The use of shrub cover to preserve Mediterranean oak dehesas: a comparison between sheep, cattle and wild ungulate management
The use of shrub cover to preserve Mediterranean oak dehesas: a comparison between sheep, cattle and wild ungulate management
复制标题
使用灌木覆盖来保护地中海橡树：羊、牛和野生有蹄类动物管理之间的比较
DOI：
10.1111/avsc.12208
复制
发表时间：
2016
影响因子：
2.8
通讯作者：
S. Roig
中科院分区：
文献类型：
--
作者：
R. Perea;A. López‐Sánchez;S. Roig
问题
橡树稀树草原样系统（dehesas）是非常有价值的和保护的系统，强烈损害了连续失败的橡树招聘。我们的问题是，涉及牛，羊和野生有蹄类动物的不同的长期管理类型是否会影响橡树招聘的安全微网站（灌木）的丰富性和多样性。我们还评估微网站的位置和物种的具体差异之间的护士灌木，以提供管理指导。
位置
产于西班牙中部的霍尔姆栎。
方法
我们研究了橡树再生在四个不同的微型网站（树冠，灌木覆盖，开放和乔木灌木），并在三个独特的和有代表性的管理类型的一段时间，至少30年：（1）传统的管理（即广泛的羊饲养）;（2）高商业竞争力的管理（广泛的牛）;和（3）野生动物管理（野生有蹄类动物放牧，主要是鹿）。
结果
野生动物管理显示灌木的丰富度和多样性较高。野生动物管理下的预测幼苗密度是绵羊的三倍，几乎是牛管理下的九倍。橡树密度最高的灌木下，树下生长，树下的两倍高，比树冠外的灌木下高10倍，比开放的微型网站高出近40倍。然而，灌木的比例促进作用是在开阔的地区比在乔木。3种灌木（埃里卡、染料木和迷迭香）对橡树幼苗的促进作用显著高于其他灌木，表明植物促进作用存在种间差异。大多数年轻的橡树（树苗和青少年）超过了灌木的平均高度，这表明，促进主要发生在幼苗阶段。
结论
只有在合理的野生动物管理下的dehesas表现出明显的三层结构，灌木层的显着代表性，增加了幼苗密度。目前的牛管理是最不可持续的橡树再生方面。即使灌木覆盖，在一般情况下，促进橡树苗，并不是所有的物种都是等价的促进者。只有三个低适口性和大型灌木物种的关键促进者，应特别考虑在恢复和管理的做法。进一步的农业政策应促进减少牲畜密度、轮牧和混合物种管理，以促进这些系统的再生。
Questions
Oak savanna-like systems (dehesas) are highly valuable and protected systems that are strongly compromised by a continuous failure of oak recruitment. Our question is whether different long-term management types involving cattle, sheep and wild ungulates affect the abundance and diversity of safe microsites (shrubs) for oak recruitment. We also assess microsite location and species-specific differences among the nurse shrubs in order to provide management guidance.
Location
Dehesas of holm oak (Quercus ilex) in central Spain.
Methods
We examined oak regeneration in four different microsites (tree canopy, shrub cover, open and tree–shrub) and across three distinctive and representative management types for a period of, at least, 30 yr: (1) traditional management (i.e. extensive sheep rearing); (2) high commercially competitive management (extensive cattle); and (3) wildlife management (wild ungulate grazing, mostly deer).
Results
Wildlife management showed higher abundance and diversity of shrubs. Predicted seedling density under wildlife management was three-fold higher than sheep, and almost nine-fold higher than under cattle management. Highest oak density was found under shrubs that grew beneath trees, twice as high than under trees, ten-fold higher than under shrubs outside the tree canopy, and almost 40-fold higher than in open microsites. However, the proportional facilitative effect of shrubs was higher in open areas than under trees. Three shrub species (Erica australis, Genista hirsuta and Rosmarinus officinalis) showed significantly higher probability of facilitating oak seedlings in comparison to other shrub species, indicating species-specific differences in plant facilitation. Most young oak trees (saplings and juveniles) exceeded the average shrub height, suggesting that facilitation occurs mostly at the seedling stage.
Conclusions
Only dehesas under reasonable wildlife management showed a clear three-layered structure with a significant representation of the shrub layer, which increased seedling density. Current cattle management was the least sustainable in terms of oak regeneration. Even though shrub cover, in general, facilitated oak seedlings, not all species were equivalent facilitators. Only three low-palatable and large-sized shrub species were keystone facilitators that should be especially considered in restoration and management practices. Further agriculture policies should promote reduction of cattle densities, rotational grazing and mixed species management to enhance the regeneration of these systems.