Novel Regimes of Extreme Climatic Events Trigger Negative Population Rates in a Common Insect
Vives Ingla, Maria (Universitat de Barcelona. Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals)
Capdevila, Pol (Universitat de Barcelona. Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals)
Clements, Christopher (University of Bristol)
Stefanescu, Constantí (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Carnicer Cols, Jofre (Universitat de Barcelona. Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals)

Date:	2025
Abstract:	The IPCC predicts that events at the extreme tail of the probability distribution will increase at a higher rate relative to less severe but still abnormal events. Such outlier events are of particular concern due to nonlinear physiological and demographic responses to climatic exposure, meaning that these events are expected to have disproportionate impacts on populations over the next decades (so called low-likelihood, high-impact events -LLHI). Because such events are historically rare, forecasting how biodiversity will respond requires mechanistic models that integrate the fundamental processes driving biological responses to our changing climate. Here we built a matrix population model (MPM) from long-term monitored populations of an insect model species in a Mediterranean area. The model simultaneously integrates the effects of extreme microclimatic heat exposure and drought-induced host-plant scarcity on early life stages, a key methodological step forward because these understudied life stages are usually very susceptible to climatic events. This model for the first time allowed us to forecast the demographic impacts that LLHI events will have on a well-known insect considering their whole life cycle. We found that juveniles were the life stage with the largest relative contribution to population dynamics. In line with field observations, simulated population rates in current climatic regimes were importantly determined by drought impacts, producing a regional mosaic of non-declining and declining populations. The simulations also indicated that in future, climate scenarios not meeting the Paris Agreement, LLHI heat extremes triggered regionally widespread and severe declines in this currently abundant species. Our results suggest that LLHI events could thus emerge as a critical new -but overlooked- driver of the declines in insect populations, risking the crucial ecosystem functions they perform. We suggest that process-based and whole-cycle modelling approaches are a fundamental tool with which to understand the true impacts of climate change.
Grants:	Ministerio de Ciencia e Innovación FPU17/05869 Agencia Estatal de Investigación TED2021-132007B-I00 Agencia Estatal de Investigación PID2020-117636GB-C21
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Black-swan events ; Extreme climatic events ; Hot drought ; Insect declines ; Matrix population model ; Novel climates ; Pieris napi ; Populationforecast
Published in:	Global change biology, Vol. 31 (April 2025) , art. e70148, ISSN 1365-2486

DOI: 10.1111/gcb.70148

21 p, 9.1 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Articles > Research articles
Articles > Published articles