| Moose(Alces alces)is a typical cold temperate and Arctic circumpolar species.In the current the sizes of moose populations are increasing and distribution ranges are expanding worldwide.On the contrary,moose population size has been declining and its range has been shrinking in Northeast China in recent decades,which distribute at the southernmost edge of its Eurasian range as well in the majority moose distribution range of China.Protection level of Chinese moose has risen from Class Ⅱ to Class Ⅰ in National Key Protected Wildlife List,and it has been evaluated as critically endangered(CR)in China Red List of Biodiversity.From December 2011 to December 2014,within the scope of the distribution area of moose in the Greater and Lesser Khingan Mountains.a total of 7 first-class,14 second-class,and 28 thirdclass sampling units(24 forest farms,4 protected areas)were surveyed.As a result,204 sample lines(belts)with a total length of 1 002.4 km were completed,as well as 38 sample plots with total area 375.3 km2.The studies of distribution,size,and habitat spatiotemporal dynamics of moose population were carried out systematically to provide the most critical background data and theoretical basis for the conservation and management of moose populations and habitats in China.The following results are obtained:1.Distribution and population size status of moose in Northeast ChinaDistribution range of moose population in Northeast China is 119°34′-130°47′E,47°46′-53°33′N,with the area totally 189 000 km2.The overall distribution range is divided into three parts:the Greater Khingan Mountains(178 000 km2),Zhanhe(8 581 km2)and Hebei(2 332 km2)in the Lesser Khingan Mountains.Average density of moose population is 0.039±0.002 ind./km2(80%confidence interval),total habitat area was 136 260.5 km2,and the total population size was 5 378±292 individuals.The highest density is found in the central of Greater Khingan Mountains in Inner Mongolia,followed by the northern of Greater Khingan Mountains in both Inner Mongolia and Heilongjiang,then the southern and central of Greater Khingan Mountains in Heilongjiang,and the lowest density is found in the southern of Greater Khingan Mountains in Inner Mongolia and Lesser Khingan Mountains.Hanma(0.083 ind./km2),Nanwenghe(0.063 ind./km2)and Zhanhe(0.061 ind./km2)constitute the three core populations of Greater Khingan Mountains in Inner Mongolia,Greater Khingan Mountains in Heilon,jiang and Lesser Khingan Mountains.respectively.Distribution range of Zhanhe in Lesser Khingan Mountains has been isolated and blocked as an island by the surrounding road network and human activities,and there is no possibility to connect with the distribution range of Greater Khingan Mountains on the west side.There is also a risk of blocked migration in the southern distribution area of Hailar District-Yakeshi City-Arong Banner in the southern of Greater Khingan Mountains,Inner Mongolia.From 1976 to 2014,the distribution area and population size of moose in Northeast China showed a significant decreasing trend,and the decreasing rate tended to slow down after 1987.Compared with the existing survey results,the distribution area was reduced by 25.3～31.3%,the average annual decline rate was 1.1～3.3%;The population size decreased by 46.0～46.6%,the average annual decline rate was 2.3～5.5%.2.Analysis of moose habitat status based on remote sensing and random forest modelThe down-sampling random forest model was combined with remote sensing derivative variables to simulate the habitat suitability of moose in Northeast China.Variables associated with human disturbance(human footprint index,farmland,and distance from town)and ambient temperature(late spring maximum temperature,coldest month minimum temperature,and annual precipitation)are the main drivers of moose occurrence.There is 67 400 km2 suitable habitat of moose in Northeast China;most of which is located in the north-central Greater Khingan Mountains,with only a small area with 2 400 km2 around Zhanhe Forestry Bureau in Lesser Khingan Mountains.Suitable habitat area of moose in Lesser Khingan Mountains is small and has been isolated in island shape,and is not connected to the range of Greater Khingan Mountains,so the population exchange between the two is blocked.Suitable habitat area beyond the Hailar District-Yakeshi City-Arong Banner traffic artery in the southern Greater Khingan Mountains of Inner Mongolia is very small(2 100 km2),and it is not connected with the suitable habitat to the north,which led to the limitation of populations exchange.3.Prediction of moose habitat dynamic variations based on future climate and land useUsing moose occurrence information trained in MaxEnt,we simulated climate change and land use change separately/combined the dynamic variations of moose suitable/non-suitable habitat change under three socio-economic and climate change pathways(SSP126,sustainable development;SSP370,moderate development and emission;SSP585,high development and emission)as well as in three periods(current(2010)and future(2041～2070、2071～2100)).Under the current scenario,the suitable habitat area of moose in Northeast China is 97 099 km2.Under all changed scenarios,there are loss and increase of suitable habitat,and generally,the loss area(10 634～80 227 km2)is greater than the increase’s(374～26 291 km2);all scenarios showed the same increasing trend of loss areas over time.Under all changed scenarios,the loss/increase of suitable habitat under the action of land use alone is higher than that under the action of climate change alone,and the combined effect of both on the habitat of moose has an offsetting effect.Only the suitable habitat of moose in 2041～2070 under land use change and SSP370 path has a small increase compared with the current(rate of change 0.03),and there are different degrees of suitable habitat reduction under other scenarios(-0.03～-0.72);average change rate is the highest in the SSP370 path and the lowest in the SSP585 path.Turnover rate of suitable habitats under each change scenario is 0.15～0.84,and it in 2071～2100 is higher than in 2041～2070 in each scenario.Turnover rate under the combined effect of land use and climate change is significantly higher than that under only climate change,but not significantly higher than that under only land use change.4.Status and future dynamic variations of landscape connectivity among moose habitatsThe landscape indices of moose habitat under three socio-economic and climate change pathways were calculated and analyzed,and resistant kernel model was used to simulate the moose habitat connectivity under different scenarios above.Under the current scenario,landscape percentage of suitable habitat patches was 19.8%,maximum patch index was 16.9%,number of patches was 131,average nearest neighbor distance was 6 263 m,and radius of gyration was 4 801 m.Current moose habitat connectivity area is 163 576 km2,which is greater than the suitable habitat area.Except for the Lesser Khingan Mountains and the southern Greater Khingan Mountains,other areas are in good connectivity condition.The high connectivity area locates in the northeast and north of Greater Khingan Mountains,and the low connectivity area locates around the edge of the moose distribution range.Under the three SSP pathways in the next two periods,suitable habitat patches show a trend of decreasing area,increasing fragmentation and more dispersed patches with climate and land use changes.In the future scenarios,the suitable habitat connectivity area(34 819～90 581 km2)will decrease significantly(44.62～78.71%),and the connectivity pattern has high similarity with the current pattern under different times and scenarios.Also,the landscape network areas of the high suitable habitat and connection areas of the moose gradually decrease,and the connections are gradually weak.Under different SSP scenarios,the trend is roughly the same over time.The highly suitable habitats and connecting areas that have existed in the three time periods are mainly distributed in the northern and central of the study area.The areas with strong adaptability under the two pathways of SSP126(32 732 km2)and SSP585(28 983 km2)are smaller and more scattered,and the area under SSP370 is larger(43 501 km2).This paper investigated the current distribution area of moose in Northeast China,comprehensively and systematically estimated the population size,and provided important management data support for the protection of Chinese moose population.The habitat suitability within the distribution range of moose population in Northeast China was systematically evaluated,which provided a theoretical basis for ecological restoration of moose habitat at landscape scale.The future dynamic trend of the suitability of the current moose habitat in Northeast China was predicted,and the landscape connectivity and its spatiotemporal dynamic changes of the moose habitat in Northeast China at the landscape scale were analyzed and predicted,which provided a scientific basis for the protection of moose populations in China and even across borders. |
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