Effects of grazing by free-ranging cattle on vegetation dynamics in a continental north-west European heathland
Effects of grazing by free-ranging cattle on vegetation dynamics in a continental north-west European heathland
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DOI：
10.1046/j.1365-2664.2000.00507.x
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发表时间：
2000-06-01
影响因子：
5.7
通讯作者：
Gleichman, JM
中科院分区：
文献类型：
--
作者：
Bokdam, J;Gleichman, JM
1.废弃物和富营养化是欧洲传统田园景观及其野生动物的主要威胁。社会和经济的发展使传统的畜牧业无法实行。需要更多地了解自由放养的食草动物放牧的影响，这种放牧越来越多地被用作传统放牧制度的替代品。我们研究了自由放养的牛在10年的时间内恢复Calluna石楠，树木侵占和植物物种丰富度在6个栖息地在草丰富的荷兰石楠。不同生境在土壤肥力、初始石楠草比和青花菜发育阶段上存在差异.尽管优先的草落叶，牛放牧既没有减少草荒原的草覆盖，也没有阻止草入侵石楠。草入侵失败，只有在氮贫草坪剥离卡鲁纳石南。放牧引起了大量的Calluna恢复在草石南灰壤，但其恢复失败的草石南磷丰富的中世纪耕地。因此，自由放养的牛所产生的草石楠镶嵌仅限于中等土壤肥力的栖息地。放牧并没有阻止松树和桦树的入侵。场地经理的搬迁阻止了10-20%的开放石南地转化为森林。在第一个5年，放牧引起的物种丰富度在所有栖息地的显着增加。在第二个5年，物种丰富度在石南石南和石南-草镶嵌群落中趋于稳定，在先锋石南群落中有所下降.我们发现各种营养物质介导的放牧对草和木本先锋之间的竞争平衡的影响的迹象。这些表明，营养物质介导的反馈可能是一个重要的解释机制描述的植被镶嵌循环在石楠。自由放牧并没有消除整个地区的高大气养分输入。大量的养分从草地重新分配到森林。自由放牧与树木砍伐相结合似乎是一个合适的管理制度，以维护物种丰富的开放式石南地与动态草石南马赛克。如果没有砍伐树木，自由放牧会在开放的石南荒原上创造出动态的树木-草-石南花镶嵌。森林牧场景观与传统定居农业系统产生的以石南花为主的开阔石南荒原有着根本的不同。石南荒原、营养丰富的农田和森林的综合放牧加速了这一变化。替代放牧制度进行了讨论。
1. Abandonment and eutrophication are major threats to traditional pastoral landscapes and their wildlife in Europe. Social and economical developments have rendered traditional pastoralism impracticable. More knowledge is needed about the effects of grazing with free-ranging herbivores, which is increasingly used as a substitute for the traditional herding system.2. We studied the effects of free-ranging cattle on the recovery of Calluna heather, tree encroachment and plant species richness in six habitats in a grass-rich Dutch heathland during a 10-year period. The habitats differed in soil fertility, initial heather-grass ratio and developmental stage of Calluna.3. Despite preferential grass defoliation, cattle grazing neither reduced grass cover in grass heath nor prevented grass invasion in heather. Grass invasion failed only in a nitrogen-poor turf-stripped Calluna heath. Grazing induced a substantial Calluna recovery in grass heaths on podzolic soils, but its recovery failed in grass heath on a phosphorus-rich medieval arable field. As a consequence, the grass-heather mosaics generated by free-ranging cattle were restricted to habitats of intermediate soil fertility.4. Grazing did not prevent encroachment by pine and birch. Removal by the site manager prevented conversion of 10-20% of the open heathland to forest.5. During the first 5 years, grazing induced a significant increase in species richness in all habitats. During the second 5 years, species richness stabilized in grass heath and heather-grass mosaics and it declined in the pioneer Calluna heaths.6. We found indications of various nutrient-mediated grazing effects on the competitive balance between grass and woody pioneers. These suggest that nutrient-mediated feedback might be an important explanatory mechanism for the described vegetation mosaic cycling in heathlands.7. Free-ranging grazing did not remove the high atmospheric nutrient inputs of the whole area. Substantial amounts of nutrients were redistributed from the grass lawns to the forest.8. Free-ranging grazing combined with tree cutting appeared to be a suitable management regime for the maintenance of species-rich open heathlands with dynamic grass-heather mosaics.9. Without tree cutting, free-ranging grazing would have created dynamic tree-grass-heather mosaics in open heathland. Wood-pasture landscapes are fundamentally different from the open heather-dominated heathlands produced by the traditional sedentary farming system. Integrated grazing of heathland, nutrient-rich farmland and forests accelerates this change. Alternative grazing regimes are discussed.