The critical role of abiotic factors and human activities in the supply of ecosystem services in the ES matrix

Urban green infrastructure: A review on valuation toolkits from an urban planning perspective

As a response to increasing urbanization and changing weather and climatic patterns, urban green infrastructure (UGI) emerged as a concept to increase resilience within the urban boundaries. Given that implementing these (semi-) natural solutions in practice requires a clear overview of the costs and benefits, valuation becomes ever important. A range of decision-support tools for green infrastructure and ecosystem services exist, developed for various purposes. This paper reviews the potential of 10 shortlisted and existing valuation tools to support investment decisions of urban green infrastructure. In the assessment, the functionality is regarded specifically from the urban planning and decision-making viewpoint. The toolkits were evaluated on 12 different criteria. After analyzing the toolkits on these criteria, the findings are evaluated on the (mis)match with specific requirements in the urban planning and management context. Secondly, recommendations and guidelines are formulated to support the design of simple valuation tools, tailored to support the development of green infrastructure in urban areas. Approaching the valuation toolkits biophysically and (socio-)economically provides an integral overview of the challenges and opportunities of the capacities of each framework. It was found that most tools are not designed for the peculiarities of the urban context. Several elements contribute to the hampering uptake of GI valuation tools. Firstly, the limited effort in the economic case for green infrastructure remains a burden to use toolkits to compare grey and green alternatives. Secondly, tools are currently seldom designed for the peculiarities of cities: urban ecosystem (dis)services, multi-scalability, life-span assessments of co-benefits and the importance of social benefits. Thirdly, toolkits should be the result of co-development between the scientific community and local authorities in order to create toolkits that are tailor made to the specific needs in the urban planning process. It can be concluded that current tools, are not readily applicable to support decision making as such. However, if applied cautiously, they can have an indicative role to pinpoint further targeted and in-depth analyses.

Ten years of ecosystem services matrix: Review of a (r)evolution

With the Ecosystem Service (ES) concept's popularisation, the need for robust and practical methodologies for ES assessments has increased. The ES matrix approach, linking ecosystem types or other geospatial units with ES in easy-to-apply lookup tables, was first developed ten years ago and, since then, has been broadly used. Whereas detailed methodological guidelines can be found in literature, the ES matrix approach seems to be often used in a quick (and maybe even "quick and dirty”) way. Based on a review of scientific publications, in which the ES matrix approach was used, we present the diversity of application contexts, highlight trends of uses and propose future recommendations for improved applications of the ES matrix.

A total of 109 studies applying the ES matrix approach and one methodological study without concrete applications were considered for the review. Amongst the main patterns observed, the ES matrix approach allows the assessment of a higher number of ES than other ES assessment methods. ES can be jointly assessed with indicators for ecosystem condition and biodiversity in the ES matrix. Although the ES matrix allows us consider many data sources to achieve the assessment scores for the individual ES, in the reviewed studies, these were mainly used together with expert-based scoring (73%) and/or ES scores that were based on an already-published ES matrix or deduced by information found in related scientific publications (51%). We must acknowledge that 27% of the studies did not clearly explain their methodology. This points out a lack of method elucidation on how the data had been used and where the scores came from. Although some studies addressed the need to consider variabilities and uncertainties in ES assessments, only a minority of studies (15%) did so. Our review shows that, in 29% of the studies, an already-existing matrix was used as an initial matrix for the assessment (mainly the same matrix from one of the Burkhard et al. papers). In 16% of the reviewed studies, no other data were used for the matrix scores or no adaptation of the existing matrix used was made. However, the actual idea of the ES scores, included in the Burkhard et al.'s matrices published 10 years ago, was to provide some examples and give inspiration for one's own studies. Therefore, we recommend to use only scores assessed for a specific study or, if one wishes to use pre-existing scores from another study, to revise them in depth, taking into account the local context of the new assessment. We also recommend to systematically report and consider variabilities and uncertainties in each ES assessment. We emphasise the need for all scientific studies to describe clearly and extensively the whole methodology used to score or evaluate ES in order to be able to rate the quality of the scores obtained. In conclusion, the application of the ES matrix has to become more transparent and integrate more variability analyses. The increasing number of studies that use the ES matrix approach confirms its success, appropriability, flexibility and utility for decision-making, as well as its ability to increase awareness of ES.