9-second gridded continental Australia disappearing ecological environments for Vascular Plants 1990:2050 MIROC5 RCP 8.5 (CMIP5) (GDM: VAS_v5_r11)

Disappearing ecological environments for Plants 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. This 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 could be thousands of kilometres apart. This 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. Data are provided in two forms: 1. 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. 2. ArcGIS layer package (*.lpk): These packages contain can be unpacked by ArcGIS as a raster with associated legend. Additionally a short methods summary is provided in the file 9sMethodsSummary.pdf for further information. Layers in this 9s series use a consistent naming convention: BIOLOGICAL GROUP _ FROM BASE_ TO SCENARIO_ ANALYSIS e.g. A_90_CAN85_S or R_90_MIR85_L where BIOLOGICAL GROUP is A: Vascular Plants, M: Vascular Plants, R: Vascular Plants 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 ecological 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. GDM Model: Generalised dissimilarity model of compositional turnover in vascular plant species for continental Australia at 9 second resolution using ANHAT data extracted 4 April 2013 (GDM: VAS_v5_r11) Climate data. Models were built and projected using: a) 9-second gridded climatology for continental Australia 1976-2005: Summary variables with elevation and radiative adjustment b) 9-second gridded climatology for continental Australia 2036-2065 MIROC5 RCP 8.5 (CMIP5): Summary variables with elevation and radiative adjustment

本数据集为基于物种组成更替的广义非相似性模型（Generalised Dissimilarity Modelling, GDM）构建的植物生境消失数据集，其以MIROC5模式下典型浓度路径8.5（RCP 8.5）情景中，以1990年为中心的当前气候与以2050年为中心的预估未来气候之间的30年长期平均变化为函数。
该指标用于描述以1990年为中心的当前时段内，每个9秒栅格单元的长期平均环境条件，在以2050年为中心的预估未来中仍可匹配的程度。通过构建物种组成更替的广义非相似性模型（即环境变化对物种群落变化的影响机制），将每个栅格点位与未来时段的澳大利亚大陆全域进行比对。针对每个栅格单元，该指标会遍历大陆内的所有其他栅格单元，记录当前栅格的生态状态与未来时段中最相似栅格单元的生态相似度。当指标取值为1时，代表该生境未发生消失，且在澳大利亚境内可找到完全匹配的类似生境；取值为0时，则代表未来可找到的最相似环境与当前环境生态差异极大，以至于可认为二者无共有物种；中间取值则反映了未来最相似栅格单元的生态相似程度。但该指标未考量最相似栅格单元的空间邻近性：即便环境特征相似，两个栅格单元之间的空间距离可能可达数千公里。
该指标与其他同类指标一同被开发，用于评估大陆及全球尺度下保护区系统应对气候变化对生物多样性的保护成效，相关成果曾在2014年世界自然保护联盟（International Union for Conservation of Nature, IUCN）世界公园大会上展示。该指标的详细说明见于《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。
数据集以两种形式提供：
1. 压缩的ESRI浮点栅格包：包含二进制浮点栅格文件（*.flt）、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（Geographic Information System, 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（*.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，随数据集一并提供了9sMethodsSummary.pdf文件，其中包含简要的方法学概述以供进一步参考。
该9秒栅格系列的图层采用统一命名格式：`生物类群_基准时段_情景_分析类型`，示例为A_90_CAN85_S或R_90_MIR85_L，其中生物类群分别对应：A：维管植物、M：维管植物、R：维管植物、V：维管植物。
计算流程：本数据集的植物生境消失指标通过运行于LINUX高性能计算集群的高度并行化定制化英联邦科学与工业研究组织（Commonwealth Scientific and Industrial Research Organisation, CSIRO）Muru软件计算得到，输入数据为经广义非相似性模型转换的环境栅格。计算过程为对每个栅格单元，求取其当前生态环境与未来时段中最相似栅格单元的相似度。更多计算细节与方法学说明见于随数据下载提供的《9sMethodsSummary.pdf》文件。
广义非相似性模型说明：本数据集所用的广义非相似性模型为针对澳大利亚大陆9秒分辨率的维管植物物种组成更替构建的模型，所用数据为2013年4月4日提取的ANHAT气候数据集（GDM: VAS_v5_r11）。模型构建与未来情景投影采用以下数据集：
a) 1976-2005年澳大利亚大陆9秒栅格气候数据集：包含经海拔与辐射校正的气候摘要变量；
b) 耦合模式比较计划第五阶段（CMIP5）中MIROC5模式典型浓度路径8.5情景下，2036-2065年澳大利亚大陆9秒栅格气候数据集：包含经海拔与辐射校正的气候摘要变量。