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Distribution models of temperate habitat-forming species on the continental shelf In eastern Australia: setting the baseline to monitor and predict future changes

conference contribution
posted on 2023-05-24, 14:48 authored by Marzloff, MP, Neville BarrettNeville Barrett, Neil HolbrookNeil Holbrook, Oliver, ECJ, James, L, Craig JohnsonCraig Johnson
Habitat-formers (e.g. kelp beds, corals, sessile invertebrate assemblages) are key to the structure and functioning of reef ecosystems worldwide. In southeast Australia, a region identified as a global hotspot for climate-driven ocean warming, the structure and distribution of deep (> 30 m) benthic sessile communities are poorly known given these habitats are hard to quantitatively survey. Using high-resolution imagery of the seafloor from a recent national-scale AUV-based survey program, we establish a critical baseline about the latitudinal gradient in benthic community composition from 27°S to 43°S on the eastern seaboard of Australia.

Over >1,800 AUV images taken across the 7 different survey regions along the eastern seaboard of Australia, we estimated percentage cover of 51 pre-selected invertebrate morphospecies, including two ascidians, four bryozoans, seven cnidarians and 38 sponges. These morphospecies were chosen for their strong features (i.e. size, shape, colour), which facilitated their identification and detectability on the images. Three levels of details (i.e. group, shape, colour) were reported for each record, so as to test the sensitivity of our results to alternative invertebrate classification schemes of increasing resolution.

Large-scale latitudinal variability between three major community types (sub-tropical, warm temperate and cool temperate) mostly correlates with primary productivity and temperature climatology, while local scale variability relates well with depth.

Using environmental variables that capture past climatology both in terms of means and extremes (frequency and magnitude), we develop alternative distribution models for several habitat-forming species. Our models characterise the thermal tolerance of individual morphospecies in terms of suitable and/or critical boundary conditions. We compare model performance, discriminate between different types of latitudinal distribution (e.g. truncated or continuous), identify indicator morphospecies more likely to respond to climate-driven changes in ocean conditions, and discuss these results in the context of ongoing and future ocean changes. Our study provides an important benchmark to detect and predict future climate-driven changes in southeastern Australia, and our methodology has general applicability for monitoring of deep reef environments.

History

Publication title

Proceedings of the 21st International Congress on Modelling and Simulation (MODSIM2015)

Editors

T Weber, MJ McPhee, RS Anderssen

ISBN

9780987214355

Department/School

Institute for Marine and Antarctic Studies

Event title

21st International Congress on Modelling and Simulation (MODSIM2015)

Event Venue

Broadbeach, QLD

Date of Event (Start Date)

2015-11-29

Date of Event (End Date)

2015-12-04

Repository Status

  • Restricted

Socio-economic Objectives

Assessment and management of terrestrial ecosystems