【摘要】 通过比较大沙鼠洞区和对照区植物种类组成、盖度和密度的差异,研究了大沙鼠掘洞对准噶尔荒漠植物群落物种组成和植被结构的小尺度影响。使用Mann-Whitney U检验表明,洞区植物种数(n=6.47)显著高于对照区(n=4.32)(z=5.55,p<0.01);洞区半灌木种数(n=0.89)显著低于对照区(n=1.21)(z=2.70,p<0.01)。由于大沙鼠的采食,建群种盐生假木贼(Anabasis salsa)在洞群区的出现频率,密度以及高度均显著低于对照区;洞区草本植物种数(n=5.55)显著高于对照区(n=3.11)(z=6.65,p<0.01)。3种多年生草本植物在洞区的密度均显著高于其在对照区的密度。在大沙鼠洞区,由于废弃的鼠洞入口塌陷而形成的坑洼中沉积的疏松粗质沙土促进了沙生针茅(Stipa glareosa)和细叶鸢尾(Iris tenuifolia)的生长发育。8种一年生植物中,盐生草(Halogeton glomeratus)、对叶盐蓬(Girgensohnia oppositiflora)、小车前(Plantagominuta)、鹤虱(Lappula semiglabra)和黄芪(Astragalussp.)的出现频率和密度在洞区均显著增加。尽管受到大沙鼠的采食,盐生草在洞区的出现频率和密度不仅没有减小,反而显著增加。这可能是由于大沙鼠对土壤的扰动,在洞区形成的裸地促进了盐生草等一年生植物的生长发育。更多还原

【Abstract】 By Comparing species composition,vegetative cover,and species density between burrow sites and random sites,we studied the impact of great gerbil(Rhombomys opimus) burrows and associated soil-surface disturbance on plant species composition and vegetative structure in the Junggar Desert.Burrow sites supported significantly greater plant species(n= 6.47) compared with control sites(n= 4.32)(z= 5.55,p<0.01).The sub-shrub species richness at burrow sites(n= 0.89) was significantly less than at random sites(n=1.21)(z = 2.70,p<0.01).The frequencies of occurrence,density,and the height of dominant sub-shrub,Anabasis salsa in the burrow sites decreased significantly in response to it foraged by great gerbil.The herb species richness at burrow sites(n=5.55) were significantly greater than at random sites (n=3.11)(z = 6.65,p<0.01).The density of three perennial herbs species at burrow sites were significantly greater than at random sites.In burrow sites,the depressions formed from collapsed entrances holes,which contained coarse and loose sand promoted the growth of two perennial herb species: Stipa glareosa and Iris tenuifolia.The disturbed soil in the bare ground on burrow sites promote the germination and growth of annual herbs. Among 8 species of annual herbs,5 species showed both significantly greater density and frequencies of occurrence in the burrow sites:Halogeton glomeratus,Girgensohnia oppositiflora,Plantago minuta,Lappula semiglabra,and Astragalus sp.Unexpectedly,Halgeton,eatenby Rhombomys,did not decrease but increased in density in burrow sites.It ispossible that burrowing activities of great gerbil facilitate the occurrence of the Halogeton.更多还原