| The Qilian Mountains is one of the priority regions of biodiversity conservation and has the important strategic position in the construction of ecological civilization in China.In recent years,due to the multi-effects of global climate change and human disturbance,there are serious rodent pests damage in desert steppe of Qilian Mountains,threatening the production and ecological services of desert steppe.At present,the strategy of rodent pest control focus on reducing the population,which ignore the multiple functions of rodents in grassland ecosystem.Therefore,it is very important to conduct precise control technology for rodent pests in desert steppe in terms of the target,time,region and measures.In order to achieve the goal of precise control for rodent pests,it is necessary to study the ecology of these rodent pests.In this study,the community composition of the rodents was investigated by using the trap method,the spatio-temporal activity pattern of the rodents and their predators was investigated by using infrared camera trap technology,and the activity pattern of rodents and their spatio-temporal overlap with predators were analyzed.Besides these,the relationship between the relative population number of the desert rodents and environmental factors was analyzed by investigating the relative population number of the desert rodents and the characteristics of soil and vegetation,and the habitat characteristics of the desert rodents were clarified.To evaluate the control effect of different concentrations of type D botulinum toxin on desert rodents,cavity elimination rate was selected as the control effect index.The results of this study not only help to understand the ecological characteristics of the rodents on desert steppe,but also provide basic data and scientific basis for the precise control of the rodent pests in desert steppe in the future.The main research results are as follows:1.The dominant prairie pests in the study area were Meriones meridianus and Rhombomys opimus.Meriones meridianus was the dominant species in the two rodent communities,accounting for 76%.The second dominant species was the Rhombomys opimus,accounting for 24%.2.The activity intensity of the Meriones meridianus showed a bimodal pattern,and the activity peaks were in March and October,respectively,while the daily activity peaks were mainly concentrated in 20:00～22:00 and 2:00～4:00.The monthly activity intensity of Rhombomys opimus was unimodal,and the activity peak occurred from February to May,while the daily activity peak mainly occurred from 12:00～13:00.3.The density of rodents holes in the mixed communities of Meriones meridianus and Rhombomys opimus was significantly negatively correlated with soil compactness of 0-30 cm,soil moisture of 0-30 cm,vegetation coverage,above-ground biomass,Patrick index and frequency of Salsola passerina(P<0.05).Rodents hole density was positively correlated with Pielou index(P<0.05).The results of redundancy analysis showed that the mixed communities of Meriones meridianus and Rhombomys opimus preferred to live the land with soil(0～30 cm)compactness below 737 pa.4.The control effect of type D botulinum toxin at 1.5%,2.0% and 2.5%concentrations were 80.9%,68.4% and 71.1%,respectively.1.5% concentration of type D botulinum toxin showed the best control effect on the mixed communities of Meriones meridianus and Rhombomys opimus.5.9 species belonging to 2 orders and 5 families predators were recorded in this survey.They were Otocolobus manul,Vulpes vulpes,Mustela nivalis,Vormela peregusna,Lynx lynx,Felis bieti,Arctonyx collaris,Aquila nipalensis and Athene noctua.The independent photographs of Otocolobus manul,Vulpes vulpes and Mustela nivalis were higher than those of other natural enemies.The relative abundance index(RAI)was 0.6,0.4 and 0.08,respectively.In conclusion,this study found that Meriones meridianus and Rhombomys opimus.were the main dominant pests in the study area.The monthly and daily activity peaks of Meriones meridianus was March and October,and 20:00～22:00 and 2:00～4:00,respectively.The monthly and daily activity peaks of Rhombomys opimus was from February to May,and 12:00～13:00,respectively.The mixed communities of Meriones meridianus and Rhombomys opimus prefer to habit the land with low soil compaction in 0～30 cm soil layer.The optimal application concentration of type D botulinum toxin for controlling Meriones meridianus and Rhombomys opimus was 1.5%.The species of natural enemies of the rodents were nine species. |
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