Errors-in-variables and validation problems in reaction norm predictions for wild populations

Studies of phenotypic responses in wild populations are often based on reaction norm models where the environmental drivers in many cases are related to climate change. Such input signals will never be exactly known, and there will always be measurement errors also in the recorded responses. In para...

Full description

Saved in:
Bibliographic Details
Main Author: Rolf Ergon
Format: Article
Language:English
Published: Norwegian Society of Automatic Control 2025-01-01
Series:Modeling, Identification and Control
Subjects:
Online Access:http://www.mic-journal.no/PDF/2025/MIC-2025-1-2.pdf
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1850029962933829632
author Rolf Ergon
author_facet Rolf Ergon
author_sort Rolf Ergon
collection DOAJ
description Studies of phenotypic responses in wild populations are often based on reaction norm models where the environmental drivers in many cases are related to climate change. Such input signals will never be exactly known, and there will always be measurement errors also in the recorded responses. In parameter estimation these errors give rise to errors-in-variables problems, especially in the form of overfitting caused by errors in the input measurements. A second important feature of such phenotypic response problems is that the environmental inputs must be given appropriate but largely unknown reference values. A third problem is that it is difficult to find good validation methods for predicted responses. Essential aspects of these problems are here studied by use of a reaction norm model in its simplest univariate form, characterized by a mean intercept value and a mean plasticity slope value, and the overall conclusion is that validated disentanglement of plasticity and genetic adaptation based on realistically short data for wild populations is a difficult task. In a proposed validation method, the available input-output data is split into one part for modeling and one part for validation, and the feasibility of this approach is studied in simulations with use of a prediction error method, which is essentially a maximum likelihood method. It is also argued that validation of a chosen or estimated reference environment in practice is impossible when the data comes from the (unintended) anthropogenic global warming experiment, where no independent experimental data exists. When the evolution is slow because of small genetic variances, overlapping generations and long lifetimes, or because of near optimal adaptive plasticity, the best quantitative genetics option may be to assume a constant plasticity slope value, equal to the initial value. It turns out to be easy to estimate this value, but that should be done without setting other unknown parameter values to zero. This option is appealing also because it removes the dependence of a guessed or estimated reference environment.
format Article
id doaj-art-7a1df12cfcda4dd682df3dbc13adb563
institution DOAJ
issn 0332-7353
1890-1328
language English
publishDate 2025-01-01
publisher Norwegian Society of Automatic Control
record_format Article
series Modeling, Identification and Control
spelling doaj-art-7a1df12cfcda4dd682df3dbc13adb5632025-08-20T02:59:22ZengNorwegian Society of Automatic ControlModeling, Identification and Control0332-73531890-13282025-01-01461133310.4173/mic.2025.1.2Errors-in-variables and validation problems in reaction norm predictions for wild populationsRolf ErgonStudies of phenotypic responses in wild populations are often based on reaction norm models where the environmental drivers in many cases are related to climate change. Such input signals will never be exactly known, and there will always be measurement errors also in the recorded responses. In parameter estimation these errors give rise to errors-in-variables problems, especially in the form of overfitting caused by errors in the input measurements. A second important feature of such phenotypic response problems is that the environmental inputs must be given appropriate but largely unknown reference values. A third problem is that it is difficult to find good validation methods for predicted responses. Essential aspects of these problems are here studied by use of a reaction norm model in its simplest univariate form, characterized by a mean intercept value and a mean plasticity slope value, and the overall conclusion is that validated disentanglement of plasticity and genetic adaptation based on realistically short data for wild populations is a difficult task. In a proposed validation method, the available input-output data is split into one part for modeling and one part for validation, and the feasibility of this approach is studied in simulations with use of a prediction error method, which is essentially a maximum likelihood method. It is also argued that validation of a chosen or estimated reference environment in practice is impossible when the data comes from the (unintended) anthropogenic global warming experiment, where no independent experimental data exists. When the evolution is slow because of small genetic variances, overlapping generations and long lifetimes, or because of near optimal adaptive plasticity, the best quantitative genetics option may be to assume a constant plasticity slope value, equal to the initial value. It turns out to be easy to estimate this value, but that should be done without setting other unknown parameter values to zero. This option is appealing also because it removes the dependence of a guessed or estimated reference environment.http://www.mic-journal.no/PDF/2025/MIC-2025-1-2.pdfenvironmental driverserrors-in-variables problemsprediction error methodreaction norm predictionsreaction norm validationreference environment
spellingShingle Rolf Ergon
Errors-in-variables and validation problems in reaction norm predictions for wild populations
Modeling, Identification and Control
environmental drivers
errors-in-variables problems
prediction error method
reaction norm predictions
reaction norm validation
reference environment
title Errors-in-variables and validation problems in reaction norm predictions for wild populations
title_full Errors-in-variables and validation problems in reaction norm predictions for wild populations
title_fullStr Errors-in-variables and validation problems in reaction norm predictions for wild populations
title_full_unstemmed Errors-in-variables and validation problems in reaction norm predictions for wild populations
title_short Errors-in-variables and validation problems in reaction norm predictions for wild populations
title_sort errors in variables and validation problems in reaction norm predictions for wild populations
topic environmental drivers
errors-in-variables problems
prediction error method
reaction norm predictions
reaction norm validation
reference environment
url http://www.mic-journal.no/PDF/2025/MIC-2025-1-2.pdf
work_keys_str_mv AT rolfergon errorsinvariablesandvalidationproblemsinreactionnormpredictionsforwildpopulations