9-second gridded continental Australia disappearing ecological environments for Reptiles 1990:2050 CanESM2 RCP 8.5 (CMIP5) (GDM: REP_r3_v2)

Disappearing ecological environments for Reptiles 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.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\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: \t\nGeneralised dissimilarity model of compositional turnover in reptile species for continental Australia at 9 second resolution using ALA data extracted 28 February 2014 (GDM: REP_r3_v2)\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\n

本数据集聚焦爬行动物所面临的生态环境消失情况，其基于物种组成更替的广义相异模型（Generalised Dissimilarity Modelling, GDM），分析了以1990年为基准的当前时段与以2050年为基准的预估未来时段之间，30年均值的长期气候变化所带来的影响，相关分析基于CanESM2模式的典型浓度路径8.5（Representative Concentration Pathway 8.5, RCP 8.5）情景。

该指标描述了以1990年为基准的当前时段中，每个9秒（9s）网格单元的长期平均环境条件，在以2050年为基准的预估未来时段中留存的程度。借助物种组成更替（即环境变化对物种变化的影响）的广义相异模型，将每个点位与未来时段的大陆环境进行比对。针对每个网格单元，该指标会遍历大陆范围内的所有其他单元，记录该单元当前状态的生态环境与未来时段中最相似单元的生态相似度。取值为1时，表示该环境并未消失，且在澳大利亚境内可找到完全匹配的类似环境；取值为0时，表示未来可找到的最相似环境与当前环境的生态差异极大，以至于可以认为二者无共有物种；中间取值则代表当前环境与最相似未来环境的生态相似程度。但该指标未考虑最相似单元的空间邻近性，即便环境相似，二者可能相距数千公里。

本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（IUCN）世界公园大会上展示。其相关描述见于《AdaptNRM指南：气候变化对生物多样性的影响：群落级建模方法》，可在线获取：www.adaptnrm.org。

数据集以两种形式提供：
1. 压缩的ESRI浮点栅格文件：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）：此类文件可由ArcGIS解压为带有配套图例的栅格图层。

此外，数据下载包中附带了9sMethodsSummary.pdf文件，其中提供了简短的方法概述以供参考。——Tom HA

本9秒系列数据集的图层采用统一命名规则：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，生物类群缩写对应的类别为：A：哺乳类（Mammals），M：哺乳类（mammals），R：爬行动物（reptiles），V：维管植物（vascular plants）。

本数据集的生成路径：爬行动物的生态环境消失情况通过运行于Linux高性能计算集群的高度并行定制化CSIRO Muru软件计算得到，输入数据为经广义相异模型（GDM）转换的环境栅格。研究计算了每个当前网格单元的环境，与未来时段中最相似单元的生态相似度。更详细的计算过程与方法，可参见数据下载包中附带的《9sMethodsSummary.pdf》文档。

广义相异模型（GDM）：
针对澳大利亚大陆9秒分辨率的爬行动物物种组成更替构建的广义相异模型，所用数据为2014年2月28日提取的澳大利亚生物图集（Atlas of Living Australia, ALA）数据（GDM模型编号：REP_r3_v2）。
气候数据：模型的构建与预估使用以下数据集：
a) 1976-2005年澳大利亚大陆9秒分辨率栅格气候数据集：包含经高程与辐射校正的汇总变量；
b) 基于CanESM2模式典型浓度路径8.5情景（耦合模式比较计划第五阶段（Coupled Model Intercomparison Project Phase 5, CMIP5））的2036-2065年澳大利亚大陆9秒分辨率栅格气候数据集：包含经高程与辐射校正的汇总变量。