摘要
通过模拟降水增加试验研究了古尔班通古特荒漠常见短命植物盖度、密度及产量对水分输入量增加的响应。结果表明:尖喙=牛儿苗、弯果胡卢巴、角果藜、琉苞菊、条叶庭芥及囊果苔草6种牧草生物量总和占总生物量的60%以上,是荒漠草原的优势牧草植物;供水量增加显著促进了角果藜、尖喙=牛儿苗、弯果胡卢巴、条叶庭芥和琉苞菊5种牧草植物的个体生长;在自然降水的基础上,增加40mm和80mm供水使这5种植物生物产量比对照增加86%～230%。供水增加后,6种重要牧草对整个群落的生物贡献比例发生很大变化,只有角果藜和尖喙=牛儿苗的贡献比例规律性增加,分别比对照增加了58%和11%,表明2种植物对供水增加的环境变化适应能力强;供水量增加促进了弯果胡芦巴、尖喙=牛儿苗和角果藜3种植物N、P和K养分的吸收量;与此同时,供水量增加也显著提高了荒漠短命植物的密度和盖度。在降水增加的背景下,古尔班通古特沙漠南缘荒漠短命植物群落结构发生改变,植被盖度和群落净初级生产力提高,这对于防风固沙、稳定沙面,增加荒漠草原载畜能力有着积极的意义。
Spring ephemerals form significant plant synusiae in the Gurbantunggut desert during April and May and are a crucial forage resource for livestock in early spring.In recent years global climate change has caused warming,increasing rainfall and flooding from snowmelt in Gurbantunggut desert.However,little is known about how the enhanced water input may influence the growth of individual plant species and the productivity of plant communities in desert grassland.A randomized block designed field trial,which contained three watering treatments（0,40 and 80 mm）,was conducted in the Gurbantunggut desert,Xinjiang,northwestern China.The sum of the biomass of six dominant ephemeral species contributed more than 60 percent of the total above-ground biomass of the synusia.Five of the six dominant species（Erodium oxyrrhynchum,Trigonella arcuata,Alyssum linifolium,Ceratocarpus arenarius and Hyalea pulchella）showed a significant positive growth response with increasing water input.Compared to the control,the above-ground biomass productivity of the five plant species watered with 40 or 80 mm was increased by 86%-230%.The composition（%）of total above-ground biomass of individual species was significantly changed by enhanced water input;values for C.arenarius and E.oxyrrhynchum increased more than for the other species.This result indicated that these two species would potentially become even more dominant in the spring ephemeral synusia following the trend of enhanced precipitation.At the same time,plant density and coverage of the ephemerals were also significantly increased by enhanced water input.Such results implied that the role of ephemerals in stabilizing sand dunes may be strengthened by enhanced water input.It is concluded that enhanced precipitation could both increase the potential livestock carrying capacity of the desert grassland and promote restoration of the desert ecosystem.
出处
《生态学报》
CAS
CSCD
北大核心
2009年第4期1859-1868,共10页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目(30770341)
新疆自治区攻关资助项目(200533124)
