Livestock browsing affects the species composition and structure of cloud forest in the Dhofar Mountains of Oman
Livestock browsing affects the species composition and structure of cloud forest in the Dhofar Mountains of Oman
复制标题
DOI：
10.1111/avsc.12493
复制
发表时间：
2020-04-29
影响因子：
2.8
通讯作者：
Tzanopoulos, Joseph
中科院分区：
文献类型：
--
作者：
Ball, Lawrence;Tzanopoulos, Joseph
问题 经常有报道称，骆驼、牛和山羊的过度饲养正在导致 Anogeissus 云林的退化，该云林是阿拉伯南部绵延 200 公里的沿海山脉的特有种。然而，牲畜对植被的影响尚未评估。此外，我们对骆驼等大型食草牲畜对林地和森林牧场的影响了解有限。因此，在本研究中，我们研究了牲畜啃食对阿曼佐法尔山脉Anogeissus云林木本植被物种组成、密度和植物形态的影响。位置数据采集于阿曼佐法尔西部Jabal Qamar山脉的30个地点。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啃食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。采用标准化长轴回归分析了不同放养率下高径异速（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。幼年动物对放养率的反应比成虫更强，一些常见物种在高放养率下表现出发育不良的形态。结论骆驼和牛等大型牲畜的啃食可以显着改变半干旱林地和森林木本植被的物种组成、结构和植物形态。幼体特别容易被啃食，这会改变木本植被的人口结构并抑制再生潜力。我们的结果支持了之前关于佐法尔省库存过剩的建议，并强调了迅速采取措施减少阿诺吉苏斯云林中牲畜啃食压力的重要性。
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 phytomorphology of woody vegetation in the Anogeissus cloud forests in the Dhofar Mountains of Oman.Location Data were collected at 30 sites in the Jabal Qamar mountain range in western Dhofar, Oman.Methods The point-centred 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.