Study On The Structures And Values Of Soil Mites In Fanjingshan World Natural Heritage Nomination

Soil mite is a species of biological organism which plays a significant role in material and energy of soil and vegetation in terrestrial ecosystems,also is an important part of the soil ecosystem.To study the structural characteristics and heritage value of soil mites communities in different habitats of Fanjingshan World Natural Heritage Nomination,we selected four typical vertical spectrums of Fanjingshan,including evergreen broad-leaved forest,evergreen and deciduous broad-leaved mixed forest,deciduous broad-leaved forest,and subalpine coniferous forest,collected mites in December 2016 and July 2017.We classified the mites by morphological feature,and analyzed the structure characteristics of mite communities by means of group numbers,individual numbers,community diversity,community similarity,MGP analysis of oritabid mites and analysis of predatory mites.The main findings are as follows:1)A total of 20,311 soil mites were captured and classified into 3 orders,4 suborders,111families and 238 genera,including Sarcoptiformes,Mesostigmata and Trombidiformes,79families,181 genera and 16,167 numbers,22 families,44 genera and 3901 numbers,10 families,13 genera and 243 numbers.They accounted for total families,genus and numbers of the study area was 71.17%,20.00%,9.09%,76.05%,18.26%,5.39%,79.60%,19.21%and 1.20%respectively.The main group consisted of common groups and rare groups,which accounted for10.33%and 87.97%of the total respectively.The dominant groups of different forest belts were quite different,Mixacarus,Scheloribates and Camisia were the dominant genera of evergreen broad-leaved forests and subalpine coniferous forests respectively,there was no dominant genus and the relative distribution of each group was relatively uniform in evergreen and deciduous broad-leaved mixed forest and deciduous broad leaved forest,Xylobates and Platynothrus accounted for a larger proportion in the former,Trimalaconothrus and Platynothrus were more in latter.2)The time and space of the genus and individual numbers of soil mites in the four forest belts were different?p<0.05?.Among the horizontal structures,the genus was evergreen broad-leaved forest>evergreen deciduous broad-leaved mixed forest>deciduous broad-leaved forest>subalpine coniferous forest,and the individual number was consistent with the genus,the order of individual density was evergreen broad-leaved forest>evergreen and deciduous broad-leaved mixed forest>subalpine coniferous forest>deciduous broad-leaved forest.In the vertical distribution,there was an inverse distribution in group numbers,and the difference was significant?p<0.05?.The individual number and individual density were litter layers(9,640,20467.09 m^-2)>upper soil layers(8,656,9189.96 m^-2)>lower soil layers(2,015,2139.07 m^-2).The genera,individual number and individual density were winter>summer in four forest belts.3)There were significant differences in vertical soil layers structures of soil mites at different elevations in the same forest belt?p<0.05?.Samples were collected in the winter,and the snow cover on the surface caused the temperature to be too low.The changes of mite numbers in soil layer showed that the litter layer was the most in summer,and the soil upper layer was the most in winter.4)The soil mite community diversity index was 3.37,which was higher than different temperature zones and neighboring regions.There was a significant difference with the communities diversity in the four forest belts?p<0.05?.The evergreen and deciduous broad-leaved mixed forest has the highest diversity index,and the subalpine coniferous forest has the lowest.The diversity index and evenness index were generally in winter>in summer,and the variation was significant.5)The degrees of similarity between evergreen broad-leaved forest and evergreen deciduous broad-leaved mixed forest,evergreen broad-leaved forest and deciduous broad-leaved forest,evergreen-deciduous broad-leaved mixed forest and deciduous broad-leaved forest were all medium similarity.The evergreen broad-leaved forests,evergreen and deciduous broad-leaved mixed forests,deciduous broad-leaved forests,and subalpine coniferous forests were medium not similar,and the forest belts in winter and summer were medium not similar.6)The community structure of oribatid mites on the genera structure in different forest belts was O-type,among which the number of G groups mostly.Quantitatively,on the individual number in evergreen broad-leaved forests,evergreen,deciduous broad-leaved mixed forests,and deciduous broad-leaved forests were O-type,and the evergreen broad-leaved forests were dominated by M groups,evergreen-deciduous broad-leaved mixed forests and deciduous broad-leaved forests were dominated by G groups,the subalpine coniferous forest was MG-type.The genera structure of winter forest belts was O-type and G-group was relatively high.The evergreen broad-leaved forests and evergreen-deciduous broad-leaved mixed forests were O-type and the proportion of G groups was larger,deciduous broad-leaved forests and subalpine coniferous forests were GP and G-type in summer.The number structure of all forest belts in winter was O-type,evergreen broad-leaved forests and subalpine coniferous forests have a larger proportion of M groups,and evergreen-deciduous broad-leaved mixed forests and deciduous broad-leaved forests account for a larger proportion of G groups.In addition to the large proportion of P groups in the evergreen broad-leaved forest in summer,all other forest belts are G-type.At different altitudes in the each belt,the number of P groups decreased with the increased of altitude,and the M group was mainly in the winter.7)The four forest belts were mainly K-selected,and the same features appeared in winter.The evergreen broad-leaved forest and subalpine coniferous forest were mainly r-selected,evergreen deciduous broad-leaved mixed forest and deciduous broad-leaved forest deciduous broad-leaf mixed forest and deciduous broad-leaved forests were K-selected in summer.The research showed that the diversity of soil mites was abundant in different vegetation zones of Fanjingshan,enriched the value of the diversity of Fanjingshan as a world natural heritage site,the community characteristics of soil oribatida mites gamasid mites indicated a good ecological environment.This study provides basic information for the follow-up monitoring of the ecological environmental quality of Fanjingshan and the comparative study of soil mites in other subtropical World Natural Heritage sites and nominations.The relationship between soil mites and environment in Fanjingshan remains to be further studied.