Yang Hang, Yu Xiaojun, Song Jianchao, Wu Jianshuang
College of Grassland Science, Gansu Agricultural University, Lanzhou, China.
Key Laboratory of Grassland Ecosystem, Ministry of Education, Gansu Agricultural University, Lanzhou, China.
Front Plant Sci. 2024 Jun 28;15:1411839. doi: 10.3389/fpls.2024.1411839. eCollection 2024.
Herbivore-avoided plant patches are one of the initial characteristics of natural grassland degradation. These vegetation patches can intensify the spatial heterogeneity of soil nutrients within these grasslands. However, the effects of non-edible plant patches patches on the spatial heterogeneity of microorganisms have not been sufficiently studied in alpine meadows of the Qinghai-Tibetan Plateau, especially patches formed by herbaceous plants. To answer this question, soil nutrients, plant assembly, and microbial communities were measured inside, around, and outside of patches. These were 0 m (within the patch), 0-1 m (one meter from the edge of the patch), 1-2 m (two meters from the edge of the patch), 2-3 m (three meters from the edge of the patch), and >30 m (non-patch grassland more than thirty meters from the edge of the patch). Our results showed that patches accumulated more aboveground biomass (AGB) within the patches (0 m), and formed fertile islands with the soil around the patches. Additionally, patches increased soil bacterial diversity within (0 m) and around (0-1 m) the patches by primarily enriching copiotrophic bacteria (Actinobacteria), while the diversity of fungal communities increased mainly in the 0-1 m area but not within the patches. Bacterial community diversity was driven by pH, urease, nitrate nitrogen (NO -N), and microbial biomass carbon (MBC). The contents of soil water (SWC), soil organic matter (SOM), urease, NO -N, and MBC were the main factors influencing the diversity of the fungal community. This study elucidates the vegetation, nutrients, and microbial heterogeneity and their interrelationships, which are observed in fertile islands of herbivore-avoided plant patches in alpine meadows, and provides further insights into the spatial pattern of nutrients in patchy degraded grasslands.
食草动物避开的植物斑块是天然草地退化的初始特征之一。这些植被斑块会加剧草地土壤养分的空间异质性。然而，在青藏高原高寒草甸中，非食用植物斑块对微生物空间异质性的影响尚未得到充分研究，尤其是草本植物形成的斑块。为回答这个问题，我们对斑块内部、周边和外部的土壤养分、植物群落和微生物群落进行了测量。测量区域分别为0米（斑块内）、0 - 1米（距斑块边缘1米处）、1 - 2米（距斑块边缘2米处）、2 - 3米（距斑块边缘3米处）和>30米（距斑块边缘超过30米的非斑块草地）。我们的结果表明，斑块在其内部（0米处）积累了更多地上生物量（AGB），并与斑块周边土壤形成了肥沃岛。此外，斑块主要通过富集富营养型细菌（放线菌）增加了斑块内部（0米处）和周边（0 - 1米处）的土壤细菌多样性，而真菌群落多样性主要在0 - 1米区域增加，斑块内部未增加。细菌群落多样性受pH值、脲酶、硝态氮（NO₃-N）和微生物量碳（MBC）驱动。土壤含水量（SWC）、土壤有机质（SOM）、脲酶、NO₃-N和MBC含量是影响真菌群落多样性的主要因素。本研究阐明了高寒草甸中食草动物避开的植物斑块肥沃岛中观察到的植被、养分和微生物异质性及其相互关系，并为斑块状退化草地养分的空间格局提供了进一步的见解。
