A quantitative framework for selecting and validating food web indicators

Trophic Interactions, Management Trade-Offs and Climate Change: The Need for Adaptive Thresholds to Operationalize Ecosystem Indicators

“…Threshold dynamics in marine ecosystems have been observed in many different systems, for example coral reefs (Knowlton, 1992) and pelagic food webs (Conversi et al, 2015). However, they are rarely accounted for in EBM indicator evaluations, perhaps due to quantitative validation schemes only being recently developed (Queirós et al, 2016;Otto et al, 2018). Non-linear effects were relatively common in our indicator networks, while threshold effects were more rare.…”

“…The zooplankton community includes a substantially larger number of species and we derived indicators of the community representing aspects of quantity and quality of food for upper trophic levels. The indicators were considered for assessment under the 'Baltic Sea Action Plan' and descriptor 4 -food websof good environmental status in the MSFD and showed a good performance when studied individually (HELCOM, 2013a,b;Otto et al, 2018). Assessments under descriptor 4 are based on trophic guilds and our indicators covered three guilds: apex fish predators, planktivorous fish, and secondary producers; and three of four assessment criteria (EU Decision 2017/848; ICES, 2015b).…”

“…Models including size-based FI had simpler structure (Figure 2), making it feasible to try all potential pressures and use threshold variables defined a priori. Models including abundance-based fish indicators had a higher number of potential trophic links and threshold variables, so we used the results of the GAM analysis and results from single-pressure analyses carried out by Otto et al (2018) to inform choice of covariates and threshold variables (see details in Supplementary Information: Appendix I).…”

From Science to Evidence – How Biodiversity Indicators Can Be Used for Effective Marine Conservation Policy and Management

“…Despite the wide range of applications of biodiversity indicators observed during recent decades, specific selection criteria have been commonly accepted within the scientific community to determine indicator suitability for operational use. These include measurability, scientific basis, interpretability, and ease of communication, but also sensitivity and responsiveness to environmental changes, specificity, robustness with well-known pressure-state relationships, and links to identified targets and thresholds (e.g., OECD, 1993;FAO, 1997;Rice and Rochet, 2005;Heink and Kowarik, 2010;Kershner et al, 2011;Queirós et al, 2016;Otto et al, 2018a). Biodiversity indicators that address policy and management goals are likely to be most effective if the relevant stakeholders and decision-makers also perceive them to be credible, salient, and legitimate (Cash et al, 2003;van Oudenhoven et al, 2018).…”

“…Linking indicators to environmental conditions and ideally to management measures requires a good understanding of indicator responses to pressures and a sound testing of indicator performance, which is often lacking for biodiversity indicators (Rossberg et al, 2017). Thus, new modeling approaches and decision support tools are emerging to tackle the performance evaluation of indicators for assessing the health status of marine ecosystem and biodiversity components (Hayes et al, 2015;Lynam et al, 2016;Otto et al, 2018a;Shin et al, 2018) (see also section Linking biodiversity indicators to ecosystem change). To complement assessments of state, additional pressure indicators can be useful, particularly to measure the impacts of human activities on the system when there can be a long time-lag before natural processes can be expected to respond (Rossberg et al, 2017).…”