Population Dynamics And Genetic Features Of Moose(Alces Alces Cameloides)in Northeastern China

With increasing impact of human activities on recent climate change,the growing threat of climate change to the ecosystem has raised attention from the public and scientists,and studies on climate change biology have become a hot-spot in recent years.As the typical species of boreal forest mammals,moose are turned out to be sensitive to climate change,and ideal model species for climate change biology studies.From Jan.2012 to Jan.2015,we surveyed moose populations in Shuanghe,Hanma,Mohe,Nanwenghe,Wuerqihan and Zhanhe in Greater and Lesser Khingan Mountains by setting transect lines and following moose snow trails,and totally,we set up 96 transect lines with an interval of 3 km,followed 84 snow trails and collected 319 moose scat samples.This research firstly explored effect of climate change in late Pleistocene on distribution and genetic fearures on moose populations,and then studied the impact of recent climate change on range contraction and habitat suitability,followed by researches on the genetic differentiation and structure of 6 populations and finally population dispersal and related factors were studied.We found:1.Generally,moose populations in Northeastern China were featured with low to moderate level of mtDNA genetic variants.The overall haplotype diversity(h)was 0.91 ±0.011,and thenucleotide dversity(?)was 1.01 ±0.07(%),both of which were lower than that in Russia Fareast and Europe,and only higher than North America.Differentiation existed aomg 6 moose populations,Hanma and Wuerqihan holding the highest and lowest genetic diversity.Phylogenetic analysis showed that thephylogenetic trees were almost the same constructed by different models,and haplotypes roughly belonged to 3 groups,namely Hanma type,North America type and mixed type.In addition,moose in Northeastern China were most close to Russia Fareast in relationship,and followed by North America,but greatly different from European populations.It was evident that genetic differentiation did exist among populations,but there was no obvious genetic structure.SAMOVA analysis showed that the most geneticly distinctive population was Hanma,and followed by Zhanhe,whereas Nanwenghe and Wuerqihan clustered together.An overall population expansion was detected in Northeastern China,and the expansion time dated back to 12 500 years ago,which was in the interval of late glacial and interglacial periods of the late Pleistocene.2.Moose in Northeastern China were on the southernmost edge of Eurasian mainland,but nearly half of historical distribution had been lost during last 40 years,with an average contraction speed of 47.85 km/10a.Since 1970s,temperature in Northeastern China increased significantly,when late spring temperature increased by 1.7 ?,and Jan.temperature increased by 3.1 ?,the temperature increasing trend in the West being much higher than the east.Precipitation exhibited an uneven distribution pattern,yearly precipitation being higher in the east than in the west.Both temperature and precipitation had a negative effect on historical distribution contraction,and NDVI had a dual effect,while human population density exerted a negativeeffect on moose populations only when human density reached the threshold.Analysis on current habitat showed that climate features played a dominant role in degrading habitat distribution and quality,and the increase of temperature and precipitation had adverse effect on moose survival.3.120 moose individuals were identified from 319 feaces,and SECR model estimated the overall density to be 0.095 ± 0.034 individual/km2,with a total population size of 6 882 ± 2 448,which decreased by 30.87%compared with survey result in 1987.Sex ratio(female:male)was determined to be 0.9 in the entire population.Genetic diversity of Northeastern China was moderate,populations on the rear(Zhanhe and Wuerqihan)and expansion edge(Mohe)were characterized with extremely low genetic diversity,and populations in the middle areas(Hanma and Nanwenghe)had high level of genetic diversity.We found no evidence of inbreeding and recent bottleneck effect in all populations,and the overall effective population size ratio exceeded 56%.Significant genetic differentiations existed among 6 populations(FST= 0.04?0.11,RST=0.04-0.17,P<0.001)and nearly 90%of genetic variants happened within populations.However,we failed to detect genetic structure(K=1)with STRUCTURE 2.3.4,indicating that highly mobile movement ability and sex-biased dispersal pattern promoted gene flow among populations.4.Spatial autocorrelation analysis found significant spatial genetic structure in Hanma Nature Reserve in 2800?3500 m distance scale,and within such distance intervals,moose individuals exhibited genetic similarity.We found a male-biased dispersal pattern in Hanma and among 6 populations using different methods.Landscape genetics analysis showed a positive IBD effect and no relationship between least-cost path distances and genetic differentiation was found among 6 populations.However,when we re-examined the relationship within the Greater Khingan Mountains(except for Zhanhe),we found the positive effect of environmental factors on current genetic structure.Dispersal rates varied among sites,generally showing a northwestward dispersal pattern,and climate features were the main driving factors,increase in temperature and precipitation pushing the dispersal out of original populations.