Climate change may cause shifts in the natural range of species especially for those that are geographically restricted and/or endemic species. In this study, the spatial distribution of five endemic and threatened species belonging to the genus Onosma (including O. asperrima, O. bisotunensis, O. kotschyi, O. platyphylla, and O. straussii) was investigated under present and future climate change scenarios: RCP2.6 (RCP, representative concentration pathway; optimistic scenario) and RCP8.5 (pessimistic scenario) for the years 2050 and 2080 in Iran. Analysis was conducted using the maximum entropy (MaxEnt) model to provide a basis for the protection and conservation of these species. Seven environmental variables including aspect, depth of soil, silt content, slope, annual precipitation, minimum temperature of the coldest month, and annual temperature range were used as main predictors in this study. The model output for the potential habitat suitability of the studied species showed acceptable performance for all species (i.e., the area under the curve (AUC)>0.800). According to the models generated by MaxEnt, the potential current patterns of the species were consistent with the observed areas of distributions. The projected climate maps under optimistic and pessimistic scenarios (RCP2.6 and RCP8.5, respectively) of 2050 and 2080 resulted in reductions and expansions as well as positive range changes for all species in comparison to their current predicted distributions. Among all species, O. bisotunensis showed the most significant and highest increase under the pessimistic scenario of 2050 and 2080. Finally, the results of this study revealed that the studied plant species have shown an acute adaptability to environmental changes. The results can provide useful information to managers to apply appropriate strategies for the management and conservation of these valuable Iranian medicinal and threatened plant species in the future.

中文翻译：

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绘制伊朗特有的 Onosma 物种的当前和未来分布图

气候变化可能会导致物种的自然范围发生变化，尤其是那些受地理限制和/或特有物种的物种。在这项研究中，在现在和未来的气候变化情景下调查了属于 Onosma 属的五种地方性和受威胁物种（包括 O. asperrima、O. biisotunensis、O. kotschyi、O. platyphylla 和 O. straussii）的空间分布：伊朗 2050 年和 2080 年的 RCP2.6（RCP，代表性浓度路径；乐观情景）和 RCP8.5（悲观情景）。使用最大熵（MaxEnt）模型进行分析，为这些物种的保护和保育提供依据。7个环境变量，包括坡向、土壤深度、淤泥含量、坡度、年降水量、最冷月最低气温、和年温度范围被用作本研究的主要预测因子。所研究物种的潜在栖息地适宜性的模型输出显示出所有物种的可接受性能（即曲线下面积 (AUC) > 0.800）。根据 MaxEnt 生成的模型，该物种的潜在电流模式与观察到的分布区域一致。2050 年和 2080 年的乐观和悲观情景（分别为 RCP2.6 和 RCP8.5）下的预测气候图导致所有物种与其当前预测分布相比减少和扩大以及积极的范围变化。在所有物种中，O. bisotunensis 在 2050 年和 2080 年的悲观情景下表现出最显着和最高的增长。 最后，这项研究的结果表明，所研究的植物物种对环境变化表现出敏锐的适应性。研究结果可为管理人员提供有用的信息，以便他们在未来应用适当的策略来管理和保护这些有价值的伊朗药用植物和受威胁的植物物种。