نتایج جستجو برای: soil seed banks
تعداد نتایج: 280122 فیلتر نتایج به سال:
In tropical forests, pioneer tree species regenerate from seeds dispersed directly into canopy gaps and from seeds that persisted in soil seed banks before gap formation. Life-history models have suggested that selection for the long-term persistence of tree seeds in the soil should be weak because persistence potentially reduces population growth rate by extending generation time and because a...
To provide more insights into the responses of the soil seed bank and vegetation to human disturbance intensity, we selected four land use types, including: native grassland (no human disturbance), abandoned artificial grassland (light human disturbance), artificial grassland (moderate human disturbance), and farmland (severe human disturbance) in a semi-arid climate of northern China. The spec...
Annual forbs form short-term persistent soil seed banks whereas perennial grasses form mostly transient ones in the central Monte desert. A conceptual framework predicts that annual forb seeds will have primary dormancy, whereas perennial grasses will have low dormancy levels. We assessed whether the dormancy traits of four annual forb species and five perennial grass species can account for th...
Ecologists have long acknowledged the importance of seed banks; yet, despite the fact that many plants rely on mycorrhizal fungi for survival and growth, the structure of ectomycorrhizal (ECM) fungal spore banks remains poorly understood. The primary goal of this study was to assess the geographic structure in pine-associated ECM fungal spore banks across the North American continent. Soils wer...
M. Brodahl U.S. Department of Agriculture, Agricultural Research Service, Water Management Research Unit, Fort Collins, CO 80526 Comparing distributions among fields, species, and management practices will help us understand the spatial dynamics of weed seed banks, but analyzing observational data requires nontraditional statistical methods. We used cluster analysis and classification and regre...
This study investigated the effects of microhabitat characteristics on soil seed bank structure, regeneration strategies, and plant composition in a Mediterranean coastal sand dune in Israel. Three different microhabitats were selected: (a) open patches between shrubs, (b) shrub understorey, and (c) open, disturbed patches in pedestrian trails. In each microhabitat two types of sampling plots w...
Seed banks are an important component of many plant populations, but few empirical studies have investigated the genetic relationship between soil seeds and surface plants. We compared the genetic structure of soil seeds and surface plants of the desert mustard Lesquerella fendleri within and among five ecologically diverse populations at the Sevilleta National Wildlife Refuge in Central New Me...
The relationship between intensity and timing of cattle grazing on changes in the size and composition of the soil seed bank were investigated in a 3-yr study in a Mediterranean grassland in northeastern Israel. Treatments included manipulations of stocking rates and of grazing regimes, in a factorial design. The retrieved soil seed bank community was rich in species, with 133 species accountin...
Pteridium aquilinum is known as an invasive species in different ecosystems of the world. The spread of this species is increasing in the north of Iran particularly outside of forest ecosystems. In this study, the amount and composition of soil seed banks in the dense pathes of Pteridium were investigated in summer rangelands of Bandpay in the south of Babol city in Mazandaran province, Iran...
The seed bank in the soil and litter of an annual grassland in the upper salt marsh of the Guadalquivir delta (SW Spain) contained on average 49 110 seeds/m2; 29 species were represented. Field censuses of the grassland, in two consecutive springs, yielded 7 410 and 9 520 plants/m2 respectively. A combined Correspondence Analysis of the seed bank samples and field censuses showed differences in...
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