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Inter-simple sequence repeats(ISSR) were used to analyze genetic diversity and genetic structure of four cultured populations of Hydropotes inermis in four farms of Zhoushan Archipelago.Twenty-six ISSR primers yielded 286 loci in 59 individuals from the four populations.Among which 184 loci were polymorphic,and percentage of polymorphic loci(PPL) was 64.34%.Primer UBC 812 revealed the highest variation with PPL(90.91%),whereas primer UBC 860 showed the lowest variation with PPL(37.50%).Twenty-six ISSR primers were selected for the analyses of genetic diversity and genetic structure in the four population.Nei′s genetic diversity(H) and Shannon′s index(I) at the species level were 0.210 and 0.318,respectively.H values were between 0.1571 and 0.1895 for the four populations of Hydropotes inermis,whereas I values for the four populations were between 0.2277 and 0.2778.When comparing with the results from other animals using ISSR,the genetic diversity of the cultured Hydropotes inermis in Zhoushan Archipelago is relatively high.Among the four populations,Zhoushan(ZS) population showed the highest genetic diversity(Na=1.486,Ne=1.333,H =0.190,I=0.278,PPL=48.60%),followed by Daishan(DS) population and Xiushan(XS) population.The lowest genetic diversity was found in Zhujiajian(ZJJ) population.The analyses of population genetic structure showed that when K=4,the △K value reached maximum,which suggests that all individuals could be divided into four groups based on their genetic data.Biological data,such as skin color collected from the four populations showed that most individuals from four geographical locations could be clustered into its own group.The color of the majority of DS population was white;the color of the majority of XS population was dark grey;the color of the majority of ZJJ population was black;and the color of the majority of ZS population was light grey.These biological data indicate that there are genetic differences among the four populations studied.Furthermore,the coefficient of differentiation,Gst(0.163) obtained for the four populations with POPGENE software was similar to that obtained by AMOVA analysis(11.96% genetic variation among four populations).In order to find out genetic relationships among the four populations,Nei′s genetic distance(GD) and Genetic identity(GI) were calculated.The results showed that the value of GD between ZS population and XS population was 0.045,showing that the genetic distance between these two populations is the nearest,while the value of GD was 0.066 between DS and ZJJ populations,indicating that the genetic distance between these two populations is the farthest.GI showed a similar trend to GD.The value of GI between ZS and XS populations was the highest(0.956),whereas the value of GI between DS and ZJJ populations was the lowest(0.936).Based on these results,we suggest that the increase of genetic exchange among different island populations of Hydropotes inermis,especially between ZJJ population and other three populations could improve quality traits of Hydropotes inermis.In practice,we could electronically tag the individuals of Hydropotes inermis,and systemically record the exchange information among individuals.The proposed genetic exchange could not only improve breeding for quality traits,but also scientifically and economically manage propagation of Hydropotes inermis.

Conventional methods for investigation on densities of small mammals unavoidably produce environmental disturbance.By using infrared-triggered camera technology(ITCT),animal densities could be obtained with minimal disturbance to animal′s habitat.For large mammals,individually unique natural markings,such as spotted and striped fields can be used for recognition,but for small mammals,it is difficult to distinguish individuals,especially for nocturnal species.In this study,we used cameras triggered by infrared sensors to obtain images of passing animals to estimate the rodent density.Three biological indexes,that is,rodent′s day range(or called speed of day movement),distance and angle with which the camera detects animals are required for the modeling.Camera detection distance(0.01 km) and angle(50°) were provided by the infrared camera manufacturers in this study,whereas the rodent′s day range had to be estimated in experimental sites.An experimental site of 600 m×400 m was selected at Gutianshan National Natural Reserve in Kaihua county,Zhejiang province.The site was divided into 18 areas based on the principle of stratified random sampling,and 20 infrared cameras were deployed in these areas.At the same time,the capture-mark-recapture method(CMR) was used to survey speed of rodent movement.The experiment was conducted from May 2009 to July 2011.The results derived from CMR,showed that the day range of rodent movement was approximately 100—300 m.By assuming the speed of day movement as v1(0.1 km/day),v2(0.2 km/day),v3(0.3 km/day),corresponding densities obtained from camera trapping were D1,D2 and D3,respectively.When these three densities were compared with the density(D) derived from CMR,the results showed that D1 was highly significantly different(P0.01) from D.However,there were no significant differences between D2 and D(P = 0.090) or between D3 and D(P = 0.679).The smallest difference was found between D3 and D.Therefore,D3 may represent the closest estimate.Taken D3 as the density estimate,rodent densities was calculated for the period from May 2009 to July 2011 by using monthly independent photographs of rodents.Average density was(657 ± 81) individuals/km2.The seasonal changes in the rodent density which obtained from camera trapping with the high camera density of 83.3/km2,confirm that our results are reliable.In this study,uninterrupted monitoring promoted efficiency of detection.Our results revealed that the density of rodent reached the peak from the beginning of May to the late summer because of abundant food resources and low interspecies competition.While from November to March,predation pressure and food shortage reduced rodent densities.As a consequence,intraspecific and interspecies competition was reduced,leading to a relatively stable community structure.In conclusions,our results demonstrate that ITCT with the aid of the capture-mark-recapture method can be used to reliably estimate rodent density with high accuracy and low costs.

We live-trapped two Niviventer confucianus populations from March to November of 2010 in Thousand Island Lake region using the capture-mark-recapture(CMR) method.We used Jolly-Seber method,modified Lincoln index method,Schnabel method and minimum number of animals alive(MNA) method to estimate population sizes of Niviventer confucianus,and discussed the applicability of these estimators in white-bellied rats on land-bridge island.Our results showed that there was no significant difference between Jolly-Seber method and modified Lincoln index method.We considered that modified Lincoln index method was more suitable for estimating the population quantity of Niviventer confucianus in the land-bridge island.The study can provide basic data for the future study of population ecology of rodent in the land-bridge island.