Periodic Reporting for period 4 - FRAGCLIM (The Combined Effects of Climatic Warming and Habitat Fragmentation on Biodiversity, Community Dynamics and Ecosystem Functioning)
Berichtszeitraum: 2021-12-01 bis 2023-05-31
Climate change and habitat fragmentation are two of the largest threats to ecosystems globally. These stressors hallenge the provision of ecosystem services to society. The overarching goal of FRAGCLIM is to determine the individual and combined effects of climatic warming and habitat fragmentation on biodiversity, community dynamics, and ecosystem functioning in complex multitrophic communities.
In FRAGCLIM we have shown important ecological and evolutionary responses of species, communities and ecosystems to climate change, habitat fragmentation, and their combination using an integrative approach that combined development of new theory and experimental manipulations. A number of general and more specific conclusions and new open questions emerge from our research:
(i) Our new theory helps forecasting the effects of warming and fragmentation on multispecies communities and ecosystem functioning. While predictable, such responses are context-dependent.
(ii) A new mechanistic approach based on the balances of energy gain and loss of interacting species increases predictive power and generality of the effects of climate warming.
(iii) Warming and fragmentation alter selective pressures on interacting species. Species’ responses solely based on ecological dynamics are insufficient and contrast with responses that account for evolution. Resource species respond in unexpected directions and we observe unanticipated population declines in top consumers.
(iv) Loosing biodiversity is more important for ecosystem functioning in more fluctuating environments, as those associated with climate change, than in constant environments.
(v) Trophic interactions are more vulnerable to habitat loss and fragmentation than species richness.
(vi) Fragmentation has larger effects than warming on plankton biodiversity across spatial scales. Warming and fragmentation interact, such that when dispersal between communities is high, warming effects on biodiversity can be reinforced through the homogenization of communities by a few dominant thermally tolerant taxa.
In FRAGCLIM we have shown important ecological and evolutionary responses of species, communities and ecosystems to climate change, habitat fragmentation, and their combination using an integrative approach that combined development of new theory and experimental manipulations. A number of general and more specific conclusions and new open questions emerge from our research:
(i) Our new theory helps forecasting the effects of warming and fragmentation on multispecies communities and ecosystem functioning. While predictable, such responses are context-dependent.
(ii) A new mechanistic approach based on the balances of energy gain and loss of interacting species increases predictive power and generality of the effects of climate warming.
(iii) Warming and fragmentation alter selective pressures on interacting species. Species’ responses solely based on ecological dynamics are insufficient and contrast with responses that account for evolution. Resource species respond in unexpected directions and we observe unanticipated population declines in top consumers.
(iv) Loosing biodiversity is more important for ecosystem functioning in more fluctuating environments, as those associated with climate change, than in constant environments.
(v) Trophic interactions are more vulnerable to habitat loss and fragmentation than species richness.
(vi) Fragmentation has larger effects than warming on plankton biodiversity across spatial scales. Warming and fragmentation interact, such that when dispersal between communities is high, warming effects on biodiversity can be reinforced through the homogenization of communities by a few dominant thermally tolerant taxa.
We have developed a new mechanistic and predictive theory on the effects of habitat change and warming on the dynamics of ecological communities. Firstly, we have developed a theory of temperature-dependent community dynamics. This new theory allows for: (i) getting simple and more accurate predictions of the effects of warming on community structure and stability, (ii) identifying which biological parameters are most sensitive to warming, and (iii) synthesizing previous contradictory experimental results. Secondly, we developed new theory that predicts how habitat fragmentation affects species interaction networks. We developed a new food web model that reveals that stability, increases if habitat loss occurs at random, but stability largely decreases if habitat fragmentation occurs in addition to loss. Thirdly, we developed a new conceptual framework to understand and predict the eco-evolutionary consequences of habitat warming, fragmentation, and their interaction.
Empirically, we have firstly developed a mechanistic approach that links the unconnected fields of thermal ecology, food webs, and eco-evolutionary dynamics. We demonstrated that we can predict the effects of consumers on resources from their combined energetic balances, depending on how they gain and loss energy as temperature changes. We also showed how evolution in response to long-term warming also influences the outcomes of current ecological consumer-resource dynamics at different temperatures.Secondly we have demonstrated that warming can alter the importance of biodiversity for ecosystem functioning. Using phytoplankton communities, we showed that biodiversity loss has a larger impact on ecosystem functioning in warmed ecosystems, and more so in systems where temperature fluctuations are large. Thirdly, we have tested theory on the effects of habitat loss and fragmentation with empirical data. The increase in the number of interactions in which each species is involved when area increases indicates that trophic interactions might be more vulnerable to habitat loss than species richness.
And finally, we showed how warming and habitat fragmentation can interact with each other altering biodiversity. We showed that the effects of warming on biodiversity are scale dependent, and that connectivity seems to have a minor effect on these patterns. However, our mesocosm experiment is challenging this observation, showing that habitat fragmentation has larger effects than warming on phytoplankton biodiversity and stability.
Even if the research conducted in FRAGCLIM is fundamental, we have tried to find applications through collaborations with applied and conservation ecologists and managers. One important example is our research on how water diversion for hydropower affected freshwater food webs, providing recommendations for managers.
