| Based on the fields investigation, The characteristics of Corylusheterophylla communities were studied by using quantitativeecology methodology, including species composition, flora, life formspectra, TWINSPAN classification and DCA ordination, speciesdiversity and spatial pattern, so that these results can be astheoretical basis for ecological conservation of this species andscientific unilization. The results showed that:(1) There were 181 kinds of vascular plants，belonging to 51families and 132 genera, including ferns 1 family, 1 genus and 1species, gymnosperms 1 family, 2 generas and 3 species,angiosperms 49 families 129 genera 177 species, dicotyledonous44 families 114 genera 161 species, monocotyledons 5 families15 genera 16 species. Dominant family and single-genera couldbe observed in the floristic composition.(2) The type of distribution was diverse, including 12distribution types and 6 variant. From the analysis of family, theworld distribution pattern was predominant that accounted for56.86% of the total families, temperate distribution pattern wasaccounted for 63.64% of the total genera, the world distributionpattern was accounted for 13.64% of all the genera, revealingnorth temperate characteristics of the flora. (3) The high bud in the study area plant communities was themost abundant species, accounting for 33.15% of the totalspecies, followed by hemicryptophyte and chamaephyte,accounting for 29.83% and 25.97%, hidden bud plant(underground bud plants) and annuals less, 20 species onlyaccounting for 2.76% and 8.29%. The result reflected that theheat conditions in the region was moderate, which was suitablefor all types of deciduous forests and shrub of the growth inwarm and humid summer. In the cold winter, the dormant buds ofthe perennial herb often need the coverage of the plant leaves orsnow in order to live through the winter in the cold winter.(4) Based on the 50 plots dataset from the fields, Corylusheterophylla communities were classified into 15 associationsby TWINSPAN, the characteristics of those communities weredescribed. The DCA ordination of the plot and the dominantspecies showed that the distribution pattern of thosecommunities were mainly dominated by the leading ecologyfactor, including elevation, aspect and moisture condition.Elevation was the critical environmental factor that affected thedistribution pattern of the plant communities. The first axis ofsample DCA ordination chart indicated the influence of elevationon the communities, the elevation ascend from left to right. Thesecond axis that reflected the changes in aspect and moisturecondition, the gradual transition from the shaded slope to sunnyslope from bottom to top, soil moisture decreased gradually. Thediagonal of DCA ordination reflected the changes in temperature,from the bottom left to top right, the temperature gradually rised. The DCA ordinations of the 84 dominant species showed that thespecies acted as indicator for habitat factors and wasimpersonally reflected characteristics of biotope, and to a greatextent, the patterns of the dominant species determined those ofthe community types.(5) The species diversity of the 15 association and the twolayers of Corylus heterophylla communities were studied byusing Patric and Margalef richness indices, Simpson andShannon-Wiener diversity indices and Pielou and Alataloevenness indices, respectively. The relationships betweenspecies diversity and community types, community structure,environmental factors were studied. In addition, the differencesamong six diversity indices for all communities were studied byANOVA. The results indicated that: The change trend of richnessindices and evenness indices was similar to that ofShannon-Wiener diversity index, but was opposite to Simpsondiversity index. Each indices has different ecologicalsignificance. Accordant result was achieved by using the fiveindices.The results from Patric and Margalef richness indices,Shannon-Wiener diversity index and Pielou and Alatalo evennessindices of herb layer were higher than shrub layer, but Simpsondiversity index of shrub layer were more abundant than that inherb. The species diversity of Corylus heterophylla communitieswas mainly correlated with the herb layer. Not only theherbaceous layer species of these communities were relativelyabundant, but shrub layer have a single type, but also ome transformation of a series environment factor will lead to changeof the species diversity. Elevation was the critical environmentalfactor that affected the species diversity of the plantcommunities. There were not significant differences among thediversity indices of 15 associations by ANOVA, which wereresulted from that the distribution of the communities wasnarrower and the habitat heterogeneous of communities was notsignificantly and the structure of the communities was stable.(6) Owing to the important role of pattern analysis, the studyanalyzed species diversity and spatial pattern of Corylusheterophylla communities in Lingkong Mountain (plot 1 and plot 2)and Xingtangsi Mountain (plot 3) of Taiyue Mountain in Shanxi byusing the point pattern analysis methods and fractal theory. Thereasons leading to the spatial pattern characteristics of Corylusheterophylla communities were analysed.The spatial pattern of several typical community was studiedby using the point pattern analysis methods. The results showedthat the species of Corylus heterophylla analysed in this paperhave obvious clumping feature, while they vary with scales.The spatial pattern of several typical community was studiedby using box-counting dimension. The results showed that thespatial distribution of variety community were high (﹥1.6, near 2),which reflected the high spatial occupation degrees of thecommunity. The results of plot 3 (1.9124) of the communities inXingtangsi Mountain was higher box-counting dimension thanthat of plot 1 (1.6560) and plot 2 (1.6452) of the communities inLingkong Mountain. The box-counting dimension of community pattern disclose the spatial occupation degrees of thecommunity and its scale variation degree, which refiected thevariation of function and position of Corylus heterophyllacommunities.This study analyzed the spatial pattern of several typicalcommunity by using information dimension. The results showedthat the information dimension of Corylus heterophyllacommunities in the three plots was lower, away from the two, andthe distribution of those communities was more even. The resultsindicated that the order of the scale variation degree of patternintensities was plot 3 (0.7575)﹥plot 1 (0.7281)﹥plot 2 (0.7100).The results of the three plots, higher box-counting dimension andlower information dimension, reflected that there was a higherspatial occupational degrees in Corylus heterophyllacommunities, but the instruction was comparative simple. Thevariation of information dimension reflected the differences ofcommunity regeneration conditions. The information dimensionof community patterns quantifies the scale variation degree ofpattern intensity, and discloses the unevenness of individualdistribution. |
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