2021 State of the Environment Report Marine Chapter – Expert Assessment – State and Trend – Bryozoan reefs

2021 年环境状况报告海洋章节 — 专家评估 — 状况与趋势 — 苔藓虫礁

• 批准号: global : 107b720c-6542-4a4a-9653-230f3454ce2c
• 金额: --
• 依托单位国家: 澳大利亚
• 资助国家: 澳大利亚
• 起止时间: 0100-11-30 至 无数据
• 项目状态: 已结题
• 来源: https://researchdata.edu.au/2021-state-environment-bryozoan-reefs/1767714
• 关键词: 2021; State; Environment; Report; Marine

The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "State and Trend of Bryozoan Reefs". <br /> ***A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - State and Trend – Bryozoan Reefs"***<br /> <br /> ----------------------------------------<br /> <br /> DESCRIPTION OF SPECIES/HABITAT/COMMUNITY FOR EXPERT ASSESSMENT<br /> Bryozoans (lace corals) are a species-rich group of colonial animals composed of soft and hard-bodied forms; almost 1,000 described and known undescribed species were recorded from Australia (Gordon 1999), occurring off both temperate and tropical coasts. Colonies vary in height or diameter from less than one millimetre to over one metre, and occur as flat sheets, plant-like tufts, fleshy lobes or coral-like growths. In association with small sponges, ascidians and hydroids they form low-relief structured matrix habitat variously termed bryozoan ‘reefs’, ‘thickets’ and ‘turf’ (depending on its height and composition). The matrix acts to stabilise sediments, and its bio-fragments are one of the most conspicuous and abundant components of shelf sediments, e.g. up to 75% of the sediment volume in the GAB (James et al. 2001). These sediments support small infauna (e.g. polychaetes, amphipods and molluscs) that are prey for larger species including fishes; the surfaces and interstices of some bryozoan colonies can support extremely high numbers of other taxa (&gt;100 spp.) including polychaetes, molluscs, crustaceans and ascidians (Bradstock and Gordon 1983). Accordingly, it may be inferred that bryozoans play a vital role in the maintenance of benthic biodiversity. <br /> Collectively, bryozoan habitats are one of the main habitat types on the deep continental shelf, shelf break and shallow margin of the upper continental slope. They are typically interspersed with plains of sediment characterised by low microfauna in association with detritus and absence of epifauna, and rocky reefs. Bryozoan matrix forms on unconsolidated sediment and may cover low profile reef. Surveys of the Tasmanian ‘shelf-edge’, the region of the seafloor where the flat continental shelf drops away rapidly to form the continental slope, between 150 and 400 m showed that most bryozoan reef occurred between 200 and 350 m where if forms an important habitat for giant crabs. However, in relatively sheltered areas, including parts of the Tasmanian east coast, bryozoan habitats extend into ~60 m depth on the shelf. Similarly, in the eastern GAB, extensive areas of the shelf and break have high cover of bryozoans (Ward et al. 2003). The shelf edge is an important area for bottom contact fisheries including trawl and trap fisheries, and these represent the major pressure on bryozoan habitats. Bottom trawling has the potential to degrade and remove these habitats (Williams et al. 2009) and impact on other fisheries such as giant crab (Leon et al. 2017). <br /> On the GBR shelf, branching and busy bryozoans cover extensive areas in the vicinity of Broad Sound and Shoalwater Bay, the Pompey & Swains Reef Complexes, and the Capricorn-Bunker Regions — in high current channels near Hydrographers Passage, encrusting types form extensive areas of nodules with other associated biodiversity (Pitcher et al. 2007). Over 320 bryozoan taxa (mostly at the genus level) were identified by the latter study, and 124 taxa were mapped in detail throughout the GBR. <br /> Bryozoan habitats have been sampled using benthic sleds and dredges in many locations across their temperate and tropical Australian distribution, including the SE, GAB, GBR, Torres Strait, Gulf of Carpentaria and Pilbara. Those samples provided details of species identity, morphology and community composition. However, in situ observations (required to assess status) are limited to the shelf in the GBR, Torres Strait, Pilbara, parts of the Twofold bio-region, but in deeper waters only a few areas around Tasmania due to the logistic difficulty of conducting research at these depths. Around Tasmania, latitudinal variation in composition (as observed in camera imagery) appeared to be slight, with differences between samples driven by depth, and whether the samples were from within canyons. <br /> <br /> DATA STREAM(S) USED IN EXPERT ASSESSMENT<br /> Data used is outlined in the reports and publications listed in reference section.<br /> <br /> ----------------------------------------<br /> <br /> 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]<br /> <br /> • 2021 •<br /> Assessment grade: Good overall. Poor in South-east and Temperate East<br /> Assessment trend: Predicted stable-to-slightly improving trend<br /> Confidence grade: Barely adequate quality evidence, some consensus<br /> Confidence trend: Limited or barely adequate evidence, some consensus<br /> Comparability: Grade and trend are comparable to the 2016 assessment<br /> • 2016 •<br /> Assessment grade: Good overall. Poor in South-east and Temperate East<br /> Assessment trend: Predicted stable-to-slightly improving trend<br /> Confidence grade: Barely adequate quality evidence, some consensus<br /> Confidence trend: Limited or barely adequate evidence, some consensus<br /> Comparability: Grade and trend are comparable to the 2011 assessment<br /> • 2011 •<br /> [only assessed in the south-east region]<br /> Assessment grade: Poor<br /> Assessment trend: Stable<br /> Confidence grade: Limited evidence or limited consensus<br /> Confidence trend: Limited evidence or limited consensus <br /> <br /> ----------------------------------------<br /> <br /> CHANGES SINCE 2016 SOE ASSESSMENT<br /> No change.

