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Regional-scale patterns of deep seafloor biodiversity for conservation assessment

Citation

O'Hara, TD and Williams, A and Althaus, F and Ross, AS and Bax, NJ, Regional-scale patterns of deep seafloor biodiversity for conservation assessment, Diversity and Distributions, 26, (4) pp. 479-494. ISSN 1366-9516 (2020) [Refereed Article]


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Copyright Statement

© 2020 The Authors. Diversity and Distributions Published by John Wiley & Sons Ltd. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/

DOI: doi:10.1111/ddi.13034

Abstract

Aim

Mining and petroleum industries are exploring for resources in deep seafloor environments. Lease areas are often spatially aggregated and continuous over hundreds to thousands of kilometres. Sustainable development of these resources requires an understanding of the patterns of biodiversity at similar scales, yet these data are rarely available for the deep sea. Here, we compare biodiversity metrics and assemblage composition of epibenthic megafaunal samples from deep‐sea benthic habitats from the Great Australian Bight (GAB), a petroleum exploration zone off southern Australia, to similar environments off eastern Australia.

Location

The Great Australian Bight (34–36°S, 129–134°E) and south‐eastern (SE) and north‐eastern (NE) Australian continental margins (23–42°S, 149–155°E) in depths of 1,900–5,000 m.

Methods

A species–sample matrix was constructed from invertebrate and fish megafauna collected from beam trawl samples across regions at lower bathyal (1,900–3,200 m) and abyssal (>3,200 m) depths, and analysed using multivariate, rarefaction and model‐based statistics. We modelled rank abundance distributions (RAD) against environmental factors to identify drivers of abundance, richness and evenness.

Results

Multivariate analyses showed regional and bathymetric assemblage structure across the region. There was an almost complete turnover of sponge fauna between the GAB and SE. SE samples had the highest total faunal abundance and species richness. RAD models linked total abundance and species richness to levels of carbon flux. Evenness was associated with seasonality of net primary production.

Conclusions

Significant assemblage structure at regional scales is reported for the first time at lower bathyal and abyssal depths in the southern Indo‐Pacific region along latitudinal and longitudinal gradients. The GAB fauna was distinct from other studied areas. Relatively high species richness, previously reported from the GAB continental shelf, did not occur at lower bathyal or abyssal depths. Instead, the abundance, richness and evenness of the benthic fauna are linked to surface primary production, which is elevated off SE Australia.

Item Details

Item Type:Refereed Article
Keywords:benthos, conservation assessment, deep sea, key ecological features, rank abundance distribution
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Palaeoecology
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Assessment and management of terrestrial ecosystems
UTAS Author:Bax, NJ (Professor Nicholas Bax)
ID Code:139551
Year Published:2020
Web of Science® Times Cited:3
Deposited By:Ecology and Biodiversity
Deposited On:2020-06-22
Last Modified:2021-02-03
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