Collation of spatial seagrass data from 1984 - 2014 for the Great Barrier Reef World Heritage Area

This dataset summarises 30 years of seagrass data collection (1984-2014) within the Great Barrier Reef World Heritage Area. The Meadow data describes seagrass at 1,169 individual or composite meadows. The data includes information on species, meadow type and age and reliability of the data. Data represented in this dataset has been collected by the TropWATER Seagrass Group and CSIRO in a GIS database.

In making this data publicly available for management, the authors from the TropWATER Seagrass Group request being contacted and involved in decision making processes that incorporate this data, to ensure its limitations are fully understood. The site and meadow GIS available on eAtlas should be considered a “living” document that will be updated and modified as new data become available.

Additional 'point' site data, and alternative download formats are available from eAtlas. https://eatlas.org.au/geonetwork/srv/eng/catalog.search#/metadata/77998615-bbab-4270-bcb1-96c46f56f85a

A later version (2020) of this dataset including 35 years of data has been published under "Seagrass mapping synthesis: A resource for coastal management in the Great Barrier Reef (NESP TWQ Project 3.2.1 and 5.4, TropWATER, James Cook University)." https://eatlas.org.au/data/uuid/5011393e-0db7-46ce-a8ee-f331fcf83a88

Data Dictionary:

Seagrass meadow data:

- NRM_REGION: The NRM region in which the survey occurred.
- SURVEY_DAT: Survey month and year, or a list of survey dates for meadows repeatedly sampled.
- METHOD: Sampling and mapping methods – GPS/aerial photography, helicopter, walking, boat with camera, diver, grab and/or sled.
- PERSISTENC: Meadows were classed according to four categories: Stable, Variable, Highly variable ephemeral, or Unknown.
- MEADOW_LOC: Meadows were classed according to three categories, although some meadows cover a range of these locations: Intertidal, Shallow subtidal, or Deep subtidal.
- DENSITY: Meadow density categories (light, dense, variable among years, unknown) were determined by the consistency of mean above-ground biomass of the dominant species among all years sampled.
- DOMINANT_S: Dominant species and species present.
- SPP_PRESEN: All species present.
- MEAN_BIOMA: Mean meadow biomass in g DW m-2 (+ standard error if available), or the minimum and maximum biomass recorded for meadows sampled more than once.
- AREA_HA: Meadow area in hectares (+ reliability estimate if available), or the minimum and maximum area recorded for meadows sampled more than once.
- HECTARES: Total extent of meadow (HA)
- PERCENT_CO: Meadow percent cover - this value represents mean seagrass percent cover, or the range of percent cover (if >1 number in the data cell). Meadow percent cover was most commonly calculated in pre-1990s surveys and recorded as “n/a” if not available.
- CUSTODIAN: Data custodians
- COMMENTS

Meadow Persistence:
- Stable: enduring meadow form; seagrass presence, biomass and area expected to be stable over time and seagrass meadow expected to be a permanent feature apart from extreme events or sustained long term impacts;
- Variable: meadow presence, biomass and area expected to fluctuate within and among years, but generally some seagrass expected to be present apart from extreme events or sustained long term impacts;
- Highly variable ephemeral: meadow not persistent over time; at some time periods seagrass will be present and at other times absent. Ephemeral meadows that have a naturally extreme level of variation in area and biomass within and among years;
- Unknown: undetermined persistence as meadow sampled only once.

Meadow Location:
- Intertidal - all sites surveyed by helicopter or walking within a meadow and/or comments in field books identified an intertidal meadow,
- Shallow subtidal - meadows where free divers SCUBA, sled collection, or cameras were used to sample and water depth was generally 10 m deep were included as deep subtidal.

本数据集汇总了大堡礁世界遗产区域内1984年至2014年间共计30年的海草调查数据。本海草床数据集涵盖1169处独立或复合海草床的海草相关信息，包含海草物种、海草床类型与形成年限，以及数据可靠性相关内容。本数据集收录的数据由TropWATER海草工作组（TropWATER Seagrass Group）与澳大利亚联邦科学与工业研究组织（CSIRO）采集，并存储于地理信息系统（GIS）数据库中。

为将该数据公开用于管理工作，TropWATER海草工作组的团队恳请在使用本数据开展决策工作时，提前与其取得联系并邀请其参与相关流程，以确保数据的局限性得到充分认知。本数据集在eAtlas平台发布的海草床与调查点位GIS数据属于「动态更新文档」，将随着新数据的持续获取进行更新与修订。

更多点位调查数据与其他格式的下载资源可从eAtlas平台获取：https://eatlas.org.au/geonetwork/srv/eng/catalog.search#/metadata/77998615-bbab-4270-bcb1-96c46f56f85a

本数据集的2020年升级版（涵盖35年调查数据）已以"Seagrass mapping synthesis: A resource for coastal management in the Great Barrier Reef (NESP TWQ Project 3.2.1 and 5.4, TropWATER, James Cook University)."为名正式发布，相关资源可通过以下链接获取：https://eatlas.org.au/data/uuid/5011393e-0db7-46ce-a8ee-f331fcf83a88

数据字典：

海草床数据集字段说明：
- NRM_REGION：调查开展所在的自然资源管理区域（NRM）
- SURVEY_DAT：调查月份与年份；对于重复采样的海草床，可填写多组调查日期
- METHOD：采样与制图方法——包括GPS/航空摄影、直升机航拍、实地踏勘、搭载相机的船只作业、潜水员调查、拖斗采样或雪橇采样等
- PERSISTENC：海草床持久性分类，共分为四类：稳定型、波动型、高度波动的短期型，以及未知型
- MEADOW_LOC：海草床生境位置分类，共分为三类（部分海草床可覆盖多种生境类型）：潮间带、浅潮下带，以及深潮下带
- DENSITY：海草床密度分类，分为低密度、高密度、年际波动型，以及未知型，分类依据为优势物种各采样年度的平均地上生物量一致性
- DOMINANT_S：优势物种与现存物种
- SPP_PRESEN：所有现存海草物种
- MEAN_BIOMA：海草床平均生物量，单位为克干重/平方米（若有则附带标准误差）；对于重复采样的海草床，可填写生物量的最大值与最小值
- AREA_HA：海草床面积，单位为公顷（若有则附带可靠性评估值）；对于重复采样的海草床，可填写面积的最大值与最小值
- HECTARES：海草床总分布面积（单位：公顷）
- PERCENT_CO：海草盖度百分比，该值为海草平均盖度，若数据单元格包含多个数值则填写盖度范围。1990年代前的调查通常会计算海草盖度，若未获取相关数据则记为"n/a"
- CUSTODIAN：数据保管方
- COMMENTS：注释说明

海草床持久性分类详解：
- 稳定型：海草床形态稳定；海草分布、生物量与面积预期长期保持稳定，除非遭遇极端事件或长期持续性影响，否则海草床将作为永久性生境存在
- 波动型：海草分布、生物量与面积预期在年度内及年度间存在波动，但除非遭遇极端事件或长期持续性影响，否则通常仍会保留一定量的海草
- 高度波动的短期型：海草床无长期持久性，部分时段存在海草，部分时段则消失。这类短期海草床在年度内及年度间的面积与生物量存在极端程度的自然波动
- 未知型：仅对海草床进行过一次采样，无法确定其持久性

海草床生境位置分类详解：
- 潮间带：所有通过直升机或实地踏勘开展调查的点位，以及野外记录手册中标记为潮间带的海草床
- 浅潮下带：采用自由潜水、水肺潜水、雪橇采样或相机作业的海草床；水深普遍为10米的海草床则被归类为深潮下带