Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Soil Seed Bank Dynamics in Planted Caragana Stands with Different Years of Sand Fixation at the Southeastern Edge of the Tengger Desert

Auteur : 常选选

Grade : Master 2022

Université : Ningxia University

Résumé partiel
In this paper,artificial Caragana groves with different years of sand fixation in each month in the Shapotou area were used as research objects.By means of aboveground vegetation survey and greenhouse sprouting,the characteristics of aboveground vegetation,spatial and temporal dynamics of soil seed bank and its relationship with aboveground vegetation were studied,and the possibility of soil seed bank on vegetation restoration was analyzed to provide theoretical guidance for the restoration of desert vegetation in arid and semi-arid areas.The main conclusions are as follows.1.There are 19 species of plants in the study area,13 species of aboveground vegetation,15 species of soil seed bank vegetation,and 9 species of total vegetation.Among the 19 species of plants,annual herbs account for the most,accounting for 68.75%of the total number of species.2.Seed bank density ranged from 0 seeds/m2-2083.33 seeds/m2,with the maximum density occurring in July and the minimum density in June.The soil seed bank density of all sites planted with Caragana trees was significantly greater than the soil seed bank density of the grass square grid sand fixation sample site,and planting Caragana trees had an enriching effect on seed bank seeds.The number of species,individuals and vegetation species diversity of the soil seed bank in different months reached the maximum in July.3.The similarity range of soil seed bank in different months was large,between 0 and 1,and the similarity between transient soil seed bank and persistent soil seed bank was extremely small.The horizontal distribution of transient soil seed bank density in different years of sand fixation was characterized as follows:with the increase of planting years,the soil seed bank density showed an increasing trend ;the vertical distribution pattern was:with the increase of soil layer depth,the soil seed bank density showed an obvious decreasing trend,and the seed storage was mainly concentrated in the 0-2cm soil layer.The species similarity between the control sample sites and the Caragana forest sample sites for 5 years of sand fixation was very low and generally lower than the species similarity between the Caragana forest sample sites,and the planting of Caragana forest could change the species composition of the ecosystem ;the species similarity between adjacent sample sites had gradual change characteristics,and the substitution rate between species was not high as the succession progressed.4.There was a positive correlation between the number of above-ground vegetation plants and soil seed bank density in the study area,and the power function and logarithmic function could describe the significant correlation between the number of above-ground vegetation plants and soil seed bank density,with P＜0.05（P=0.006）for the power function and P＜0.05（P—0.022）for the logarithmic function.The similarity level between soil seed bank and above-ground vegetation in the study area was moderate,so the restoration of above-ground vegetation with the soil seed bank in the Caragana stand sample was possible

Mots clés : Caragana forest ;soil seed bank ;species diversity ;vegetation restoration ;

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