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

《2021年环境状况报告(SOE)》的海洋章节包含了从海洋数据流开发的多个专家模板。这一元数据记录描述了专家评估“苔藓虫礁的状况和趋势”。<br/> *完整的专家评估PDF，包括图表(如果提供)，可在本记录的“在线资源”部分下载，名称为“专家评估2021--国家和趋势--苔藓虫珊瑚礁”*<br/> <br/> <br/> 用于专家评估的物种/栖息地/群落描述<br/> 苔藓虫(蕾丝珊瑚)是一组物种丰富的集群动物，由软体和硬体组成；澳大利亚记录了近1,000种已描述和已知的未描述物种(Gordon，1999)，分布在温带和热带海岸。菌落的高度或直径从不到一毫米到一米多不等，以扁平的床单、植物状的簇状、肉质的裂片或珊瑚状的生长形式出现。它们与小海绵、海鞘和水生动物结合在一起，形成了低起伏的结构基质栖息地，被称为苔藓动物的不同名称，如珊瑚礁、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)。这些沉积物支持小型底栖动物(如多毛类、两足类和软体动物)，它们是包括鱼类在内的较大物种的猎物；一些苔藓虫群落的表面和间隙可以支持极高数量的其他类群(&gt；100 spp.)包括多毛类、软体动物、甲壳类和海鞘类(Bradstock和Gordon 1983)。因此，可以推断苔藓虫在维持底栖生物多样性方面起着至关重要的作用。<br/> 苔藓虫生境总体上是上陆坡深陆架、陆架折断和浅缘的主要生境类型之一。它们通常点缀着以低微型动物为特征的平原沉积，伴随着碎屑和缺乏表层动物，以及岩礁。苔藓虫基质形成在松散的沉积物上，可能覆盖低剖面的生物礁。对塔斯马尼亚大陆架边缘的调查表明，大多数苔藓虫礁位于200至350米之间，在那里形成了巨型螃蟹的重要栖息地。塔斯马尼亚大陆架边缘是海底平坦的大陆架迅速下降形成大陆斜坡的区域。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大陆架上约60 m的深度。同样，在东部GAB，陆架和断裂的大片区域有很高的苔藓动物覆盖率(Ward等人。2003年)。陆架边缘是底接触渔业的重要区域，包括拖网和诱捕渔业，这是苔藓虫栖息地的主要压力。底拖网捕捞有可能退化和移除这些栖息地(Williams等人。对其他渔业的影响，如巨蟹(Leon等人，2009年)。2017年)。<br/> 在GBR大陆架上，分枝和忙碌的苔藓虫覆盖了宽阔海湾和浅水湾、庞贝和斯旺斯珊瑚礁复合体以及摩羯座-燃料库区域附近的大片地区--在水文测量员航道附近的强流水道中，结壳类型形成了广泛的结核区域，并与其他相关生物多样性有关(Pcher等人。2007)。后一项研究确定了320多个苔藓虫类群(大部分在属水平上)，并在整个GBR中详细绘制了124个类群。<br/> 在澳大利亚温带和热带分布的许多地点，包括东南部、GAB、GBR、托雷斯海峡、卡奔塔利亚湾和皮尔巴拉，使用底栖雪橇和挖掘机对苔藓动物的栖息地进行了采样。这些样本提供了物种特征、形态和群落组成的详细信息。然而，现场观察(需要评估状况)仅限于GBR、托雷斯海峡、皮尔巴拉、双重生物区的部分区域的大陆架，但由于在这些深度进行研究的后勤困难，仅在塔斯马尼亚周围的几个较深水域进行观察。在塔斯马尼亚周围，成分的纬度变化(如在相机图像中观察到的)似乎很小，样本之间的差异取决于深度，以及样本是否来自峡谷内部。<br/> <br/> 数据流(S)在专家评估中的应用<br/> 参考部分中列出的报告和出版物中概述了使用的数据。<br/> <br/> <br/> 2021年国企评估总结[详见所附专家评估报告]<br/> <br/> ·2021年·<br/> 评估等级：总体良好。东南部和温带东部贫困<br/> 评估趋势：预测为稳定至略有改善的趋势<br/> 置信度：质量证据不足，有一定共识<br/> 信心趋势：证据有限或勉强足够，达成一些共识<br/> 可比性：等级和趋势与2016年的评估相当<br/> ·2016年·<br/> 评估等级：总体良好。东南部和温带东部贫困<br/> 评估趋势：预测为稳定至略有改善的趋势<br/> 置信度：质量证据不足，有一定共识<br/> 信心趋势：证据有限或勉强足够，达成一些共识<br/> 可比性：等级和趋势与2011年评估相当<br/> ·2011年·<br/> [仅在东南部地区评估]<br/> 评估等级：差<br/> 评估趋势：稳定<br/> 可信度：证据有限或共识有限<br/> 信心趋势：证据有限或共识有限<br/> <br/> <br/> 2016年国企考核以来的变化<br/> 没有变化。

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.