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SCI论文目录 |
祁连山海北高寒湿地气候变化及植被演替分析 |
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出 版 社:冰川冻土25(1):243-249 |
发表时间:2003 |
台 站:
海北高寒草甸生态系统定位研究站
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作 者:李英年 赵新全 赵亮 王启基 沈振西 |
点 击 率:5214 |
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关 键 字:关键词:气候变化;高寒湿地;冻土退化;植被演替 |
摘 要:摘 要:分析了近40a海北高寒湿地区域气候变化特征,以及近期湿地退化和植被演替的情况.结果表明:祁连山海北地区自1957年以来年平均气温以0 157℃·10a-1的倾向率升高,年降水量约以18 59mm·10a-1的倾向率递减,年平均地温比同期气温的增加更为迅速,表现出海北地区气候及土壤性状均向干暖化趋势发展,特别是土壤干暖化程度尤为明显.由于人类活动加剧影响,超载过牧,原生植被遭受破坏,草场退化严重,地表潜在蒸散力加大.深层的多年冻土退化,冻胀草丘坍塌,导致湿地植被发生变化,使沼泽化草甸向典型草甸演替.不同年度调查结果表明,高寒湿地植被在气候干暖化趋势的加剧影响下,植物群落组成发生变异,物种多样性、生态优势度均比湿地原生植被的物种有增多的趋势.原生适应寒冷、潮湿生境的藏嵩草为主的草甸植被类型逐渐退化,有些物种甚至消失,而被那些寒冷湿中生为主的典型草甸类型所替代.组成植物群落的湿中生种类减少,中生种类(如线叶嵩草)大量增加,群落盖度相对降低,群落生产量大幅度下降. |
关 键 字(英文):Keywords:climatechange;alpinemarsh;vegetationdegradation |
摘 要(英文):Abstract:TheregionalclimatechangefeaturesofHaibeialpinemarshduringtherecent40yearsanditspossibleimpactsonmarshdegradationandvegetationsuccessionareanalyzed.ItisfoundthatannualmeanairtemperatureofTibetanAutonomousPrefectureofHaibeiintheQilianMountainshasincreasedintherateof0 157℃·10a-1,annualprecipitationhasde creasedintherateof18 59mm·10a-1since1957,andtheincreasingrateofannualmeansoiltempera turewashigherthanthatofairtemperature.Adry ingandwarmingtrendtakesplacebothinclimateandsoilintheprefecture,especiallyinsoil.Additionally,intensivehumanactivityandovergrazingbringaboutsomeconsequences,suchasprimordialvegetationde struction,grasslanddegradationanduppertranspira tionincrease.Marshvegetationchangeshowsmarshmeadowtransformingintotypicalmeadow,resultinginancientpermafrostdegradingandfrozengrassyhillockcollapsing.Studyresultsindicatethatplantcommunityofalpinemarshvegetationischangingundertheimpactofclimatedryingandwarming.Thereisanincreas ingtrendofbiodiversityandecologicalpredominanceascomparedwithmarshprimordialvegetation.TheprimordialmeadowvegetationdominatedbyKobresiatibetica,whichisadaptivetoshiveryandmoistenvi ronment,isdegradingpiecebypieceandissubstitut edbysometypicalmeadow,evensomespeciesdiesaway.Speciesofmoistplantdecreaseandneutralspecies(Kobresiacapillifolia)increase,communitycoveragereducesrelativelyandproductivitydeclineslargely. |
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