9-second gridded continental Australia potential degree of ecological change for Mammals 1990:2050 CanESM2 RCP 8.5 (CMIP5) (GDM: MAM_R2)

Potential degree of ecological change in 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 CanESM2 model (RCP 8.5) based on Generalised Dissimilarity Modelling (GDM) of compositional turnover.

This metric describes the change in long term average environmental conditions at a single location (9s grid square) from the present (1990 centred) to a 2050 centred future, scaled in terms of its expected effects on the turnover of species. Compositional turnover patterns in amphibian species across continental Australia were derived using Generalised Dissimilarity Modelling (GDM). These models use best-available biological data extracted from the Atlas of Living Australia (ALA) in 2013, and spatial environmental predictor data compiled at 9 second resolution. GDM-scaled environmental grids were used as the basis for pairwise cell comparisons across space and time using the highly parallel CSIRO Muru software to derive the potential degree of ecological change. Each location is compared with its future state. The difference in environment is presented as an expected ecological similarity, ranging from 1 (completely similar) to 0, for which we would expect no species in common. If this environmental difference was observed in a different spatial location within the present, we would expect to observe such a difference if we visited both sites.

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.Tom HA

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: Mammals, M: mammals, R: reptiles and V: vascular plants

本数据集基于群落物种组成更替的广义差异建模（Generalised Dissimilarity Modelling，GDM），展示了在CanESM2模式（RCP 8.5）下，以1990年为中心的当前时段与以2050年为中心的未来时段之间，长期（30年平均）气候变化所对应的哺乳动物生态变化潜在程度。

该指标描述了单个点位（9秒栅格）的长期平均环境条件从当前（以1990年为基准）到2050年基准未来的变化，并以其对物种组成更替的预期影响进行了标准化。澳大利亚大陆两栖动物的物种组成更替模式通过GDM推导得到，这些模型使用了2013年从澳大利亚生物图集（Atlas of Living Australia，ALA）获取的最优可用生物数据，以及分辨率为9秒的空间环境预测因子数据。研究使用高度并行化的CSIRO Muru软件，以GDM标准化后的环境栅格为基础，开展空间与时间上的成对栅格单元对比，从而推导得到生态变化潜在程度。每个点位均与其未来状态进行对比，环境差异以预期生态相似度表示，取值范围为1（完全相似）到0，当取值为0时，两个点位预计无共有物种。若在当前时段的不同空间点位观测到该环境差异，则在同时访问这两个点位时可观测到类似差异。

该指标与其他指标一同被开发，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的生物多样性保护效能，相关成果发表于2014年世界自然保护联盟（IUCN）世界公园大会。相关描述可参见AdaptNRM指南《气候变化对生物多样性的影响：群落水平建模方法》，在线访问地址为：www.adaptnrm.org。

数据集以两种形式提供：
1. 压缩的ESRI浮点栅格：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，这些文件可导入多数地理信息系统（GIS）软件，通过替换对应头文件，也可作为其他二进制文件格式使用。
2. ArcGIS图层包（*.lpk）：此类包可通过ArcGIS解压为带有关联图例的栅格数据。

此外，文件9sMethodsSummary.pdf中提供了简短的方法摘要，以供进一步参考。Tom HA

本9秒系列栅格采用统一命名规范：生物类群_基准时段_情景_分析类型，例如A_90_CAN85_S或R_90_MIR85_L，其中生物类群代码含义如下：A对应哺乳纲动物（Mammals）、M对应哺乳类（mammals）、R对应爬行纲动物、V对应维管植物。