Positive species interactions strengthen in a high-CO2 ocean
Negative interactions among species are a major force shaping natural communities and are predicted to strengthen as climate change intensifies. Similarly, positive interactions are anticipated to intensify, and could buffer the consequences of climate-driven disturbances. We used in situ experiment...
| Main Authors: | , , , |
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| Format: | Dataset |
| Language: | unknown |
| Published: |
2021
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| Subjects: | |
| Online Access: | https://zenodo.org/record/4997919 https://doi.org/10.5061/dryad.vdncjsxtk |
| Summary: | Negative interactions among species are a major force shaping natural communities and are predicted to strengthen as climate change intensifies. Similarly, positive interactions are anticipated to intensify, and could buffer the consequences of climate-driven disturbances. We used in situ experiments at volcanic CO2 vents within a temperate rocky reef to show that ocean acidification can drive community reorganization through indirect and direct positive pathways. A keystone species, the algal-farming damselfish Parma alboscapularis, enhanced primary productivity through its weeding of algae whose productivity was also boosted by elevated CO2. The accelerated primary productivity translated into increased densities of primary consumers (herbivorous invertebrates), which indirectly supported increased secondary consumers densities (predatory fish) (i.e. strengthening of bottom-up fuelling). However, this keystone species also reduced predatory fish densities through behavioural interference, releasing invertebrate prey from predation pressure and enabling a further boost in prey densities (i.e. weakening of top-down control). We uncover a novel mechanism where a keystone herbivore mediates bottom-up and top-down processes simultaneously to boost populations of a co-existing herbivore, resulting in altered food web interactions and predator populations under future ocean acidification. Data was blinded analyzed. Samples labels were randomly assigned in the field. Sample label and local (vent or control site), as well as the photo-quadrat ID, were noted underwater in an underwater paper sheet. These notes were only revised and added to sample labels after all laboratory analyses (productivity measurements) and count been performed (prey and predator abundances). We were unable to collect data on productivity for the year 2017 (missing values = 20) and to use the farming exclusion plot photos to access predator density (missing values = 36; year 2016b). Data files contain all data used in the manuscript ... |
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