The role of soil temperature and seed dormancy in the creation and maintenance of persistent seed banks of Nassella trichotoma (serrated tussock) on the Northern Tablelands of New South Wales

2020 ◽  
Vol 42 (2) ◽  
pp. 85
Author(s):  
Annemieke Ruttledge ◽  
Ralph D. B. Whalley ◽  
Gregory Falzon ◽  
David Backhouse ◽  
Brian M. Sindel
Keyword(s):  
Seed Bank ◽  
New South ◽  
Soil Seed Bank ◽  
Seed Banks ◽  
Early Summer ◽  
Secondary Dormancy ◽  
South Wales ◽  
The Creation ◽  
Persistent Soil Seed Bank

A large and persistent soil seed bank characterises many important grass weeds, including Nassella trichotoma (Nees) Hack. ex Arechav. (serrated tussock), a major weed in Australia and other countries. In the present study we examined the effects of constant and alternating temperatures in regulating primary and secondary dormancy and the creation and maintenance of its soil seed bank in northern NSW, Australia. One-month-old seeds were stored at 4, 25°C, 40/10°C and 40°C, in a laboratory, and germination tests were conducted every two weeks. Few seeds germinated following storage at 4°C, compared with seeds stored at 25°C, 40/10°C and 40°C. Nylon bags containing freshly harvested seeds were buried among N. trichotoma stands in early summer, and germination tests conducted following exhumation after each season over the next 12 months. Seeds buried over summer and summer plus autumn had higher germination than seeds buried over summer plus autumn plus winter, but germination increased again in the subsequent spring. Seeds stored for zero, three, six and 12 months at laboratory temperatures were placed on a thermogradient plate with 81 temperature combinations, followed by incubation at constant 25°C of un-germinated seeds. Constant high or low temperatures prolonged primary dormancy or induced secondary dormancy whereas alternating temperatures tended to break dormancy. Few temperature combinations resulted in more than 80% germination.

Seed production and seedling emergence of Giant Parramatta grass on the north coast of New South Wales

1996 ◽  
Vol 36 (3) ◽  
pp. 299 ◽  
Author(s):  
TS Andrews ◽  
RDB Whalley ◽  
CE Jones
Keyword(s):  
Seed Production ◽  
Seed Bank ◽  
New South ◽  
New South Wales ◽  
Seed Banks ◽  
North Coast ◽  
The North ◽  
South Wales ◽  
Seed Fall ◽  
The Impact

Inputs and losses from Giant Parramatta grass [GPG, Sporobolus indicus (L.) R. Br. var. major (Buse) Baaijens] soil seed banks were quantified on the North Coast of New South Wales. Monthly potential seed production and actual seed fall was estimated at Valla during 1991-92. Total potential production was >668 000 seeds/m2 for the season, while seed fall was >146000 seeds/m2. Seed fall >10000 seeds/m2.month was recorded from January until May, with further seed falls recorded in June and July. The impact of seed production on seed banks was assessed by estimating seed banks in the seed production quadrats before and after seed fall. Seed banks in 4 of the 6 sites decreased in year 2, although seed numbers at 1 damp site increased markedly. Defoliation from mid-December until February, April or June prevented seed production, reducing seed banks by 34% over 7 months. Seed banks in undefoliated plots increased by 3300 seeds/m2, although seed fall was estimated at >114 000 seeds/m2. Emergence of GPG seedlings from artificially established and naturally occurring, persistent seed banks was recorded for 3 years from bare and vegetated treatment plots. Sown seeds showed high levels of innate dormancy and only 4% of seeds emerged when sown immediately after collection. Longer storage of seeds after collection resulted in more seedlings emerging. Estimates of persistent seed banks ranged from 1650 to about 21260 seeds/m2. Most seedlings emerged in spring or autumn and this was correlated with rainfall but not with ambient temperatures. Rates of seed bank decline in both bare and vegetated treatment plots was estimated by fitting exponential decay curves to seed bank estimates. Assuming no further seed inputs, it was estimated that it would take about 3 and 5 years, respectively, for seed banks to decline to 150 seeds/m2 in bare and vegetated treatments.

