SOIL SEED BANK CHARACTERISTICS BENEATH AN AGE SEQUENCE OF CARAGANA MICROPHYLLA SHRUBS IN THE HORQIN SANDY LAND REGION OF NORTHEASTERN CHINA

Abstract

To understand how shrub cover affects the spatiotemporal patterns of the soil seed bank and to assess the role of vegetation in the restoration of desertified land in a semi‐arid region of China, we investigated the species composition and seed density of the soil seed bank under and outside the canopies over two seasons for an age sequence of Caragana microphylla shrubs in the Horqin Sandy Land region, Inner Mongolia. The results showed that a total of 24 plant species seeds were present in the soil seed bank, of which 20 were annuals or biennials. The seed densities in the soil seed bank were in the range of 830 – 13882·5 seeds m−2 at 10 cm depth. Species richness in the soil seed bank did not increase as the shrubs aged, whereas the seed densities increased significantly. Five annual species: Setaria viridis, Eragrostis pilosa, Chenopodium acuminatum, Chenopodium glaucum and Corispermum acuminatum, contributed above 90 per cent of the seeds to the soil seed bank. On the basis of seed characteristics and seed reduction amount during the growing season, we concluded that it represents a mixture of persistent and transient seeds in different proportions. More seeds accumulated under the canopies than outside the mature shrub cover, but no significant difference was found the younger cover. These results suggest that shrub size and age had an important role in augmenting seed abundance of the soil seed bank but not the species richness. We confirmed the important effects of shrub cover on seed accumulation and vegetation recovery, especially the value of more mature age vegetation for countering land degradation. Copyright © 2012 John Wiley & Sons, Ltd.

A reliable and non-destructive method for estimating forage shrub cover and biomass in arid environments using digital vegetation charting technique

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The good with the bad: when ecological restoration facilitates native and non‐native species

“…Relative to interspaces between perennial plants, increased biological activity in fertile islands can be triggered by several mechanisms. These include shading and ameliorated microclimates below perennial plants, greater soil moisture, concentrated soil nutrients, trapping of seeds, and animal–plant interactions (El‐Bana et al ; Schneider & Allen ; Li et al ). Nurse plant effects often accompany fertile islands, whereby the fertile island‐forming perennial serves as a “nurse” facilitating the recruitment and growth of other plant species.…”

“…Although seeding and outplanting both have advantages and disadvantages, outplanting is often more reliable than seeding for reestablishing perennial plants to priority sites in drylands (e.g. Commander et al ; Li et al ; Rathore et al ). This is because outplanting bypasses the need for germination and survival of vulnerable young seedlings at restoration sites subject to limited and unpredictable precipitation.…”

Experimental sand burial affects seedling survivorship, morphological traits, and biomass allocation of <i>Ulmus pumila</i> var. <i>sabulosa</i> in the Horqin Sandy Land, China

“…Sand movement, the most direct evidence of land degradation, is regarded as a selective force determining colonization, establishment, and development of vegetation (Maun, 1994;Maun and Lapierre, 1986). Plants might respond differently to various degrees of sand burial and evolve different regenerative adaptations during the periods of soil seed bank formation, seed germination, and seedling emergence and development (Li et al, 2014;Qian et al, 2015;Tang et al, 2016).…”