Flagged observation analyses as a tool for scoping and communication in integrated ecosystem assessments.

Autor: Solvang HK; Marine Mammals Research Group, Institute of Marine Research, Bergen, Norway., Arneberg P; Ecosystem Processes Research Group, Institute of Marine Research, Fram Centre, Langnes, Norway.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2024 Sep 23; Vol. 19 (9), pp. e0305716. Date of Electronic Publication: 2024 Sep 23 (Print Publication: 2024).
DOI: 10.1371/journal.pone.0305716
Abstrakt: Working groups for integrated ecosystem assessments are often challenged with understanding and assessing recent change in ecosystems. As a basis for this, the groups typically have at their disposal many time series and will often need to prioritize which ones to follow up for closer analyses and assessment. In this article we provide a procedure termed Flagged Observation analysis that can be applied to all the available time series to help identifying time series that should be prioritized. The statistical procedure first applies a structural time series model including a stochastic trend model to the data to estimate the long-term trend. The model adopts a state space representation, and the trend component is estimated by a Kalman filter algorithm. The algorithm obtains one- or more-years-ahead prediction values using all past information from the data. Thus, depending on the number of years the investigator wants to consider as "the most recent", the expected trend for these years is estimated through the statistical procedure by using only information from the years prior to them. Forecast bands are estimated around the predicted trends for the recent years, and in the final step, an assessment is made on the extent to which observations from the most recent years fall outside these forecast bands. Those that do, may be identified as flagged observations. A procedure is also presented for assessing whether the combined information from all the most recent observations form a pattern that deviates from the predicted trend and thus represents an unexpected tendency that may be flagged. In addition to form the basis for identifying time series that should be prioritized in an integrated ecosystem assessment, flagged observations can provide the basis for communicating with managers and stakeholders about recent ecosystem change. Applications of the framework are illustrated with two worked examples.
Competing Interests: The authors have declared that no competing interest exist.
(Copyright: © 2024 Solvang, Arneberg. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
Databáze: MEDLINE
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