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首页> 外文期刊>Catena: An Interdisciplinary Journal of Soil Science Hydrology-Geomorphology Focusing on Geoecology and Landscape Evolution >Moderate sheep grazing in semiarid shrubland alters small-scale soil surface structure and patch properties.
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Moderate sheep grazing in semiarid shrubland alters small-scale soil surface structure and patch properties.

机译：在半干旱灌木丛中放牧适度的绵羊会改变小规模的土壤表面结构和斑块特性。

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摘要

We investigated whether long-term moderate livestock grazing by sheep (ca. 10 animal unit days/ha) in a semiarid shrubland with a long-term average annual rainfall of 200 mm causes changes in soil surface structure and dimensions of shrub and intershrub patches. We examined grazing-induced changes in landscape patchiness, patch structure, and soil moisture in three grazed and three ungrazed plots of 4 m x 4 m on a south-facing slope and the opposite, more productive north-facing slope. The measurements were done in early spring 2001 and 2002 before grazing started, in two surveys, one using two parallel transects and one using sample quadrats of 20 cm x 30 cm under three shrubs per plot and on an adjacent part of the intershrub matrix. On the north-facing slope, the sheep reduced shrub patch size as they trampled the soil mounds under the shrubs and browsed the shrub canopy. Reduced shrub patch size decreases the area and resources available for plant production. On the south-facing slope, the sheep mainly disrupted the soil crust in the intershrub area. This may increase soil erosion, but also seedling establishment. The contrast in impacts on the two slopes is due to the interaction between environment (productivity, exposure and vegetation) and sheep behaviour (herbivory and trampling). On both slopes, the changes due to grazing are significant, though small. Changes in patch size and properties induced by moderate grazing can have positive and negative effects on productivity and diversity, but may also be viewed as early signs of landscape degradation as is often caused by heavy grazing..
机译：我们调查了长期平均年降雨量为200 mm的半干旱灌丛中长期适度放牧绵羊（约10动物单位天/公顷）是否引起土壤表面结构和灌丛和灌丛间斑的变化。我们研究了放牧引起的景观斑驳，斑块结构和土壤湿度的变化，这些变化分别在朝南的斜坡和生产力更高的朝北的斜坡上的三个4 m x 4 m的放牧和三个非湿地样地中进行。在放牧开始之前的2001年春季和2002年春季进行了两次测量，一次是使用两个平行样条，一次是使用20 cm x 30 cm的样方，每个样地在三个灌木下以及灌木间基质的相邻部分进行。在朝北的山坡上，绵羊踩踏灌木下的土丘并浏览灌木冠层时，会减小灌木丛的大小。缩小的灌木丛尺寸会减少可用于植物生产的面积和资源。在朝南的斜坡上，绵羊主要破坏了灌木间地区的土壤结皮。这可能会增加水土流失，也可能增加幼苗的生长。这两个斜坡的影响之所以形成对比，是由于环境（生产力，暴露和植被）与绵羊行为（草食和践踏）之间的相互作用。在两个坡度上，由于放牧而产生的变化虽然很小，但意义重大。中度放牧引起的斑块大小和特性变化可能对生产力和多样性产生正面和负面影响，但也可能被视为景观恶化的早期迹象，这通常是大量放牧造成的。

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