Integrated Marine and Coastal Regionalisation of Australia (IMCRA) v4.0 - Provincial Bioregions

﻿ Abstract A regionalisation of Australian waters (excluding waters adjacent to the Territory of Heard Island and McDonald Islands, and waters adjacent to the Australian Antarctic Territory) derived from deep-water demersal fish assemblages. A total of 41 onshelf and offshelf provincial bioregions were identified for Integrated Marine and Coastal Regionalisation of Australia (IMCRA) v4.0. Onshelf provincial bioregions are based on the 17 IMCRA v3.3 demersal provinces and biotones identified in 1997. Offshelf provincial bioregions were defined in 2004 as part of a program run by Geoscience Australia, CSIRO Marine Research and the National Oceans Office. They represent units that contain broad patterns in biodiversity, as represented by deep-water demersal fish assemblages, based on the assumption that the demersal fish distributions are a surrogate of marine faunal distributions. Below 2,000 m water depth, the boundaries of the benthic provincial bioregions are defined solely by the National Marine Bioregionalisation (NMB) geomorphic features dataset. A total of 24 offshelf benthic provincial bioregions were defined on this basis, including 15 core bioregions representing areas of endemism, and 9 transition zones representing areas of faunal mixing. For IMCRA v4.0 the coastline was replaced with the national 100k coastline to provide greater consistency. The Australian Exclusive Economic Zone (EEZ) limit was sourced from Australian Maritime Boundaries (AMB) v2. Based on a decision by the Bioregionalisation Working Group, the shelf break from IMCRA v3.3 was largely retained, although in some instances the shelf break from the NMB provincial bioregions was used. Continental slope provinces have been extended to the edge of the EEZ using either geomorphological features or the line of least distance in areas where there were no distinguishing seafloor features. Core provinces are centres of demersal fish endemicity. Transitions are regions of overlap between core provinces. CAVEATS 1. Provincial boundaries below 1200m are based on geomorphological surrogates in the absence of biological data for deep waters. 2. Shelf and slope provinces have been defined in separate analyses. Currency Date modified: 1 November 2006 Modification frequency: None Data extent Spatial extent North: -8.47° South: -58.45° East: 171.8° West: 93.41° Source information This dataset is provided by the Department of Climate Change, Energy, the Environment and Water * [Map Server] * [Metadata] * [Public listing] Lineage statement The benthic Provincial Bioregions were defined in 2004 as part of a program run by Geoscience Australia, CSIRO Marine Research and the National Oceans Office to create a spatial inventory of large-scale benthic biogeographical regions for Australia's EEZ. The Provincial Bioregions were defined by the regional structure in demersal fishes as represented by a one-dimensional made up of 281 nodes that correspond to the 500 m isobath around the Australian mainland. The analysis of the demersal fish data was undertaken by CSIRO Marine Research (Last et al., 2004). None of the offshore island territories were included in this assessment and each island territory was considered a separate bioregion. The boundaries of the Provincial Bioregions below 2,000 m water depth were defined solely by the geomorphic features, which were defined by the International Hydrographic Office (IHO, 2002), and were identified using a 250 m spatial resolution bathymetry model with reference to previously published geological studies. In the analysis of the demersal fish data, the boundaries between the Provincial Bioregions were defined by a Jaccard Analysis of the distributions. The final boundaries were drawn by eye around the boundaries of geomorphic features by a panel of scientific experts at a series of workshops with reference to previous studies. When completed, the boundaries defined the separate polygons and they were stored as an ArcGIS shapefile. Care was taken to include as much biological information as possible when positioning the boundaries, particularly in shallow water (500 m). Data dictionary All layers ──────────────┬─────────────────────────────────────────────────── Attribute name│Description ──────────────┼─────────────────────────────────────────────────── AREA_KM2 │Enclosed area of the bioregion in square kilometres ──────────────┼─────────────────────────────────────────────────── PB_NAME │Name of the bioregion ──────────────┼─────────────────────────────────────────────────── PB_NUM │Unique number for the bioregion ──────────────┼─────────────────────────────────────────────────── WATER_TYPE │Brief description of water climate region ──────────────┴─────────────────────────────────────────────────── Contact Department of Climate Change, Energy, the Environment and Water, [GeoSpatial@dcceew.gov.au]