Walker’s Manihot, Manihot walkerae, is an endangered plant that is endemic to the Tamaulipan thornscrub ecoregion of extreme southern Texas and northeastern Mexico. M. walkerae populations are highly fragmented and are found on both protected public lands and private property. Habitat loss and competition by invasive species are the most detrimental threats for M. walkerae; however, the effect of climate change on M. walkerae’s geographic distribution remains unexplored and could result in further range restrictions. Our objectives are to evaluate the potential effects of climate change on the distribution of M. walkerae and assess the usefulness of natural protected areas in future conservation. We predict current and future geographic distribution for M. walkerae (years 2050 and 2070) using three different general circulation models (CM3, CMIP5, and HADGEM) and two climate change scenarios (RCP 4.5 and 8.5). A total of nineteen spatially rarefied occurrences for M. walkerae and ten non-highly correlated bioclimatic variables were inputted to the maximum entropy algorithm (MaxEnt) to produce twenty replicates per scenario. The area under the curve (AUC) value for the consensus model was higher than 0.90 and the partial ROC value was higher than 1.80, indicating a high predictive ability. The potential reduction in geographic distribution for M. walkerae by the effect of climate change was variable throughout the models, but collectively they predict a restriction in distribution. The most severe reductions were 9% for the year 2050 with the CM3 model at an 8.5 RCP, and 14% for the year 2070 with the CMIP5 model at the 4.5 RCP. The future geographic distribution of M. walkerae was overlapped with protected lands in the U.S. and Mexico in order to identify areas that could be suitable for future conservation efforts. In the U.S. there are several protected areas that are potentially suitable for M. walkerae, whereas in Mexico no protected areas exist within M. walkerae suitable habitat.

中文翻译：

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气候变化对濒危植物Manihot walkerae地理分布的潜在影响

沃克的Manihot，Manihot walkerae是一种濒临灭绝的植物，在得克萨斯州南部和墨西哥东北部的Tamaulipan荆棘生态区特有。沃氏支原体种群高度分散，在受保护的公共土地和私人财产上均存在。生境的丧失和外来入侵物种的竞争是对华枝杆菌的最大危害; 但是，气候变化对沃克分枝杆菌地理分布的影响尚未发现，可能会进一步限制射程。我们的目标是评估气候变化对W. Walkerae分布的潜在影响并评估自然保护区在未来保护中的用处。我们使用三种不同的一般环流模型（CM3，CMIP5和HADGEM）和两种气候变化情景（RCP 4.5和8.5）来预测华氏沼虾（2050年和2070年）的当前和未来的地理分布。将共计十九个步履梭菌的空间稀疏事件和十个非高度相关的生物气候变量输入最大熵算法（MaxEnt），以每个场景产生二十次重复。共识模型的曲线下面积（AUC）值高于0.90，部分ROC值高于1.80，表明具有较高的预测能力。沃克分枝杆菌的地理分布可能减少在整个模型中，气候变化的影响是可变的，但总的来说，它们预测了分布的限制。CM3模型在8.5 RCP时，最严重的降低是2050年的9％，而CMIP5模型在4.5 RCP时，2070年的最大降低是14％。在美国和墨西哥，沃克分枝杆菌的未来地理分布与受保护土地重叠，以便确定可能适合未来保护工作的区域。在美国，有几个潜在的适合于沃克沃克线虫的保护区，而在墨西哥，沃克沃克线虫合适的栖息地内没有任何保护区。