不同放牧强度季节调控对短花针茅草原植物种间关系的影响

Effect of seasonal regulation of grazing intensity on inter-specific relationship of Stipa breviflora

【目的】探讨不同放牧强度季节调控方式下短花针茅(Stipa breviflora)荒漠草原植物种关联关系的变化规律,研究不同放牧强度季节调控对荒漠草原植物种间关联性的影响。【方法】以短花针茅荒漠草原植物种为研究对象,在内蒙古苏尼特右旗附近的荒漠草原试验示范基地,设置5个放牧强度季节调控方式和对照(CK)处理,于2013年8月对不同试验处理区植物种存在状况、出现频率及物种间关联性进行调查和统计。【结果】在6个处理区内共发现植物27种,春季零放牧+夏季重度放牧+秋季适度放牧(SA1区)平均物种数最多,对照区最小。从植物种出现频率看,不同放牧强度季节调控方式对3个主要植物种的影响大小依次为碱韭(Allium polyrhizum)>无芒隐子草(Cleistogenes songorica)>短花针茅,且以春季零放牧+夏季适度放牧+秋季重度放牧(SA2区)的植物种出现频率较低。短花针茅与无芒隐子草主要表现为无关联性,短花针茅与碱韭主要表现为负关联性。春夏秋重度放牧(SA3区)和春夏重度放牧+秋季适度放牧(SA4区)导致显著正相关种对数减少,物种关联链简单,关联物种对较少。春夏秋适度放牧(SA5区)、SA1区及SA2区群落内物种间关联链增多,关联链趋于复杂化。【结论】春季放牧(无论是重度放牧还是适度放牧)均导致植物种总体关联性降低,甚至使植物种总体关联性呈现负关联;春季零放牧有利于植物种间关系的稳定和提高。

[Objective] Effect of seasonal regulation of grazing intensity on inter-specific relationship of desert grassland plants was investigated to reveal change of population relationships of Stipa breviflora. [Method] In the desert steppe trial base in Sonid Youqi, Inner Mongolia, 5 different seasonal regulation patterns with different grazing intensities and control （CK） were set up. The status,occurrence frequency, and of population relationships were surveyed on August 2013. [Result] A total of 27 populations were found in the 6 treatments,with the most in SA1 （banning grazing in spring.heavy grazing in summer＋ moderate grazing in autumn） and the least in CK. Effect of seasonal regulation of grazing intensity on three populations was in the order of Allium polyrhizum 〉 Cleistogenes songorica 〉 Stipa brevi flora. Populations in SA2 （banning grazing in spring＋moderate grazing in summer＋heavy grazing in autumn） had lower frequency of occurrence. Stipa breviflora and Cleistogenes songorica had no correlation while Allium polyrhizum and Stipa breviflora were negatively correlated. SA3 （continuous heavy grazing） and SA4 （heavy grazing in spring and summerq-moderate grazing in autumn） caused significant decrease of species with positive correlation. SA5 （continuous moderate grazing）,SA1 and SA2 increased the associated chain among species. [Conclusion] Grazing in spring （either moderate or heavy） caused reduction in overall association of populations, while banning in spring was beneficial to stabilize and increase inter-species relationship.