Parviz Gholami; Mohammad Farzam; Nateq Lashkari sanami; Lale Amouzgar
Abstract
The study of soil seed bank provides vital information for rehabilitation and restoration of rangeland ecosystem. In the arid and semi-arid environments, shrub plants may cause accumulation of seed bank under their canopy, thereby protecting them against the livestock herbivory and the other environmental ...
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The study of soil seed bank provides vital information for rehabilitation and restoration of rangeland ecosystem. In the arid and semi-arid environments, shrub plants may cause accumulation of seed bank under their canopy, thereby protecting them against the livestock herbivory and the other environmental factors. This study was conducted with objective to investigate effect of Astragalus brachycalyx on composition of soil seeds bank, in two area of enclosure and under grazing. For this purpose, sampling of soil seed bank under the canopy of this species and its open space adjacent was measured using a flexible plot along the 100 meters transect. Soils were sampled from 0-5 and 5-10 cm depths. Then seed bank composition was identified after seed germination in glasshouse. The results showed that 16 species under the canopy of Astragalus brachycalyx and 12 plant species in the open space adjacent in enclosure area and 21 species under the canopy of Astragalus brachycalyx and 11 plant species in the open space adjacent in under grazing area. In the soil seed bank of an area under the livestock grazing and understory of Astragalus brachycalyx, the species namely Silene longipetala, Mentha longifolia, Veronica anagallis-aquatica and Anthemis odontostephana had the greatest numbers of seeds respectively. The area under livestock grazing had higher density of seed bank of plants with annual and perennial life, Therophytes and Hemicryptophytes biological forms, annual and perennial vegetative forms of forbs, and palatable classes II and III in understory compared to the open space.
zahra nikbakht; Mohammad Farzam; Mohammad Khajeh Hosseini; Hamid Ejtehadi
Abstract
The study of soil seed bank provides useful information on management and restoration of natural ecosystems. In the arid environments, some perennial plants may cause accumulation of seed bank under their canopy, thereby protecting them against the livestock herbivory and the other environmental factors. ...
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The study of soil seed bank provides useful information on management and restoration of natural ecosystems. In the arid environments, some perennial plants may cause accumulation of seed bank under their canopy, thereby protecting them against the livestock herbivory and the other environmental factors. This study was conducted with objective to investigate effect of perennial plants on density of soil seeds bank, under different utilization levels in an arid steppe rangeland. Three adjacent rangeland sites were selected, i.e. intense grazing, moderate grazing and no grazing (enclosure), and three line transects were randomly located within each site. Along each transect, soil samples were taken from the depth of 0–5 cm under the canopy of perennial plants or the nearby open space. The seed bank density was determined by the technique for separating seeds from the soil. The density of soil seed bank in the moderate and intensive grazing sites was higher than in the enclosure. In addition, seed bank density under the canopy of perennial plants was significantly higher than in open space, in each of three sites. The highest and lowest seed bank density were observed under the canopy of Rosa persica and Astragalus heratensis, respectively. Generally, the results of this research indicate the key role of perennial range plants in protecting soil seed bank of other plants, under the circumstances of high livestock grazing in the arid steppe rangelands.