2021, Sensitivity of a cold-water coral reef to interannual variability in regional oceanography, Diversity and Distributions, 00, 1-13, doi:10.1111/ddi.13363.
Aim
We assessed the effects of regional oceanographic shifts on the macrofaunal biodiversity and biogeography of cold-water coral reefs (CWCRs). CWCRs are often hotspots of biodiversity and ecosystem services and are in the frontline of exposure to multiple human pressures and climate change. Almost nothing is known about how large-scale atmospheric variability affects the structure of CWCRs鈥 communities over ecological timescales, and this hinders their efficient conservation. This knowledge gap is especially evident for species-rich macrofauna, a key component for ecosystem functioning.
Location
The Mingulay Reef Complex, a protected biogenic ecosystem in the northeast Atlantic (120鈥190 m).
Methods
A unique time series (2003鈥2011) at 79 stations was used to make the first assessment of interannual changes in CWCRs鈥 macrofaunal biodiversity, biogeography and functional traits. We quantified the impacts of interannual changes in North Atlantic Oscillation Index (NAOI)鈥攖he major mode of atmospheric variability in the North Atlantic, bottom temperature and salinity alongside static variables of seafloor terrain and hydrography.
Results
Environmental gradients explained a significant amount of community composition (
= 26.7%, p < .01) with interannual changes in bottom temperature, salinity and NAOI explaining nearly twice as much variability than changes in terrain or hydrography. We observed significant differences in community composition, diversity and functional traits but not in species richness across interannual variability in bottom temperature. In warmer years, the biogeographic composition shifted more towards a temperate and subtropical affinity.
Main Conclusions
Our findings highlight the necessity for thorough investigations of faunal communities in CWCRs as they may be sensitive to interannual changes in regional oceanography. Considering the scientific consensus on the substantial warming of North Atlantic by 2100, we recommend the establishment of programmes for the monitoring of CWCRs. This will support an advanced understanding of CWCRs鈥 environmental status over time and will serve their conservation for the future.