| It is well known that frogs are important predators of agricultural pests and can prey on many pests in the field.In recent years,agricultural cultivation measures,such as single scale planting,centralized regulation of high standard field and unreasonable application of chemical pesticides,have worsened the habitat of frog in agricultural ecosystem,which resulted in a significant decrease of frog species and population.It has always attached importance to the protection and utilization of frogs in paddy fields in China.,and even the method that artificially increases frog in paddy field is used to improve the controlling ability of frog in agricultural ecosystem.However,most of the current research focus on the effect of frog on rice output growth,the description and causes of frog species diversity and population decline,and the lack of data support and theoretical support for the analysis of the factors affecting frog species diversity and population richness in paddy field ecosystems.Based on the study of the ecosystem service function in different regions of Jiangxi under the rape-rice rotation model,this paper systematically investigates the species diversity,population richness and several dominant species of the rice field in the area.It is aim to provide basic data and theoretical support for improving the ecological control function of frogs in rice field habitats.1.The diversity and richness of frog species were systematically investigated in 19 experimental paddy fields plots under different agricultural landscape patterns.The results of the 4-9-month period of 2016 and 2017 indicate that there are 12 species of frog species in all experimental plots,of which 11 species(total 7,554)were found in the rice fields in2016-2017 annual repeat found 9 species(total of 5,845),the dominant species of different years are Rana limnocharis(accounted for 92%～96.46%),in addition to adorn Microhyla ornata and Pelophylax nigromaculata is also relatively common species,pelophylax plancyi and other species are rare speci es.The seasonal dynamics of population quantity of 3 dominant species,such as R.limnocharis,were further analyzed,and the trend of population number in the year was the same,which was the peak of population growth in June,followed by slow decline.The overall density of t P.nigromaculata and M.ornata frog was significantly lower than that of the R.limnocharis in the season.The comparison of the number of frog species in different populations shows that the average number of frog population is similar in the year,but the number of frog species varies significantly.The relationship between the richness of frog species and Landscape Shannon Diversity index in rice field was analyzed by GLM,and it was found that the small scale of 400 m radius and the large scale range of 1600 m radius showed that the number of frog population tended to decrease with the increase of Shannon Diversity index,but the correlation did not reach a significant level.Further refinement and analysis of the relationship between the factors of agricultural landscape and the number of frog species in different scales the results showed that there were significant positive correlations between the proportion of early rice area and the area distribution of two landscape factors in agricultural landscape pattern.2.Systematic analysis of the diversity of the prey species of 3 dominant frogs in rice fields,such as R.limnocharis,P.nigromaculata and M.ornata.The results show that the prey of R.limnocharis includes 7classes,21 order,72 families and more than 200 species.The insect of prey is 82.6%～83.2%,the spider shape occupies 8.35%～8.96%,the other food is small in proportion,but each has difference.The first three targets of the insect-prey are Hymenoptera,Hemiptera,Diptera,in the prey insects and spiders,involving multiple families of prey for a variety of pests in paddy fields,such as ground beetle and spider,it is indicated that R.limnocharis in the field of arthropod predation there is a common natural enemy group predation phenomenon.The prey of P.nigromaculata frog involves 5 classes,16 oder,and 42 families,of which the insect accounts for 69.1%～83.1%,and the spider is the 8.2%～12.7% of all prey.Among the prey insects,Lepidoptera,Hemiptera,Coleoptera,Hymenoptera,and Lepidoptera larvae reached 7%,the proportion of 2.3%～4.2% to rice planthopper,the predator-prey in the group of predators is also more common.The paddy adorn the frog to prey on the prey to be involved in the arthropod 4 12 head 26 families,the insect species which preys on the prey and the individual frog preys on the prey number to reach 24.3 ～44.48 head,the insect outline occupies the prey the 95.6%～97.1%,the ant division is mainly prey prey,The natural enemy spiders have a certain group of predators.It is found that the predator species of frogs in different stages of rice were different in the seasonal dynamics of frog prey.This chapter analyzes the contents of the rice-field frog species in the area.3.The relationship between the predation of frog species and arthropod taxa in the paddy field.The predator-prey changes of the rice field insects in different periods were compared,and it was found that the April frog-prey pests accounted for 23.4% of all the prey,May was 8.9%,and the late period gradually increased with the passage of the month,which reached 30.3% in August.In the predator-prey group of the paddy field,the predators of the frogs were gradually decreasing with the increase of the month.At different stages of the frog,the parasitic natural enemy insects have feeding phenomenon,but the proportion is low.The predation rate of the frog on the neutral insect in paddy field was relatively high.The benefit ratio(pest and natural enemy ratio)of farm frog prey in different months shows: This is consistent with the trend of arthropod composition in paddy field using total sampling survey.There was a negative correlation trend between frog density and pest quantity in paddy field,but it did not reach the significant level.In order to prove the pest control level of frogs,the frog predation rice planthopper was observed by the cage experiment,and the results showed that the single R.limnocharis could prey on 71 heads of rice planthopper.The study focuses on the qualitative and quantitative evaluation of species diversity,richness and ecological control function of frog in paddy fields under different agricultural landscape patterns.This paper systematically analyzes the diversity of frog species,population dynamics in different periods under different landscape patterns,the establishment of dominant frogs and their richness and seasonal dynamics,and the influence of agricultural landscape differences on frog species distribution and frog population quantity,and the structure of 3 dominant frogs in paddy field on the prey of arthropod in paddy field are clarified,The research content is to promote the protection of frog diversity and promote its ecological control... |
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