Influence of Afforestation on the Species Diversity of the Soil Seed Bank and Understory Vegetation in the Hill-Gullied Loess Plateau, China.

Ning Wang,Dongli Wang,Juying Jiao,Yanfeng Jia

doi:10.3390/ijerph14101285

Abstract

The Chinese Loess Plateau region has long been suffering from serious soil erosion. Thus, large-scale afforestation has continued during the past decades in order to control soil erosion. Afforestation can dramatically alter nutrient cycles, affect soil-carbon storage, and change hydrology. However, it is unknown how afforestation influences species diversity of the soil seed bank and understory vegetation compared with spontaneous restoration of abandoned land. Forest land with trees planted 30 years ago, abandoned slope land restored spontaneously for 30 years, and the corresponding slopes with remnant natural vegetation were selected as sampling sites. The species richness both in the soil seed bank and vegetation was significantly higher on the afforested slope compared to the spontaneously restored abandoned land. The species similarity between the afforested slope and the remnant slope land was high both in the soil seed bank and standing vegetation compared to the abandoned land. The soil seed bank density varied from 1778 ± 187 to 3896 ± 221 seeds/m2, and more than half of it was constituted by annual and biennial species, with no significant difference among sampling habitats. However, the afforested slope had higher seed density of grass and shrub/subshrubs compared to the abandoned slope. The present study indicates that in the study region, characterized by serious soil erosion, afforestation can better facilitate vegetation succession compared to spontaneously restoration of abandoned slope land.

Highlights

Soil erosion is regarded as one of the global environmental problems which cause land degradation and ecosystem disequilibrium [1]
The soil seed bank density was significantly different among the habitats (F = 3.988, p = 0.007)
On the south-facing slope, the seed bank density was significantly lower on the abandoned land (1778 ± 187 seeds/m2 ) than on both the planted slope land (3415 ± 415 seeds/m2 ) and the land with remnant vegetation (3249 ± 348 seeds/m2 ), but there was no significant difference between the last two

Summary

Introduction

Soil erosion is regarded as one of the global environmental problems which cause land degradation and ecosystem disequilibrium [1]. A large part of the natural vegetation had been destroyed and the land turned into farmland, aggravating soil erosion and ecological degradation [3]. It is estimated that nearly 1.6 billion tons of soil are lost from the plateau each year, and droughts, floods, and dust storms are common occurrences [4]. Soil and water conservation is a vital problem that compromises the safety of both ecosystem and society. Revegetation is an effective approach to control soil erosion and improve the ecosystem. The presence of grass or trees can reduce runoff and conserve soil and water [5,6,7]. Slope farmlands have been increasingly abandoned for revegetation [2,3]

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Discussion

Conclusion