| Dalongtan is one of the most attractive scenic spot in the Yinchanggou Scenic Area.After the“5.12”earthquake,due to the effect of earthquake and landslides and mud flows,the natural environment has had an inestimable impact.This paper mainly discusses the interspecific relationship and niche analysis of shrubs,herbaceous plants and their plant communities in the plant community in Dalongtan,in order to scientifically and accurately understand the status quo of the Dalongtan debris flow gully plant community,to provide reliable information for vegetation restoration.The result indicates:(1)Species composition:There are 39 species of plant species in the mudstone gully plant community in Dalongtan in 2017,belonging to 19 families and 36 genera.The majority of plant composition is single family,single genera and single specie,and only a few plants are single family,multiple genera,multiple species,or single family,single genera and mutiple species.Among them former five families are Compositae,Rosaceae,Saxifragaceae,Gramine and Araliaceae.(2)Test for the total connection between species and species:The significance was tested according to the variance ratio method(VR)and the statistic W.the degree of detection showed that there was a significant positive correlation between species in the shrub layer;there is no significant negative correlation between the overall species in the herb layer;the total community of the debris-growth plant community in Dalongtan was significantly positively connected.(3)Species interspecific association test:In the(34)~2 test,the percentage of the pairs that showed positive coupling among the 28 pairs of shrub layers was71.43%,which was represented by the species pairs that were negatively linked.The percentage was 28.578%,of which only 1 pair was generally significantly associated,and the remaining 27 pairs of species were independently distributed.Among the 45 pairs of herbaceous species,46.66%of the total species were positive pairs,51.11%of the species were negative pairs,and the unpaired species accounted for the total species.2.22%of the numbers,of which only 1 pair showed significant correlation,and the remaining 44 pairs showed an independent distribution.Among the 80 species in the plant community,57.50%of the species were positively associated,38.75%of the species were negatively associated,and3.75%were unrelated species.Significantly linked species,significantly linked species,generally significant species,and independently distributed species were1 pair,2 pairs,3 pairs,and 74 pairs.Coupling coefficient AC value:The percentage of species-pairs in shrub layer interspecies association coefficient showed positive coupling was 78.57%,and negative coupling was 21.43%.In the herb layer,the proportion of positive couplings was 44.44%,that of independent distributions was 2.22%,and that of negative couplings was 53.33%.There were 46 pairs of species that exhibited positive association in the plant community.3 pairs showed independent distribution and 31 pairs showed negative association.OI value of similarity index:17 pairs of shrub layer OI values greater than0.5,11 pairs of OI values less than 0.5.There were 34 pairs of herbage pairs with OI values greater than 0.5 and 14 pairs less than 0.5.Among the shrub-grass communities,there were 35 pairs with OI values greater than 0.5 and 45 pairs with less than 0.5.(4)Interspecies correlation analysis of species:In the Pearson correlation test,among the 28 pairs of shrub layers,there were 12 pairs of positive correlations among species,and 16 pairs of negative correlations.There are 1 pair belonging to significantly related and 2 pairs belonging to extremly significant.There were 21pairs of negative correlations in the herb layer of 45 pairs,and 24 pairs of positively correlated pairs,and 2 pairs exhibiting extremely significant positive correlations.In the plant community,there were 33 pairs of negative relationships and 47 pairs of positive pairs.The positive and negative correlation ratios of the pairs were 1.42:1,of which 4 pairs were significantly related.In the Spearman rank correlation test,there were 16 pairs of total 28 pairs that were positively correlated in the shrub layer,and 12 pairs were negatively correlated,of which 5 pairs were significantly correlated,and 2 pairs were extremly significantly associated.25 pairs of total 45 pairs in herb layer showed positive correlation,22 pairs of negative correlation,of which 2 pairs were significantly correlated and 1 pair of species was extremly significantly correlated.Among the 80 pairs in plant communities,49 pairs were positively correlated,31were negatively correlated,and the positive-negative species-pair correlation ratio was 1.58:1,and there were 4 pairs of significant correlations among the 80 pairs of species.There are 4 pairs of extrmely significant related.(5)Niche analysis:From the niche breadth and niche overlap values in shrub layer,herb layer,and plant community,we can get a conclusion,in general,if the calculated niche breadth of the species is higher,The higher the niche overlap value between the two species,and vice versa.For example,in the shrub layer,the niche value of the niche breadth is ranked first,with a Bi value of 1.065 and a Ba value of 0.851,and a niche with a niche breadth(Bi value of 1.063 and Ba value of 0.852).The maximum niche overlap between the individuals was also 0.855;the overlap between the herbaceous layer of A.falcata(Bi value of 1.125,Ba value of 0.657)and Saccharum spontaneum Linn(Bi value of 1.114,Ba value of0.647).The value was 0.774.The niche overlap values of Salix cupularis and Saccharum spontaneum Linn,Hydrangea strigosa and Ajania salicifolia(Mattf.)Poljak.,Hydrangea strigosa and Saccharum spontaneum Linn of shrub-grass community were all above 0.7.(6)In the study,in general,it was also found that the larger importance value is,the larger the niche breadth is,for example,Salix cupularis(IV value of 0.428,Bi value of 1.063,Ba value of 0.852),and Hydrangea strigosa(IV value 0.116).,Bi value of 1.065,Ba value is 0.851),Liu Yeyaju(IV value of 0.240,Bi value of1.125,Ba value of 0.657),etc.Of course,there are also a few species with special conditions such as Aralia chinensis L.(IV value of 0.035,Bi value of 0.668,Ba value of 0.313,Cyperus rotundus L.(IV value of 0.051,Bi value of 1.119,Ba value of 0.651)and other important values. |
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