青藏高原草枯期植物群落与海拔对西藏马鹿食物组成的影响

Effects of plant community and altitude on food composition of Cervus elaphus wallichii during the withered grass period on the Tibetan Plateau,China

西藏马鹿如何适应草枯期高海拔环境是其维持营养摄入所面临的挑战之一。深入研究草枯期植物群落随海拔变化规律以及二者变化如何影响西藏马鹿食物组成是开展高原生态系统野生大型有蹄类营养生态学研究的重要基础。本研究以西藏山南地区桑日县西藏马鹿种群为对象,于2021年3月和2022年3月青藏高原草枯期,对西藏马鹿种群出现点的海拔、植物群落和采食痕迹开展野外调查,通过去趋势对应分析和典范对应分析分别研究植物群落随海拔变化的特点和西藏马鹿食物组成随海拔变化的规律。结果表明:西藏马鹿草枯期食物组成主要包括褐背柳、腺果大叶蔷薇和小叶金露梅等,其中褐背柳的采食比例超过50%,为草枯期西藏马鹿重要食物来源;在低海拔区域(4100~4300 m),植物群落主要包括变色锦鸡儿、腺果大叶蔷薇和西藏沙棘等,西藏马鹿主要以腺果大叶蔷薇、变色锦鸡儿和藏沙蒿为食物;在高海拔区域(4300~4600 m),植物群落由雪层杜鹃、草莓花杜鹃和窄叶鲜卑花等组成,西藏马鹿主要以褐背柳、毛坡柳、康藏嵩草等为食物。西藏马鹿在不同海拔均以植物群落优势种为主要食物,表明植物群落组成随海拔的变化直接影响西藏马鹿的食物组成,即西藏马鹿随海拔变化具有不同的食物组成模式。

How Tibetan red deer(Cervus elaphus wallichii)acclimates to high altitude environment during the withered grass period is one of the challenges in maintaining their nutrient intake.It is an important basis to study the nutritional ecology of wild large ungulates in alpine ecosystems by investigating the changes in plant communities with altitude during the withered grass period and how these changes affect the food composition of Tibetan red deer.In this study,we selected the Tibetan red deer in Sangri County,Shannan region of Tibet as the research subject.We carried out field surveys on the altitude,plant communities,and feeding traces of the Tibetan red deer in March of 2021 and 2022 during the withered grass period on the Tibetan Plateau.Detrended correspondence analysis and canonical correspondence analysis were used to study altitudinal variations in plant communities and the regularity of food composition.The results showed that during the period of withered grass,Tibetan red deer ate primarily Salix daltoniana,Rosa macrophylla var.glandulifera and Dasiphora parvifolia.S.daltoniana accounted for more than 50%of the food composition,as the main food resources for red deer in withered grass period.In the low altitude area(4100-4300 m),plant community included Caragana versicolor,R.macrophylla and Berberis temolaica,and Tibetan red deer mainly ate R.macrophylla,C.versicolor and Artemisia wellbyi.In higher altitude area(4300-4600 m),plant community consisted of Rhododendron nivale,Rhododendron fragariiflorum,and Sibiraea angustata,and Tibetan red deer mainly fed on S.daltoniana,Salix obscura,and Carex littledalei.At different altitudes,the dominant plant species were the main food of Tibetan red deer.It is suggested that the changes of plant community composition with altitude directly affected food composition of Tibetan red deer,indicating different food composition patterns with altitude gradients.