Abstract:

Exploring the annual, monthly and seasonal variation of the population size and composition of Apodemus agrarius can provide the basis for the forecasting, prevention and control, ecological and environmental governance of it. Based on the night trapping method, we analyzed the annual, monthly and seasonal population dynamics of A. agrarius capture rate in paddy field and dryland farming area of Kaili city, Guizhou Province from 1984 to 2022. The results showed that A. agrarius was mainly distributed in paddy fields and dryland farming areas in this area, accounting for 62.36% of the total number of captured rodents. The population composition in each year ranged from 50.69% to 94.44%, which was the absolute dominant species in the region and was the main monitoring and control object. There were significant inter-annual variations in population size of A. agrarius in different years, the capture rate ranging from 0.70% to 6.38%, with a 9.11-fold difference and an average capture rate of 3.92%. From 1984 to 1992, the capture rate was high, with an average of 4.86%, and the population density exhibited significant fluctuations. In contrast, from 2011 to 2022, the capture rate remained consistently low with an average of 1.20%, and the population density exhibited stability. There were significant variations in population size across different months and seasons, with the highest in July and the lowest in February. Correspondingly, the capture rates stood at 3.52% and 0.95%, respectively. In different seasons, the highest capture rate was in summer (3.05%) and the lowest was in winter (1.29%). The results showed that A. agrarius was the dominant species in Kaili City, and the population had remained in a low-density over the past decade. The population densities were highest in July and summer. This study provides an important basis for listing A. agrarius as the main rodent monitoring and control object in Kaili City, and also provides an important basis for accurate prediction and formulation of reasonable comprehensive control measures and the natural ecological environment management.

Key words: Apodemus agrarius, capture rate, population size, variation regularity, Kaili city