| Top predators are indicators of ecosystem stability,as one of the indicator species,Asian black bear(Ursus thibetanus)performs multiple ecological functions and plays a crucial role in keeping stability of forest ecosystem.Moreover,high-quality habitat and sufficient supportive food resource during non-hibernation are required for both fat storage in hibernation and breeding.Therefore,selection of habitat and dens are closely tied to population stability and wintering safety.Moreover,high-quality habitat and sufficient supportive food resource during non-hibernation seasons are required for both fat storage in hibernation season and breeding.Therefore,selection of habitat and dens are closely tied to population stability and wintering safety.And to be further,conservation of Asian black bear relied on population dynamic monitor,and suitable habitat and overwinter dens.Researching the spatial distribution,population,habitat selection,and den site selection of black bear populations not only enriches the ecological research on bears in China but also provides scientific basis and fundamental data for the conservation and management of black bear populations.Jointly with parallel Asian black bear surveys conducted by other provinces,co-respond to one motion of WCC-2012-Rec-139-EN which formed on The World Conservation Congress in Jeju,Republic of Korea,6-15 September 2012 that in other words,“whether bear farming have influence on wild black bear resources in China,is bear farming stimulating poaching or promoting resources protection of wild black bear”.Main results are as follows:1.From September 2015 to February 2019,we randomly selected 112 grids from 540 grids(15 km×15 km)for our research in the eastern Jilin Province.Stratified sampling,field survey and interview,and camera trap monitoring were used to investigate the presence of black bear.Results showed that 43 grids(38.4%of 112 grids)have been directly observed or indirectly evidential suggested the presence of bears.Logistic regression model predicted that 275 grids were suitable for black bear habitat,accounting for 50.9%of the entire sampling area and covering an area of 61,875 km~2.Main factors driving the distribution were distance to protected areas,forest coverage,distance to main roads,and water area,indicating that forest habitat quality and human disturbance are the main driving forces affecting the distribution of black bears.The main measures to expand the distribution range of black bear populations include improving forest coverage and habitat quality,rational land use planning,and increasing protection efforts.2.In July 2022,a non-marking spatial capture-recapture model(SPA)based on the Bayesian framework using data augmentation and Markov Chain Monte Carlo methods was applied to estimate the population size.SPA was optimized through spatial sparsification and spatial autocorrelation tests.Results showed that estimated population size of black bears was 346(95%CI:281-399),population density is 4.33/100km~2(95%CI:3.51/100km~2-4.99/100km~2),with spatial scale parameter of 2.08(95%CI:1.76-2.46)and detection probability of 0.26(95%CI:0.17-0.34).The population of black bears has increased from 213 individuals 23 years ago to346 individuals,with an average annual growth rate of 2.1%,indicating the population is increasing.The density is at a moderate level compared to other national parks.3.From 2021 to 2022,suitable habitat of black bears was evaluated using transect method and camera traps combined with multi-scale habitat assessment model.Model fitting ability was improved through factor screening and model optimization,and the habitat was evaluated more accurately.Results showed that:1)suitable habitat area was 7879 km~2,accounting for 78.79%of the study area.2)Main factors influencing black bear habitat selection were food factors(Gross primary productivity in October and broad-leaved forest)and human interference(distance to human settlement and distance to railways).Although contribution rates of other factors were low,they were also related to the above factors,so protecting suitable habitats should increase food resources and reduce human disturbance.3)The multiscale model performed better than single-scale model in many indicators,which indicated that it was more suitable for black bear habitat evaluation and protection planning.4.Habitat selection of overwintering black bears was studied from 2015 to 2019.Principal component analysis and random forest statistical methods were used in this part.Bear dens selection was evaluated from den structure,microhabitat,and den site.The study results showed that:1.The trees selected were mainly poplars,relatively single compared to other studied.Diameter at breast height(DBH)of the selected trees was around 120 cm,and diameter of den’s entrance was about 40 cm in diameter.The orientation of the entrance was within the range of the solar altitude angle and sheltered from the wind,indicating that the selection of den entrance by black bears was related to temperature.2.Microhabitat study showed that the orientation of den entrance was the first principal component with the highest contribution rate,indicating that the orientation of den entrance was crucial for den selection.The second principal component was DBH and the entrance size.Contribution rate of the first and second principal components reached 0.84,meaning they could explain almost all the variables.It also indicated that the orientation of the entrance,breast diameter,and entrance size were the main factors considered in the selection of den.3.Main factors affecting the selection of den sites were distance to rivers,distance to main roads,gross primary productivity in October,and distance to human settlements.From the ecological significance of each factor,primary factors influencing the selection of den sites were safety,insulation,and food resources.In conclusion,black bears’distribution and habitat selection and den selection are all related to human disturbance and food resources.Therefore,protecting high-quality areas for food resources and reducing human disturbance within their habitat range is recommended. |
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