Studies On Spatial Distribution Pattern Of Three Oaks Population In Baotianman Nature Reserve

The biological characteristics of population,interacting with the environmental factors,result in spatial pattern formation in its habitat,studies on spatial distribution pattern of dominant species is conducive to understanding of the underlying ecological processes and also provide a scientific basis for the rational management of ecosystems. In recent years, research of spatial pattern of population in dynamic monitoring tropical rain forest has become hotspots. However, scholars has not carried out studies on spatial distribution pattern of species in dynamic monitoring temperate - subtropical zone.Baotianman Nature Reserve lying in the northern subtropical and warm temperate transitional regions is rich in ecosystems and species.In 2008,Henan Agricultural University and the Institute of Botany of Chinese Academy of Sciences established a 25ha of deciduous broad-leaved forest of fixed monitoring plot and 5 different vegetation types of satellite plots in Baotianman Nature Reserve by referring to Colorado Island 50 ha plot of tropical rain forests of technical specifications,and every satellite plot is 1 ha. On the basis of these spots ,we selected Quercus aliena var. acuteserrata plot,Quercus variabilis plot and Quercus glandulifera var.brevipetiolata plot for our study. Spatial distribution pattern of three oaks population in Baotianm Nature Reserve were analyzed in different sampling scales,development stages and altitudinal gradient by the test of discrete distribution fitting,variance/mean ration and the measurement of aggregation intensity.The research results are as follows:(1) At different sampling scales,the spatial distribution pattern of three oaks population in Baotianm Nature Reserve all show aggregated distribution,the levels of aggregation are different at different sampling scales, variance/mean ration and six aggregated intensity indicators are basically the same trend with increment of sampling scales.Moreover,at the same sampling scale,variance/mean ration and six aggregated intensity indicators of three oaks are also different.(2) At different developmental stages,the spatial distribution pattern of three oaks population in Baotianm Nature Reserve is different,sapling and middle tree stage showed aggregated distribution,but the degree of aggregation was different, the sapling tree had a higher degree of aggregation than the middle tree,while the spatial pattern of the large tree showed random distribution.Values of patchiness index m*/m and dispersion index Iδof the population decreased with the increase of developmental stages.And at the same developmental stage,variance/mean ration and six aggregated intensity indicators of three oaks are also different.(3) In the case of different altitudes,the spatial distribution pattern of three oaks population in Baotianm Nature Reserve is different,in the 1332m and 1420m altitude areas,the spatial distribution pattern of the Quercus aliena var. Acutesrrata populations showed aggregated distribution,the levels of aggregation are different at different altitudes;In the 1250m and 1301m altitude areas,Quercus variabilis populations and Quercus glandulifera var.brevipetiolata populations showed aggregated distribution,the levels of aggregation are different at different altitudes.