What potential is there for regeneration of native species from the soil seed bank in Coast Tea Tree-dominated scrub?

2014 ◽  
Vol 15 (1) ◽  
pp. 80-83 ◽  
Author(s):  
Luke S. O'Loughlin ◽  
Peter T. Green ◽  
John W. Morgan
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.


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.


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.


2020 ◽  
pp. 1-4
Author(s):  
Claudiana M. Pereira ◽  
Rebeca N.A. Figueirôa ◽  
Hudson G.V. Fontenele ◽  
Heloisa S. Miranda

Abstract The Cerrado is a Neotropical savanna where grasses are a major biomass component in the open vegetation physiognomies. Invasive grasses are widely used as pastures in the Cerrado, and their presence may displace native species. The persistence of native grasses relies also on reproduction via seeds, which is often dependent on seeds found buried in the soil seed bank. The literature about the effects of light availability on the germination of Neotropical savanna grasses is scarce, and germination may lead to abnormal seedlings that develop only the root or the shoot. Germination trials that overlook this fact may overestimate the potential for seedling recruitment. Therefore, we tested the effects of light availability on the germination of nine native and two invasive grasses, addressing the production of normal seedlings. Seeds were germinated in the complete absence or the presence of light (12 h photoperiod under white light) for 30 days. Germination was defined as the sum of normal and abnormal seedlings. Eight species were light-dependent, decreasing the production of normal seedlings in the dark. Two native and one invasive species were non-responsive to the dark treatment, showing no change in germination or production of normal seedlings. Our results suggest that seeds buried in the soil seed bank are likely to show reduced germination and develop abnormal seedlings, reinforcing a bottleneck for the recruitment of native grasses. For invasive species, however, the potential of seedling recruitment was minimally reduced by light, suggesting a competitive advantage for the recruitment of these species.


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.


1997 ◽  
Vol 75 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Gary W. Schott ◽  
Steven P. Hamburg

The ability of a grassland to regenerate following disturbance depends on the presence of seeds of native plants and the ability of the seeds to germinate. To examine whether the presence or absence of plant propagules influences reestablishment of tallgrass prairie on abandoned agricultural lands, we sampled the seed rain and soil seed bank across a transition from native tallgrass prairie to unmanaged successional grassland (old field). The native prairie seed rain was seven times greater than that of the old field, richer in species (33 vs. 27), and more diverse (diversity index 0.96 vs. 0.73). In addition, the native tallgrass prairie seed bank was three times as dense as the old-field seed bank and contained the seeds of more species (23 vs. 19), but had a lower index than did the old field (0.81 vs. 1.08). One species, Sphenopholis obtusata, present in the prairie, was observed dispersing to the old-field plot, but was absent in the old-field plot; this observation suggests that at least some species are unable to establish on the old-field plot. Thus, the ability of a native grassland to reestablish may be limited by the dispersal ability of native species and the ability to establish once dispersed. Key words: seed rain, seed bank, native tallgrass prairie, old-field succession.


2022 ◽  
Vol 12 ◽  
Author(s):  
Ryan Tangney ◽  
David J. Merritt ◽  
Ben P. Miller

Changes in fire regimes due to climate change and fire management practices are affecting the timing, length, and distribution of vegetation fires throughout the year. Plant species responses and tolerances to fire differ from season to season and are influenced by species-specific phenological processes. The ability of seeds to tolerate extreme temperatures associated with fire is one of these processes, with survival linked to seed moisture content at the time of exposure. As fire is more often occurring outside historic dry fire seasons, the probability of fire occurring when seeds are hydrated may also be increasing. In this study, we set out to understand the seasonal dynamics of seed hydration for seeds of Banksia woodland species, and how certain seed traits interact with environmental conditions to influence survival of high temperatures associated with fire. We measured the moisture content of seeds buried to 2 cm in the soil seed bank for four common native species and one invasive species on a weekly basis throughout 2017, along with soil moisture content and environmental correlates. We determined water sorption isotherms at 20°C for seeds of each species and used these functions to model weekly variation in seed water activity and predict when seeds are most sensitive to soil heating. Using Generalised additive models (GAMs), we were able to describe approximately 67% of the weekly variance in seed water activity and explored differences in seed hydration dynamics between species. Seed water activity was sufficiently high (i.e., ≥ 0.85 aw) so as to have created an increased risk of mortality if a fire had occurred during an almost continuous period between May and November in the study period (i.e., 2017). There were brief windows when seeds may have been in a dry state during early winter and late spring, and also when they may have been in a wet state during summer and late autumn. These data, and the associated analyses, provide an opportunity to develop approaches to minimize seed mortality during fire and maximize the seed bank response.


2013 ◽  
Vol 6 (1) ◽  
pp. 118-129 ◽  
Author(s):  
Hondo Brisbin ◽  
Andrea Thode ◽  
Matt Brooks ◽  
Karen Weber

AbstractThe continued threat of an invasive, annual brome (Bromus) species in the western United States has created the need for integrated approaches to postfire restoration. Additionally, the high germination rate, high seed production, and seed bank carryover of annual bromes points to the need to assay soil seed banks as part of monitoring programs. We sampled the soil seed bank to help assess the effectiveness of treatments utilizing the herbicide Plateau® (imazapic) and a perennial native seed mix to control annual Bromus species and enhance perennial native plant establishment following a wildfire in Zion National Park, Utah. This study is one of few that have monitored the effects of imazapic and native seeding on a soil seed bank community and the only one that we know of that has done so in a pinyon–juniper woodland. The study made use of untreated, replicated controls, which is not common for seed bank studies. One year posttreatment, Bromus was significantly reduced in plots sprayed with herbicide. By the second year posttreatment, the effects of imazapic were less evident and convergence with the controls was evident. Emergence of seeded species was low for the duration of the study. Dry conditions and possible interactions with imazapic probably contributed to the lack of emergence of seeded native species. The perennial grass sand dropseed outperformed the other species included in the seed mix. We also examined how the treatments affected the soil seed bank community as a whole. We found evidence that the herbicide was reducing several native annual forbs and one nonnative annual forb. However, overall effects on the community were not significant. The results of our study were similar to what others have found in that imazapic is effective in providing a short-term reduction in Bromus density, although it can impact emergence of nontarget species.


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