Different response of transient and persistent seed bank of alpine wetland to grazing disturbance on the Tibetan Plateau

2021

Ecology and Evolution

The soil seed bank (SSB) is the basis for the natural regeneration of vegetation, especially in severely eroded or degraded ecosystems (Baskin & Baskin, 1978). In rangelands, the degree of heterogeneity among SSBs is strongly influenced by livestock pressure through selective grazing and grazing-related environmental impacts (Kassahun et al., 2009;Solomon et al., 2006). The diversity of seeds in disturbed habitats is determined by the original plant populations, propagule production, and soil seed reserves (Grime, 1979), all of which are affected by ecological perturbations. The quality of the SSB declines as a function of time as vegetation is destroyed (Bakker et al., 1996). Therefore, the SSBs of arid and semiarid ecosystems are highly variable over space and time, and are linked to factors that influence seed production, mortality, and spatial distribution (Kemp, 1989). Drought cycles (Msangi, 2004) and overgrazing (Klintenberg & Seely, 2004) are the primary drivers of dryland degradation, and together can result in broad-scale restructuring of vegetation and

Section: Methodsmentioning

confidence: 99%

Effect of sheep grazing on seed circulation on the Loess Plateau

Wang

2021

Ecology and Evolution

“…Emerging seedlings were recorded and removed as soon as they could be identified or were transplanted into separate pots for later identification. Whenever seedlings were removed, the dung/sand mix sample was gently stirred to facilitate additional germination of buried seeds (He et al, 2021).…”

Section: Germination To Assess the Livestock Dsbmentioning

confidence: 99%

Precipitation regulates the livestock dung seed bank through above ground vegetation productivity in the Qaidam basin

Wang

2022

Land Degrad Dev

“…After weighing each dung piece, the dung piece was compressed gently to avoid damaging seeds, mixed with ~50 g sterile sand, and spread in a pot (length 35 cm, width 18 cm, height 10 cm) at 2 cm thickness on a 5-cm-thick bed of vermiculite. Pots (each dung piece in one pot) were placed in the Maqu Research Station yard under natural conditions (He et al 2020). As a control, 10 pots that contained only sterilized sand and vermiculite were placed alongside the dung pots to check for contamination by seeds blown in by wind or other potential means.…”

Section: Germinationmentioning

confidence: 99%

Short-term study on the yak dung seed bank on the Qinghai-Tibetan Plateau: effects of grazing season, seed characteristics and forage preferences

2021

Plant Soil

Aims Viable seeds in herbivore dung constitute the dung seed bank, and the contribution of livestock dung to this seed bank in grazing pastures is often overlooked. Grazing season (warm and cold), seed characteristics (size and shape), and forage preference are the main factors that affect the size and composition of the dung seed bank and ultimately affect grassland ecology. However, how these three factors interact is unclear. Methods We collected yak dung as well as seeds of the common plant species from warm- and cold-season alpine meadows in northeastern Qinghai-Tibetan Plateau, and explored how grazing season (warm and cold), seed characteristics (size and shape) and foraging preferences (temporary cages method) affects yak dung seedling density, richness and diversity in an alpine pasture. Results Forty-three plant species (mainly perennials) germinated from yak dung. Dung seedling density, richness, and diversity did not differ significantly between the two grazing seasons. Small to medium-sized spherical seeds (seed size < 10 mg, shape index < 0.5) had the greatest germination potential. Conclusions Yaks vary their forage preference depending on the season (phenological period), and endozoochory occurs throughout both grazing seasons. Seed shape and size directly regulate the dung seedling density, richness, and diversity. Dung seedlings increase the heterogeneity of the aboveground vegetation near the microsites of the dung pieces and therefore promote grassland patching. Our study demonstrates that grazing season, seed characteristics, and yak forage preferences affect the dung seed bank in grazing ecosystems.