Soil Seed Bank Changes after Forest Clearing and Agricultural Use in Alaska

Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 343-347 ◽  
Author(s):  
Jeffery S. Conn ◽  
Catherine L. Cochrane ◽  
John A. Delapp

Soil samples representing a time series from forest before clearing to land in cultivation for 20 yr were taken near Delta Junction, AK, to determine the changes that occur in the soil seed bank following clearing and agricultural use. The total number of seed was initially low in the forested sites but increased after 3 to 5 yr in cultivation due to seed production by native colonizers and by introduced weeds such as common lambsquarters (Chenopodium albumL. ♯3CHEAL). Viability of seed of several mature forest species was low. There was a shift from a seed bank dominated by native species in the forest and newly cleared sites to a seed bank dominated by introduced colonizers in the older fields. Although seed of introduced species increased in importance over time, native species, especially native colonizers, continued to be an important component of the seed bank throughout the 20-yr period represented.

2019 ◽  
Vol 43 (1) ◽  
Author(s):  
Wakshum Shiferaw ◽  
Tamrat Bekele ◽  
Sebsebe Demissew ◽  
Ermias Aynekulu

AbstractThe aims of the study were to analyze (1) the effects of Prosopis juliflora (Prosopis) on the spatial distribution and soil seed banks (SSB) diversity and density, (2) the effects of environmental factors on SSB diversity and density (number of seeds in the soil per unit area), and (3) the effects of animal fecal droppings on SSB diversity, density, and dispersal. Aboveground vegetation data were collected from different Prosopis-infested habitats from quadrats (20 × 20 m) in Prosopis thickets, Prosopis + native species stand, non-invaded woodlands, and open grazing lands. In each Prosopis-infested habitats, soil samples were collected from the litter layer and three successive soil layer, i.e., 0–3 cm, 3–6 cm, and 6–9 cm. Seeds from soil samples and animal fecal matter were separated in the green house using the seedling emergence technique. Invasion of Prosopis had significant effects on the soil seed bank diversity. Results revealed that the mean value of the Shannon diversity of non-invaded woodlands was being higher by 19.2%, 18.5%, and 11.0% than Prosopis thickets; Prosopis + native species stand and open grazing lands, respectively. The seed diversity and richness, recovered from 6–9-cm-deep layer were the highest. On the other hand, the density of Prosopis seeds was the highest in the litter layer. About 156 of seeds/kg (92.9%) of seeds were germinated from cattle fecal matter. However, in a small proportion of seedlings, 12 of seeds/kg (7.1%) were germinated from shot fecal matter. Thus, as the seeds in the soil were low in the study areas, in situ and ex situ conservation of original plants and reseeding of persistent grass species such as Cynodon dactylon, Cenchrus ciliaris, Chrysopogon plumulosus, and Brachiaria ramosa are recommended.


2001 ◽  
Vol 49 (6) ◽  
pp. 717 ◽  
Author(s):  
Scott A. King ◽  
Rod T. Buckney

Native vegetation reserves in urban areas have been invaded by exotic plants, particularly along edges. However, it is not known whether the seeds of exotic plants in the soil-stored seed bank are also largely restricted to edges. Ten urban bushland sites in northern Sydney were randomly selected and the readily germinable, soilstored seed bank examined to assess whether the number of exotic and native species varied with distance from an urban edge. The similarity of the contents of the seed bank and the composition of the above-ground vegetation was also examined. Soil samples were collected from quadrats 0–10, 20–30 and 50–60 m from the edge at each site, then spread on germination trays in a glasshouse and germinated seedlings identified. Soil samples were collected every 3 months for a year. The number of exotic species in the seed bank was found to be highest near urban edges, as was the total number of species. The above-ground vegetation was found to be a poor indicator of the contents of the seed bank, for both native and exotic species. Most of the exotic species found in the seed bank were not found in the immediately surrounding vegetation. Furthermore, some exotic species were found in the seed bank at sites where no exotic species were present in the vegetation. The results suggest that it is the lack of suitable conditions that is largely restricting invasion of exotic species to edges of bushland. The results also highlight the need for seedbank studies to assess the contents of the soil seed bank in urban bushland in order to prevent further invasions of exotic plants.


