全球气候变暖对极小种群植物扣树生境适宜性的影响

Effects of Global Warming on Habitat Suitability of Ilex kaushue, a Plant with an Extremely Small Population

摘要

极小种群植物扣树(Ilex kaushue S. Y. Hu)是分布于中国南方的特有树种, 易受到气候变化的影响。为加强扣树的保护, 有必要研究气候变暖背景下其生境适宜性范围的变化。通过对10种物种分布模型的预测精度进行对比, 选择3种预测性能较好的物种分布模型(GBM、MaxEnt和RF)的平均值来评估气候变暖对扣树生境适宜性的影响。当前气候下扣树适宜生境区的预测结果表明, 扣树的分布较为集中, 最冷月最低温度(bio6)、降雨量季节性变化(bio15)和最干旱月降雨量(bio14)对模型贡献最大, 说明扣树对温度和降水较为敏感。在未来气候情景下, 扣树的生境适宜区呈现向北迁移的趋势, 适宜分布范围存在不同程度的缩小; 预测到2070年, 随着温室气体排放增加, 扣树的适生范围由RCP2.6情景下的92.70%缩小到RCP8.5情景下的51.52%, 特别是在低纬度的海南省, 4种情景的平均适生生境缩减了93.67%。因此, 在制定极小种群植物扣树的保护策略时应考虑气候变暖的影响。

Abstract

Ilex kaushue, a tree species with an extremely small population, is uniquely distributed in southern China and is vulnerable to climate change. In order to strengthen the protection of I. kaushue, it is necessary to study its habitat suitability range in the background of climate warming. Based on the current bioclimatic data and future climate prediction, 10 species distribution models were used to predict the potential distri-bution of I. kaushue. Among them, 3 species distribution models (GBM, MaxEnt and RF) with good prediction performance were selected out to evaluate the impact of climate warming on the habitat suitability of I. kaushue. In the current climate, the distribution range of I. kaushue was predicted to be relatively concen-trated. The lowest temperature in the coldest month (bio6), the seasonal variation of precipitation (bio15) and the precipitation in the driest month (bio14) contributed the most to the models, indicating that I. kaushue should be more sensitive to the temperature and precipitation. Under the future climate conditions, the habi-tat suitable area of I. kaushue would move northward and its habitat suitability range would decrease. The suitable growth range of I. kaushue may be reduced from 92.70% in RCP2.6 scenario to 51.52% in RCP8.5 scenario in 2070, with increasing emissions of greenhouse gases. Especially in the low-latitude Hainan Province, the average suitable habitat under the 4 scenarios decreased by 93.67%. Therefore, the influence of climate change should be taken into account in protection strategies for plant species with extremely small populations like I. kaushue.

关键词

扣树 / 适宜生境 / 气候变暖 / 物种分布模型(SDM)

Key words

Ilex kaushue / suitable habitat / global warming / species distribution model (SDM)