At the beginning of the 1980s, the Central Place Theory(CPT) was introduced into China from the West. The authors of this article are the initiators of applying this model to China's urban and regional planning as...At the beginning of the 1980s, the Central Place Theory(CPT) was introduced into China from the West. The authors of this article are the initiators of applying this model to China's urban and regional planning as well as to the allocation of commercial activities. Since the commodity economy has been developing in China for thousands of years,most of the areas in eastern plains and inland basins of the country show the spatial structure of typical central places scene. During some six years, the authors participatd in a lot of rural, urban and regional planning projects in which the spatial phenomena and relevant internal mechanism proved this medel and its deformation. This paper gives only a few examples of the application of CPT in China. 1. The distribution of rural markets: the empirical study is based mainly on the situation in Shengfang Town and its vicinal area, 2. The spatial combination of urban Systems; problems about city allocation in North China are emphasized, 3. Commercial centres in city and the networks: a crucial study on commercial distribution of the metropolis Beijing is done by using the central place model.展开更多
This is a very attractive article. It combines fascinating new methodology with a most interesting dataset, and a highly motivating presentation. However, despite the many
The authors are to be congratulated for an innovative paper in terms of both modelling methodology and subject matter significance. The analysis of short time series is known to be
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 resilien...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.展开更多
文摘At the beginning of the 1980s, the Central Place Theory(CPT) was introduced into China from the West. The authors of this article are the initiators of applying this model to China's urban and regional planning as well as to the allocation of commercial activities. Since the commodity economy has been developing in China for thousands of years,most of the areas in eastern plains and inland basins of the country show the spatial structure of typical central places scene. During some six years, the authors participatd in a lot of rural, urban and regional planning projects in which the spatial phenomena and relevant internal mechanism proved this medel and its deformation. This paper gives only a few examples of the application of CPT in China. 1. The distribution of rural markets: the empirical study is based mainly on the situation in Shengfang Town and its vicinal area, 2. The spatial combination of urban Systems; problems about city allocation in North China are emphasized, 3. Commercial centres in city and the networks: a crucial study on commercial distribution of the metropolis Beijing is done by using the central place model.
文摘This is a very attractive article. It combines fascinating new methodology with a most interesting dataset, and a highly motivating presentation. However, despite the many
文摘The authors are to be congratulated for an innovative paper in terms of both modelling methodology and subject matter significance. The analysis of short time series is known to be
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.
文摘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.
