May the matrix be with you! Guidelines for the application of expert-based matrix approach for ecosystem services assessment and mapping

Abstract

Matrices or look-up tables are increasingly popular flexible tools for ecosystem services mapping and assessment. The matrix approach links ecosystem types or land cover types to ecosystem services by providing a score for ecosystem service (ES) capacity, supply, use, demand or other concepts. Using expert elicitation enables quick and integrative ES scoring that can meet general demand for validated ES mapping and assessment at different scales. Nevertheless, guidance is needed on how to collect and integrate expert knowledge to address some of the biases and limits of the expert elicitation method. This paper aims to propose a set of guidelines to produce ES matrices based on expert knowledge. It builds on existing literature and experience acquired through the production of several ES matrices in several ES assessments carried out in France. We propose a 7-steps methodology for the expert-based matrix approach that aims to promote cogency in the method and coherency in the matrices produced. The aim here is to use collective knowledge to produce semi-quantitative estimates of ES quantities and not to analyse individual or societal preferences or importance of ES. The definition of the objectives and the preparation phase is particularly important in order to define the components of capacity to demand ES chain to be addressed. The objectives and the ES components addressed will influence the composition of the expert panel. We recommend an individual ‡ ‡ © Campagne C, Roche P. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.filling of an empty matrix in order to strengthen the statistical analysis of the scores' variability and the analysis of congruency between experts. Expert scoring should follow a process of discussion, information-sharing and collective appropriation of a list of ecosystem types and ES to be assessed. We suggest that the ES matrix should not only focus on ES central scores but also address the variabilities and uncertainties as part of the ES assessment. The analysis of these sources of variability allows the documentation of variations in the ES quantity but also an exploration into the lack of consensus or knowledge gaps that needs to be addressed.

Linking ecosystem services and measures in river and floodplain management

“…To maintain a reasonable timeframe, the first step of our expert-based approach included five to six experts, followed by a second step where all 17 experts could express their potential disagreement on the matrix links established by the smaller expert groups as well as through the literature-based approach. This approach is in line with the proposed 'partial individual fill in' and 'adjustment in consensus' as described in Campagne and Roche (2018) and added the component of asking the experts to reflect the results of the literature.…”

Berries, greens, and medicinal herbs—mapping and assessing wild plants as an ecosystem service in Transylvania (Romania)

“…The two main groups of the target species (wild edible and medicinal plants) were modelled separately according to prior categorizations that were revised after the workshops for final model building. Residents invited to the workshops were selected specifically by recommendations (and with help of the local NGO leading the study) based on their knowledge of wild food, who we thus regarded as local experts in accordance with [73].…”

“…Our approach involved several scorable elements (the frequency of each species in each ecosystem type, as well as the subjective importance (personal value) of the species), which made them aggregatable at the landscape scale (the species scores aggregated for each ecosystem type, in fact, make up a "matrix model" in an ES assessment terminology, see e.g. [72], or [73]). As a comparison, we also tried the "traditional" MAES approach (asking a few key experts to fill in the "matrix" scores directly (i.e.…”

Evaluation of the Potential Change to the Ecosystem Service Provision Due to Industrialization

“…After developing the supply and demand matrices, the exercise was expanded by subtracting one from the other to calculate a final balance matrix that indicates whether a change in LULC improves or deteriorates the ES regime in a region (see Figure 3). experts (an expert is a person with extensive knowledge within a field of study acquired due to experiences such as research, field work, or being a stakeholder, who can provide educated guesses about the field about which they are being consulted [41]), who were asked to examine the list of LULC types and set a value from 0 to 5 to represent the level of provision of any given ES type (out of those listed in the MEA). The advantages of using Burkhard et al's method include the possibility of setting a geographic reference for the provision and demand of ES.…”