Grazing disturbance increases transient but decreases persistent soil seed bank

Journal Article · Mon Apr 30 00:00:00 EDT 2018 · Ecological Applications

DOI:https://doi.org/10.1002/eap.1706· OSTI ID:1435401

Ma, Miaojun ^[1]; Walck, Jeffrey l. ^[2]; Ma, Zhen ^[3]; Wang, Lipei ^[1]; Du, Guozhen ^[1]

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1. State Key Laboratory of Grassland and Agro‐ecosystems School of Life Sciences Lanzhou University Lanzhou 730000 China
2. Department of Biology Middle Tennessee State University Murfreesboro Tennessee 37132 USA
3. Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau Biology Chinese Academy of Sciences Xining Qinghai 810008 China

Abstract Very few studies have examined whether the impacts of grazing disturbance on soil seed banks occur directly or indirectly through aboveground vegetation and soil properties. The potential role of the seed bank in alpine wetland restoration is also unknown. We used SEM (structural equation modeling) to explore the direct effect of grazing disturbance on the seed bank and the indirect effect through aboveground vegetation and soil properties. We also studied the role of the seed bank on the restoration potential in wetlands with various grazing intensities: low (fenced, winter grazed only), medium (seasonally grazed), and high (whole‐year grazed). For the seed bank, species richness and density per plot showed no difference among grazing intensities for each depth (0–5, 5–10, 10–15 cm) and for the whole depth (0–15 cm) in spring and summer. There was no direct effect of grazing disturbance on seed bank richness and density both in spring and summer, and also no indirect effect on the seed bank through its direct effect on vegetation richness and abundance. Grazing disturbance indirectly increased spring seed bank density but decreased summer seed bank density through its direct effect (negative correlation) on soil moisture and total nitrogen and its indirect effect on vegetation abundance. Species composition of the vegetation changed with grazing regime, but that of the seed bank did not. An increased trend of similarity between the seed bank and aboveground vegetation with increased grazing disturbance was found in the shallow depth and in the whole depth only in spring. Although there was almost no change in seed bank size with grazing intensities, grazing disturbance increased the quantity of transient seeds but decreased persistent seeds. Persistent seeds stored in the soil could play a crucial role in vegetation regeneration and in restoration of degraded wetland ecosystems. The seed bank should be an integral part of alpine wetland restoration programs.

• Sponsoring Organization: USDOE
• OSTI ID: 1435401
• Journal Information: Ecological Applications, Journal Name: Ecological Applications Vol. 28 Journal Issue: 4; ISSN 1051-0761
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: United States
• Language: English