Soil Seed Bank and Standing Vegetation of Abandoned Croplands on Chinese Loess Plateau: Implications for Restoration

Abstract

Abstract Vegetation succession depends on the availability of suitable propagules in the soils, and an understanding of soil seed banks is important for effective vegetation restoration of abandoned croplands. Aims of this study were to identify characteristics of soil seed bank, relationship with standing vegetation, and potential significance of soil seed bank for vegetation restoration in abandoned croplands on the hilly-gullied Loess Plateau. Results of field survey, germination, and correspondence analysis showed that density of soil seed bank ranged from almost 900 through almost 6470 seeds m−2 at 0–5 cm depth and almost 120 through almost 2470 seeds m−2 at 5–10 cm depth, with species richness of 7–14. Early successional species dominated soil seed bank, while later successional species occurred only at low densities. Similarity between soil seed bank and standing vegetation was low (with an average of 0.261). Most important variables contributing to the variation of the standing vegetaion included soil water, extractable P, soil seed bank density, and aspect. Soil seed bank alone explained 32% of vegetation community variation. Potential for vegetation restoration from soil seed banks is limited, and it is recommended to transplant some later successional species into abandoned croplands to accelerate succession. Keywords: community similaritycorrespondence analysisseed germination methodsoil erosion We thank the NSFC projects (40771126; 40571094; 40271074) for funding this research, the assistance of Ansai Ecological Experimental Station of Soil and Water Conservation, CAS. We are also grateful to X. H. Ma, Z. G. Zhang, L. R. Xu, H. Y. Zou, and J. M. Cheng for field survey and experiment suggestions. We would like to thank the three anonymous reviewers for constructive comments. Notes SW0-5, soil water content in 0–500 cm layers; SW2-5, soil water content in 200–500 cm layers; SOM, soil organic matter. CV, Coefficient of variation; SE, Standard Error. Frequency of seeds (%) in the soil seed bank is based on presence in 144 sampling points and in vegetation is based on 72 sampling points; Seed density is the range of the mean value (6 sub-samples) in the plots in which it occurred. CVA, Canonical Variate Analysis; PCVA, Partial Canonical Variate Analysis; ∗P < 0.05; ∗∗P < 0.01; the inertia of CVA is 3.000; "/", "partialling out" the following variable. Bs, species forming a persistent seed bank; V, possessing lateral vegetative spread; VBs, species characterized by Bs and V; W, producing numerous widely dispersed seeds.