Habitat Analysis Of Wild Bactrian Camel (camelus Ferus) And Impact Of Climate Change In Kumtag Desert

Wild Bactrian camel (Camelus ferus)which just ditributed in China and Mongolia is a critically endangered species with international concern. This species characterized by narrow distribution area and small size of population, the total population in all over the world is less than 1000. The Kumtag Desert region, at the junction of Xinjiang province and Gansu province, is the most important distribution area in China. However, few studies were carried out about the population status of wild Bactrian camel in this region. In this study, the population status, activity patterns, and current potential geographical distribution of wild Bactrian camel in Kumtag Desert region were analyzed based on field survey, infrared-triggered cameras, fecal DNA analysis and niche models. The impact of climate change on wild Bactrian camel was also estimated in this study. We simulated and predicted the potential geographical distribution and change trends of wild Bactrian camel on 2050s and 290s respectively based on RegCM3 A1B scenario. Furthermore, the main threats to wild Bactrian camel population were surveyed and relevant protection measures were proposed.The main conclusions are as follows:(1) We documented 96 wild Bactrian camel individuals in a total of 30 groups, the largest group of 22, the least group of 1, the average group size of 3.2. The average group size, according the data from 17 infrared-triggered cameras place on 5 different water source, is 2.9. Both the 2 results of average group size are far less than the previous surveys.(2) The filed survey and infrared-triggered cameras monitoring results on available water source for wild Bactrian camel indicated that the water resource is scanty in study area, especially in freshwater resource. Only 2 freshwater sources were found in 9 water resources, the rest are varying degrees of salt water. The activity frequency of wild Bactrian camel on every water source point are different, and the highest frequency of activities were documented on No.1 water source point which with lower level human disturbance. There is a certain pattern of wild camel drinking water at different times of the day, and a drinking peak was recorded during the day and night respectively.The dependence of wild Bactrian camels on water source in different months of the year is also varies, and the highest occurres on February, March, April and July, the lowest dependence occurred on August and September. (3) In 223 wild Bactrian camel scats, a total of 161 scats (72.2%) were successfully amplified for seven loci, and Aqik Valley and the north piedmont of Arjinshan Mountain are 69 and 92 scats, respectively. From these 161 samples, 96 unique genotypes were obtained which 38 unique genotypes belong to the north piedmont of Arjinshan Mountain and 58 belongs to AqikValley. There was no significant difference (P>0.05) for the number of alleles (A), effective number of alleles(Ae), expected heterozygosity (He) and polymorphism information content (PIC) between the two populations, however, the Aqik Valley population showed the lower level for all parameters. The results of this study indicated that the two wild Bactrian camel populations went through a bottleneck. Considering the population genetic structure observed, the main problems were small population size and genetic degeneration, with consequent loss of genetic and allelic diversity.(4) Spatial distribution patterns of species is the embodiment of ecological process and environment. It reflects the interaction of biotic factors and abiotic factors in the ecosystem. In this study, more environment variables were selected include human disturbances, distribution of water sources, vegetation and 19 bioclimatic variables, using MAXENT and GARP models to predict the potential distribution of wild Bactrian camel in Kumtag Desert region. The result indicates that wild Bactrian camels mainly distributed in Aqik Valley, Xihu wetland and the north piedmont of Arjinshan Mountain, and the later region has high level of suitable for wild Bactrian camels. The suitable distribution area predicted by MAXENT is 22914km~2, accounted for 33% of total study area, predicted by GARP is 34709km~2, accounted for 50% of total study area.(5) Monitoring data from 5 weather stations around Kumtag Desert region showed that there was a continued rise of the mean temperature in the last 50 years, and the rise trend is obviously than the global average. The simulation and prediction of climate change showed that the temperature and precipitation will also increase in the next 50 to 100 years based on RegCM3 A1B scenario. In this study, we use MAXENT model simulated the impact of climate change on wild Bactrian camels on 2050s and 290s respectively based on RegCM3 A1B scenario. The results showed that the suitable area for wild Bactrian camels in study area will decrease on 2050s, then increase on 2090s. There will be an obviously change on the north piedmont of Arjinshan Mountain. The suitable distribution area will expand to the edge of the Kumtag Desert on 2050s, however, with the temperature rising in the desert, the suitable area will shrink from desert to Arjinshan Mountain.(6) Although 4 national nature reserves has been established, there are still management gaps due to poor natural condition. Human disturbance like occupancy of water source point lead to loss of available water source for wild Bactrian camel, and mining and road construction not only result in declines in distribution of wild Bactrian camels, but also disturb the mitigation activity. Furthermore, the continue raise of temperature caused the glacier which distributed on Arjinshan Mountain decreased year by year. So in next few decades, the water supply for desert vegetation could decrease and will lead to vegetation degradation in study area and then effect the distribution of wild Bactrian camels. In response to these threats, some protection recommendations are proposed include strengthening exchanges and cooperation between neighbouring protected areas, establishing biodiversity monitoring network, strengthening protection of water sources, clamp down illegitimate mining, establishing biological corridors to promote exchange between different wild Bactrian camel populations.