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

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. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

荒漠区不同放牧干扰下五趾跳鼠的巢区变化及影响因素

于2017～2019年在阿拉善荒漠区的过度放牧区和轮牧区,采用标志重捕法对五趾跳鼠种群进行监测,并应用最小凸多边形法研究其巢区变化。结果表明：雄性五趾跳鼠巢区面积大于雌性,但差异不显著;五趾跳鼠平均巢区面积表现出夏季(1085.56±676.93m²)>春季(856.47±779.40m²)>秋季(834.42±793.56m²)的趋势,季节之间有显著差异(P<0.05);五趾跳鼠平均巢区面积在过牧区为1084.82±873.44m²,轮牧区为766.15±585.15m²,过牧区显著大于轮牧区(P<0.05)。五趾跳鼠的巢区主要受季节、放牧方式及栖息地食物资源影响。