Ribero Martín Nicolás, Schiaffino María Romina, Filloy Julieta
Laboratorio de Ecología de Comunidades y Macroecología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, IEGEBA UBA-CONICET, Buenos Aires, Argentina.
Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires (UNNOBA), Buenos Aires, Argentina.
Mol Ecol. 2025 Jan;34(2):e17617. doi: 10.1111/mec.17617. Epub 2024 Dec 9.
Grassland afforestation poses a threat to biodiversity beyond land-use conversion. Diversity patterns are shaped by temporal dynamics, particularly, time since afforestation can decline beta diversity and lead to biotic homogenisation. Our study examines the effect of grassland afforestation on soil prokaryotic and fungal beta diversity. We evaluate the contributions of colonisation and extinction processes to beta diversity, as well as the replacement of endemic species by ubiquitous ones. Along a 200 km climatic gradient in Argentina's Pampas region, we analysed grasslands and mature eucalypt plantations at different times since afforestation. Soil samples were collected at each site and analysed using 16S (V3-V4) and ITS2 amplicon sequencing to identify prokaryotic and fungal communities, respectively. The analyses revealed biotic homogenisation at the transition from grassland to newly planted stands, evidenced by a decrease in intratreatment beta diversity. Increasing time since afforestation did not exacerbate this decline. However, our findings indicate that there are different responses between prokaryotes and fungi. The homogenisation of prokaryotes in young stands is due to the low heterogeneity in colonising communities. On the other hand, the decline in fungal beta diversity is likely caused by other mechanisms beyond extinction or replacement. The study highlights the impacts of the afforestation process on the beta diversity of soil microbial communities of grasslands, affecting taxonomic groups in different ways. Although microbial diversity may be partially restored in time in eucalypt plantations, it is important to investigate its underlying mechanisms and the ecological implications for microbial diversity and its spatial distribution.
草原造林对生物多样性构成的威胁不仅限于土地利用的转变。多样性模式受时间动态影响，特别是造林后的时间会降低β多样性并导致生物同质化。我们的研究考察了草原造林对土壤原核生物和真菌β多样性的影响。我们评估了定殖和灭绝过程对β多样性的贡献，以及特有物种被常见物种取代的情况。沿着阿根廷潘帕斯地区200公里的气候梯度，我们分析了不同造林时间后的草原和成熟桉树林。在每个地点采集土壤样本，并分别使用16S（V3 - V4）和ITS2扩增子测序分析来鉴定原核生物和真菌群落。分析揭示了从草原到新造林地过渡阶段的生物同质化，表现为处理内β多样性的降低。造林后时间的增加并未加剧这种下降。然而，我们的研究结果表明原核生物和真菌之间存在不同的反应。幼龄林中原核生物的同质化是由于定殖群落中的低异质性。另一方面，真菌β多样性的下降可能是由灭绝或取代之外的其他机制引起的。该研究突出了造林过程对草原土壤微生物群落β多样性的影响，以不同方式影响分类群。虽然桉树林中的微生物多样性可能会随时间部分恢复，但研究其潜在机制以及对微生物多样性及其空间分布的生态影响很重要。
