| With an aim to test the continental island effect in the Sichuan Basin,this study analysed the morphological characteristics and genetic structure inside and outside of the Sichuan Basin with a focus on the tree sparrow(Passer montanus)population.Seven morphological features were measured in 558 adult of the tree sparrows,correlation was analysed between morphological characteristics and altitude and latitude in the Sichuan Basin and surrounding areas.The results were as follows:(1)There was significant difference in the body mass(P<0.05),wing length(P<0.01)and tarsus(P<0.05)(ANOVA)among the geographical populations of the north,west,southeast,and inside of the Sichuan Basin.Multiple comparative analysis showed there were significant differences in body mass,wing length,and tarsus of the tree sparrows in the west of the basin and three other regions(P<0.05).This was due to the plateau region in the western part of basin,thus the altitude factor has great influence on the morphological characteristics of the tree sparrow compared to other factors.(2)Partial correlation analysis showed the morphological characteristics,such as body mass,tail length and tarsus were very significantly positively correlated with the altitude factor(P<0.01),In addition,there was a significant positive correlation between the body length and altitude factor(P<0.05).(3)The populations were divided into 3 parts: the Sichuan Basin(mean 484.25 m,219～725 m),the surrounding mountainous area of the Sichuan Basin(mean 2 260.42 m,807～4 472 m)and Central China plain(average 250.70 m,46～784m).Multiple comparative showed that there is a significant difference in body mass,wing length,tail length and tarsus length among the surrounding mountains of the Sichuan Basin,Central China plain and inside the Sichuan Basin(P<0.05).The body mass,wing length,tail length and tarsus of the surrounding mountains of the basin were significantly larger than that in Central China plain(P<0.01).The body mass of the surrounding mountains was significantly higher than that in the basin(P <0.05).The size of the tree sparrow increases with altitude.Changes in body size were consistent with the Bergmann rule.However,there was no significant difference in morphological size between the population in Sichuan Basin and Central China plain,which indicated that there was no continental island effect in the Sichuan Basin based on morphological characteristic of the tree sparrows.In order to obtain the results of nucleotide diversity,genetic distance,phylogenetic tree and haplotype net map,population dynamics and genetic structure,the researcher used mitochondrial genes(12sr RNA,Cytb,Dloop,COI)and nuclear gene(Myo)as molecular markers to study 29 geographical populations and 172 tree sparrows.The results were as follows:(1)In addition to the high genetic diversity of the few populations distributed in uninhabited areas,the remaining populations showed lower genetic diversity(Pi<0.01).The overall genetic diversity displayed an increasing trend from the Sichuan Basin to the surrounding mountainous area(western Sichuan plateau and Yunnan-Guizhou plateau).(2)The genetic variation mainly comes from the mountain population around the basin.There were gene exchange between the population in the basin and the outside the basin.In addition,there were higher genetic distance and genetic differentiation of the tree sparrows in the western Sichuan plateau and Sichuan Basin.(3)The population inside and outside the basin generally showed interruption of phylogenesis,Space isolation distribution pattern.The population in the basin expands outward to the basin in the northwest of Sichuan Basin.(4)In terms of genetic structure,the mountain system around Sichuan Basin has a certain isolation effect on the population of tree sparrow in Sichuan Basin and outside Sichuan Basin.It shows the continental island effect of Sichuan Basin. |