Our production and dissemination activities are considerable, presenting our work at scientific conferences, producing several press releases and given interviews for the general public (25 in total), as well as publishing our work in diverse scientific journals (35 in total), including papers in top disciplinary and inter-disciplinary journals as Nature Eco Evo (4), Nature Comms. (2), PNAS, Global Change Biology (3) or Ecology Letters (3).
Empirically, we have firstly developed a mechanistic approach that links the unconnected fields of thermal ecology, food webs, and eco-evolutionary dynamics. We demonstrated that we can predict the effects of consumers on resources from their combined energetic balances, depending on how they gain and loss energy as temperature changes. We also showed how evolution in response to long-term warming also influences the outcomes of current ecological consumer-resource dynamics at different temperatures.Secondly we have demonstrated that warming can alter the importance of biodiversity for ecosystem functioning. Using phytoplankton communities, we showed that biodiversity loss has a larger impact on ecosystem functioning in warmed ecosystems, and more so in systems where temperature fluctuations are large. Thirdly, we have tested theory on the effects of habitat loss and fragmentation with empirical data. The increase in the number of interactions in which each species is involved when area increases indicates that trophic interactions might be more vulnerable to habitat loss than species richness.
And finally, we showed how warming and habitat fragmentation can interact with each other altering biodiversity. We showed that the effects of warming on biodiversity are scale dependent, and that connectivity seems to have a minor effect on these patterns. However, our mesocosm experiment is challenging this observation, showing that habitat fragmentation has larger effects than warming on phytoplankton biodiversity and stability.
Even if the research conducted in FRAGCLIM is fundamental, we have tried to find applications through collaborations with applied and conservation ecologists and managers. One important example is our research on how water diversion for hydropower affected freshwater food webs, providing recommendations for managers.
Our production and dissemination activities are considerable, presenting our work at scientific conferences, producing several press releases and given interviews for the general public (25 in total), as well as publishing our work in diverse scientific journals (35 in total), including papers in top disciplinary and inter-disciplinary journals as Nature Eco Evo (4), Nature Comms. (2), PNAS, Global Change Biology (3) or Ecology Letters (3).
Our research provides results beyond the state of the art on the effects of global change on complex communities:
1. We built a new theory that advances the field of the consequences on climatic warming on communities beyond the state of the art in three specific directions: (i) It provides general and more accurate predictions of the effects of warming on interacting species; (ii) It allows for detecting, attributing, and predicting which biological parameters are the most important to predict climate change effects on ecosystems; (iii) It provides a framework to synthesize contradictory experimental results.
2. We provide breakthroughs in how climate change alters the importance of biodiversity for ecosystem functioning. As climate change will increase temperature fluctuations, we demonstrated that in more fluctuating environments, biodiversity is more important for ecosystem functioning than in constant environments.
3. We developed a new conceptual framework on the combined effects of climate change and habitat fragmentation on ecosystems. We demonstrated how warming and fragmentation can individually alter selective pressures of populations, interacting species, and more complex communities.
4. Our work is a breakthrough on what are the effects of habitat loss and fragmentation on species interaction networks. We found that the complexity of networks generally increases with area. The increase in the number of interactions in which each species is involved when area increases indicates that trophic interactions might be more vulnerable to habitat loss than species richness.
5. Our mesocosms experiment is moving the state of the art on the field, showing that habitat fragmentation has larger effects than warming on phytoplankton biodiversity across spatial scales, challenging prevailing wisdom. Our results show that warming and fragmentation interact, such that when dispersal between communities is high, warming effects on biodiversity can be reinforced through the homogenization of communities by a few dominant thermally tolerant taxa.
1. We built a new theory that advances the field of the consequences on climatic warming on communities beyond the state of the art in three specific directions: (i) It provides general and more accurate predictions of the effects of warming on interacting species; (ii) It allows for detecting, attributing, and predicting which biological parameters are the most important to predict climate change effects on ecosystems; (iii) It provides a framework to synthesize contradictory experimental results.
2. We provide breakthroughs in how climate change alters the importance of biodiversity for ecosystem functioning. As climate change will increase temperature fluctuations, we demonstrated that in more fluctuating environments, biodiversity is more important for ecosystem functioning than in constant environments.
3. We developed a new conceptual framework on the combined effects of climate change and habitat fragmentation on ecosystems. We demonstrated how warming and fragmentation can individually alter selective pressures of populations, interacting species, and more complex communities.
4. Our work is a breakthrough on what are the effects of habitat loss and fragmentation on species interaction networks. We found that the complexity of networks generally increases with area. The increase in the number of interactions in which each species is involved when area increases indicates that trophic interactions might be more vulnerable to habitat loss than species richness.
5. Our mesocosms experiment is moving the state of the art on the field, showing that habitat fragmentation has larger effects than warming on phytoplankton biodiversity across spatial scales, challenging prevailing wisdom. Our results show that warming and fragmentation interact, such that when dispersal between communities is high, warming effects on biodiversity can be reinforced through the homogenization of communities by a few dominant thermally tolerant taxa.