9-second gridded continental Australia revegetation benefit (cleared natural areas) for Reptiles 1990:2050 CanESM2 RCP 8.5 (CMIP5) (GDM: REP_r3_v2)

Benefits of revegetation index for Reptiles as a function of land clearing within the present long term (30 year average) climate (1990 centred) based on Generalised Dissimilarity Modelling (GDM) of compositional turnover. \nThis metric represents the marginal benefit from a unit increase of vegetation at the site, which is a direct function of the slope of the species area curve at the test state of the site. In practice, revegetation of the whole cell is likely to be impractical due to the availability of cleared land within the cell, and practical limitations such as land ownership and revegetation cost. The metric therefore excludes these factors from the analysis, allowing direct comparison of the relative benefit of a given area of revegetation between cells. The values of the index generated according to the above formula are generally low (since a significant area is required to support additional species) and the index is rescaled by multiplying by 1000 to bring it into an approximate 0-1 range.\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 “Helping Biodiversity Adapt: Supporting climate adaptation planning using a community-level modelling approach”, available online at: www.adaptnrm.org. \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.\nAdditionally a short methods summary is provided in the file BiodiversityModellingMethodsSummary.pdf for further information.\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\nLineage: Benefits of revegetation index was 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 index of revegetation was calculated as the marginal gain from revegetation actions at a cleared location as a function of the area of similar ecological environments More detail of the calculations and methods are given in the document “BiodiversityModellingMethodsSummary.pdf” provided with the data download. \nGDM Model: \nGeneralised dissimilarity model of compositional turnover in reptile species for continental Australia at 9 second resolution using ALA data extracted 27 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\nNatural Areas Layer (intact to degraded land)\nAustralian Government Department of the Environment (2014) Natural areas of Australia - 100 metre (digital dataset and metadata). Available at http://www.environment.gov.au/metadataexplorer/explorer.jsp and up to date information for Western Australia were provided at 25m Albers projection were reprojected to GDA94, merged and aggregated to a continuous measure of proportion of intact area per grid cell at 9s.\n

以1990年为基准的长期（30年平均）气候情景为基础，通过物种组成更替的广义相异性建模（Generalised Dissimilarity Modelling, GDM），分析土地清理对爬行动物植被恢复收益指数的影响。
该指标表征研究样地内植被每单位增加所带来的边际收益，其直接取决于样地当前状态下种-面积曲线的斜率。实际应用中，由于地块内可清理土地的可用性、土地所有权及植被恢复成本等现实限制，对整个栅格单元进行全面植被恢复往往不具备可行性。因此，该指标在分析中剔除了上述因素，以便直接比较不同栅格单元间特定面积植被恢复的相对收益。按上述公式生成的指数数值普遍偏低（因为需要较大面积才能支撑新增物种），故通过乘以1000对其进行重新缩放，使其大致处于0-1区间内。
该指标与其他指标一同开发，用于评估气候变化背景下大陆及全球尺度上保护地体系的生物多样性保护成效，相关成果已在2014年世界自然保护联盟（IUCN）世界公园大会上发表。其相关说明见于AdaptNRM指南《助力生物多样性适应：基于群落级建模方法支持气候适应规划》，可在线访问：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（*.flt）、关联的ESRI头文件（*.hdr）及投影文件（*.prj）。从压缩包中解压后，这些文件可导入绝大多数GIS软件，通过替换对应头文件的方式，也可作为其他二进制文件格式使用。
2. ArcGIS图层包（*.lpk）：此类包可由ArcGIS解压为带关联图例的栅格图层。
此外，数据包中附带了《BiodiversityModellingMethodsSummary.pdf》文件，其中提供了简短的方法学概述以供参考。
该9秒分辨率系列栅格图层采用统一命名规则：
生物类群_基准情景_目标情景_分析类型
示例：A_90_CAN85_S 或 R_90_MIR85_L
其中，生物类群对应如下：A代表两栖动物，M代表哺乳动物，R代表爬行动物，V代表维管植物。
数据集溯源：植被恢复收益指数通过运行部署于LINUX高性能计算集群的CSIRO Muru定制并行软件计算得到，输入数据为经GDM模型转换的环境栅格。该植被恢复指数的计算逻辑为：在已清理区域开展植被恢复行动所带来的边际增益，其为相似生态环境面积的函数。更多计算细节与方法说明可参见数据下载包中附带的《BiodiversityModellingMethodsSummary.pdf》文件。
GDM模型：
以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）数据为基础，针对澳大利亚大陆构建的9秒分辨率爬行动物物种组成更替广义相异性模型（GDM: REP_r3_v2）。
气候数据：模型构建与投影采用以下数据集：
a) 1976-2005年澳大利亚大陆9秒分辨率网格化气候数据集：经海拔与辐射校正的综合变量数据集
b) 2036-2065年澳大利亚大陆9秒分辨率网格化气候数据集（基于CanESM2模式RCP 8.5情景，CMIP5框架）：经海拔与辐射校正的综合变量数据集
自然区域图层（原生至退化土地覆盖度）
澳大利亚环境部（2014）《澳大利亚自然区域——100米分辨率数字数据集及元数据》，可通过http://www.environment.gov.au/metadataexplorer/explorer.jsp 访问。西澳大利亚州的最新25米阿尔伯斯投影数据被重投影至GDA94坐标系，随后进行合并与聚合，得到9秒分辨率下每个栅格单元的原生区域占比连续度量值。