20世纪后期以来四合木分布区气候变化及其影响

Climatic Changes and Its Impact in the Distributive Region of Tetraena mongolica in the Late 20th Century

利用1971—2005年间的气象观测资料,系统分析了四合木分布区35 a来的气候变化特点及其对四合木生境与其种群动态的影响。结果表明:35 a来四合木分布区气温尤其是冬温持续上升,平均风速与大风日数逐年增加,而20世纪80年代中期以来降水逐渐减少,干燥度逐年增大,气候要素的年际与季节间波动较大,造成了四合木生境的暖冬、旱化、环境频变、生态脆弱及多灾易灾的环境效应。气候条件的不利变化,对四合木生长与繁殖有不利影响,四合木种群面积的动态监测及其与气象数据的相关分析表明,四合木种群数量的减少与相应年代的气温、大风日数、蒸发量的变化密切相关。

Tetraena mongolica, which is an endemic and endangered species in China listed in the Red Data Book, is one of the Chinese national second protective wild plants. T. mongolica is distributed mainly in Western Ordos Plateau of Inner Mongolia, but, for some reasons, the range of the population has been declining. The paper, taking the distributive district of T. mongolica as research area, the climate fluctuation and T. mongolica＇s population area as research object, analyzes the climate change characteristic and its impact on T. mongolica. On the basis of the meteorological observation data of 35 years during 1971 - 2005 in the distributive district of T. mongolica, the climate change feature and its impact on habitat and population dynamics of T. mongolica are discussed in this paper. The results show： the temperature had a process of continuous rise in the distributive district of T. mongolica, especially the temperature in winter had a distinct rising process. And the mean wind velocity and gale days had a process of rising too. While the precipitation in the distributive district of T. mongolica had a process of reducing and dry/wet index increased year after year since the mid 1980s and the inter-annual and seasonal fluctuation of climate elements is obvious. The process of climate change had such effect on habitat of T. mongolica as warm winter, more drought weather, frequent change of environment, eco- logical weakness and more disasters. The disadvantageous change of climate had an adverse impact on T. mongolica＇ s growth and reproduction. It was showed from the satellite remote monitoring information on population area of T. mongolica and correlativity analysis between climatic change and T. mongolica＇ s population area that there was a close relationship between the change of temperature, gale days, evaporation and the reducing of T. mongolica population area.