Research On Structure, Dynamic,Spatial Distribution Pattern And Interspecific Association Of Dominant And Associated Populations In Tropical Evergreen Monsoon Elfin Forest

Tongguling National Nature Reserve is located in Longlou town of Wenchang in the northeastern Hainan Province, including the unique vegetation types-tropical evergreen monsoon elfin forest in the coastal area of Hainan.There are abundant species in this community. Because many vegetations have small dimeter and height and are not layered obviously, it is named "elfin forest". Nowaday, the research of low elevation forest community in Hainan coastal area is still at the starting stage, but the study of the obvious charateristics coastal forest community as tropical evergreen monsoon elfin forest is rarer than others.On the basis of2.56hm2big plot and combined with the methods of community investigation、the research of population structure、O-ring statistics of point pattern analysis, the diameter classes structure of dominant populations、the dynamic of dominant populations、spatial distribution patterns and interspecific association in the community of tropical evergreen monsoon elfin forest are researched. The results of this study are as follows:(1) It is found that there are a tatal of171plant species, belonging to55families and121genera, which are106trees,25shrubs and40woody climbers with the dominant of Schefflera octophylla、Syzygium tephrodes、Olea dioica、Aeronychia oligophlebia、Xantolis longispinosa、Koilodcpas hainanense、Arytera littoralis and Syzygium buxifolioideum by the investigation of tropical evergreen monsoon elfin forest plot.(2) The results show diameter classes distribution of25dominant and main associated populations present "J" type approximately,in which seedlings and young trees accounted for the large proportion through the research of diameter classes and dynamic of the important value of first25plant populations. The other populations belong to increasing type except3populations like Schefflera octophylla、Aeronychia oligophlebia and Syzygium buxifolioideum.The size class distrbution present ’Pyramid type" approximately, but these3populations are stable angina populations in which the number of gender individuals are more than adult individuals. This shows that these dominant and main associated populations are in stable and increasing condition.The analysis results of the static life table show that the mortality of25populations increase with the diameter classes increasing and the change range of it get bigger in the earlier stage, but becomes flat at the larger diameter classes.The life expectation of populations is contrary to the mortality, and the biggest survival of25populations present at I or II age class.The analysis of survival curve shows that survival curve of the most populations present Deevey I type, only rare ones show Deevey Ⅰ type to Deevey Ⅱ type or Deevey Ⅲ type.(3) The spatial distribution pattern of8dominant populations that important value is more than3.0are calculated by univariate statistics of O-ring fuction.The results show that the spatial distribution of8dominant populations present significant aggregation distribution basically at small scales, but manifest as random distribution or regular distribution with the scales increasing gradually.But among these,also present indistinctive aggregation distribution at some scales. The biggest aggregation intensity of23populations of important value first25ones show among1-3meter scale, only Camellia furfuracea and Dillenia turbinata appear at6m and26m.The gathering scales of these two populations are larger than other23populations,113.09m2and2123.71m2respectively. The dominance and the largest aggregation intensity of these25populations show linear positive correlation, whith is very significant(P=0.005<0.01), the regression equation:y=0.053x+0.026. To some extent, it can predict the largest aggregation intensity of different populations in this community by dominance(important value).(4) The interspecific association of first25important value populations and first8important value dominant populations are calculated by means of bivariate O-ring statistics, whith combine with the spatial distribution pattern of8dominant populations.So the effect of the interspecific association to spatial distribution of species are analysed. The results show that there is a range of effect among populations, and the effect maybe become weak or uncorrelated even beyond this range. In different populations, positive correlation or negative correlation are produced by which other populations have influence on the aggregation populations at the their respective aggregation scales.But different populations show different results.The population that produced positive correlation provides for good reciprocity to the aggregation distribution of this population; due to the repellent action, the population that produced negative correlation has influence on the development of this population.When population reach the real optimal density of itself under the environmental carrying capacity at the larger scales, not only do the aggregation not produce, but also the population will present random distribution or regular distribution.