Drastic seasonal changes in higher latitudes and altitudes impact the phenology of plant growth forms differently and thus diet of ungulates feeding on them. We examined how fecal nitrogen (N), an indicator of diet quality, varied with season against the background variation in forage biomass and N in habitats of two sympatric ungulates in subtropical Himalaya. We conducted this study in Kyongnosla Alpine Sanctuary, Sikkim, where the Himalayan goral Naemorhedus goral occurred from 3000 to 3600 m and Himalayan musk deer Moschus chrysogaster from 3300 to 4200 m. We measured biomass and N content of forbs and graminoids and browse in their habitats and proportions of monocots and dicots and N content in their fecal pellets. Seasonal variation in biomass, primarily determined by forbs, was similar in goral and musk deer habitats. Goral had a graminoid-dominated diet switching to dicots in autumn and winter. Musk deer had a dicot-dominated diet in all seasons. Fecal N in both the ungulates was higher than forage N in all seasons except spring when the latter was greater. Forage and fecal N declined sharply from spring as seasons progressed. Fecal N in goral was considerably lower than in musk deer in all seasons, probably below maintenance levels in autumn and winter. As evident from peaks and duration of high diet quality, goral is likely a capital breeder and musk deer an income breeder. Results suggest that linkages between diet and reproductive seasonality in ungulates will have important implications in face of climate change.

高纬度和高海拔地区的剧烈季节性变化对植物生长形态的物候学产生不同的影响，因此以它们为食的有蹄类动物的饮食。我们研究了作为饮食质量指标的粪便氮 (N) 如何随季节变化，而背景是草料生物量和亚热带喜马拉雅两种同域有蹄类动物栖息地中氮的变化。我们在锡金的 Kyongnosla Alpine Sanctuary 进行了这项研究，那里的喜马拉雅斑羚Naemorhedus 斑羚发生在 3000 到 3600 米之间，喜马拉雅麝鹿Moschus chrysogaster从 3300 到 4200 m。我们测量了杂草和禾本科植物的生物量和 N 含量，并浏览了它们的栖息地以及单子叶植物和双子叶植物的比例以及它们粪便颗粒中的 N 含量。主要由杂草决定的生物量的季节性变化在斑羚和麝的栖息地中是相似的。Goral 的饮食以禾本科植物为主，在秋季和冬季改用双子叶植物。麝鹿在所有季节都以双子叶植物为主。两种有蹄类动物的粪便N在所有季节都高于饲料N，但春季除外。随着季节的推进，草料和粪便 N 从春季开始急剧下降。在所有季节，斑羚的粪便 N 显着低于麝香鹿，可能低于秋季和冬季的维持水平。从高饮食质量的高峰期和持续时间可以看出，斑羚很可能是一种资本饲养者，麝香鹿可能是一种收入饲养者。结果表明，面对气候变化，有蹄类动物的饮食和繁殖季节性之间的联系将具有重要意义。