Response of coastal food webs to climate change – the role of biodiversity and latitude

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Patterns of rock pool molluscs in differing shore exposures

Publication . Gonçalves, Inês; Vinagre, Catarina; Silva, Ana

Rock pools are understudied systems of extreme importance due to their proven vulnerability to climate change. Rock pool molluscs play essential ecological roles therein, directly by acting both as prey and predator and, indirectly by influencing the macroalgal canopy/vegetation topography via grazing. However, the environmental factors driving their rock pool occupation remain largely unknown. Our study is one of the few to focus on community patterns in rock pool molluscs, particularly at a large scale between shores of differing exposure to wave action, being the first focused assessment of rock pool molluscs in Portugal. Overall, 32 intertidal rock pools on four rocky shores were studied during the summer spring tide of 2015. We used multivariate analysis to evaluate the potential impact of sheltered versus exposed wave action, physical pool structure (length, width, and depth), and relationships within the pool community on the abundance and diversity of molluscs. Wave exposure significantly influenced mollusc abundance and diversity. The majority of the 37 different taxa identified were grazing gastropods (62.2%), followed by bivalves (27.0%) and chitons (10.8%). We suggest that mollusc taxa may have preferences for particular rock pool habitats depending on the type of algae present rather than pool size. We also suggest that species-specific mollusc presence in rock pools can be related to their shell size, aperture, and foot size due to corresponding variation in musculature needed to hold the snail to the substrate in hydrodynamic conditions. Further investigation would benefit from disentangling the potential role of algal pool coverage as a refuge for molluscs.

2023Journal article

Open Access

Biodiversity of intertidal food webs in response to warming across latitudes

Publication . Gauzens, Benoit; Rall, Bjoern C.; Mendonca, Vanessa; Vinagre, Catarina; Brose, Ulrich

Global warming will affect food-web structure and species persistence, and real world data is needed for better prediction. Combining species counts and temperature data from rock pools with dynamic modelling predicts biodiversity increases in arctic to temperate regions and declines in the tropics. Global warming threatens community stability and biodiversity around the globe. Knowledge of the mechanisms underlying the responses to rising temperatures depends heavily on generic food-web models that do not account for changes in network structure along latitudes and temperature gradients. Using 124 marine rock-pool food webs sampled across four continents, we show that despite substantial variation in ambient temperature (mean 11.5-28.4 degrees C), similar empirical food-web and body-mass structures emerge. We have used dynamic modelling to test whether communities from warmer regions are more sensitive to warming and found a general hump-shaped relationship between simulated biodiversity and temperature (gradient from 0-50 degrees C). This implies that an expected anthropogenic global warming of 4 degrees C should increase biodiversity in arctic to temperate regions while biodiversity in tropical regions should decrease. Interestingly, simulations of synthetic networks did not yield similar results, which stresses the importance of considering the specificities of natural food webs for predicting community responses to environmental changes.

2020-03Journal article

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