The impact of cattle dung pats on earthworm distribution in grazed pastures
The impact of cattle dung pats on earthworm distribution in grazed pastures
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DOI：
10.1186/s12898-018-0216-6
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发表时间：
2018-12-19
期刊：
影响因子：
--
通讯作者：
Schmidt, O.
中科院分区：
文献类型：
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作者：
Bacher, M. G.;Fenton, O.;Schmidt, O.
背景放牧草地管理制度可以对土壤动物产生各种影响。例如，对蚯蚓的影响可能是负面的，通过放牧动物引起的压实，或积极介导的草地生产力和牛粪提供食物来源的增加。知识差距存在于不同的蚯蚓物种的行为，即他们的运动和聚集在粪拍下，拍的遗产影响和空间领域的招聘。本研究解决了这些知识的差距，在田间实验中，超过2 years，使用天然和模拟粪拍两个永久性的，集中放牧牧场在爱尔兰.ResultsDung拍强烈影响空间分布，多达四倍以上的蚯蚓聚集在拍下，比在控制位置远离拍。在这些群落包括11个物种，时间上不同的聚集和分散模式进行了观察，包括没有个别物种从控制位置，但没有明确的演替反应。地上种一般，但也有某些物种的anecic和endogeic集团聚集在粪便。粪垫完全消失后取样（施用后27周）表明，粪垫对群落没有遗传效应。根据蚯蚓的种类分布，估计蚯蚓向粪块迁移的最大补充面积为3.8m2/粪块。由于实际放牧超过6 weeks将导致沉积约300粪拍每公顷，据估计，表面积1140米（2）或约11%的总放牧面积可以影响粪拍在给定的grazingperiod.ConclusionsThis研究表明，粪拍在牧场的存在下，创造临时热点的空间植被物种分布，随着时间的推移而变化。研究结果强调了在放牧牧场对蚯蚓进行采样时，在时间和空间上考虑粪块的重要性。发表的放牧和切割草地的比较可能会得出错误的结论，忽略或故意避免粪拍。此外，所观察到的蚯蚓在粪块下的密集聚集表明，需要在这些热点单独评估蚯蚓的功能。
BackgroundGrazed grassland management regimes can have various effects on soil fauna. For example, effects on earthworms can be negative through compaction induced by grazing animals, or positive mediated by increases in sward productivity and cattle dung pats providing a food source. Knowledge gaps exist in relation to the behaviour of different earthworm species i.e. their movement towards and aggregation under dung pats, the legacy effects of pats and the spatial area of recruitment. The present study addressed these knowledge gaps in field experiments, over 2years, using natural and simulated dung pats on two permanent, intensively grazed pastures in Ireland.ResultsDung pats strongly affected spatial earthworm distribution, with up to four times more earthworms aggregating beneath pats, than in the control locations away from pats. In these earthworm communities comprising 11 species, temporally different aggregation and dispersal patterns were observed, including absence of individual species from control locations, but no clear successional responses. Epigeic species in general, but also certain species of the anecic and endogeic groups were aggregating under dung. Sampling after complete dung pat disappearance (27weeks after application) suggested an absence of a dung pat legacy effect on earthworm communities. Based on species distributions, the maximum size of the recruitment area from which earthworms moved to pats was estimated to be 3.8m(2) per dung pat. Since actual grazing over 6weeks would result in the deposition of about 300 dung pats per ha, it is estimated that a surface area of 1140m(2) or about 11% of the total grazing area can be influenced by dung pats in a given grazing period.ConclusionsThis study showed that the presence of dung pats in pastures creates temporary hot spots in spatial earthworm species distribution, which changes over time. The findings highlight the importance of considering dung pats, temporally and spatially, when sampling earthworms in grazed pastures. Published comparisons of grazed and cut grasslands probably reached incorrect conclusions by ignoring or deliberately avoiding dung pats. Furthermore, the observed intense aggregation of earthworms beneath dung pats suggests that earthworm functions need to be assessed separately at these hot spots.