title: Agricultural irrigation mediates climatic effects and density dependence in population dynamics of Chinese striped hamster in North China Plain.
abstract: Several studies show that climatic (extrinsic) factors can interact with density-dependent (intrinsic) factors to alter long-term population dynamics, yet there is a surprising lack of investigations of how anthropogenic disturbance modifies such dynamics. Such interactions could be especially important in agricultural systems subject to climate change. We investigated the effects of density dependence, climate, recurrent disturbance from flood irrigation and their interactions on the population dynamics of an important rodent pest, the Chinese striped hamster (Cricetulus barabensis), over 27 years in the croplands of the North China Plain. Strong density-dependent feedbacks occurred at both annual and seasonal scales. While warmer weather increased population sizes in nonbreeding seasons, this effect was counteracted by the negative effect of flood irrigation in breeding seasons. Precipitation showed significant positive effects in nonbreeding seasons, but negative effects in breeding seasons. There were important interactions between intrinsic dynamics, extrinsic dynamics and disturbance. Low temperature significantly increased the strength of density dependence in nonbreeding seasons, whereas intensification of flood irrigation area significantly increased the strength of density dependence but reduced the effect of summer precipitation in breeding seasons. Overall climate change is expected to increase population levels, but anthropogenic disturbance from flood irrigation will help prevent long-term population increases. The interactions between anthropogenic disturbance and both intrinsic and extrinsic (weather-driven) population dynamics caution that we need to consider anthropogenic disturbance as an integral component of population responses to climate change.
authors.affiliation: State Key Laboratory of Integrated Management on Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China; Graduate University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Yan
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Tongqin
authors.initials: T
authors.lastname: Xu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Cao
authors.forename: Fusheng
authors.initials: F
authors.lastname: Wang
authors.forename: Shuqing
authors.initials: S
authors.lastname: Wang
authors.forename: Shoushen
authors.initials: S
authors.lastname: Hao
authors.forename: Hefang
authors.initials: H
authors.lastname: Yang
authors.forename: Zhibin
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D057914:Agricultural Irrigation; D000818:Animals; D002980:Climate; D003412:Cricetulus / Q000502:physiology*; D008954:Models, Biological; D011157:Population Dynamics; D012621:Seasons