2005 ◽  
Vol 27 (2) ◽  
pp. 73 ◽  
Author(s):  
C. H. A. Huxtable ◽  
T. B. Koen ◽  
D. Waterhouse

Native grasses have an important role to play in mine rehabilitation throughout Australia, but there have been few scientifically designed studies of field establishment of native grasses from sown seed in this country. Current recommendations for rehabilitation of open-cut coal mines in the Hunter Valley involve the sowing of exotic pasture species to reinstate mined land to Class IV and V under the Rural Land Capability System. Despite the importance of native grasses in the pre-mined landscape, they are currently not widely included in mine rehabilitation. To address this issue a project was conducted between 1994 and 2000 to research the use of native grasses for rehabilitation of open-cut coal mines in the Hunter Valley. This paper reports on 2 mine site experiments that aimed to assess establishment and persistence of a broad range of native and exotic grass species from an autumn sowing in both topsoil and raw spoil over a period of 61 months. The most promising natives in terms of early establishment, persistence and spread over time, included six C3 accessions (five Austrodanthonia spp. and Austrostipa bigeniculata) and one C4 accession (Cynodon dactylon). Persistence of these accessions was better in raw spoil than topsoil, despite initial low numbers, due to a lack of weed competition and their ability to spread by self-seeding. In topsoil, and in the absence of any biomass reduction, native species were mostly out-competed by vigorous exotic perennial grasses which were sown in these experiments and from seed influx from adjacent rehabilitation areas or from the soil seed bank. The effects of climatic conditions and differences in soil physical, chemical and seed bank characteristics at the 2 mine sites are also discussed.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5466 ◽  
Author(s):  
Stefan A. Goets ◽  
Tineke Kraaij ◽  
Keith M. Little

Background Invasive alien plants with long-lived dormant seed banks and fast growth rates are difficult to manage. Acacia mearnsii and Acacia melanoxylon are two such invaders in the southern Cape of South Africa which occasionally co-occur with a native, ecologically analogous species, Virgilia divaricata. We compared the performance of these three species to determine potential for the native species to be used in management of the invasives. Methods We compared the study species in terms of (i) soil seed bank densities, their vertical distribution, and the viability of seeds underneath the canopies of mature trees; (ii) seedling growth from planted seeds over a period of three months; and (iii) growth rates of saplings over a period of 10 months in stands that have naturally regenerated in the field (these stands were dominated by A. mearnsii) and where saplings have been exposed to varying levels of competition from surrounding saplings. Results Seed bank densities differed significantly among species but not among soil depth classes. Acacia mearnsii had the highest seed bank densities (mean of 7,596 seeds m−2), followed by V. divaricata (938 seeds m−2) and A. melanoxylon (274 seeds m−2). Seed viability was high (87–91%) in all three study species and did not differ significantly among species or soil depth classes. As seedlings, V. divaricata significantly outgrew A. mearnsii in terms of height, root and shoot dry mass, and root:shoot ratio. Relative growth (the relationship between growth in height and initial height) was negative in the seedlings of both species. Trends during the sapling stage were opposite to those during the seedling stage; A. mearnsii (but not A. melanoxylon) saplings significantly outgrew V. divaricata saplings in height, while relative growth rates were positive in all species. Sapling growth of all species was furthermore uninfluenced by the collective biomass of surrounding competitors. Discussion Our findings suggest that amongst the measures considered, A. mearnsii’s success as an invader is primarily attributable to its large seed banks, and secondly to its vigorous growth in height as saplings. However, the superior growth performance of V. divaricata seedlings and no apparent negative effect of competition from the acacias on sapling growth show promise for its use in integrated management of the acacias.


2018 ◽  
Vol 7 (2) ◽  
pp. 131
Author(s):  
Nurmuliayanti Muis ◽  
Titiek Setyawati ◽  
Soekisman Tjitrosoedirjo ◽  
Yuliana Diah Ratnadewi

The composition of soil-seed bank reflects the condition of vegetation in the past and could be used for predicting the composition of plants that will grow in the future. This study aims to determine the amount and composition of soil-seed bank in Bekol savanna, Baluran National Park. Soil samples were taken using a combination method of quadrat-transect on the invaded and not invaded areas by Acacia nilotica. Soil samples were extracted using wet-sieving method. After the extraction process, the seeds were identified and calculated using a stereo microscope. The result showed that soil-seed bank density was lower at the invaded location (7,566.88 seeds/m3) as compared to the uninvaded location (16,798.3 seeds/m3). The soil-seed bank was found in the invaded site comprising 12 species of broadleaved weeds and 5 species of grasses from 7 families, whereas those in the uninvaded area consisted of 10 species of broadleaved weeds and 7 species of grass from 8 families. This study showed that the invasion of A. nilotica significantly affected the amount and composition of soil-seed bank in various soil depths of Bekol savanna.


Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 511-517 ◽  
Author(s):  
Daniel A. Ball ◽  
Stephen D. Miller

Research was conducted to evaluate the effects of primary tillage (moldboard plowing and chisel plowing), secondary tillage (row cultivation), and herbicides on weed species changes in the soil seed bank in three irrigated row cropping sequences over a 3-yr period. The cropping sequences consisted of continuous corn for 3 yr (CN), continuous pinto beans for 3 yr (PB), and sugarbeets for 2 yr followed by corn in the third year (SB). A comparison between moldboard and chisel plowing indicated that weed seed were more prevalent near the soil surface after chisel plowing. The density of certain annual weed seed over the 3-yr period increased more rapidly in the seed bank after chisel plowing compared to moldboard plowing. Species exhibiting the most pronounced increase included hairy nightshade and stinkgrass in the PB cropping sequence and redroot pigweed and common lambsquarters in the SB sequence. Conversely, kochia seed density in the SB sequence decreased more rapidly in chisel-plowed plots. Row cultivation generally reduced seed bank densities of most species compared to uncultivated plots. Herbicide use in each cropping sequence produced a shift in the weed seed bank in favor of species less susceptible to applied herbicides. In particular, seed of hairy nightshade became prevalent in the PB cropping sequence, and seed of kochia, redroot pigweed, and common lambsquarters became prevalent in the SB sequence.


Web Ecology ◽  
2000 ◽  
Vol 1 (1) ◽  
pp. 70-75 ◽  
Author(s):  
J. E. Malo

Abstract. The seed content of soils is often estimated through germination tests, though these methods are always somewhat inaccurate due to the presence of dormant seeds in the samples. The researcher thus faces the question of whether to continue the germination test or to stop it in the search for an accuracy-to-effort balance. In this paper I analyze the accuracy of seed content estimates obtained after a first-year germination test, by comparison to the germination recorded after three-year cultivation, in 48 soil seed bank samples and 389 from herbivore dung. After the first 9-month cultivation, I recorded 85 ± 1% seedlings and 90 ± 1% species in soil samples, while the accuracy in those of dung was significantly lower, 48 ± 1% seedlings and 65 ± 1% species. The accuracy of estimations varied among samples within experiments, with significant differences in the estimation of species richness in both cases. I did not find consistent differences in the accuracy of estimations linked to seedling densities in growing pots, but the taxonomic composition of samples was a major source of bias. Thus, 22% and 36% of the most frequent species showed germinabilities in the first year significantly different from the rest, and some generalities arose, like the high germinability of grasses and the hardseededness of legumes. I would thus recommend the use of at least two germination cycles for seed bank estimations and a cautious approach when comparing samples with very different origin and/or taxonomic composition.


2019 ◽  
Vol 132 ◽  
pp. 94-101
Author(s):  
Aurino Miranda Neto ◽  
Sebastião Venâncio Martins ◽  
Kelly de Almeida Silva

1991 ◽  
Vol 69 (4) ◽  
pp. 831-834 ◽  
Author(s):  
Per Milberg

Large numbers of fern spores germinated in soil samples from a grassland trail. The trail was established in central Sweden 35 years ago to study the effect of different treatments on grassland vegetation. The density of prothallia varied between 57 000 and 170 000 m−2 in the different treatments. There were no ferns in the treatment plots, and none of the three fern species identified from the spore bank were found in the surrounding area. This suggests that the large spore bank has accumulated over a long period of time and that fern spores are capable of remaining viable in the soil for several years. A large spore bank can enhance the chance for intergametophytic crossing in fern species. Key words: fern, grassland, Pteridophyta, soil seed bank, spore bank.


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