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

Novel 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.

This metric describes the nature of the projected 2050 centred future environmental conditions for each 9s grid square. Using a Generalised Dissimilarity Model of compositional turnover (the effects of changing environment on changing species), each future location is compared with the continent in the present. For each cell, the metric looks out to all other cells in the continent, and records the ecological similarity of the future state of the cell to the most similar cell in the present. A value of 1 indicates that the future environment is similar to a current location in the present, and perfect analogue can found somewhere in Australia. A value of 0 indicates that the most similar environment to be found in the present is ecologically so different that we would expect no species in common, i.e. there are no current analogues for this environment; it is novel. 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.

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: Reptiles, M: Reptiles, R: reptiles and V: vascular plants

基于物种组成周转的通用相异性建模（Generalised Dissimilarity Modelling, GDM），本数据集以CanESM2模式（典型浓度路径8.5, RCP 8.5）下，当前（以1990年为中心）与预测未来（以2050年为中心）的30年平均气候变化为依据，生成爬行动物的新型生态环境数据集。

该指标用于描述每个9秒网格单元在以2050年为中心的未来环境条件特征。借助刻画物种组成周转（即环境变化对物种群落变化的影响）的通用相异性模型，将每个未来样点与当前大陆的所有样点进行比对。针对每个网格单元，该指标会遍历大陆内全部其他网格单元，记录该单元未来生态状态与当前最相似单元的生态相似度。取值为1时，表示未来环境与当前某一现存位置的环境高度相似，且可在澳大利亚境内找到完美匹配的类似环境；取值为0时，则表示当前现存环境中与该未来环境最相似的二者生态差异极大，几乎不存在共有物种，即该环境无现存类似物，属于新型生态环境。中间取值则代表最相似单元的生态相似程度。但该指标未考量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。

该指标与其他指标一同开发，用于评估大陆及全球尺度下，保护区系统在气候变化背景下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。相关描述可参阅《AdaptNRM指南：气候变化对生物多样性的影响：群落级建模方法》，该指南可在线获取：www.adaptnrm.org。

本数据集以两种形式提供：
1. 压缩的ESRI浮点栅格数据集：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）：该类数据包可通过ArcGIS解压为带有配套图例的栅格图层。

此外，数据集附带了简短的方法总结文件9sMethodsSummary.pdf，以供进一步查阅详细信息。

本9秒系列数据集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
其中生物类群对应为：A：爬行动物，M：爬行动物，R：爬行动物，V：维管植物