Conservation physiology offers powerful approaches to develop mechanistic explanations of shifts in species’ biogeography putatively attributed to Global Warming. Nevertheless, a comparative framework that integrates the multiple physiological traits underlying species’ thermal biology is to date still lacking. Here I demonstrate the fundamental importance of integrating metabolic performance, thermal tolerance and plasticity to provide more accurate predictions on species’ relative vulnerability to Global Warming. Six Caridean species occurring in a common garden were selected as model and acclimated to four temperature treatments: 10, 15, 20 and 25 °C. The effect temperature on their metabolic rates and thermal tolerance limits was tested, and plasticity for these physiological abilities was calculated according to a Reaction Norm approach. Metabolic rate increased exponentially with increasing temperature in all the species examined (except in Pandalus montagui). Nevertheless, species living in thermally unstable environments (Palaemon elegans and Palaemonetes varians) showed higher temperature dependence of metabolism than their subtidal counterparts (Crangon crangon and Palaemon serratus), thereby appearing to be at greater risk from sub-lethal effects of Global Warming. By contrast, the hypothesis of an evolutionary/functional trade-off between thermal tolerance and its plasticity suggests that both the most heat-tolerant species (P. elegans, P. varians and C. crangon) and the most plastic species (P. serratus) are likely to be in danger from acute lethal effects of Global Warming. Both P. montagui and Palaemon macrodactylus are exceptions, appearing to be the most and the least vulnerable species to Global Warming respectively.
La fisiologia della conservazione offre un approccio esaustivo per spiegare, in maniera meccanicistica, i cambiamenti nella biogeografia delle specie attribuiti al riscaldamento globale. Tuttavia, ad oggi manca un approccio comparativo che integri molteplici tratti fisiologici tipicamente associati al metabolismo termico delle specie. Questa tesi dimostra la fondamentale importanza di integrare performance metabolica, tolleranza termica e plasticità al fine di predire, in maniera accurata, la vulnerabilità relativa delle specie al riscaldamento globale. Sono stati selezionati come modello sei specie di crostacei decapodi dell’infraordine Caridea, presenti all’interno della stessa area geografica, e acclimatati a quattro temperature: 10, 15, 20 e 25 °C. È stato testato l’effetto della temperatura sui tassi metabolici e limiti di tolleranza termica, e la plasticità di questi tratti fisiologici è stata calcolata con l’approccio delle Reaction Norms. Il tasso metabolico aumenta esponenzialmente con la temperatura in tutte le specie esaminate (ad eccezione di Pandalus montagui). Tuttavia, le specie che vivono in ambienti termicamente instabili (Palaemon elegans e Palaemonetes varians) mostrano maggiore dipendenza del metabolismo dalla temperatura rispetto alle loro controparti subtidali (Crangon crangon e Palaemon serratus), e sono quindi potenzialmente più sensibili agli effetti sub-letali del riscaldamento globale. Al contrario, l’ipotesi di un trade-off evolutivo e/o funzionale tra tolleranza termica e plasticità suggerisce che sia le specie più tolleranti al calore (P. elegans, P. varians e C. crangon), sia quelle più plastiche (P. serratus), sono a rischio per via degli effetti acuti del surriscaldamento. P. montagui e Palaemon macrodactylus sono entrambi eccezioni, e sembrano essere rispettivamente la specie più e quella meno sensibile al riscaldamento globale.
Fisiologia della conservazione: verso un approccio integrativo-comparativo per predire la vulnerabilità relativa delle specie al riscaldamento globale
MAGOZZI, SARAH
2021/2022
Abstract
Conservation physiology offers powerful approaches to develop mechanistic explanations of shifts in species’ biogeography putatively attributed to Global Warming. Nevertheless, a comparative framework that integrates the multiple physiological traits underlying species’ thermal biology is to date still lacking. Here I demonstrate the fundamental importance of integrating metabolic performance, thermal tolerance and plasticity to provide more accurate predictions on species’ relative vulnerability to Global Warming. Six Caridean species occurring in a common garden were selected as model and acclimated to four temperature treatments: 10, 15, 20 and 25 °C. The effect temperature on their metabolic rates and thermal tolerance limits was tested, and plasticity for these physiological abilities was calculated according to a Reaction Norm approach. Metabolic rate increased exponentially with increasing temperature in all the species examined (except in Pandalus montagui). Nevertheless, species living in thermally unstable environments (Palaemon elegans and Palaemonetes varians) showed higher temperature dependence of metabolism than their subtidal counterparts (Crangon crangon and Palaemon serratus), thereby appearing to be at greater risk from sub-lethal effects of Global Warming. By contrast, the hypothesis of an evolutionary/functional trade-off between thermal tolerance and its plasticity suggests that both the most heat-tolerant species (P. elegans, P. varians and C. crangon) and the most plastic species (P. serratus) are likely to be in danger from acute lethal effects of Global Warming. Both P. montagui and Palaemon macrodactylus are exceptions, appearing to be the most and the least vulnerable species to Global Warming respectively.File | Dimensione | Formato | |
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Descrizione: Tesi "Fisiologia della conservazione: verso un approccio integrativo-comparativo per predire la vulnerabilità relativa delle specie al riscaldamento globale" di Sarah Magozzi, LM Biologia Marina, AA 2021/2022, Sessione Estiva
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https://hdl.handle.net/20.500.12075/9935