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by claude@2026-07, 2026-07-16
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The paper studied the 12-year population dynamics of a group-living degu (Octodon degus) in central Chile from 2009–2020, spanning a decade-long megadrought, using capture-mark-recapture models to estimate survival, recruitment, and population growth and relate them to climate and ecosystem variables. Population growth was positive for most of the period, suggesting resistance to long-term drought, but in 2019 an extreme drought year caused gross primary productivity (GPP) to cross a critical threshold, leading to sharp declines in survival and recruitment, an abrupt state shift, rapid collapse, and local extinction. The authors report that variation in GPP was the strongest predictor of both survival and recruitment and argue that the extinction was driven by the proximate extreme 2019 event rather than cumulative drought effects. This paper does not explicitly discuss endometriosis or adenomyosis; it was included in the corpus via a keyword match in the upstream search index.
Abstract
Some species exhibit physiological and behavioral plasticity to survive adverse periods, such as changing climates or reduced food availability. Yet, during extreme climatic events the mechanisms to respond to these adverse periods may not be sufficient, potentially driving local population extinctions. We studied the population dynamics of a common degu (Octodon degus) population in central Chile using a 12-year long dataset (2009-2020) and investigated what environmental factors affected recruitment, survival and population growth. Our study period also coincided with a decade-long megadrought, allowing us to examine how this extreme climatic event contributed to the observed local extinction of this population in 2020. We used Pradel’s capture–mark–recapture (CMR) modeling framework to assess what factors influence population parameters. We analyzed two seasons: the breeding season, which aligns with the austral winter and coincides with the mating, gestation and lactation period, and the nonbreeding season spanning austral spring, summer, and fall, which coincides with offspring care. We found that survival and recruitment varied by year, season, and sex. Female survival was higher during the breeding season than in the nonbreeding season whereas male survival was higher in the nonbreeding season. Recruitment primarily occurred during the breeding season and was higher for males. Population growth was positive from 2009 to 2019. When incorporating environmental covariates, season, and sex, we found that survival was primarily driven by gross primary production, and recruitment by seasonality and gross primary production. We suggest that a year with very low gross primary production, induced by a decade-long megadrought contributed to the local extinction of this population. Our results provide important insight into which populations may be vulnerable to population declines in face of a changing climate, or instead, will be resilient to forecasted climate change.
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Wildlife populations worldwide are increasingly exposed to climatic extremes, yet demographic mechanisms linking environmental variability to local extinction remain poorly understood. We evaluated the population dynamics of a degu (Octodon degus) population in central Chile over a 12-year period (2009-2020) encompassing a decade-long megadrought. Using capture-mark-recapture models, we estimated apparent survival, recruitment, and population growth rates and assessed their relationships with climatic and ecosystem variables. Population growth remained positive throughout most of the study period despite prolonged drought conditions, indicating substantial resistance to long-term environmental stress. However, in 2019, an extreme drought year characterized by markedly reduced precipitation and resource availability, where gross primary productivity (GPP) crossed a critical threshold (tipping point) causing sharp declines in survival and recruitment, resulting in an abrupt state shift, rapid population collapse, and subsequent local extinction. Our analyses indicate that variation in GPP was the strongest predictor of both survival and recruitment, highlighting the importance of resource availability in mediating demographic responses to drought. These results show that the extreme environmental conditions in 2019 acted as the proximate driver of extinction, rather than a cumulative effect of the preceding megadrought. We discuss how species-specific traits, including short lifespan, seasonal reproduction, and social organization, may limit the ability of degus to buffer consecutive demographic failures under extreme conditions, contributing to threshold-like population collapse. Our findings suggest that populations may persist under prolonged adverse conditions yet remain vulnerable to rare but severe environmental events, emphasizing the importance of extreme climatic variability in driving local extinction risk.
https://doi.org/10.32942/X2B649
Ecology and Evolutionary Biology
population crash, mammal, Population Dynamics, human-induced climate change, extreme climatic event, semi-arid environment, drought, local exctinction, drought, mammal, population dynamics, human-induced climate change, extreme climatic event, semi-arid environment
Published: 2025-03-13 15:10
Last Updated: 2026-04-06 02:10
CC-BY Attribution-NonCommercial 4.0 International
Conflict of interest statement:
none
Data and Code Availability Statement:
All data have been deposited at the GitHub repository annemarievdmarel/degu-pop-crash (van der Marel 2025). The used MODIS data are available at https://lpdaacsvc.cr.usgs.gov/appeears (accessed 17 December 2023).
Language:
English
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