Edge effects and spatial degradation process in highly fragmented grassland – impact on soil microbial community

Zhao, Xuan; Song, Yueqing; Xu, Tongtong; Xu, Minggang; Cai, Jinting; Li, Zhiqiang

doi:10.1016/j.ecolind.2021.108307

Cited by 14 publications

(8 citation statements)

References 61 publications

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“…We established spatially‐paired 25 m × 25 m (NSEW‐oriented) plots in each land cover type at both sites. These paired plots were less than 500 m apart within each site, with native plots situated at least 100 m away from the adjacent cleared land to reduce the edge effects (Zhao, Song, et al., 2021 ). We collected soil moisture and below (−10 cm) and aboveground temperatures (+0 cm, +10 cm) with TMS‐4 data loggers (TOMST, Prague, Czech Republic), which were installed at each plot for the duration of the study period (6 weeks), recording at 15‐min intervals (Wild et al., 2019 ).…”

Section: Methodsmentioning

confidence: 99%

Light–dark cycles may influence in situ soil bacterial networks and diurnally‐sensitive taxa

Fickling,

Abbott,

Brame

et al. 2024

Ecology and Evolution

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Soil bacterial taxa have important functional roles in ecosystems (e.g. nutrient cycling, soil formation, plant health). Many factors influence their assembly and regulation, with land cover types (e.g. open woodlands, grasslands), land use types (e.g. nature reserves, urban green space) and plant–soil feedbacks being well‐studied factors. However, changes in soil bacterial communities in situ over light–dark cycles have received little attention, despite many plants and some bacteria having endogenous circadian rhythms that could influence soil bacterial communities. We sampled surface soils in situ across 24‐h light–dark cycles (at 00:00, 06:00, 12:00, 18:00) at two land cover types (remnant vegetation vs. cleared, grassy areas) and applied 16S rRNA amplicon sequencing to investigate changes in bacterial communities. We show that land cover type strongly affected soil bacterial diversity, with soils under native vegetation expressing 15.4%–16.4% lower alpha diversity but 4.9%–10.6% greater heterogeneity than soils under cleared vegetation. In addition, we report time‐dependent and site‐specific changes in bacterial network complexity and between 598–922 ASVs showing significant changes in relative abundance across times. Native site node degree (bacterial interactions) at the phylum level was 16.0% higher in the early morning than in the afternoon/evening. Our results demonstrate for the first time that light–dark cycles have subtle yet important effects on soil bacterial communities in situ and that land cover influences these dynamics. We provide a new view of soil microbial ecology and suggest that future studies should consider the time of day when sampling soil bacteria.

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Section: Methodsmentioning

confidence: 99%

Light–dark cycles may influence in situ soil bacterial networks and diurnally‐sensitive taxa

Fickling,

Abbott,

Brame

et al. 2024

Ecology and Evolution

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“…The study areas had experienced varying degrees of saline-alkaline degradation historically due to intensive grazing and mowing. The degraded areas showed obvious characteristics of gradual formation of saline-alkaline degraded patches, that is, PD (Figure 1c,e; Zhao et al, 2021). The soil salinization of degraded patches inhibited original plant growth and supported growth of only annual salt-tolerant plants such as A. anethifolia, K. sieversiana, and Chloris virgata (Wang & Guo, 2019).…”

Section: Study Sitementioning

confidence: 99%

“…Grassland degradation commonly exhibits obvious features of gradual formation of degraded patches, that is, patchy degradation (PD) (Che et al, 2017(Che et al, , 2019Howison et al, 2017;Zhao et al, 2021;Figure 1c,e). Degraded patches are usually unsuitable for original plant survival (Che et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Changes in plant community assembly from patchy degradation of grasslands and grazing by different‐sized herbivores