《2021年环境状况报告》的海洋章节包含了从海洋数据流中开发的多个专家模板。该元数据记录描述了专家评估“苔藓虫礁的状态和趋势”。<br /> * 完整的专家评估PDF，包括图和表（如提供），可在本记录的“在线资源”部分下载，名为“专家评估2021 -状态和趋势-苔藓虫礁”*<br /> <br /> ----------------------------------------<br /> <br /> 供专家评估的物种/生境/群落描述<br /> 苔藓虫（花边珊瑚）是一个物种丰富的群体的殖民动物组成的软和硬的身体形式;近1,000个描述和已知的未描述的物种记录在澳大利亚（戈登1999年），发生在温带和热带海岸。 菌落的高度或直径从不到一毫米到超过一米不等，呈平板状、植物状丛生、肉质裂片或珊瑚状生长。与小海绵、海鞘和水螅虫一起，它们形成了低起伏结构的基质栖息地，被称为苔藓虫的“礁石”、“灌木丛”和“草皮”（取决于其高度和组成）。基质起到稳定沉积物的作用，其生物碎片是陆架沉积物中最显著和最丰富的成分之一，例如，高达GAB沉积物体积的75%（James等人，2001年）。这些沉积物支持小型的底栖动物（例如多毛类，端足类和软体动物），这些动物是包括鱼类在内的大型物种的猎物;一些苔藓虫群落的表面和空隙可以支持极高数量的其他类群（100种）。包括多毛类、软体动物、甲壳类和海鞘（Bradstock和Gordon 1983）。因此，可以推断苔藓动物在维持底栖生物多样性方面起着至关重要的作用。<br /> 苔藓动物生境是我国大陆架深水区、陆坡折带和陆坡浅缘的主要生境类型之一。 它们通常散布着沉积平原，其特点是与碎屑有关的小型动物和缺乏表生动物以及岩礁。苔藓虫基质形成于松散沉积物上，可能覆盖低矮的礁。对塔斯马尼亚“陆架边缘”（即平坦大陆架迅速下降形成大陆坡的海底区域）150米至400米之间的调查表明，大多数苔藓虫礁出现在200米至350米之间，形成了巨大螃蟹的重要栖息地。 然而，在相对隐蔽的地区，包括塔斯马尼亚东海岸的部分地区，苔藓虫的栖息地延伸到60米深的货架上。 同样，在GAB东部，大陆架和断裂的广大地区苔藓虫覆盖率很高（Ward等人，2003年）。陆架边缘是底质接触渔业（包括拖网和诱捕渔业）的重要区域，是苔藓虫栖息地面临的主要压力。 底拖网捕捞有可能使这些生境退化和消失（威廉姆斯等人，2009年），并对其他渔业产生影响，如巨蟹（Leon等人，2017年）。<br /> 在大不列颠及北爱尔兰联合王国大陆架上，分枝和忙碌的苔藓虫覆盖了布罗德湾和肖尔沃特湾、庞培和斯温斯珊瑚礁复合体以及摩羯-邦克地区附近的广大区域---在水文学家通道附近的高水流通道中，结壳类型形成了具有其他相关生物多样性的广大区域的结核（Pitcher等人，2007年）。后一项研究确定了320多个苔藓虫分类群（主要是属级），并在整个GBR详细绘制了124个分类群。<br /> 苔藓虫的栖息地进行了采样，使用底栖雪橇和挖泥船在许多地方在其温带和热带澳大利亚的分布，包括东南，GAB，GBR，托雷斯海峡，卡奔塔利亚湾和皮尔巴拉。 这些样本提供了物种特征、形态和群落组成的详细资料。然而，现场观测（评估现状所需的）仅限于大不列颠及北爱尔兰联合王国大陆架、托雷斯海峡、皮尔巴拉、部分双重生物区，但在更深的沃茨，由于在这些深度进行研究的后勤困难，仅限于塔斯马尼亚周围的几个地区。在塔斯马尼亚岛周围，成分的纬度变化（如在相机图像中观察到的）似乎很轻微，样本之间的差异由深度驱动，以及样本是否来自峡谷内。<br /> <br /> 用于专家评估的数据流<br /> 所用数据概述于参考文献章节中列出的报告和出版物中。<br /> <br /> ----------------------------------------<br /> <br /> 2021年国有企业评估摘要[详细信息请参见随附的专家评估]<br /> <br /> · 2021 ·<br /> 评价等级：总体良好。东南部和温带东部贫困<br /> 评估趋势：预测稳定至略有改善的趋势<br /> 置信度：几乎没有足够的质量证据，一些共识<br /> 信心趋势：证据有限或几乎不充分，达成一些共识<br /> 可比性：等级和趋势与2016年评估相当<br /> · 2016 ·<br /> 评价等级：总体良好。东南部和温带东部贫困<br /> 评估趋势：预测稳定至略有改善的趋势<br /> 置信度：几乎没有足够的质量证据，一些共识<br /> 信心趋势：证据有限或几乎不充分，达成一些共识<br /> 可比性：等级和趋势与2011年评估相当<br /> · 2011 ·<br /> [only在东南地区评估]<br /> 评价等级：差<br /> 评估趋势：稳定<br /> 置信度：证据有限或共识有限<br /> 可信度趋势：证据有限或共识有限<br /> <br /> ----------------------------------------<br /> <br /> 2016年以来的变化<br /> 没有变化。