Land-use intensification threatens biodiversity conservation of grasslands worldwide. One example of intensification is overseeding legumes in natural grasslands coupled with phosphorus fertilization, a management practice oriented to increase forage production and quality. Several studies show increases in forage due to this practice, at least in the short term, but less is known about impacts on diversity. We analyzed the effects of overseeding cv. “El Rincón” coupled with phosphorus fertilization on plant diversity and composition of natural grasslands of Uruguay. We used floristic data from 29 intensified versus natural paired paddocks from a geographical wide net of observations distributed across two separated areas with distinct plant communities. Besides, a set of land-use intensification indicators were used to explore its relationship with intensification impact on plant composition and diversity. Overall, the effects of overseeding with legumes and fertilization on species richness (total, native and exotic richness) and beta diversity depended on community type. Our data evidenced that the community lost native species with intensification, affecting total richness that showed a 15.3% decrease. The community, in turn, was enriched by exotic species. It increased 96.4% but without affecting total species richness. Beta diversity, for its part, showed a reduction associated with intensification only in the community. Our results show that neither amount of applied fertilizer nor time since overseeding and fertilizing were directly related to intensification impacts. These findings highlight the importance of accounting for various dimensions of diversity to assess community responses to land use changes. Our results point out that even slight intensification affects plant diversity of Campos Grasslands. The lack of predictability of impact magnitude by simple land-use intensity indicators challenges prevention and mitigation of this technology.

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在天然草地上播种豆科植物的土地利用集约化：对植物多样性的影响

土地利用集约化威胁着全世界草原生物多样性的保护。集约化的一个例子是在天然草地上监督豆类作物并施磷肥，这是一种旨在提高饲料产量和质量的管理实践。多项研究表明，这种做法至少在短期内会导致草料增加，但对多样性的影响却知之甚少。我们分析了监督简历的效果。 “El Rincón”结合磷肥对乌拉圭植物多样性和天然草原组成的影响。我们使用了来自 29 个强化与自然配对围场的植物区系数据，这些围场来自分布在两个具有不同植物群落的独立区域的广泛地理观察网络。此外，还利用一组土地利用集约化指标来探讨其与集约化对植物组成和多样性影响的关系。总体而言，豆类监管和施肥对物种丰富度（总丰富度、本地丰富度和外来丰富度）和β多样性的影响取决于群落类型。我们的数据证明，随着集约化，群落失去了本地物种，影响了总丰富度，减少了 15.3%。反过来，外来物种也丰富了这个群落。增加了 96.4%，但不影响总物种丰富度。就其本身而言，β多样性仅在社区中表现出与集约化相关的减少。我们的结果表明，施肥量和监督和施肥后的时间都与集约化影响没有直接关系。这些发现强调了考虑多样性的各个方面以评估社区对土地利用变化的反应的重要性。我们的结果表明，即使是轻微的集约化也会影响坎波斯草原的植物多样性。简单的土地利用强度指标缺乏对影响程度的可预测性，对这项技术的预防和缓解提出了挑战。