Breeding versus survival:proximate causes of abrupt population decline under environmental change in a desert rodent,the midday gerbil(Meriones meridianus)  

作　　者：Andrey TCHABOVSKY Ludmila SAVINETSKAYA Elena SURKOVA 

机构地区：[1]Laboratory for Population Ecology,A.N.Severtsov Institute of Ecology and Evolution,Russian Academy of Sciences,Moscow,Russia

出　　处：《Integrative Zoology》2019年第4期366-375,共10页整合动物学（英文版）

基　　金：the Russian Foundation for Basic Research(grants 13-04-00086 and 16-04-00739);the Program for Fundamental Studies“Biological Resources”of the Russian Academy of Sciences.

摘　　要：Studying abrupt ecological shifts under gradual environmental change caused,in particular,by human activi­ty is important for understanding the fundamental aspects and underlying mechanisms of ecological resilience.One of the rare well-documented examples of an abrupt ecological shift is the delayed step transition of the population of a desert rodent,the midday gerbil(Meriones meridianus),from high-abundance(1994-2002)to low-abundance(2003-2017)regimes.This was in response to landscape transformation from desert to steppe caused by the drastic reduction of livestock in the rangelands of southern Russia after the collapse of the USSR in the early 1990s.In this study,we tested whether demographic parameters were correlated with the observed abrupt downward population shift.We found that reproductive activity(the percentage of breeding females,the number of litters,fecundity and the number of young recruited per female)showed no trend over time and did not differ between periods of high and low abundance.In contrast,the adult sex ratio(SR=males:females)de­creased significantly with time and was as much as twice more female-biased for the low-abundance population regime.However,SR was not related to any reproductive parameter,including the percentage of breeding fe­males.We conclude that proximate reasons for an abrupt population decline in M.meridianus are not associat­ed with the changes in breeding patterns or mate limitation caused by the Allee effect but relate to the increased mortality as a result of the desert landscape being fragmented by steppezation.The mortality is expected to be higher for males as the mobile and dispersing sex.

关 键 词：DEMOGRAPHY landscape change RANGELANDS REPRODUCTION threshold population dynamics 

分 类 号：R76[医药卫生—耳鼻咽喉科]