Dr Maria Beger1,2, Dr Mark Miller1, Ms Katie Cook1, Dr Brigitte Sommer2,3, Professor John Pandolfi2, A/ Prof James Reimer4
1University Of Leeds, Leeds, United Kingdom, 2University of Queensland, Brisbane, Australia, 3University of Sydney, Sydney, Australia, 4University of the Ryukyus, Nishihara, Japan
Multi-species range shifts of multiple species transform communities, but these changes remain largely unquantified. Seasonal and latitudinal gradients within tropical-to-temperate biogeographic transition zones represent a model system to examine the resulting community reorganisation and potential changes in function. Using the example of high-latitude subtropical reef communities that receive range shifting tropical species and loose temperate species, we quantify the dynamics of functional types of fishes. First, we identify and test functional groups of reef-associated fishes based on their anatomic, physiological, and behavioural traits with hierarchical clustering. Assuming a certain function is represented by each group, we then test whether and how such function is changing in response to environmental (e.g. temperature) and biological (e.g. habitat engineers) drivers. All functional types exist throughout the environmental gradient, but their biomass is mediated by characteristic traits, biological interactions, and temperature. Despite a slight functional simplification of the available trait combinations in subtropical and temperate communities, loss of constituent species within each functional type is compensated by increased biomass of the remaining species for some groups. Seasonal fluctuations in functional type biomass apply only to some of the groups, with relatively more important changes associated with warm vs cold years rather than summer and winter. Our findings point to both preserved and changing functioning within coastal marine ecosystems that are reconfigured by multi-species range shifts, with species biomass tracking long-term and spatial but not seasonal environmental change. Our study highlights both the vulnerability and stability of reorganizing communities and their functioning.
Maria is an University Academic Fellow in Conservation Science at the University of Leeds, UK. Her research stands on three pillars: (i) spatial conservation science, with a particular focus on connectivity, (ii) multi-taxon functional community shifts in marine systems along human-use and environmental gradients, and (iii) understanding and managing the impacts of climate change on marine ecosystems.