Periodic Reporting for period 4 - ECOFEED (Altered eco-evolutionary feedbacks in a future climate)
Reporting period: 2023-10-01 to 2025-03-31
Given climate change is a major threat to biodiversity and ecosystem functioning, accurately predicting its consequences is a pressing challenge. While current scenarios predict an accelerated erosion of biodiversity with climate change, the reliability of these predictions remain limited. This uncertainty stems from our incomplete understanding of the numerous and interconnected ways climate change can impact life at all biological levels, from genes to ecosystems. Climate change can modify species phenotype and performance through phenotypic plasticity and evolution. The microevolution of keystone species can propagate across ecological networks due to changes in species interactions, while direct impacts of climate on communities and ecosystems can have ripple effects on the phenotypic distribution and evolution of all species of ecological networks.
Hence, climate-driven changes at individual and population levels can shape community composition and ecosystem functioning, and vice versa, establishing eco-evolutionary feedbacks. However, our understanding of how these feedbacks mediate climate change impacts on biological systems remains limited by the scarcity of empirical evidence, as ecological and evolutionary responses to climate change are often investigated separately. The role of eco-evolutionary feedbacks in climate change impacts on biological systems therefore hinges on little concrete empirical evidence contrasting with a profuse despite considerable theoretical developments.
ECOFEED investigates climate-dependent eco-evolutionary feedbacks using a realistic warming experiment reproducing natural conditions and thus allowing for both evolutionary and ecological dynamics to occur under a predicted climate change scenario. The first two objectives were to quantify the impacts of warmer climates on the evolution of top predator’s phenotype (Common lizards, Zootoca vivipara, WP1) and on community structure and ecosystem functioning (WP2). The second set of objectives were to test for the reciprocal effects of evolutionary and ecological dynamics with additional experimental studies (WP3-4) and isolate the direct impacts of climate-induced changes of top predator phenotype on community and ecosystem functioning, and in turn the direct effects of climate-induced changes of community and ecosystem on this top predator. Finally the reciprocity of effects between ecological and evolutionary dynamics outlines the extent of eco-evolutionary feedbacks (WP5).
Hence, climate-driven changes at individual and population levels can shape community composition and ecosystem functioning, and vice versa, establishing eco-evolutionary feedbacks. However, our understanding of how these feedbacks mediate climate change impacts on biological systems remains limited by the scarcity of empirical evidence, as ecological and evolutionary responses to climate change are often investigated separately. The role of eco-evolutionary feedbacks in climate change impacts on biological systems therefore hinges on little concrete empirical evidence contrasting with a profuse despite considerable theoretical developments.
ECOFEED investigates climate-dependent eco-evolutionary feedbacks using a realistic warming experiment reproducing natural conditions and thus allowing for both evolutionary and ecological dynamics to occur under a predicted climate change scenario. The first two objectives were to quantify the impacts of warmer climates on the evolution of top predator’s phenotype (Common lizards, Zootoca vivipara, WP1) and on community structure and ecosystem functioning (WP2). The second set of objectives were to test for the reciprocal effects of evolutionary and ecological dynamics with additional experimental studies (WP3-4) and isolate the direct impacts of climate-induced changes of top predator phenotype on community and ecosystem functioning, and in turn the direct effects of climate-induced changes of community and ecosystem on this top predator. Finally the reciprocity of effects between ecological and evolutionary dynamics outlines the extent of eco-evolutionary feedbacks (WP5).
