| Soil fauna is an important component of forest soil ecosystems,however,studies on the diversity of soil fauna in plantation forests are rarely reported.Ground-dwelling beetles and soil springtails are two common soil fauna,and which have strong activities and a strong impact on soil ecosystems and detritus food webs.This study analyzed ground-dwelling beetles and soil springtails in poplar plantation soil.The data of various biotic and abiotic factors that may affect these two types of soil fauna were collected.Through data analysis,to explore the changes of ground-dwelling beetles and soil springtails in different growth stages of poplar plantations and the environmental factors that have a major impact on the two types of soil fauna,and whether the distribution of the two types of soil fauna responds significantly to different environmental factors difference.The purpose is to provide scientific basis for the sustainable management of poplar plantation ecosystem and biodiversity conservation.In this paper,five poplar plantations(6 years,9 years,12 years,15 years,and 18 years)in Dongtai Forest Farm,Dongtai City,Jiangsu Province were used as the research objects.Ground-dwelling beetles composition,soil springtails composition,soil physical and chemical properties,litter index,microbial biomass index and surface vegetation index,etc.were collected and processed for analysis.The main results are as follows:(1)A total of 1,460 ground-dwelling beetles were captured in 5 forest ages,belonging to 7families and 28 species,among which the dominant species were Dolichus,halensis Agonum gracilipes,Harpalus chalcentus Bates and Amara gigantea;1766 soil springtails were collected,belonging to 7 families,20 genera and 30 species,of which the dominant species were Sminthurides sp1 and Tomocerina sp3.(2)In terms of different forest ages,collected in 6 years,9 years,12 years,15 years and 18 years respectively: 349,257,600,201 and 53 ground-dwelling beetles;350,211,650,439 and 116 soil springtails.Both reached their peak at 12 years old.In different seasons: 117,90,217 and 1041ground-dwelling beetles were collected in January(winter),April(spring),July(summer)and October(autumn),respectively;In January(winter),April(spring)and October(autumn),625,264 and 877 were collected respectively.Both peaked in October(autumn).(3)Diversity characteristics of ground-dwelling beetles and soil springtails:a)Different seasons of forest ageGround-dwelling beetles: Shannon diversity was greatest in October(autumn)in 6-,9-,15-,and 18-year-old poplar plantations,and in April(spring)in 12-year-old poplar plantations.The maximum Simpson diversity occurred in April(spring)in the 9,12,15,and 18-year-old poplar plantations,and in October(autumn)in the 6-year-old poplar plantation.Soil springtails: Shannon diversity was greatest in October(autumn)in 6-,9-,15-,and 18-year-old poplar plantations,and in April(spring)in 12-year-old poplar plantations.The maximum Simpson diversity appeared in January(winter)in the 6-and 9-year-old poplar plantations,in October(autumn)in the 15-and 18-year-old poplar plantations,and in the 12-year-old poplar plantations appear in April(spring).b)Different forest ages in the same seasonGround-dwelling beetles: Shannon diversity was greatest in 12-year-old poplar plantations in January(winter),April(spring),and July(summer),and in 6-year-old poplars in October(autumn).The maximum Simpson diversity occurred in the 18-year-old poplar plantation in January(winter),April(spring),and July(summer),and in October(autumn)in the 6-year-old poplar plantation.Soil springtails: Shannon diversity was greatest in the 6-year-old poplar plantation in January(winter)and October(autumn),and appeared in the 12-year-old poplar plantation in April(spring).The maximum Simpson diversity occurred in January(winter),April(spring),and October(autumn)in 6-,12-,and 18-year-old poplar plantations,respectively.(4)Environmental factors affecting the community distribution pattern of ground-dwelling beetles and soil springtails:a)The environmental factor with the highest interpretation rate for the community distribution of ground-dwelling beetles in the 6-year-old poplar plantation was soil carbon-nitrogen ratio,with an interpretation rate of 23.58%;in the 9-year-old poplar plantation was the soil carbon-nitrogen ratio,with an interpretation rate of 21.71%;in the 12-year-old poplar plantation was soil nitrate nitrogen,with an interpretation rate of 15.56%;in the 15-year-old poplar plantation was soil ammonia nitrogen,with an interpretation rate of 15.07%;in the 18-year-old poplar plantation was soil nitrate nitrogen,with an interpretation rate of 24.48%.The soil environmental factors had the greatest influence on the distribution pattern of the ground-dwelling beetles community in different forest ages.In addition,among the 6,9,and 15-year-old forests,the top three explanation rates are soil environmental factors,and two of the top three among the 12-and 18-year-old forests are soil environmental factors.It can be seen that soil environmental factors are the dominant factors in the formation of the local ground-dwelling beetles community pattern.b)The environmental factor with the highest interpretation rate for the community distribution of soil springtails in the 6-year-old poplar plantation was soil ammonia nitrogen,with an interpretation rate of 23.97%,in the 9-year-old poplar plantation was the soil nitrate nitrogen,with an interpretation rate of 23.36%;in the 12-year-old poplar plantation was soil organic carbon,with an interpretation rate of 14.42%;in the 15-year-old poplar plantation was soil p H,with an interpretation rate of 21.08%;in the 18-year-old poplar plantation was microbial biomass Carbon,with an interpretation rate of 25.17%.Except for the 18-year-old forest age,the soil environmental factors had the greatest influence on the distribution pattern of the soil springtails community among the other forest ages.Secondly,the top three explanation rates in 6 and 9-year-old forests are soil environmental factors,and two of the top three in 12-and 15-year-old forests are also soil environmental factors.It can be seen that soil environmental factors are very likely to be the dominant factors in the formation of the local soil springtails community pattern.(5)Correlation analysis of the number and diversity of ground-dwelling beetles and soil springtails with environmental factors:There is no significant difference in the influencing factors that are strongly correlated with the number and diversity of ground-dwelling beetles in different forest ages,mainly soil environmental factors include: soil ammonia nitrogen,soil nitrate nitrogen,soil carbon-nitrogen ratio,soil total nitrogen,etc.,followed by microbial biomass and litter nutrient content.There are slight differences in the influencing factors that are strongly correlated with the number and diversity of soil springtails in different forest ages.The forest ages of 6,9,12,and 15 are mainly soil environmental factors,including soil ammonia nitrogen,soil nitrate nitrogen,soil carbon-nitrogen ratio,soil total nitrogen,etc.,followed by microbial biomass and litter nutrient content.Among the 18-year-old forest age,the influencing factors with strong correlation with the quantity and diversity of soil springtails mainly included litter factors and soil environmental factors.It can be seen that the soil environmental factors have the greatest influence on the quantity and diversity of ground-dwelling beetles and soil springtails of different forest ages.Above all,most of the environmental factors that have a greater impact on the distribution,quantitative characteristics and diversity characteristics of the ground-dwelling beetles and soil springtails community in different forest ages are soil environmental factors.Soil has become a limiting factor for the survival and reproduction of ground-dwelling beetles and soil springtails because of its high salinity and nutrient-poor. |
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