2016 SoE Marine Chapter - State and Trends - Seamounts

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "The state and trends of quality of habitats and communities – Seamounts". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record.----------------------------------------DESCRIPTION OF HABITAT/COMMUNITY FOR EXPERT ASSESSMENTSeamounts (undersea mountains, often with volcanic origin) provide ‘oasis’ habitats of hard substratum and are widely considered to represent sites of elevated biomass and productivity in the deep ocean. Their habitats can support dense aggregations of corals and associated high biodiversity; these represent vulnerable marine ecosystems (VME) (e.g. UNGA 2006; Clark et al 2011). The geological definition of a seamount (elevation of >1000 m) has no relevance to biodiversity valuation because smaller features are frequently found to support high, if not the highest, biodiversity. An ecological definition (e.g. Pitcher et al. 2007) is recommended.Australia’s marine realm encompasses many seamounts; the best known are the Tasmanian seamounts and the Tasmantid seamount chain. Additional seamounts have been discovered and mapped on the Lord Howe Rise and the Norfolk Ridge, as well as on Australia’s southern margin in the GAB.Seamount communities to ~1500 m depth in the south-east and south-west regions are associated with biogenic habitats formed mostly by the stony coral Solenosmilia variabilis (Koslow et al 2000; Thresher et al. 2014). Its matrix of dead and life coral, built up to a layer of at least 1.6 m thickness in places, forms a habitat for other corals, urchins, brittle- and snakestars and crustaceans (Thresher et al. 2014). Communities and habitats on deeper reaches of seamounts (>1500 m) are less well studied; they are usually less diverse and sparser, although areas of extraordinary high biomass have been observed in the south-east region (Thresher et al. 2014). The seamounts in the Tasmantid chain are mapped and well used by various commercial fisheries, but their epifaunal communities remain poorly documented (Williams et al. 2012).DATA STREAM(S) USED IN EXPERT ASSESSMENTThis assessment is based on data derived from Marine National Facility Surveys described in MarLIN (http://www.marine.csiro.au/marlin/search.html) and accessible through the CSIRO Data trawler (http://www.cmar.csiro.au/data/trawler/). Links to specific data sets are provided in the "On-line resources" section of this record.• Voyage of Discovery north-west (SS05/2007)• Voyage of Discovery south-west (SS07/2005 & SS10/2005)• Tasmanian seamounts surveys (SS01/2000, SS04/2006 & SS02/2007, SS01/2008 & TT01/2008)• Habitat Mapping (SS01/2000, SS04/2004)• Habitat and population assessment of giant crabs (2003 - 2005) • NORFANZ survey of Lord Howe Rise and Norfolk Ridge (TAN0308 - NORFANZ)----------------------------------------2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]• 2016 •Assessment grade: Very good-PoorAssessment trend: Stable- ImprovingConfidence grade: Adequate high quality evidence and high level of consensusConfidence trend: Adequate high quality evidence and high level of consensusComparability: Grade and trend are somewhat comparable to the 2011 assessment• 2011 •Assessment grade: Very goodAssessment trend: StableConfidence grade: Limited evidence or limited consensusConfidence trend: Limited evidence or limited consensus----------------------------------------CHANGES SINCE 2011 SOE ASSESSMENTThere is substantial information on the impact of trawling on seamounts in the South-East Marine Region available.2016年《环境状况报告》（State of the Environment (SoE)）海洋章节纳入了多套基于海洋数据流构建的专家模板。本元数据记录针对专家评估报告《生境与群落质量现状及趋势——海山》（Seamounts）进行说明。本记录附带完整的专家评估报告，含附图与附表（如已提供）。若有可用数据，本评估所依托的数据流可通过本记录的"在线资源"板块获取。 ### 专家评估用生境与群落说明 海山（Seamounts，通常为火山成因的海底山脉）为硬质基底提供了"绿洲"生境，被广泛认为是深海中生物量与生产力提升的区域。其生境可支撑密集的珊瑚集群及相关的高生物多样性群落，属于脆弱海洋生态系统（Vulnerable Marine Ecosystems, VME）（如联合国大会2006年决议；Clark等2011年研究）。海山的地质学定义（海拔高于1000米）与生物多样性评估无关，因为研究发现小型海底地貌同样能支撑极高（即便不是最高）的生物多样性，因此推荐采用生态学定义（如Pitcher等2007年研究）。 澳大利亚海域分布有大量海山，其中最为人熟知的是塔斯马尼亚海山及塔斯曼海海山链。此外，在豪勋爵海岭、诺福克海岭以及澳大利亚南部边缘的大澳大利亚湾（GAB）也已发现并测绘了多处海山。 澳大利亚东南及西南海域约1500米以浅的海山群落，主要依托石珊瑚*Solenosmilia variabilis*形成的生物成因生境（Koslow等2000年；Thresher等2014年研究）。该珊瑚的死体与活体堆积形成的基底在部分区域厚度可达1.6米以上，为其他珊瑚、海胆、蛇尾类、蛇海星及甲壳类动物提供栖息环境（Thresher等2014年研究）。1500米以深的海山群落与生境研究相对较少，通常多样性更低、群落更稀疏，但东南海域曾观测到生物量极高的区域（Thresher等2014年研究）。塔斯曼海海山链已完成测绘，且被各类商业渔业广泛利用，但其表生底栖生物群落的记录仍较为匮乏（Williams等2012年研究）。 ### 专家评估所依托的数据流 本评估基于《海洋生物多样性信息库》（MarLIN，http://www.marine.csiro.au/marlin/search.html）中记载的海洋国家设施调查数据，可通过CSIRO数据拖网平台（http://www.cmar.csiro.au/data/trawler/）获取。本记录的"在线资源"板块提供了指向特定数据集的链接： - 西北海域探索航次（SS05/2007） - 西南海域探索航次（SS07/2005与SS10/2005） - 塔斯马尼亚海山调查航次（SS01/2000、SS04/2006与SS02/2007、SS01/2008与TT01/2008） - 生境测绘航次（SS01/2000、SS04/2004） - 巨型蟹生境与种群评估（2003-2005） - 豪勋爵海岭与诺福克海岭NORFANZ调查航次（TAN0308 - NORFANZ） ### 2016年SoE评估摘要（完整细节请参阅附带的专家评估报告） - **2016年** 评估等级：极佳-较差 评估趋势：稳定-改善 置信等级：具备充足高质量证据与高度共识 置信趋势：具备充足高质量证据与高度共识 可比性：本次评估的等级与趋势与2011年评估具有一定可比性 - **2011年** 评估等级：极佳 评估趋势：稳定 置信等级：证据有限或共识不足 置信趋势：证据有限或共识不足 ### 2011年SoE评估以来的变化 目前已有大量关于东南海域海山拖网作业影响的研究资料。