Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.

Anthropogenic environmental change is causing unprecedented rates of population extirpation and altering the setting of range limits for many species. Significant population declines may occur however before any reduction in range is observed. Determining and modelling the factors driving population...

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Main Authors: Daniel Ayllón, Graciela G Nicola, Benigno Elvira, Irene Parra, Ana Almodóvar
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3840006?pdf=render
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author Daniel Ayllón
Graciela G Nicola
Benigno Elvira
Irene Parra
Ana Almodóvar
author_facet Daniel Ayllón
Graciela G Nicola
Benigno Elvira
Irene Parra
Ana Almodóvar
author_sort Daniel Ayllón
collection DOAJ
description Anthropogenic environmental change is causing unprecedented rates of population extirpation and altering the setting of range limits for many species. Significant population declines may occur however before any reduction in range is observed. Determining and modelling the factors driving population size and trends is consequently critical to predict trajectories of change and future extinction risk. We tracked during 12 years 51 populations of a cold-water fish species (brown trout Salmo trutta) living along a temperature gradient at the warmest thermal edge of its range. We developed a carrying capacity model in which maximum population size is limited by physical habitat conditions and regulated through territoriality. We first tested whether population numbers were driven by carrying capacity dynamics and then targeted on establishing (1) the temperature thresholds beyond which population numbers switch from being physical habitat- to temperature-limited; and (2) the rate at which carrying capacity declines with temperature within limiting thermal ranges. Carrying capacity along with emergent density-dependent responses explained up to 76% of spatio-temporal density variability of juveniles and adults but only 50% of young-of-the-year's. By contrast, young-of-the-year trout were highly sensitive to thermal conditions, their performance declining with temperature at a higher rate than older life stages, and disruptions being triggered at lower temperature thresholds. Results suggest that limiting temperature effects were progressively stronger with increasing anthropogenic disturbance. There was however a critical threshold, matching the incipient thermal limit for survival, beyond which realized density was always below potential numbers irrespective of disturbance intensity. We additionally found a lower threshold, matching the thermal limit for feeding, beyond which even unaltered populations declined. We predict that most of our study populations may become extinct by 2100, depicting the gloomy fate of thermally-sensitive species occurring at thermal range margins under limited potential for adaptation and dispersal.
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spelling doaj.art-0a783383de7348178bbfd40dca0365192022-12-21T22:04:43ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-01811e8135410.1371/journal.pone.0081354Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.Daniel AyllónGraciela G NicolaBenigno ElviraIrene ParraAna AlmodóvarAnthropogenic environmental change is causing unprecedented rates of population extirpation and altering the setting of range limits for many species. Significant population declines may occur however before any reduction in range is observed. Determining and modelling the factors driving population size and trends is consequently critical to predict trajectories of change and future extinction risk. We tracked during 12 years 51 populations of a cold-water fish species (brown trout Salmo trutta) living along a temperature gradient at the warmest thermal edge of its range. We developed a carrying capacity model in which maximum population size is limited by physical habitat conditions and regulated through territoriality. We first tested whether population numbers were driven by carrying capacity dynamics and then targeted on establishing (1) the temperature thresholds beyond which population numbers switch from being physical habitat- to temperature-limited; and (2) the rate at which carrying capacity declines with temperature within limiting thermal ranges. Carrying capacity along with emergent density-dependent responses explained up to 76% of spatio-temporal density variability of juveniles and adults but only 50% of young-of-the-year's. By contrast, young-of-the-year trout were highly sensitive to thermal conditions, their performance declining with temperature at a higher rate than older life stages, and disruptions being triggered at lower temperature thresholds. Results suggest that limiting temperature effects were progressively stronger with increasing anthropogenic disturbance. There was however a critical threshold, matching the incipient thermal limit for survival, beyond which realized density was always below potential numbers irrespective of disturbance intensity. We additionally found a lower threshold, matching the thermal limit for feeding, beyond which even unaltered populations declined. We predict that most of our study populations may become extinct by 2100, depicting the gloomy fate of thermally-sensitive species occurring at thermal range margins under limited potential for adaptation and dispersal.http://europepmc.org/articles/PMC3840006?pdf=render
spellingShingle Daniel Ayllón
Graciela G Nicola
Benigno Elvira
Irene Parra
Ana Almodóvar
Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.
PLoS ONE
title Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.
title_full Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.
title_fullStr Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.
title_full_unstemmed Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.
title_short Thermal carrying capacity for a thermally-sensitive species at the warmest edge of its range.
title_sort thermal carrying capacity for a thermally sensitive species at the warmest edge of its range
url http://europepmc.org/articles/PMC3840006?pdf=render
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