Song

et al. 2023

Ecological Applications

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Grassland degradation caused by increases in livestock grazing threatens a variety of ecosystem services. Understanding changes in plant community assembly during the process of grassland degradation in the presence of grazing is important to help restore degraded grasslands worldwide but has received little attention thus far. The grassland degradation process is typified by heterogeneous degradation, that is, gradual formation of degraded patches (hereafter “patchy degradation”). Here, we experimentally examined the effects of herbivore grazing and patchy degradation on plant community assembly using nine pairs of non‐degraded (intact) and patch‐degraded (fragmented) grasslands subject to grazing by different‐sized herbivores (i.e., NG, no grazing; SG, sheep grazing; CG, cattle grazing) over 4 years. Using a null‐model approach, we estimated the relative magnitude of deterministic processes of community assembly by comparing the observed and expected β‐diversity. We found that in the absence of herbivore grazing, deterministic processes played a greater role in community assembly, regardless of whether patchy degradation had occurred. However, the deterministic processes resulted in plant communities being more spatially similar in non‐degraded grasslands while being more dissimilar in patchy degraded grasslands. Compared with non‐degraded grasslands, species with strong competitive abilities (i.e., Leymus chinensis) were less dominant in patchy degraded grasslands, indicating relaxed competition and a reduced role of species interactions over plant communities. Instead, patchy degradation added the role of environmental variables over plant communities. SG consistently promoted more stochastic plant community assembly in both non‐degraded and patch‐degraded grasslands, while CG promoted more stochastic plant community assembly only in the non‐degraded state, having no effect in the patch‐degraded state. Our study offers important insights into changes in plant community assembly during ongoing patch‐degradation of grasslands, indicating the role of increased environmental filtering of soil and reduced species interactions in driving plant community dynamics with increasing grassland patchy degradation. We also uncovered an herbivore species‐specific effect on plant community assembly during the process of grassland degradation, which will better inform and improve future grassland restoration planning efforts.

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“…Here, we focus on the SAR of plants and soil microbes on remnant grassland habitat islands following habitat loss and fragmentation. When grasslands are degraded or converted to other habitat types, smaller and more fragmented (i.e., isolated) habitat islands remain as intact remnants of more natural vegetation surrounded by degraded matrix habitat (Che et al., 2019; Howison et al., 2017; Qian et al., 2022; Song et al., 2022; Zhao et al., 2021; Figure 1a,b). These remnant habitat islands provide a natural platform to examine the effects of habitat size of the remnant patches on the patterns and potential processes leading to the SAR of plants and soil microbes.…”

Section: Introductionmentioning

confidence: 99%

Species–area relationships of plants and microbes are driven by different mechanisms in patchy grassland fragments

Song,

Chase,

Zhou

et al. 2023

Journal of Ecology

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The island species–area relationship (SAR) describes how the number of species on an island varies with its area and provides important information about the maintenance of species diversity and how species might be lost as habitats are lost and fragmented. While the island SAR has been widely studied among macroorganisms, patterns for soil microbes have been less forthcoming, as have analyses of potential underlying mechanisms. We examined the SAR patterns of plants, soil fungi and bacteria among remnant grassland fragments isolated by degraded habitat matrix in a steppe grassland. As expected, we found that the total species richness of plants, fungi and bacteria in the entire fragment decreased with decreasing fragment area. However, the mechanisms differed among taxa. For plants, the lower diversity was most likely because of decreases in habitat quality and habitat heterogeneity on smaller fragments. For fungi, we found similar results, but also an important interaction with plant diversity, suggesting they were coupled via their functional associations. For bacteria, the lower diversity on smaller fragments primarily resulted from a sampling effect from the larger species pool, which outweighed the effect of higher habitat heterogeneity on smaller fragments. Synthesis: Our study highlights that fragmentation‐induced loss of diversity can have many different underlying mechanisms and that understanding these mechanisms can provide useful insights to project future biodiversity loss and conservation.

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Edge effects and spatial degradation process in highly fragmented grassland – impact on soil microbial community

Cited by 14 publications

References 61 publications

Light–dark cycles may influence in situ soil bacterial networks and diurnally‐sensitive taxa

Light–dark cycles may influence in situ soil bacterial networks and diurnally‐sensitive taxa

Changes in plant community assembly from patchy degradation of grasslands and grazing by different‐sized herbivores

Species–area relationships of plants and microbes are driven by different mechanisms in patchy grassland fragments

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