Questions: It is frequently reported that overstocking of camels, cattle and goats is degrading the Anogeissus cloud forest, which is endemic to a 200 km stretch of coastal mountains in southern Arabia. However, livestock impacts on the vegetation have not been assessed. Furthermore, we have a limited understanding of the impacts of large-bodied browsing livestock, such as camels, in woodland and forest rangelands. Therefore, in this study, we examine the effects of livestock browsing on the species composition, density, and hytomorphology of woody vegetation in the Anogeissus cloud forests in the Dhofar Mountains of Oman. Location: Data was collected at 30 sites in the Jabal Qamar mountain range in western Dhofar, Oman. Methods: The point-centered quarter method was used to sample the composition, density and structure of woody vegetation. Constrained correspondence analysis was used to quantify the effects of livestock browsing on woody plant species composition, whilst effects on plant density were analysed using mixed effects models. Standardised major axis regression was used to examine differences in height-diameter allometry (stunting) under different stocking rates. Results: Fog density, topographic position and long-term stocking rates were found to be important factors affecting woody species composition. We found lower species diversity and plant density, and higher frequencies of unpalatable species, under higher stocking rates. Juveniles showed a stronger response to stocking rates than adults, and several common species exhibited stunted morphology under high stocking rates. Conclusions: Browsing by large-bodied livestock, such as camels and cattle, can substantially alter the species composition, structure, and phytomorphology of woody vegetation in semi-arid woodlands and forests. Juveniles are particularly susceptible to browsing which alters woody vegetation demography and inhibits regeneration potential. Our results support previous suggestions of overstocking in Dhofar and highlight the importance of swift measures to reduce livestock browsing pressure in the Anogeissus cloud forests.

中文翻译：

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牲畜浏览影响阿曼佐法尔山脉云林的物种组成和结构

问题：经常有报道称，骆驼、牛和山羊的过度放养正在破坏 Anogeissus 云雾林，这是阿拉伯南部 200 公里长的沿海山脉特有的。但是，尚未评估牲畜对植被的影响。此外，我们对大型食肉牲畜（如骆驼）在林地和森林牧场的影响了解有限。因此，在本研究中，我们研究了牲畜浏览对阿曼佐法尔山脉 Anogeissus 云林中木本植被的物种组成、密度和植物形态学的影响。地点：数据是在阿曼佐法尔西部 Jabal Qamar 山脉的 30 个地点收集的。方法：采用点中心四分之一法对木本植被的组成、密度和结构进行采样。约束对应分析用于量化牲畜浏览对木本植物物种组成的影响，同时使用混合效应模型分析对植物密度的影响。标准化的长轴回归用于检查不同放养率下高度-直径异速生长（发育迟缓）的差异。结果：发现雾密度、地形位置和长期放养率是影响木本物种组成的重要因素。我们发现，在较高的放养率下，物种多样性和植物密度较低，难吃物种的频率较高。幼鱼对放养率的反应比成鱼更强，几种常见物种在高放养率下表现出发育不良的形态。结论：由骆驼和牛等体型较大的牲畜浏览，可以显着改变半干旱林地和森林中木本植被的物种组成、结构和植物形态。幼鱼特别容易受到浏览的影响，这会改变木本植被的人口结构并抑制再生潜力。我们的结果支持先前关于佐法尔库存过多的建议，并强调了迅速采取措施减少 Anogeissus 云雾林中牲畜浏览压力的重要性。