Structure Of The Rodent Community In Mosuowan Reclaim Ationand Dynamics Analysis Of The Time

Rodent community was sampled in 150 regiment of Mosowan region from June to August 2004. The purpose of study is to explore the character of the structure and law of succession of rodent community in artificial ecosystem of interior arid region . Rodent community of 18 samples in different habitats in Mosuowan reclaimation were investigated .According to the results of sampling and cluster analysis, the rodent community in mosuowan reclamation can be divided into six types: (1) rodent community of eremic type dominated by Rhombomys opimus+ Meriones meridianus;(2) semi-desert brush type community dominated by Meriones erythrourus+ Allactaga elater; (3) forest type community dominated by Meriones tamariscinus+ Apodemus sylvaticus; (4) cropland type community dominated by Mus musculus+ Apodemus sylvaticus; (5) abandoned field type community dominated by Cricetulus migratorius+ Meriones meridianus; (6) residential area type community dominated by Rattus norvegicus. From eremic to cropland , Shannon-Weiner diversity index showed increasing trend (1.1053—1.2744)and reached maximum (1.3931) in cropland and showed decreasing trend (1.2744) from cropland to residential area. Pielow evenness index showed irregular change(0.6423≤J≤0.9207). Simpson dominance index showed decreasing trend(0.4176—0.3368). The diversity of rodent community were affected by the difference of habitats,vegetation coverage and human disturbance.Diversity index of rodent community showed increasing trend with the better habitats and higher vegetation coverage from desert to brush,forest and cropland. Low-grade and high-grade disturbance might cause the decreasing of diversity of rodent community. Intermediate disturbance, however,could lead to the increasing of diversity. Rodent community in different habitats were combined into six types according to the time sere.Structure of rodent community show orderly changes with the time: rodent community of eremic type dominated by Rhombomys opimus+ Meriones meridianus→semi-desert brush type community dominated by Meriones erythrourus+ Allactagaelater→semi-desert forest type community dominated by Merionestamariscinus+ Meriones erythrourus →desert-semi-desert brush typecommunity dominated by Meriones erythrourus+ Merionesmeridianus→forest type community dominated by Apodemus sylvaticus+ Meriones tamariscinus→cropland type community dominated by Mus musculus+ Apodemus sylvaticus. In local extreme geographic environment,the time was the main factor of the changes of the structure of rodent community,which was affected by the frequency and the intensity of human disturbance. Too low-grade human disturbance could not lead to succession; Sequential ,steady disturbance frequency was interrupted ,regressive succession would take place after enough long time.Disturbance frequency could accelerate succession,if added properly.High-grade human disturbance could change the structure of rodent community .As a result,the change could accelerate succession and could also decelerate it.From desert to residential area ,with the increasing of diversity index of rodent community ,ecosystem became more and more stable. The results showed ,the succession of rodent community was stable and slow in the artificial ecosystem without intense human disturbance. Thirty years were needed from eremic type dominated by Rhombomys opimus+ Meriones meridianus to forest type community dominated by Apodemus sylvaticus+ Meriones tamariscinus.At least forty years were needed from eremic type dominated by Rhombomys opimus+ Meriones meridianus to cropland type community dominated by Mus musculus+ Apodemus sylvaticus. The cropland rodent community reached only the beginning phrase.Quite long time was needed from eremic type to residential area type community dominated by Rattus norvegicus.