| The agricultural areas in Southeast China is the most important agricultural ecosystem concentrated distribution areas in our country,and plays an important role in China’s ecological and economic construction.The rapid growth of economy and dramatic change in the environment have greatly transformed the diversity of soil animals in the agricultural ecosystem,causing that the soil animals in this areas face significant loss of diversity and the crisis of depletion as well as serious disruption of ants diversity.To understand the current situation of ants species and the distribution rule of diversity in the agricultural areas of the southeastern China,this research adopted a total of 78 sampling cells from 10 provinces of the middle and lower reaches of the Yangtze River and the southern part of China and chose the Lishui district of Nanjing city and Mazhang district of Zhanjiang city as the seasonal sampling cells.How to determine the sampling cells: first,we created 50 km×50 km grids in the southeastern part of China,including which grids with agricultural acreage of more than 50 percent were designated as the qualified cells in agricultural areas to meet the requirements of investigation.In addition,we chose the sampling cells with more than 50 percent of cells in agricultural areas in various provinces.In each sampling cell,3 different sampling areas were set up(with a spacing of more than 5 km),and three different habitats for cropland,grassland and planted forset were selected in each sampling area,and 5quadrats were set up for each habitat.A small sampling square of 1 m×1 m(with a spacing of more than 10 m)was used to collect all the surface ants in the square using an improved trematode method,and placed in absolute ethanol and brought back to the laboratory for ant species identification and data analysis.The results showed that:(1)A total of 29718 ants were collected from agricultural areas in southeastern China,belonging to 153 species,50 genera and 7 subfamilies.Among them,there are 18 genera and 70 species of Myrmicinae,with a total of 17278 ants;14 genera and 49 species of Formicidae,with a total of 7865 ants;9 genera and 17 species of Ponerinae,with a total of 760 ants;1 genera and 1species of Proceratiinae,with a total of 1 ant;6 genera and 12 species of Dolichoderinae,with a total of 3804 ants;1 genera and 2 species of Pseudomyrmecinae,with a total of 4 ants;1 genera and 2 species of Dorylinae,with a total of 6 ants.(2)The species abundance of ants in agricultural areas of southern China is greater than that in agricultural areas of the middle and lower reaches of the Yangtze River.The specific performance is that in three habitats in the middle and lower reaches of the Yangtze River,a total of 11775 ants were collected,belonging to 5 subfamilies,35 genera and 89 species.The dominant species are Tetramorium caespitum,Monomorium chinense and Nylanderia bourbonica,among them the number of Monomorium chinense is the largest,accounting for 15.11% of the total collection in the middle and lower reaches of the Yangtze River.A total of 17943 ants were collected from 3 habitats in southern China,belonging to 7 subfamilies,43 genera and 125 species.The dominant species are Tapinoma melanocephalum and Solenopsis invicta,of which Solenopsis invicta have the largest number,accounting for 39.58% of the total ants collected in southern China.In the southeastern part of China,it shows an overall trend of gradual dropping in the density of ants and abundance of species in the agricultural areas from south to north and from the coastal land to inland.(3)Indicators of diversity of ants species in the middle and lower reaches of the Yangtze River and the southern agriculture areas of China vary from each other significantly,so do the indicators of various habitats.The indexes of overall advantage,biodiversity and richness of the southern agricultural areas are all higher than that in the agricultural areas of the middle and lower reaches of the Yangtze River,and index of evenness is lower than that in the agricultural areas of the middle and the lower reaches of the Yangtze River.In light of various habitats,the indexes of diversity,evenness and richness rise and the index of advantage drops as the cropland,grassland and planted forests varied.Then NMDS analysis of three habitats in two areas showed that three habitats in the middle and lower reaches in the Yangtze River and the southern agricultural areas of China are similar,including the similarity between the cropland and the grassland is the highest.(4)The density and abundance of ants species in Lishui agricutural areas vary from different seasons.On the whole,Lishui agricultural area collected the most ant species in March,with 17 species.The density of spring ants in cropland is the highest while the density of summer ants in grassland and planted forest is the highest;the abundance of ants of cropland in May is the most while the abundance of ants of grassland in May and July is the most,and the abundance of ants of planted forest in March is the most.In different seasons,the most similar situation in Lishui agricultural areas are biocoenosis in spring and fall(0.5000),while the least similar season are summer and winter(0.1905).As for various habitats,the most similar places are grassland and planted forest in winter(0.7500),and the least similar places are cropland and grassland in winter(0.2000).(5)The density and abundance of ants species in Mazhang agricultural areas vary from different seasons.On the whole,Mazhang agricultural area collected the most ant species in August,with 14 species.The density of fall ants is the highest among the three habitats;the abundance of cropland ants in August is the most,while the abundance of ants of cropland and planted forest in October is the most.In different seasons,the most similar situation in Mazhang agricultural areas are biocoenosis in summer and winter(0.5455),while the least similar season are in spring and fall(0.2174).As for various habitats,the most similar places are cropland and grassland in spring(0.5714),and the least similar places are cropland and planted forest in winter(0.1667).Above all,the diversity of ants species in the southern agricultural areas is more than that of agricultural areas in the middle and the lower reaches of the Yangtze River.Indicators of ants diversity vary significantly from regions and habitats.And the density of ants and abundance of species in agricultural areas in Lishui and Mazhang vary obviously from different seasons.Overall,the similarity of biocoenosis in Lishui agricultural areas is in the middle level,while the Mazhang agricultural area is among the middle level of dissimilarity and the middle level of similarity. |