The project is taking advantage of a long-term warming experiment started in 2015 completed with the databases from short-term warming experiments ran between 2012 and 2014. From 2015 to 2022, we ran a long-term warming experiment, quantifying the population dynamics and the phenotypic changes of common lizards, our top predator, and the evolutionary processes involved in these changes (i.e. selection and plasticity, WP1). To do so, we monitored the survival, growth rate, reproduction and phenotypic traits of adult lizards and newborns inhabiting the mesocosms undergoing present-day and warm climates. The phenotypic traits chosen belong to the management of thermal conditions (e.g. melanism and thermal preferences) and to their interactions with other species (e.g. diet, microbiome). We examined the climate-induced temporal changes, heritability and strengths of selective and plastic responses of these traits. Our results support our “live fast, die young” scenario with a faster growth rate in juveniles, an earlier reproductive onset and a faster ageing. This faster pace-of-life led to population structure towards younger and bigger individuals matching predictions made in natural populations and was coupled with a paler color and a lower thermal preference, plasric changes preventing overheating. Lizards also increased their activity in early life, likely to sustain the increased energetic needs of a faster growth, and had a more specialized diet towards predator invertebrates. These changes were further related to changes in gut microbial communities, with a loss of diversity in warmer climates increasing over time and may have knock-on effects on invertebrates’ communities (WP2).
We indeed quantified climate-induced changes across the ecological network including or not the top predator. Our results revealed that the presence of top predators reversed the effect of warming on ecological networks. In their presence, we observed a decrease of invertebrate predators – on which they preferentially feed on – together with an increase of invertebrates herbivores and a decrease of plants and soil microbes diversity. An opposite trend was found when lizards were absent.
The last project’s objective was to study reciprocal effects on the top predator and on the ecological networks. On one hand in warmer climates lizards consumed more invertebrate predators than herbivores leading to their lower proportions in the invertebrate communities and to a reduced pressure on invertebrate herbivores cascading down to plants and related soil communities. This suggests top-down cascading effects through a diet shift in top predators caused by warming. On the other hand, climate-induced changes in invertebrate communities, a lower abundance of predator invertebrate, strengthened diet shit in the top predators which should reinforced the changes of ecological networks and may endanger invertebrate community. Overall, the project demonstrates that the evolutionary and ecological impacts of climate change, acting directly or indirectly through trophic cascades at multiple biological levels. These evidences underscore the critical need to better account for incorporate eco-evo dynamics into our climate change impact predictions.
We indeed quantified climate-induced changes across the ecological network including or not the top predator. Our results revealed that the presence of top predators reversed the effect of warming on ecological networks. In their presence, we observed a decrease of invertebrate predators – on which they preferentially feed on – together with an increase of invertebrates herbivores and a decrease of plants and soil microbes diversity. An opposite trend was found when lizards were absent.
The last project’s objective was to study reciprocal effects on the top predator and on the ecological networks. On one hand in warmer climates lizards consumed more invertebrate predators than herbivores leading to their lower proportions in the invertebrate communities and to a reduced pressure on invertebrate herbivores cascading down to plants and related soil communities. This suggests top-down cascading effects through a diet shift in top predators caused by warming. On the other hand, climate-induced changes in invertebrate communities, a lower abundance of predator invertebrate, strengthened diet shit in the top predators which should reinforced the changes of ecological networks and may endanger invertebrate community. Overall, the project demonstrates that the evolutionary and ecological impacts of climate change, acting directly or indirectly through trophic cascades at multiple biological levels. These evidences underscore the critical need to better account for incorporate eco-evo dynamics into our climate change impact predictions.
A main objective was to predict whether species will be able to adapt to climate change fast enough. While several studies achieved this objective, evidences are still sporadic, often on the short term or missing a suitable longitudinal monitoring to understand the path of adaptation. The coupling of experimental approach is ecologically realistic setup and field monitoring allows to predict the adaptive potential of a species in its environment and to provide path of actions by an intensive study of life history and phenotypic traits. The match between results in our experimental and natural populations, here and in past results, validate the mixed approach and suggest that the consequences of lizard responses to ecological networks and the association of eco-to-evo and evo-to-eco effects, observed in our warming experiments, could also occur in natural environments. The presence of a top predator appears to be central in the impacts of warmer climates on ecological networks and reversely the ecological networks alter the response of a top predator to warming. Unsurprisingly, all elements of a network are intertwined and the changes at a given biological level can cascade down or up to other levels. However, a large majority of studies are still focusing on the adaptation of a species or a few species without considering their ecological networks which may lead biased estimates of climate impacts.