Research Of Rodents Distribution And Comparative Studies On The Morphology Of Dominant Rodents Digestive Tracts In The West Hillside Of Helan Mount Ains

The paper is mainly about the research and analysis carried out for the small rodents which were captured in the west hillside of Helan Mountain (the compass of competency of National Natural Reserve of Helan Mountain in Inner Mongolia) from March 2013 to December 2013. Geographical distribution of rodents in the area was gained. Meanwhile, the anatomy was performed on the captured samples to get the data of weights and lengths of their digestive organs. The study, combining the information about the geography of Helan Mountain and the environmental factor, also analyzed and discussed the relationship between the digestive organs of the rats in the area and the seasons. Furthermore, via the DNA barcode technique, a new-distributing species -- Microtus Fortis was identified. The main study results are as follows:(1) Rodents captured in the west hillside of Helan Mountain were divided into 16 species, 10 genera,5 families and 2 orders, which accounted for 64% of the past record of 25 species and 61.54% of the current record of 26 species.(2) Via the DNA barcode technique, the identification of a new-distributing species was performed. The comparison of gene segment sequences showed that the rat with the highest homology was Microtus Fortis, which enhanced the persuasion of morphological classification in the identification of species. Microtus Fortis is a newly recorded species and is a new distributing one in Helan Mountain.(3) Multiple comparisons were conducted via One-Way ANOVA and Least-significant difference (LSD). Then weight was taken as covariant and One-Way ANCOVA was performed for each index to compare and determine the indices of the digestive tract, including lengths, fresh weights (including content), net fresh weights (excluding content) and others of the whole digestive tract and digestive organs. The results indicated that extremely significant differences existed in the whole digestive organs of different types of rodents; in regard to the changes in digestive organs, the significant differences of different types of rodents varied.(4) The analysis of the digestive tract of Spermophilus alashanicus as the dominant species indicated that the digestive organs of the same species also changed seasonally. For the dominant spermophilus alaschanicus, the total fresh weight and total length of the digestive tract were highest in autumn, followed by summer and lowest in spring; The variations of fresh weights of stomach and caecum and the net fresh weight of caecum were up to the level of the significant difference, which were heaviest in autumn and lighter in spring and summer.