Forecasting climate-driven extinction risk and distributional change of the Karner blue butterfly to guide managed relocation

The Karner blue butterfly (Kbb) (Plebejus samuelis) is a federally listed endangered species whose decline is exacerbated by climate change. Evaluating how climate shapes population dynamics and the distribution of the Kbb may help develop adaptation plans. We applied mixed endo-exogenous models to examine the extinction risk and the likely distributional shift of some existent Kbb populations under several climatic change scenarios (elevated temperature and increased precipitation variance) by 2049. The predictions showed that local management of Kbb populations in Central Wisconsin and at Indiana Dunes National Park might not have been sufficient to mitigate adverse effects of climate change, and Kbbs were projected to reach higher abundance in the northern Midwest. These results suggest that some threatened populations might benefit from managed relocation and that it would be possible to reintroduce the Kbb back to Minnesota. To identify target sites for relocation, we overlapped model projections with the Minnesota soil classification map. We found a large expanse of sandy and loamy sandy soils geographically coincident with high climatic suitability for the Kbb. If those areas were planted with the host wild lupine (Lupinus perennis) and other native nectar plants, they have the potential to be developed as climate refugia of this imperiled butterfly. However, habitat management in currently occupied sites can be a more effective conservation strategy for populations with lower extinction risks.

The uploaded data include 1. future climate envelops of the upper Midwest region till 2049 we extracted from the four RCPs of GFDL in terms of mean, max, and min temperature and total precipitation as well as three additional scenarios (+0.5/1%, +1.0/2%, +1.5/3%), which are the inputs of our endo-exogenous models for prediction; 2. all the pseudo-extinction risk outputs for each population and ecoregion, as well as four-way ANOVA test results of pairwise comparison between treatments (i.e., four climate scenarios, two habitat areas, four time windows, and two models); 3. all the projected maps of suitable habitats in the upper Midwest for the populations in each of the five ecoregions; 4. Some demo codes for extracting raw climate date and making predictions.

卡恩蓝蝶（Kbb，学名为Plebejus samuelis），作为一种被联邦政府列为濒危物种，其数量的减少受到了气候变化的加剧影响。评估气候变化如何塑造种群动态及卡恩蓝蝶的分布，有助于制定适应性规划。本研究采用混合的内生-外生模型，考察了在2049年之前，若干气候变化情景（包括温度升高和降水变率增加）下，一些现有卡恩蓝蝶种群灭绝风险及可能的分布变化。预测结果显示，在威斯康星州中部和印第安纳州大沼泽国家公园对卡恩蓝蝶种群的本地管理可能不足以缓解气候变化的不利影响，预计卡恩蓝蝶在北中西部将达到更高的数量。这些结果暗示，一些受威胁的种群可能从有序迁移中获益，且有可能将卡恩蓝蝶重新引入明尼苏达州。为了确定迁移目标地，我们将模型预测与明尼苏达州土壤分类图叠加。我们发现，一大片沙质和沙壤质土壤在地理上与卡恩蓝蝶高度适宜的气候条件相吻合。若在这些地区种植宿主野生羽扇豆（Lupinus perennis）和其他本地蜜源植物，它们有可能发展成为这种濒危蝴蝶的气候避难所。然而，对于灭绝风险较低的种群而言，目前在占据地段的栖息地管理可能是一种更为有效的保护策略。

所上传的数据包括：1. 从GFDL的四个RCPs中提取的直至2049年上中西部地区的未来气候范围，包括平均、最高和最低温度以及总降水量，以及三个额外的情景（+0.5/1%、+1.0/2%、+1.5/3%），这些是本内生-外生模型预测的输入；2. 每个种群和生态区域的伪灭绝风险输出，以及四个气候情景、两个栖息地区域、四个时间窗口和两个模型之间成对比较的四向方差分析测试结果；3. 上中西部五个生态区域中各种群适宜栖息地预测图；4. 一些用于提取原始气候数据和进行预测的示例代码。