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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (11): 36-47.DOI: 10.11686/cyxb2021429

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Harmful and economic thresholds for rodent pests in the Alxa desert area under different grassland utilization patterns

Ke YANG1(), Shuai YUAN1, Xiao-dong WU1, Hao-ting ZHANG1, Shan-shan SUN1, He-ping FU1(), Yong-quan ZHAO2, Shu-yan WANG3, Qi-fu LIU4   

  1. 1.College of Grassland,Resource and Environment,Inner Mongolia Agricultural University,Hohhot 010011,China
    2.Hulunbuir Forestry and Grassland Enterprise Development Center,Hailar 021008,China
    3.Hulunbuir Grassland Science Research Institute,Hailar 021006,China
    4.Xingan League Forestry and Grassland Workstation,Ulanhot 137400,China
  • Received:2021-11-24 Revised:2022-02-08 Online:2022-11-20 Published:2022-10-01
  • Contact: He-ping FU

Abstract:

The rodent damage threshold and the rodent economic threshold are indicators that must be clearly defined in the practice of grassland rodent prevention and control. Different grassland types or different utilization methods of the same grassland type have completely different values for these two indicators. The damage threshold is the population density of pests at which the grassland is obviously compromised, and the economic threshold is the population density at which further pest population increases will cause economic losses. The Alxa desert region is ecologically fragile, and rodents are endemic. This study selected continuous grazing areas and prohibited grazing areas in the desert area of Alxa Left Banner and from 2015 to 2019 to investigated the species and density of pests using the ‘mark and recapture’ method, together with sampling to investigate the aboveground plant biomass in the sample area in August. The measured rodent unit densities and their daily food intakes were used to estimate the amount of forage loss, and a regression equation was used to obtain a fitted relationship between the rodent density and the ratio of forage loss. It was found that: 1) The fitted curves for the ratio of pest density and forage loss in the continuous and prohibited grazing areas took the form of logistic three-parameter, S-shaped curves. 2) According to the regression equation, the damage threshold in continuous grazing areas was 26 standard rodent units·ha-1 and the economic threshold was 39.3 standard rodent units·ha-1. In prohibited grazing areas, the damage threshold was 33.2 standard rodent units·ha-1 and the economic threshold was 30.2 standard rodent units·ha-1. Thus, the economic threshold pest density of continuous grazing areas was slightly higher than that of prohibiting grazing areas.

Key words: Alxa desert area, rodent control, damage threshold, economic threshold