Understanding dietary selection and feeding strategies is important for the conservation and management of endangered primate species. Here, we conducted a preliminary study on the diet and feeding behavior of endangered Shortridge's langurs ( Trachypithecus shortridgei) within the Drung River Valley (Dulongjiang) in southwestern China. The study site lies at a high latitude (N27°47.5') and elevation (1 900 m a.s.l.) and is characterized by substantial annual rainfall (2 745.1 mm). From August 2012 to September 2013, we observed five groups of langurs and analyzed their overall food composition and dietary variation in spring and autumn. To understand their dietary adaptations to the distinctive habitat of the Drung River Valley, we also compared the diet of Shortridge's langurs to that of other Trachypithecus species inhabiting different environments. Results indicated that T. shortridgei fed on 52 plant species, 23 of which each accounted for ≥1% of their annual feeding time. Their primary dietary components included leaves (46.2%, young, mature, and petioles), fruits (28.7%, unripe 17.6%, ripe 11.1%), and mosses (10.2%). The langurs mainly consumed mature (34.2%) and young leaves (27.5%) in spring and ripe fruits (39.4%) and mature leaves (24.7%) in autumn. Two species of moss ( Macrothamnium macrocarpum and Scapania verrucosa, 21.2% of annual feeding time), which are usually found growing together on cliffs, played a relatively important role in the diet of T. shortridgei. The langurs mainly consumed ripe fruits of Saurauia napaulensis (7.1%) and Dendropanax burmanicus (7.1%), which were abundant at lower elevations. Trachypithecus species in temperate forests consumed more fruits and seeds but fewer leaves (similar mature leaves but fewer young leaves) than those species in tropical forests, which may be related to their availability and abundance. Compared to Trachypithecus species in temperate forests, the higher proportion of mosses and mature leaves but fewer young leaves in the annual diet of T. shortridgei are likely a response to the distinctive Drung River Valley habitat. Therefore, conservation of the main food plants of this threatened species could be vital for its survival and conservation management.
了解濒危灵长类动物食性选择和取食策略对保护和管理具有重要意义。本文初步报道了中国独龙江戴帽叶猴 ( Trachypithecus shortridgei) 的食性和取食行为。独龙江地区纬度 (N27°47.5′) 和海拔 (1 900 m a.s.l.) 较高、降雨量大 (2 745.1 mm)。我们分析了2012年8月至2013年9月间5群戴帽叶猴的食物组成、对比了它们春秋季两季的食性差异。此外，通过与其他乌叶猴的食性对比，说明戴帽叶猴对独龙江地区独特生境的适应。结果表明，戴帽叶猴共取食52种植物，其中主要食物23种（全年取食时间≥1%）；其食性主要为叶 (46.2%，包含叶嫩、成熟叶和叶柄)、果实 (28.7%，未成熟果占17.6%，成熟果占11.1%) 和苔藓 (10.2%)。春季主要取食成熟叶 (34.2%) 和嫩叶 (27.5%)，秋季主要取食成熟果实 (39.4%) 和成熟叶 (24.7%)。南木藓 ( Macrothamnium macrocarpum) 和粗疣合叶苔 ( Scapania verrucosa) 在戴帽叶猴食谱中占重要地位 (全年取食21.2%)。此外，戴帽叶猴主要取食低海拔尼泊尔水东哥 (Saurauia napaulensis, 7.1%) 和缅甸树参 ( Dendropanax burmanicus, 7.1%) 的成熟果实。温带乌叶猴相比于热带取食更多的果实和种子、较少的叶 (其中成熟叶取食比例相似，嫩叶较少)，这可能与其可获得性和丰富度有关。与温带乌叶猴相比，戴帽叶猴全年取食苔藓和成熟叶比例较高、嫩叶较少，这可能是其对独龙江地区特殊生境的适应。因此，保护这种受威胁物种的主要食物对其生存和保护管理至关重要。.
Keywords: Diet; Drung River Valley; Elevation; Trachypithecus shortridgei.