Abstract

Aims

Management of silvo-pastoral systems in planted and natural forests in semi-arid Mediterranean regions often employs seasonal night corrals for animal protection. This management system changes the spatial distribution of animal excreta, resulting in a net transfer of soil mineral resources and their accumulation in the corrals. After abandonment, corrals are colonized by ruderal species, becoming focal sources for their spread in the forest. We aimed to implement a rational management of seasonal sheep corrals based on a better understanding of the vegetation processes occurring in abandoned corrals, in order to alleviate their negative impact in the forest.

Methods

Relationships between temporal changes in the vegetation, the soil seed-bank and levels of soil nutrients were studied in a chronosequence of abandoned sheep corrals and compared with nearby reference plots in planted Eucalyptus forests grazed by sheep in the semi-arid North-Western Negev, Israel. The region has a bi-seasonal Mediterranean climate, with high dominance of annual species in the grazing range.

Important Findings

Abandoned sheep corrals were colonized by seeds of ruderals originating in older abandoned corrals. Subsequent successional changes occur at a slow rate, driven by the depletion of soil resources in the abandoned corrals, and were still in progress 20 years after abandonment. Ruderals were gradually replaced, first by taller grasses and followed by short grasses, but most forbs and particularly geophytes did not recover during this period. Recovery of the original herbaceous vegetation in the corrals was through seed dispersal from the surrounding vegetation, not from the original soil seed-bank remaining in the corrals after abandonment. Ruderal species in the grazed, planted forests behave as patch-tracking metapopulations. Their persistency depends on constant creation of new corrals compensating for the gradually dwindling populations in older abandoned corrals, and on the availability of dispersal vectors.

中文翻译：

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废弃的畜栏：林牧系统中短暂生境的定居和植被恢复

摘要

目的

在地中海半干旱地区的人工林和天然林中，造林-牧草系统的管理通常采用季节性夜间畜栏来保护动物。该管理系统改变了动物排泄物的空间分布，导致土壤矿产资源的净转移及其在畜栏中的积累。遗弃后，畜栏被种eral的物种殖民，成为它们在森林中传播的主要来源。我们的目的是在更好地了解废弃畜栏内的植被过程的基础上，对季节性绵羊畜栏进行合理管理，以减轻它们对森林的负面影响。

方法

在废弃绵羊畜栏的时序上研究了植被的时间变化，土壤种子库和土壤养分含量之间的关系，并将其与附近半干旱的西北内盖夫的绵羊放牧的桉树人工林中的附近参考样地进行了比较，以色列。该地区为双季节地中海气候，在放牧范围内一年生物种占主导地位。

重要发现

被遗弃的绵羊畜栏被原来较旧的废弃畜栏中的子种子定殖。在废弃的畜栏土壤资源枯竭的驱动下，随后的连续变化发生的速度很慢，并且在废弃20年后仍在进行。陆续被逐渐取代，首先是高高的草丛，然后是矮小的草丛，但是在这一时期，大多数的前额草，特别是地上植物没有恢复。通过从周围植被中散布种子，而不是从废弃后保留在畜栏中的原始土壤种子库中恢复畜栏中原始的草木植被。放牧的人工林中的Ruderal物种表现为斑块追踪的种群。