Population dynamics ofEchinops gmeliniiTurcz. at different successional stages of biological soil crusts in a temperate desert in China

Abstract

The effects of biological soil crusts (BSC) on vascular plant growth can be positive, neutral or negative, and little information is available on the impacts of different BSC successional stages on vascular plant population dynamics.• We analysed seedling emergence, survival, plant growth and reproduction in response to different BSC successional stages (i.e. habitats: bare soil, cyanobacteria, lichen and moss crusts) in natural populations of Echinops gmelinii Turcz. in the Tengger Desert of northwest China. The winter annual E. gmelinii is a dominant pioneer herb after sand stabilisation.• During the early stages of BSC succession, the studied populations of E. gmelinii were characterised by high density, plant growth and fecundity. As the BSC succession proceeded beyond moss crusts, the fecundity decreased sharply, which limited seedling recruitment. Differences in seedling survival among the successional stages were not evident, indicating that BSC have little effect on survival in arid desert regions. Moreover, E. gmelinii biomass allocation exhibited low plasticity, and only reproductive allocation was sensitive to the various habitats. Our results further suggest that the negative effects of BSC succession on population dynamics are primarily driven by increasing topsoil water-holding capacity and decreasing rain water infiltration into deeper soil.• We conclude that BSC succession drives population dynamics of E. gmelinii, primarily via its effect on soil moisture. The primary cause for E. gmelinii population decline during the moss-dominated stage of BSC succession is decreased fecundity of individual plants, with declining seed mass possibly reducing the success of seedling establishment.

Life history response of Echinops gmelinii Turcz. to variation in the rainfall pattern in a temperate desert

“…The plant mortality was recorded every three days in all treatments from April to July. Our field investigation of E. gmelinii population for three years (2016 to 2018) showed that less than 30% of seedlings could successfully overwinter in our study area (Wang et al, 2019b). Thus, survival of overwintered seedlings is a key factor for affecting population dynamics of E. gmelinii .…”

“…E. gmelinii seeds germinate in summer and autumn, and plants overwinter as rosettes and complete their life cycle quickly by utilizing spring and early summer rainfall (Wang et al, 2019a), which could avoid resource competition with other summer annuals (Tobe, Zhang & Omasa, 2005). At a field site in the Tengger Desert, we found that the population dynamics of E. gmelinii were very sensitive to rainfall variation (Wang et al, 2019b); thus, the species may be particularly threatened by climate change. Furthermore, E. gmelinii provides an ideal opportunity to understand the response of the life history adaptation strategies of winter annuals in temperate desert to rainfall variation in the context of global climate change.…”

Peer Review #1 of "Life history response of Echinops gmelinii Turcz. to variation in the rainfall pattern in a temperate desert (v0.1)"

“…E. gmelinii seeds germinate in summer and autumn, and plants overwinter as rosettes and complete their life cycle quickly by utilizing spring and early summer rainfall (Wang et al 2019a), which could avoid resource competition with other summer annuals (Tobe et al 2005). At a field site in the Tengger Desert, we found that the population dynamics of E. gmelinii were very sensitive to rainfall variation (Wang et al 2019b); thus, the species may be particularly threatened by climate change.…”

Effects of Biological Crust on Soil Properties under Different Karst Rocky Desertification Habitats

“…However, due to the long growth cycle, sparse branches and leaves of walnut and Zanthoxylum bungeanum trees, the interception effect of rainfall infiltration and runoff erosion is limited. [36] At the same time, owing to their strong nutrient plunder in the soil to make it difficult for the shrubs and grasses under the trees to survive, it is very easy to cause large area of surface exposure, everserious soil erosion and underground leakage, which further induces the formation of rocky desertification [37]. With its high compatibility with different types of habitats and strong stress resistance, BSCs can directly absorb water and nutrients from the body surface through special physiological structure and root system to promote the accumulation of nutrient content in soil, and effectively improve soil physical and chemical properties, so as to maintain the dynamic balance of karst soil system [38].…”