Search Results
| dcterms created |   |
|||
|---|---|---|---|---|
| dcterms modified | |
|||
| broader |
|
|||
| definition | An areas dominated by accumulations of living shells other that oysters, mussels, clams of screwshells, that are attached or closely associated with the substratum. | |||
| dcterms created | |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| dcterms modified | |
|||||||||
| definition | The Seamap classification for substrate is based on the CMECS (FGDC, 2012) Substratum component, but with the modification of introducing a level describing the hardness of the substratum, which replaces the CMECS 'Origin' classifier. This modification is the same as is described in Edmunds and Flynn (2015). The Substratum Component of the CMECS is useful because it defines unique classes based on specific grainsizes or compositions, and the lower levels can be collapsed into higher level groups as required by the resolution of mapping. However, using standard CMECS, it is not possible to collapse the lower levels into hard and soft categories, and this represented a disadvantage of the scheme. The distinction between hard and soft substrata is one of the simplest and most common distinctions made when mapping the seafloor, and can be determined in all methods used for habitat mapping, including the use of satellite imagery, aerial photography, acoustic surveys and underwater video/photography. In terms of ecology, this characteristic also represents an important division between substratum types that are able to support reef ecosystems (hard), and those that cannot (soft). For these reasons a node describing the hardness of the substratum was included as indicated earlier. This modification is the same as that proposed in Edmunds and Flynn (2015). Hardness refers to the physical properties of the substratum, and can be determined through knowledge of acoustic or optical reflectivity, as well as by the stability of the substratum. This means that habitats such as worm or shell reefs and rhodolith beds are all classified as hard substratum, despite not being hard in the literal sense, whilst pebble habitats are not considered hard because they are not sufficiently stable to support a reef ecosystem. | |||||||||
| narrower |
|
|||||||||
| dcterms created | |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| dcterms modified | |
|||||||||
| definition | The CMECS (FGDC, 2012) 'origin' classifier provides valuable information on the source of substrate (geologic, biogenic and anthropogenic); however, it can also be one of the more difficult characteristics to classify as identified by Edmunds and Flynn (2015). The resolution required to clearly identify the origin of a substratum depends on the substratum in question. For example, rhodolith beds can be identified from acoustic surveys with simple in situ observation e.g. camera drop, whereas determining whether a sand is dominated by a mineral composition or Halimeda sp. may require analysis of sediment samples. CMECS includes 'origin' at the highest level of the substratum component hierarchy, which makes subsequent classification of substrata difficult if the 'origin' is unknown. Generally, 'origin' might be something identified at finer (lower) levels in a substrate because one would need to be at this level of resolution to obtain the information. Seamap has therefore included the origin classifier in the Seamap scheme, but has included it as a 'floating' category (rather than anchoring it within the substratum category). | |||||||||
| narrower |
|
|||||||||
| dcterms created | |
|||||||
|---|---|---|---|---|---|---|---|---|
| dcterms modified | |
|||||||
| definition | The Seamap classification of biota is a modification of the CMECS (FGCD, 2012) Biotic Component classification. The CMECS partitions have been redefined into broad biotic groups and taxonomic classes, which more accurately reflect the spatial resolution at which information in the Australian context is available. These hierarchical Seamap divisions encompass 'presence', 'class', 'subclass', 'group', 'CATAMI morphospecies' and 'species'. The new divisions are based loosely on phylogenetic groups, with the broadest grouping in the higher levels. By using broad phylogenetic groups any dependency on substratum type (as is the case in CMECS) is removed and a true hierarchical structure is enforced. Seamap also introduces concepts for bare and unmapped areas, both of which can have important ecological ramifications. The CATAMI classification (CATAMI Technical Working Group, 2013) is the 5th level of the Seamap scheme. Once biota have been identified to the finest level of the CATAMI scheme, species identifications are added where available. | |||||||
| narrower |
|
|||||||
| dcterms created | |
|||
|---|---|---|---|---|
| dcterms modified | |
|||
| broader |
|
|||
| definition | A hard substratum composed of a mix of Consolidated Hard Substrata and Unconsolidated Hard Substrata where neither class is dominant (i.e. does not exceed ≥ 80 %) of the substratum surface/composition. | |||
| dcterms created | |
|||
|---|---|---|---|---|
| dcterms modified | |
|||
| broader |
|
|||
| definition | A habitat where the dominance of a single Shelled Biota group (Oyster, Mussel, Screwshell, Other) cannot be identified, or where the composition/biomass/surface coverage of the second-most dominant group lies within 30 % margin of the most-dominant group. | |||
| dcterms created | |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| dcterms modified | |
|||||||||
| broader |
|
|||||||||
| definition | Substrata of any origin where ≥ 80% of the substratum surface is hard (i.e. acoustically or optically hard and/or stable enough through time to be able to maintain a reef ecosystem of some form). | |||||||||
| narrower |
|
|||||||||
| dcterms created | |
|||
|---|---|---|---|---|
| dcterms modified | |
|||
| broader |
|
|||
| definition | Consolidated substratum where ≥ 80 % of the consolidated surface comprises of more or less continuous rock formations where individual clasts are > 1049 m in any dimension. This is equivalent to the monolith and megalith categories of Blair and McPherson (1999) grain size classes. | |||
| dcterms created | |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| dcterms modified | |
|||||||||||
| broader |
|
|||||||||||
| definition | A hard substratum where the dominant grainsize is ≥ 256 mm in any dimension. | |||||||||||
| narrower |
|
|||||||||||