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Accueil du site → Doctorat → Chine → 2014 → Activity Pattern and Habitat Analysis of Wild Bactrian Camel (Camelus Ferus) in Kumtag Desert

China Forestry Science Academy (2014)

Activity Pattern and Habitat Analysis of Wild Bactrian Camel (Camelus Ferus) in Kumtag Desert

薛亚东;

Titre : Activity Pattern and Habitat Analysis of Wild Bactrian Camel (Camelus Ferus) in Kumtag Desert

Auteur : 薛亚东;

Grade : Doctoral Dissertation 2014

Université : China Forestry Science Academy

Résumé
Wild Bactrian camel (Camelus ferus) is a critically endangered species, which has highadaptability in extreme arid environments of Central Asia. Wild camel population anddistribution areas have decreased significantly since middle of19th century. Most researchesabout wild camel were difficult as the species was cryptic and distributed in arid and semi-aridareas. There are great knowledge gaps concerning the ecology of the wild camels. Even thegenetic status and the purity of wild camel populations have not yet been fully resolved andpreliminary results need to be treated with caution. In recent years, mineral activity, roadconstruction and livestock development have been increasing, which caused habitat loss andfragmentation of wild camel population. It’s urgent to focus on metapopulation dynamic and itsresponse to habitat fragmentation under human disturbance.In this paper, various methods and technics were used to study the ecology of wild camel,including field survey, camera traps, occupancy estimate, and niche models. Water, vegetation,and human disturbance were three important factors that influence the distribution of wildcamel in Kumtag Desert region. The water utilization and habitat selection of wild camel werestudied to identify the key environmental factors, and futher to analyse the suitable habitatdistribution. Habitat connectivity of wild Bactrian camel in Kumtag Desert region wereanalyzed based on suitable habitat and human disturbance. Meanwhile, we simulated thepotential migration path and identified the sensitive area of wild camel. Then the influence oflandscape pattern and key threat on wild camel migration were evaluated. The mainconclusions are as follows :(1) To examine the diversity and abundance of wildlife at water source, camera-trappingwas conducted at seven sites from2010to2012in the northern slope of Altun Mountains.Totally26species were captured in the survey. There are11species of mammal includingCamelus ferus, Equus kiang, Uncia uncia, Lynx lynx, and15species of birds including Gypaetus barbatus, Aquila chrysaetos, and Gyps himalayensis in photos. Wild camel (Camelusferus) was the only species captured at all observation sites and was photographed in almost66%of the total pictures. It suggested that wild camel is the dominant species of herbivore atwater source area, the time and intense of wild camel occurrence at water sources play animportant role in other herbivores’ time budget at water source. For carnivores, wolf (Canislupus) and red fox (Vulpes vulpes) were the dominant species of carnivores at water sourcesince they had been captured in123and268pictures respectively. In the Dunhuang Xihuwetland, six species were recorded with camera traps at four water sites,including Camelusferus, Gazella subgutturosa, Canis lupus, Vulpes vulpes, Lynx lynx, Lepus capensis.There were191independent pictures of wild camel in the total257pictures. For carnivores, Lynx lynx wasthe dominant species. The species diversity in the northern slope of Altun Mountains washigher than Dunhuang Xihu wetland. And the relative abundance of wild camel was muchhigher in the northern slope of Altun Mountains(72.94) than that in Dunhuang Xihu wetland(6.15).(2) During2011-2013, eight field surveys were conducted in Kumtag desert, and observedindividual and population of wild camel were recorded to evaluate the group in differentseasons.We recorded430wild Bactrian camel individuals in a total of64groups, the largestgroup of71, the least group of1. The average group size is10.74during October-April, and2.94during May-September. Our data on group membership or stability of camel groups,including average group size, numbers of group less than three individuals, and maximumgroup size supported that wild camels live in open fission fusion groups, which tend toconcentrate during the rutting season in winter. Occupancy models showed that disturbanceand rain season were the most important factors influencing the occupancy of wild camel andother species.(3) In the northern slope of Altun Mountains, our camera monitoring efforts ranged from224to1,830camera trapping days for a total of7,098camera trapping days for the studyduration. The proportion of relative activity at watering sites differed by monitoring interval (F23,144=8.870, P<0.001). Wild camels used watering sites all through the day, but visitedmore frequently during the daytime (0700–1700,68.69%). The relative activity revealed anincreasing trend in the morning (0500–1100), and showed a decreasing trend during theafternoon (1100–1800) and evening (1800–0500). The proportion of the relative activity atwatering sites was greatest from1000to1100(=8.33, SE=0.76). The relative activity of wildcamels was highest during the transition seasons (April and October) and lowest in July. Thewild camels visited watering sites in differing ways in different months (F11,63=3.385,P=0.001). Wild camels visited watering sites rarely in July (=2.6days, SE=1.54), but maderegular visits to watering sites in April (=17.57days, SE=2.63). The present days of wildcamels at watering sites in winter was5.8±0.3higher than in summer (t=3.733, df=56,P<0.001).(4) The method of Receiver Operating Characteristic (ROC) curve analysis was used toassess the accuracy of MAXENT model. In the300m and30m scale, the area under ROCcurve (AUC) of the model was0.961, indicating that the result of assessment was excellent.The result of Jackknife test indicated that the distance to water, the distance to mining sites, thedistance to residence, and altitude were the main factors influencing habitat selection of wildcamel. The accumulating contribution of these four factors were87.5%and93%respectively.The suitable habitat of wild camel predicted by MAXENT is5068.7km2, and divided to threeseperated patches, the northern slope of Altun Mountains, the Aqike valley, and the Xihuwetland. The suitable habitat of the northern slope of Altun Mountains covers the most of thesuitable habitat with an area of3581.9km2.The habitat connectivityof wild camel wasinfluenced by exploring travel in the northern edge of the desert.(5) MCP home range analysis showed that at the beginning (June-July), the home range ofreleased wild camel covers a small area around the old enclosure.

Mots clés : Wild Bactrian camel (Camelus ferus); infrared-triggered cameras; activity pattern; suitable habitat; habitat connectivity;

Présentation (CNKI)

Page publiée le 26 septembre 2017