| Taking the alpine grassland in the northwest of Sichuan as the research object,three types of rodents damaged rangelands were selected as study plots in Zoige grassland,they were Extreme damaged plot by Plateau Pika(plot I),Mediumn damaged plot by Plateau Pika(plot II),Extreme Damaged area by Plateau Zoker(plot III).During the warm season in July and the cold season in November,sampling investigations were made on the composition of major rodent pests,the amount of burrows,and the vegetation community structure,soil physical and chemical properties,and biological characteristics.Taking the rodents damaged rangeland in Shiqu counties as an example,the aim was to restore vegetation.research on governance,the results are as follows:1.Changes of species and number distribution of rodents damaged rangelands in cold and warm seasonsAmong the three plots with an area of 2500 m~2,the warm-season rodents plot I(EDP)and plot II(MDP)were Ochotona curzoniaes,and the plot III(EDZ)was Myospalax bayieyi.The active footprint of plateau moths also appeared in bare ground on plots I(EDP)and plots II(MDP)in the cold season.The total number of burrows(mounds)in the warm season plot II(MDP)was the highest,reaching913/hm~2,while plot III(EDZ)in the cold season was the highest,reaching 932/hm~2;The effective burrows(mounds)rate was 42.86%,43.04%,and 53.08%in the warm season respectively,among the plot I(EDP),plot II(MDP)and the plot III(EDZ),and it was 27.87%,25.12%,and 67.06%in the cold season.2.A survey of the vegetation in warm season at rodents damaged rangelands and the change of biomass in the cold and warm seasonsThe number of plant species in plot I(EDP),plot II(MDP)and plot III(EDZ)were 2 species/m~2,9 species/m~2,and 6 species/m~2,all of the samples contained the typical indicator plants of the Potentilla anserina.The order of community height was:plot III(9.66 cm)>plot II(6.81 cm)>plot I(5.54 cm);plot II had the highest vegetation coverage(71.67%),plot I was the smallest(43.03%),and the Shannon-Wiener index(0.96)and Patrick index(2.00)of the plot I(EDP)were the lowest among the three plots.In the warm season,the aboveground biomass of the Myospalax bayieyi like land was higher than that of the Ochotona curzoniae like land,and the highest level in the plot III reached 163.12 g/m~2,the minimum in the plot I was only 75.05 g/m~2,and the Myospalax bayieyi like land in the cold season(EDZ)was lowest,only 102.87 g/m~2,a decrease of 36.94%.The belowground biomass was the highest in the cold and warm plots II(MDP),among which the distribution of underground soil biomass in the Myospalax bayieyi like land in the cold season was distinct different.The surface layer 0~10cm accounted for 79.70%of the total underground biomass,10~20cm and 20~30cm soil layer accounted for 6.64%and13.66%respectively.3.Soil physicochemical and biological characteristics in the cold and warm seasons of the rodents damaged rangelandsIn the warm-seasonal topsoil,plot II had the highest soil water percentage(45.42%),plot III had the lowest(30.40%),and the soil bulk density and pH varied from 0.82 to 1.13g/cm~3 and 7.10 to 8.26.And the sample land was alkaline soil;the soil organic matter content of plot III(4.18 g/kg)was the lowest,and the plot I was the highest(30.02 g/kg);the total nitrogen and soil available nitrogen(EDP)of the plot I was the highest,the plot III(EDZ)was the minimum,the soil total phosphorus content of the sample has a significant difference(P<0.05);the highest soil available phosphorus content was plot I(35.86 mg/kg),and the lowest was plot II(25.17mg/kg);three plots of soil total potassium and soil available potassium showed significant differences(P<0.05).The overall soil nutrient content decreased with the deepening of the soil depth.The ranges of soil urease,invertase and phosphatase were0.33 to 9.36 mg/g,29.18 to 539.53 mg/g and 132.73 to 375.94 mg/g,respectively.The contents of urease and phosphatase in Ochotona curzoniae were higher than those in the Myospalax bayieyi.The number of bacteria was the highest and fungus was the minimum.In the cold season,surface bacteria,actinomycetes,and fungi accounted for 51.32%to 86.67%,13.28%to 48.44%,and 0.05%to 0.34%of the total number of microorganisms,respectively.4.Vegetation restoration and comprehensive control of rodents damaged rangelandsThe method of"rodent pest investigation+rodent control+fertilization+agronomic measures+reseeding+fertilization+spraying pesticides"can be used in view of the restoration and treatment of rodents damaged rangelands.For the serious sandy area of the rat,the bamboo strip or bamboo weaving barrier with length of5m*5m can be added,the vertical tie up and the dense layout can prevent the rangelands desertification from aggravating,and the soil mound movement affecting the grass root and germination. |
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