further propel the simulation and optimization of NBS at the catchment scale with SWAT+, we propose establishing a community to harmonize and synergize the efforts of SWAT+ users worldwide in the field of NBS implementation and management. The envisioned SWAT+ NBS community would comprise researchers and scientists sharing a common vision, engaged in co-developing frameworks, addressing policy imperatives, co-creating knowledge, and advocating for best practices in applying the SWAT+ model for advanced NBS optimization and management. The objectives of this presentation are 1) to discuss the phases of NBS development and management at catchment scale, 2) to identify the research gaps in using SWAT+ in NBS studies, and 3) to propose a structure and a coordination framework to shape the SWAT+ NBS community.

Abstract

The use of SWAT+ model is increasingly prevalent in the simulation and evaluation of Nature-Based Solutions (NBS) at the catchment scale. Compared to the SWAT model, the SWAT+ model offers several advancements, including enhanced catchment configuration, improved representation of connectivity between man-made hydrologic systems and the catchment stream network, and new algorithms for implementing rule sets for management actions. In this presentation, we outline our methodology and present some preliminary findings from implementing SWAT+ in a South-Eastern Norwegian catchment. The catchment has a relatively large proportion of agricultural land based on Norwegian standards, with several natural lakes. Our modelling results underscore the importance of the spatial configuration phase, particularly in detailed spatial settings and HRU characterization, for simulating catchment-NBS interactions. We found that integrating reanalysis of spatial meteorological data in 1x1 km resolution could significantly improve streamflow simulation. In our case study, by using Met Nordic Reanalysis Dataset from Norwegian Meteorological Institute, the NS efficiency increased from -0.05 to 0.4 prior to any calibrations. Furthermore, we discuss challenges in simulating catchment-NBS interactions with SWAT+, particularly concerning “prospective impact evaluation” in the planning phase of constructed wetlands (design, placement, and optimization).