黄土高原半干旱区云雾山封禁草原30年植被恢复对气候变化的响应

植被是区域气候与环境的综合反映,研究特定地区草地植被与气候变化的关系,寻找影响植被变化的关键因子,是植被重建和生态环境恢复的前提。利用1957-2008年的气候数据和1982-2008年的植被定位监测资料,分析了黄土高原半干旱区的宁夏云雾山植被动态变化规律及其与温度和降水的关系。结果表明:51a来,该区年平均温度明显升高,而年平均降水量总体呈减少趋势,显示黄土高原地区气候暖干化趋势明显。统计分析表明,研究区年平均温度对植被的重要值年际变化有极显著影响(P0.01),而年降水量与植被的重要值呈极显著正相关(P0.01),表明气候持续干旱化对该区植被的生长有较大影响,该区降水的多寡是直接影响植被生长优劣的决定性因子,改善区域水分状况和封禁是推进植被恢复与重建的主要措施。

Responses of vegetation restoration to climate change during the past 30 years in enclosed grassland of Yunwu Mountain in semi-arid region of the Loess Plateau

Vegetation is a complex reflection of regional climate and environment. Determining the relationship between grassland and climate changes and the key factor effecting on vegetation change plays an important role on vegetation and ecological environment restoration. In this study, the climate data (rainfall and temperature) during 1957-2008, and vegetation data during 1982-2008 were analyzed to evaluate the relationship between vegetation change and temperature and rainfall in semi-arid grassland of Yunwu Mountain in Ningxia in the Loess Plateau. The results showed that: During 1957-2008, an upward trend in annual average temperature, and a downward trend of annual rainfall volume indicated that climate in the Loess Plateau evidently trends warm and dry. Statistical analysis showed that annual average temperature took significantly (P < 0.01) impact on variation of vegetation importance value, and there is an evidently (P < 0.01) positive correlation between annual rainfall and vegetation importance value. Overall, consistently drying climate has a serious effect on vegetation growth, and rainfall volume is a key factor effecting on vegetation growth in that region. Therefore, improving regional water condition and enclosing grassland are efficient ways to accelerate vegetation restoration and re-vegetation in semi-arid region of the Loess Plateau.