Periodic Reporting for period 2 - EVOLMARIN (Rapid evolution and geographic ranges: predicting marine species persistence and distribution in a changing ocean)
Periodo di rendicontazione: 2017-09-01 al 2018-08-31
The global change is expected to cause stressful environmental conditions for many species, and there is concern that many of them will not be able to keep pace with the direct and indirect impacts of these changes. Species-specific responses to multiple climate drivers are causing modifications in the timing, direction, and magnitude of movements and life events among biota and regions and may have adverse impacts on the distribution and viability of biological communities, species and populations. Ultimately, the reshuffling of communities and declines of populations have the potential to impact ecosystem structure, function, and productivity, threatening the many goods and services that humans depend on. Biodiversity and ecosystem services are intrinsically linked, and biodiversity is often considered an ecosystem service in itself.
Establishing general patterns of biodiversity response under rapid environmental changes, and identifying generalities on an important paradigm such as the dichotomy between rare and common species, are central issues in ecology and conservation biology. The wider geographic distribution of common species is linked to their capacity to survive in a greater array of environmental conditions, guaranteeing their persistence in a wider range of environments. Conversely, the infrequent occurrence of rare species can be often explained by their narrower tolerance windows and lower level of phenotypic plasticity. Consequently, rare species are expected to be more sensitive to even small shifts from their optimal range of environmental conditions, and thus more at the risk of decline or local and global extinction under future global changes. Given the increasing evidence of rare species’ importance in supporting unique ecosystem functions, their higher sensitivity represent a threat for the integrity of ecosystems, and the services they provide.
The acquisition of a mechanistic understanding of common and rare species' responses to multiple global change drivers may serve as a tool to improve predictions on species’ distributional shifts or loss under future global change scenarios. The rapid rates of increase of seawater temperatures and decrease in pH, known as ocean warming and ocean acidification, respectively, can lead to the impairment of the physiological performance of organisms, with detrimental effects on individual fecundity, growth and survival. In order to not overestimate or underestimate the impacts of the global changes, we need to investigate all the mechanisms and processes that may prevent species loss, such as trans-generational plasticity (the capacity of one generation to influence the way the next generations interact with their environment), and rapid adaptation.
The EvolMarin project – ‘Rapid evolution and geographic ranges: predicting marine species persistence and distribution in a changing ocean’ – aimed at investigating the relationship between species tolerance, plasticity and patterns of geographic distribution, seeking to more reliably predict species persistence in a changing ocean. This was achieved by comparing the capacities for trans-generational plasticity and rapid adaptation in common and rare marine benthic species from coastal habitats, assessing their level of vulnerability to ocean warming and acidification scenarios, in isolation and combined, after a multigenerational exposure.
The EvolMarin project provides among the few empirical evidence on the higher vulnerability of rare species under scenarios of ocean warming, offering a mechanistic understanding of the patterns underlying commonness and rarity in marine ectotherms from coastal habitats. Given the increasing evidence of rare species’ importance in supporting unique ecosystem functions, their higher sensitivity to ocean warming represent a threat for the integrity of ecosystems, and the services they provide.
Establishing general patterns of biodiversity response under rapid environmental changes, and identifying generalities on an important paradigm such as the dichotomy between rare and common species, are central issues in ecology and conservation biology. The wider geographic distribution of common species is linked to their capacity to survive in a greater array of environmental conditions, guaranteeing their persistence in a wider range of environments. Conversely, the infrequent occurrence of rare species can be often explained by their narrower tolerance windows and lower level of phenotypic plasticity. Consequently, rare species are expected to be more sensitive to even small shifts from their optimal range of environmental conditions, and thus more at the risk of decline or local and global extinction under future global changes. Given the increasing evidence of rare species’ importance in supporting unique ecosystem functions, their higher sensitivity represent a threat for the integrity of ecosystems, and the services they provide.
The acquisition of a mechanistic understanding of common and rare species' responses to multiple global change drivers may serve as a tool to improve predictions on species’ distributional shifts or loss under future global change scenarios. The rapid rates of increase of seawater temperatures and decrease in pH, known as ocean warming and ocean acidification, respectively, can lead to the impairment of the physiological performance of organisms, with detrimental effects on individual fecundity, growth and survival. In order to not overestimate or underestimate the impacts of the global changes, we need to investigate all the mechanisms and processes that may prevent species loss, such as trans-generational plasticity (the capacity of one generation to influence the way the next generations interact with their environment), and rapid adaptation.
The EvolMarin project – ‘Rapid evolution and geographic ranges: predicting marine species persistence and distribution in a changing ocean’ – aimed at investigating the relationship between species tolerance, plasticity and patterns of geographic distribution, seeking to more reliably predict species persistence in a changing ocean. This was achieved by comparing the capacities for trans-generational plasticity and rapid adaptation in common and rare marine benthic species from coastal habitats, assessing their level of vulnerability to ocean warming and acidification scenarios, in isolation and combined, after a multigenerational exposure.
