PDF(Pubmed)
Abstract：
Agricultural grasslands play an important role in conserving the biodiversity of the European cultural landscape. Both, litter cover and soil nutrient availability, change with grassland management, but it is not well-studied how seedling recruitment and growth of multiple grassland species are influenced by their single or combined effects. Therefore, we studied the effects of nitrogen fertilization (100 kg N per year and ha) and litter cover (250 gdw per m2) on seedling recruitment and growth of 75 temperate grassland species (16 graminoid species, 51 forb species, 8 legume species) in a full factorial microcosm experiment. Overall, fertilizer reduced seedling emergence, while litter cover increased it even when combined with fertilization. Fertilization increased seedling height and biomass, and the combination of fertilizer and litter resulted in even stronger responses. Litter cover alone did not influence seedling biomass or seedling height. While the overall direction of treatment effects was similar across functional groups, their strengths were mostly weaker in graminoids than in non-legume forbs and legumes. Positive litter effects on seedling emergence were stronger in large-seeded species. Positive fertilization effects on seedling growth were stronger in small-seeded species, while their seedling biomass was negatively affected by litter cover. In summary, our results show for multiple grassland species that the combination of litter cover and fertilization modulates their single effects. The varying sensitivity of how grassland species representing different functional groups and seed sizes respond with their seedling emergence and growth to litter cover and nitrogen fertilization indicates that the consequences of land-use change on grassland diversity and composition already start to manifest in the earliest stages of the plant life cycle.
摘要：
农业草原在保护欧洲文化景观的生物多样性方面发挥着重要作用。两者,凋落物覆盖和土壤养分利用率，随着草地管理的变化，但是，尚未充分研究多种草地物种的幼苗招募和生长如何受到其单一或综合作用的影响。因此,我们研究了氮肥（每年100kgN和ha）和凋落物覆盖（每平方米250gdw）对75种温带草地物种（16个类线虫物种，51个forb物种，8种豆科植物）在全因子微观实验中。总的来说,肥料减少了幼苗出苗，而即使与施肥相结合，凋落物的覆盖率也会增加。施肥增加了幼苗高度和生物量，肥料和凋落物的结合产生了更强的反应。仅凋落物覆盖不会影响幼苗生物量或幼苗高度。虽然不同功能组的治疗效果总体方向相似，它们的强项大多比非豆类和豆类弱。在大种子物种中，凋落物对幼苗出苗的积极影响更强。小种子物种对幼苗生长的积极施肥作用更强，而它们的幼苗生物量受到凋落物覆盖的负面影响。总之,我们的结果表明，对于多个草地物种，凋落物覆盖和施肥的组合调节了它们的单一效应。代表不同功能群和种子大小的草地物种对幼苗出苗和生长对凋落物覆盖和氮肥的敏感性不同，这表明土地利用变化对草地多样性和组成的影响已经开始显现在植物生命周期的最早阶段。
