Projected Change in Climatically Relevant Variables for Boreal Toad

To assess how climate change may impact Southern Rocky Mountain Boreal Toad (Anaxyrus boreas boreas) populations, we present observed and projected climate summaries of 'active season length' and 'water availability'. Active season length is represented by ACTLEN2 and ACTLEN1 and utilizes daily minimum temperature (Lambert et al. 2016). Water availability is represented by the formula: precipitation minus potential evapotranspiration. Four future climates model outputs were chosen to bracket a representative range of outcomes for temperature and precipitation changes projected for the Southern Rocky Mountain region: a relatively hot and wet future (CanESM2); a relatively hot and dry future (IPSL-CM5A-LR); a relatively warm and wet future (GFDL-ESM2M); a relatively warm and dry future (inmcm4). Daily minimum temperature observations were 800-meter gridded data from TopoWx. Annual precipitation and potential evapotranspiration observations were summarized from 4-kilometer gridded monthly data from Gridmet. The years 1980-2009 defined the observed period. Delta (change) values were obtained from the Multivariate Adaptive Constructed Analogs (MACA) datasets and are based on General Circulation Model forecast minus hindcast for the periods 2040-2069 (forecast) and 1971-2000 (hindcast). MACA data are statistically downscaled from CMIP5 model output to a 4-kilometer resolution. We selected Representative Concentration Pathway (RCP) 8.5. Future projections for each climate variable were obtained by applying the delta values to the average across the 30-year observed.

Lambert, B. A., Schorr, R. A., Schneider, S. C. and Muths, E. (2016), Influence of demography and environment on persistence in toad populations. Jour. Wild. Mgmt., 80: 1256â 1266. doi:10.1002/jwmg.21118

为评估气候变化对南方落基山脉北方蟾蜍（Anaxyrus boreas boreas）种群的潜在影响，我们呈现了‘活动季长度’与‘水分可利用性’的观测及预测气候摘要。

活动季长度由ACTLEN2和ACTLEN1两个指标表征，其计算基于日最低气温（Lambert等人，2016）。水分可利用性通过公式‘降水量减去潜在蒸散量’计算。

我们选取了四种未来气候模型输出结果，以涵盖南方落基山脉区域温度与降水变化预测的代表性结果范围：相对炎热湿润的未来（CanESM2）、相对炎热干燥的未来（IPSL-CM5A-LR）、相对温暖湿润的未来（GFDL-ESM2M）及相对温暖干燥的未来（inmcm4）。

日最低气温观测数据为TopoWx提供的800米网格数据；年降水量与潜在蒸散量观测数据则汇总自Gridmet提供的4公里网格月度数据。观测期设定为1980-2009年。

变化量（delta）值取自多变量自适应构造类比数据集（Multivariate Adaptive Constructed Analogs, MACA），其计算基于大气环流模式对2040-2069年（预测期）与1971-2000年（回溯期）的预测值减去回溯值。MACA数据通过统计降尺度方法，由CMIP5模型输出转换至4公里分辨率。我们选取了典型浓度路径8.5（Representative Concentration Pathway, RCP 8.5）情景。

Lambert, B. A., Schorr, R. A., Schneider, S. C. and Muths, E. (2016), Influence of demography and environment on persistence in toad populations. Jour. Wild. Mgmt., 80: 1256–1266. doi:10.1002/jwmg.21118