内蒙古主要草原类型植物物候对气候波动的响应

Responses of phenology to climate change over the major grassland types

物候是气候变化的指示者,由于不同地区植被类型不同,导致其对气候波动的响应方式不同。利用2004—2013年内蒙古草原区生态监测站群落优势种物候观测资料和同时段的气象资料,分析了不同草原类型区优势种物候期变化及其与气候因子间的相互关系,结果表明:(1)2004—2013年内蒙古草原区各时段气候波动趋势均不显著,返青前以气温降低、降水增加趋势为主;黄枯前草甸草原、典型草原以气温降低、降水增加趋势为主,荒漠草原变化趋势相反。(2)2004—2013年典型草原植物返青期平均提前4.01 d,黄枯推后10.35 d,生长季延长14.36 d;草甸草原返青期提前2.04 d,黄枯期推后12.68 d,生长季延长14.72 d;荒漠草原物候变化趋势最小,返青期平均提前了1.32 d,黄枯期平均推后了9.58 d,生长季延长了10.90 d。(3)内蒙古草原区植物返青期主要受气温波动的影响,草甸草原返青期与前3个月平均气温的负相关最为显著,气温每升高1℃,返青期约提前1.123 d;典型草原、荒漠草原返青期与前2个月平均气温的负相关最为显著气,气温每升高1℃,返青期约提前1.137 d和1.743 d。(4)典型草原区植物黄枯期受前1—2月平均气温和累积降水的共同影响,与夏季平均气温和当月降水量的相关最为显著,夏季气温每升高1℃,黄枯期约提前2.250 d,当月降水每增加1 mm,黄枯期约推后0.119 d。草甸草原、荒漠草原植物黄枯期与各时段降水、气温的相关均不显著,影响黄枯机制比较复杂。

Plant phenology, studing periodic life cycle of plant and animal, always is used to indicate climate change Various vegetation types show different phenological responses to change change. of changes between phenology phases of dominant species and climate variables This study aims to analyze the relationships over the three major grassland types in the Mongolia Plateau, including meadow grassland, typical grassland, and desert grassland. This analysis used phenological and meteorological data from 24 ecological monitoring station in the grassland of inner Mongolia between 2004 and 2013. The results showed that ： （ 1 ） precipitation shows the increased trend and air temperature decreases before the start of the growing season （SOS） in the study area. Before the end of the growing season （ EOS）, air temperature decreased and precipitation increased in meadow grassland. （2） through 10 years （ and typical grassland, but air temperature increased and precipitation decreased in desert 2004--2013）, the SOS of meadow grassland advanced by 2.04 days and EOS delayed by 12.68 days, and which lengthened the growth duration about 14.72 days. The SOS of typical grassland advanced by 4.01 days and EOS delayed by 10.35 days; the total growth duration was lengthened by 14.36 days in 10 years. In desert grassland, SOS and EOS advanced by 1.32 days and delayed by 9.58 days, and the growth duration lengthened by 10.90 days. （3） The dominant factor affecting SOS was temperature, rather than precipitation, in grassland vegetation. The SOS showed a significantly negative correlation with the mean air temperature in meadow grasslands in the previous three months, and it advanced 1.123 days with a I^C increase in average air temperature in the three months prior. However, in typical and desert grasslands, the SOS significantly negatively correlated with the average air temperature of the two months prior, and it advanced by 1.137 days and 1.743 days, respectively, with a I^C increase in average air temperature in the two months prior. （4） The EOS in typical steppe was jointly controlled by both of air temperature and precipitation of previous 1--2 months. In particular, there was a significant relationship between the average summer air temperature and precipitation in the current month. In addition, the EOS was delayed by 0. 119 days with increased precipitation in the current month. However, a more complicated mechanism presumably controls the EOS of typical and desert grasslands, and no significant relationships between the EOS and climate factors were found.