9-second gridded continental Australia disappearing ecological environments for Amphibians 1990:2050 CanESM2 RCP 8.5 (CMIP5) (GDM: AMP_r2_PTS1)

Disappearing ecological environments for Amphibians as a function of change in long term (30 year average) climates between the present (1990 centred) and projected future (2050 centred) under the CanESM2 model (RCP 8.5) based on Generalised Dissimilarity Modelling (GDM) of compositional turnover. \n\nThis metric describes the extent to which the long term average environmental conditions for each 9s grid square in the present (1990 centred) will be present in a projected 2050 centred future. Using a Generalised Dissimilarity Model of compositional turnover (the effects of changing environment on changing species), each location is compared with the continent in the future. For each cell, the metric looks out to all other cells in the continent, and records the ecological similarity of the present state of the cell to the most similar cell in the future. A value of 1 indicates that the environment is not disappearing, and perfect analogue is found somewhere in Australia. A value of 0 indicates that the most similar environment to be found in the future is ecologically so different that we would expect no species in common. Intermediate values show how ecologically similar the most similar cell is. However, no weight is given to the proximity of the most similar cell. The environment may be similar, but the cells thousands of kilometres apart.\n\nThis metric was developed along with others for use in an assessment of the efficacy of the protected area system for biodiversity under climate change at continental and global scales, presented at the IUCN World Parks Congress 2014. It is described in the AdaptNRM Guide “Implications of Climate Change for Biodiversity: a community-level modelling approach”, available online at: www.adaptnrm.org. \n\nData are provided in two forms:\n1. Zipped ESRI float grids: Binary float grids (*.flt) with associated ESRI header files (*.hdr) and projection files (*.prj). After extracting from the zip archive, these files can be imported into most GIS software packages, and can be used as other binary file formats by substituting the appropriate header file.\n2. ArcGIS layer package (*.lpk): These packages contain can be unpacked by ArcGIS as a raster with associated legend.\n\nAdditionally a short methods summary is provided in the file 9sMethodsSummary.pdf for further information.\n\nLayers in this 9s series use a consistent naming convention:\nBIOLOGICAL GROUP _ FROM BASE_ TO SCENARIO_ ANALYSIS\ne.g. A_90_CAN85_S or R_90_MIR85_L\nwhere BIOLOGICAL GROUP is A: amphibians, M: mammals, R: reptiles and V: vascular plants\n\nLineage: Disappearing ecological environments were calculated using the highly parallel bespoke CSIRO Muru software running on a LINUX high-performance-computing cluster, taking GDM model transformed environmental grids as inputs. The similarity of the most similar future cell to the present environment of each cell was calculated. More detail of the calculations and methods are given in the document “9sMethodsSummary.pdf” provided with the data download. \nGDM Model: \nGeneralised dissimilarity model of compositional turnover in amphibian species for continental Australia at 9 second resolution using ALA data extracted 27 February 2014 (GDM: AMP_r2_PTS1)\nClimate data. Models were built and projected using:\na) 9-second gridded climatology for continental Australia 1976-2005: Summary variables with elevation and radiative adjustment\nb) 9-second gridded climatology for continental Australia 2036-2065 CanESM2 RCP 8.5 (CMIP5): Summary variables with elevation and radiative adjustment

本数据集聚焦澳大利亚两栖类的生态环境消失情况，以物种组成更替的广义相异性建模（Generalised Dissimilarity Modelling, GDM）为分析方法，依托CanESM2模式（RCP 8.5）下的长期（30年平均）气候数据，对比以1990年为中心的当前气候态与以2050年为中心的预估未来气候态之间的变化。

该指标用于量化以1990年为中心的当前时段下，每一个9秒分辨率网格单元的长期平均环境条件在以2050年为中心的未来预估气候中保留的程度。本研究采用物种组成更替的广义相异性模型（即环境变化对物种变化的影响机制），将每个现状网格单元与未来澳大利亚大陆的所有网格单元进行比对。针对每个现状网格单元，该指标会遍历大陆范围内的全部未来网格单元，记录该现状单元的生态环境与未来最相似网格单元之间的生态相似性程度。指标取值为1时，代表该区域的生态环境未发生消失，在澳大利亚境内可找到完全匹配的类似环境；取值为0时，则代表未来可找到的最相似环境与现状生态环境差异极大，二者预期无共有物种；中间取值则反映了现状与最优匹配未来环境的生态相似性水平。需注意，该指标未考虑最优匹配网格单元的空间邻近性，即便两处网格相距数千公里，只要环境相似即会被计入。

该指标与其他同类指标一同开发，用于大陆与全球尺度下气候变化背景下生物多样性保护区系统的效能评估，相关成果发表于2014年世界自然保护联盟（International Union for Conservation of Nature and Natural Resources, IUCN）世界公园大会。其详细说明见于AdaptNRM指南《气候变化对生物多样性的影响：群落级建模方法》，可通过网址www.adaptnrm.org在线获取。

本数据集提供两种格式：
1. 压缩版ESRI浮点栅格数据：包含二进制浮点栅格文件（*.flt）、配套的ESRI头文件（*.hdr）与投影文件（*.prj）。从压缩包解压后，这些文件可导入绝大多数地理信息系统（GIS）软件；若需用作其他二进制栅格格式，仅需替换对应的头文件即可。
2. ArcGIS图层包（*.lpk）：此类包可通过ArcGIS软件解压为带配套图例的栅格图层。

此外，随数据附带了方法概述文件《9sMethodsSummary.pdf》，供用户查阅更多细节。

本9秒分辨率系列栅格图层采用统一命名规范：
`生物类群_基准时段_情景_分析类型`
示例：A_90_CAN85_S 或 R_90_MIR85_L
其中，生物类群代码含义如下：A代表两栖类，M代表哺乳类，R代表爬行类，V代表维管植物。

数据集生成流程：本数据集的消失型生态环境指标通过澳大利亚联邦科学与工业研究组织（Commonwealth Scientific and Industrial Research Organisation, CSIRO）定制的高并行Muru软件计算完成，该软件运行于Linux高性能计算集群，输入数据为经GDM模型转换的环境栅格数据。计算过程为：针对每个现状网格单元，求取其与未来所有网格单元中生态相似度最高的单元的相似性值。详细的计算流程与方法说明可随数据下载附带的《9sMethodsSummary.pdf》文件获取。

GDM模型：
本研究采用2014年2月27日提取的澳大利亚生物多样性图谱（Atlas of Living Australia, ALA）数据，构建了澳大利亚大陆范围内9秒分辨率下两栖类物种组成更替的广义相异性模型（模型标识：AMP_r2_PTS1）。
气候数据：模型构建与预估采用以下两套数据：
a) 1976-2005年澳大利亚大陆9秒分辨率网格化气候数据集：包含经高程与辐射校正的综合气候变量；
b) 基于CMIP5计划的CanESM2模式RCP 8.5情景下2036-2065年澳大利亚大陆9秒分辨率网格化气候数据集：包含经高程与辐射校正的综合气候变量。