9-second gridded continental Australia disappearing ecological environments for Mammals 1990:2050 MIROC5 RCP 8.5 (CMIP5) (GDM: MAM_R2)

Disappearing ecological environments for Mammals as a function of change in long term (30 year average) climates between the present (1990 centred) and projected future (2050 centred) under the MIROC5 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.Tom HA\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: Mammals, M: mammals, R: reptiles and V: vascular plants\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 mammal species for continental Australia at 9 second resolution using ALA data extracted 26 February 2014 (GDM: MAM_r2)\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 MIROC5 RCP 8.5 (CMIP5): Summary variables with elevation and radiative adjustment\n

基于物种组成更替的广义相异性模型（Generalised Dissimilarity Modelling, GDM），本数据集呈现了以1990年为中心的当前时段与以2050年为中心的未来时段（在MIROC5模型（典型浓度路径8.5，Representative Concentration Pathway 8.5, RCP 8.5）情景下），30年平均长期气候变化对澳大利亚大陆哺乳动物适宜生态环境的影响情况。

该指标量化了以1990年为中心的当前时段中，每个9秒栅格单元的长期平均环境条件，在以2050年为中心的未来时段中仍可保留的程度。通过构建物种组成更替的广义相异性模型（即环境变化对物种群落变化的影响机制），将每个栅格位置与未来时段的大陆环境进行对比：针对每个栅格单元，该指标会检索大陆范围内所有其他栅格单元，记录当前单元的生态状态与未来时段最相似栅格单元的生态相似度。数值为1代表该环境未发生消失，且在澳大利亚境内可找到完全匹配的类似环境；数值为0则代表未来可找到的最相似环境与当前环境差异极大，以至于二者预计不存在共有物种；中间数值则反映了最相似未来环境与当前环境的生态相似程度。但该指标未考虑最相似栅格单元的空间邻近性，即便二者相距数千公里，环境相似性依然会被计入。

该指标与其他指标一同开发，用于评估大陆及全球尺度下保护区体系应对气候变化的生物多样性保护效能，相关成果已在2014年IUCN世界公园大会（IUCN World Parks Congress）上展示。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》（AdaptNRM Guide "Implications of Climate Change for Biodiversity: a community-level modelling approach"），可在线获取：www.adaptnrm.org。

本数据集以两种格式提供：
1. 压缩的ESRI浮点栅格包：包含二进制浮点栅格文件（*.flt）、关联的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，也可通过替换对应头文件的方式作为其他二进制文件格式使用。
2. ArcGIS图层包（ArcGIS layer package, *.lpk）：此类包可通过ArcGIS解压为带有关联图例的栅格图层。

此外，数据压缩包中附带了《9sMethodsSummary.pdf》文件，其中提供了简短的方法概述以供进一步参考。
作者：Tom HA

本9秒分辨率系列数据集的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，生物类群的缩写含义为：A代表哺乳动物（Mammals），M代表哺乳动物，R代表爬行动物，V代表维管植物。

数据处理流程：本数据集的生态环境消失情况通过运行于LINUX高性能计算集群的定制化并行CSIRO Muru软件计算得到，输入数据为经过GDM模型转换的环境栅格数据。计算过程为：针对每个栅格单元，求解其当前环境与未来时段所有栅格单元中最相似的那一个的相似度。更详细的计算方法与流程可参见数据下载包中附带的《9sMethodsSummary.pdf》文件。

GDM模型：
基于2014年2月26日提取的ALA数据（ALA data），构建了澳大利亚大陆9秒分辨率下哺乳动物物种组成更替的广义相异性模型（GDM: MAM_r2）。

气候数据：
模型构建与投影使用了以下数据集：
a) 1976-2005年澳大利亚大陆9秒分辨率栅格气候数据集：包含经海拔与辐射校正的综合气候变量；
b) CMIP5（Coupled Model Intercomparison Project Phase 5）框架下，MIROC5模型RCP 8.5情景对应的2036-2065年澳大利亚大陆9秒分辨率栅格气候数据集：包含经海拔与辐射校正的综合气候变量。