高寒草甸植物群落生长发育特征与气候因子的关系

为合理利用高寒草甸资源,探讨近年来气候变化对高寒草甸的影响,以青海省甘德县高寒草甸为例,基于牧业气象站1976-2006年的气象资料和1994-2006年的牧草观测资料,分析了草地植被地上生物量、高度、盖度和物候期等群落特征以及当地气温、降雨等气象因素的年际变化趋势,采用典型相关分析法和逐步回归分析法对草地植物群落特征变化与气象因子的关系进行了研究,综合分析了影响植被生长状况的关键因子,结果表明：（1）青藏高原高寒草甸总体呈年均气温和平均地温上升、年降水量下降的"暖干化"趋势,牧草盖度高度增大,产量减少,整体观测水平下的牧草物候期推迟。（2）牧草的高度、盖度及产量对不同气候因子的响应程度不同。牧草高度与盖度对温度因子的变化更敏感,牧草产量对水分因子的变化更敏感。平均地温和相对湿度越高,牧草高度越高,产量越多。（3）不同牧草的物候期受不同气象因子的影响,变化趋势也不相同。从整体水平上看,牧草物候期对温度因子更敏感,温度越高,物候期越提前。

Relationship between the characteristics of plant community growth and climate factors in alpine meadow

The impact of global climate change and human activities on grassland ecosystems has been increasing in recent years. The sensitivity of alpine grassland ecosystems to global changes has attracted the attention of many scholars. Forage height, coverage and yield are important basis for determining the growth of grasses. Grassland biomass, as an important indicator of grassland productivity, is of great significance for studying changes in grassland vegetation, evaluating the growth of grassland, and providing reference for grassland management. Coverage, as one of the important parameters of grassland community structure, can reflect the health status of grasslands. Plant phenology is an important indicator of environmental change, and in alpine meadow ecosystems, which is more sensitive to climate change. At the same time, precipitation and temperature, as important climatic factors, have become the focus of research on factors affecting the growth of grasslands. Alpine meadow is one of the most sensitive alpine grassland type in response to climate change. Studying the response of changes in plant growth characteristics of alpine meadow to the meteorological factors is important for analyzing the effects of climate change on alpine meadow. Therefore, in order to make rational use of alpine meadow resources and explore the impact of climate change on alpine meadow in recent years, this paper takes alpine meadow in Gande County, Qinghai Province, as an example. We analyze the community characteristics such as above-ground biomass, height, coverage and phenological stage of meadow vegetation based on the pasture observation data from 1994-2006, as well as local air temperature, rainfall and other meteorological data from 1976-2006. The results showed that (1) the alpine meadow on the Qinghai-Tibet Plateau was warming and drying with averagely annual temperature and average ground temperature rising and annual precipitation falling. The coverage and height of forage were increasing, while the yield is decreasing, and the forage phenology was delayed at the overall observed level. (2) Forage height, coverage, and yield responded differently to different climatic factors. Forage height and coverage were more sensitive to changes in temperature, and forage yield was more sensitive to changes in moisture. The higher the average ground temperature and relative humidity, the higher the height and yield of forage. (3) The trend of phenology is influenced by different meteorological factors. On the whole, the phenological phase of forage is more sensitive to the temperature factor, and the higher the temperature, the earlier the phenological phase.