4th International Submarine Canyon Symposium (INCISE2018)
5-7 November 2018, Shenzhen, CHINA
This is the detail of Scaling canyon ecology: multi-resolution consideration of biodiversity in Explorer Canyon.
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A. Callaway, K. Robert, C. Lo Iacono, R. Hall, V. Huvenne
Scaling canyon ecology: multi-resolution consideration of biodiversity in Explorer Canyon.
Ecological research in deep-water environments has historically seen a trade-off between data resolution and data coverage. To achieve comprehensive, broad-scale coverage the resolution of data is necessarily low. Yet when examining key fine-scale features the data resolutions are comparatively, incredibly high, though over very small areas. This results in fine-scale relationships being extrapolated across broad-scale data although the implications of doing so are rarely considered due to the lack of an alternative approach. Recent implementation of multibeam echosounder (MBES) survey techniques from underwater robotic systems such as Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs) has enabled acquisition of fine-scale information over broad-scale areas in deep water allowing the implication of resolution on biodiversity to be interrogated more effectively. In addition, novel imaging techniques such as Structure from Motion (SfM) can yield ecological studies an order of magnitude higher to centimetric resolution, a scale unobtainable through other methods.
During the JC125 expedition, multi-scale MBES data in Explorer Canyon, NE Atlantic were collected. This work was funded by the ERC CODEMAP (Complex Deep-sea Environments: Mapping habitat heterogeneity As Proxy for biodiversity) project (Starting Grant no 258482) and the NERC MAREMAP programme. A combination of shipboard and AUV (Autosub 6000) acquired bathymetry was analysed to explore the role of terrain at different scales (metres to 10s of metres) in Explorer Canyon which is part of the wider Whittard Canyon complex. Using the ROV Isis, three video transects were collected to quantify biodiversity and community assemblages, and to ground-truth habitat occurrence. We explore the relationship further and investigate the role of very fine-scale, centimetric resolution terrain complexity derived from SfM, in the form of 40 reconstructed 3D 25 m transects. Fine-scale structural complexity strongly influenced community assemblage and biodiversity in tandem with, but not limited to cold-water coral reef occurrence. Comparing these scales give us greater insight into the canyon system from an ecological perspective. These data provide insight into how reliable broad-scale ecological assumptions are, with special reference to habitat mapping and species distribution modelling.
Session 3: Patterns and heterogeneity in submarine canyons