The EvolMarin project provides among the few empirical evidence on the higher vulnerability of rare species under scenarios of ocean warming, offering a mechanistic understanding of the patterns underlying commonness and rarity in marine ectotherms from coastal habitats. Given the increasing evidence of rare species’ importance in supporting unique ecosystem functions, their higher sensitivity to ocean warming represent a threat for the integrity of ecosystems, and the services they provide.
The experimental work planned to accomplish the EvolMarin’s objectives was carried out during the out-going phase at the Département de Biologie, Chimie et Géographie of the Université du Québec à Rimouski (Canada) under the supervision of Prof Piero Calosi, while the statistical analyses of the data and interpretation of the results was performed during the return phase at the Centre d’Ecologie Fonctionnelle et Evolutive (Montpellier, France), under the supervision of Luis-Miguel Chevin. Experiments consisted in exposing for multiple generations (3-6) common and rare benthic species within the genus Ophryotrocha (Annelida) to laboratory conditions mimicking ocean warming and ocean acidification scenarios, in isolation and combined. To assess whether any change observed along generations was plastic or adaptive, reciprocal transplant experiments were performed at the end of the multigenerational exposure. At each generation, species physiological responses (respiration rates and upper thermal tolerance limits) and life history traits (survival, reproductive and growth performance) were measured.
The EvolMarin project showed that rare species are physiologically more vulnerable to ocean warming mainly due to reduced upper thermal tolerance. Rare species were unable to thrive to the next generation when temperatures raised to values mimicking ocean warming, suggesting that transgenerational plasticity or rapid adaptation may not represent rescue mechanisms for this group. Conversely, common species persisted for multiple generations under all scenarios, showing signs of rapid adaptation of their physiological thermal tolerance. Ocean warming was the main driver of species’ responses, while ocean acidification was not a threat to their persistence. Moreover, rare species shows to live closer to or at the thermal optimum for reproduction. Consequently, even relatively small increases in temperature could result in a drop of their performance, posing them at higher risk of local and regional decline, especially in the southern range of their distribution. The results obtained through the EvolMarin project will be disseminated through the publication of scientific papers, and have already been, and will be, presented at international conferences and seminars.
The EvolMarin project showed that rare species are physiologically more vulnerable to ocean warming mainly due to reduced upper thermal tolerance. Rare species were unable to thrive to the next generation when temperatures raised to values mimicking ocean warming, suggesting that transgenerational plasticity or rapid adaptation may not represent rescue mechanisms for this group. Conversely, common species persisted for multiple generations under all scenarios, showing signs of rapid adaptation of their physiological thermal tolerance. Ocean warming was the main driver of species’ responses, while ocean acidification was not a threat to their persistence. Moreover, rare species shows to live closer to or at the thermal optimum for reproduction. Consequently, even relatively small increases in temperature could result in a drop of their performance, posing them at higher risk of local and regional decline, especially in the southern range of their distribution. The results obtained through the EvolMarin project will be disseminated through the publication of scientific papers, and have already been, and will be, presented at international conferences and seminars.
Many studies have investigated single species’ responses to major global change drivers, while a few compared the sensitivity of biogeographical and functional groups, i.e. common versus rare species. Being impossible to test every single species, it is fundamental to provide evidence from case studies for patterns of response to climate change that guides biodiversity conservation decisions.
Rare species’ higher risk of decline and extinction, especially in the southern part of their distribution, is a threat to current patterns of biodiversity and to the ecosystem services they provide. Northwards migration would allow all species to track the thermal conditions more suitable for their persistence, but limited dispersal capacity or barriers to migrations may limit the search for new thermal refugia. Providing empirical evidence on the fate of marine species under a global change scenarios is of fundamental importance to make effective decisions for biodiversity conservation. The patterns shown by the EvolMarin project not only identify priority targets for decisions on biodiversity conservation, but also help predict which regions will be much more negatively impacted by ocean changes in terms of loss of biodiversity and ecosystem services.
Rare species’ higher risk of decline and extinction, especially in the southern part of their distribution, is a threat to current patterns of biodiversity and to the ecosystem services they provide. Northwards migration would allow all species to track the thermal conditions more suitable for their persistence, but limited dispersal capacity or barriers to migrations may limit the search for new thermal refugia. Providing empirical evidence on the fate of marine species under a global change scenarios is of fundamental importance to make effective decisions for biodiversity conservation. The patterns shown by the EvolMarin project not only identify priority targets for decisions on biodiversity conservation, but also help predict which regions will be much more negatively impacted by ocean changes in terms of loss of biodiversity and ecosystem services.