The role of seedbanks in invasions by Hyparrhenia hirta (L.) Stapf in Australia

2019 ◽  
Vol 41 (5) ◽  
pp. 383 ◽  
Author(s):  
Vinod K. Chejara ◽  
Paul Kristiansen ◽  
R. D. B. (Wal) Whalley ◽  
Brian M. Sindel ◽  
Christopher Nadolny
Keyword(s):  
South African ◽  
Seed Production ◽  
Seed Dormancy ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Perennial Grass ◽  
Seed Banks ◽  
Invasive Weed ◽  
South Wales ◽  
Poor Seed

Hyparrhenia hirta (L.) Stapf (also known as Coolatai grass, South African bluestem or thatching grass) has become a serious invasive weed in Australia. Within its native range, it is generally regarded as a useful grass particularly for thatching, and seed production is low with a low soil seed bank of from 2 to 200seedsm–2. Several hundred accessions of H. hirta were deliberately introduced into Australia up until the 1980s and nearly all were discarded because of poor seed production. However, at least one introduction in the 1890s in northern New South Wales (NSW), Australia, has possibly contributed to the present serious weed problem. Annual seed production from roadside stands in northern NSW ranged from 7000 to 92000seedsm–2 in 2015. The soil seed bank under dense H. hirta infestations in the same region in 2006 and 2007, was found to be ~30000seedsm–2 mostly confined to the top 2cm, with few dormant seeds and a large reduction of these numbers over the next 12 months when further seed input was prevented. Similar studies of other perennial grass weeds have found seed banks of similar sizes, but dormancy mechanisms ensure that their seed banks last for at least 10 years without further seed input. These results suggest that the present weedy populations of H. hirta have dramatically increased fecundity enabling a large seed bank to develop beneath dense stands. The development of seed dormancy and consequently a long-lived seed bank would make this weed even more difficult to control. Until seed dormancy develops, control of H. hirta in northern NSW can be effective provided further input into the seed bank can be prevented.

Seed biology implications for the maintenance and establishment of Tetratheca juncea (Tremandraceae), a vulnerable Australian species

2006 ◽  
Vol 54 (1) ◽  
pp. 35 ◽  
Author(s):  
S. M. Bellairs ◽  
F. V. Bartier ◽  
A. J. Gravina ◽  
K. Baker
Keyword(s):  
Seed Bank ◽  
Fire Management ◽  
New South ◽  
Soil Seed Bank ◽  
Seed Viability ◽  
Management Options ◽  
Seed Biology ◽  
South Wales ◽  
Poor Recruitment ◽  
Preliminary Study

Tetratheca juncea Smith is an endemic and vulnerable shrub species with apparently poor recruitment from New South Wales, Australia. Lack of understanding of seed biology limits management options for promoting survival of existing populations and recruitment of new populations. This study investigated the soil seed bank, seed viability, germination and seed dormancy. The plants release seeds in January but no seeds germinated from soil collected near the plants in September 1999, irrespective of the soil being treated by smoke, heat or fire. When sampled again in February 2001, seeds were present in the soil seed bank but were not viable. Viability testing of seeds collected from the plants determined that at least a third of the seeds being produced were viable, even after storage for 6 months. Seed germination and dormancy investigations found that the seeds germinated following exposure to smoke or scarification of the seed coat. Untreated seeds did not germinate during the preliminary study, although a proportion of untreated seeds germinated from a later seed lot. Fire management is important for promoting the survival of this species and the soil seed bank cannot be relied on for re-establishment of populations as the longevity of the soil seed bank seems to be short. Many other species of Tetratheca are also rare or threatened and this study suggests that hand-collected seeds treated with fire-related stimuli may be important for re-establishing those species and that the soil seed bank requires assessment before being relied on as a source of propagules or for maintaining a population.

Psychiatry trainees’ views and educational needs regarding the care of patients with a life-limiting illness

2016 ◽  
Vol 15 (2) ◽  
pp. 231-241 ◽  
Author(s):  
Benjamin C. Forster ◽  
Helen Proskurin ◽  
Brian Kelly ◽  
Melanie R. Lovell ◽  
Ralf Ilchef ◽  
...  
Keyword(s):  
New South ◽  
Psychiatric Morbidity ◽  
Educational Needs ◽  
Physical Illness ◽  
South Wales ◽  
Dying Patients ◽  
Semistructured Interviews ◽  
Case Based Learning ◽  
Psychiatric Intervention

AbstractObjective:People with a life-limiting physical illness experience high rates of significant psychological and psychiatric morbidity. Nevertheless, psychiatrists often report feeling ill-equipped to respond to the psychiatric needs of this population. Our aim was to explore psychiatry trainees’ views and educational needs regarding the care of patients with a life-limiting physical illness.Method:Using semistructured interviews, participants’ opinions were sought on the role of psychiatrists in the care of patients with a life-limiting illness and their caregivers, the challenges faced within the role, and the educational needs involved in providing care for these patients. Interviews were audiotaped, fully transcribed, and then subjected to thematic analysis.Results:A total of 17 psychiatry trainees were recruited through two large psychiatry training networks in New South Wales, Australia. There were contrasting views on the role of psychiatry in life-limiting illness. Some reported that a humanistic, supportive approach including elements of psychotherapy was helpful, even in the absence of a recognizable mental disorder. Those who reported a more biological and clinical stance (with a reliance on pharmacotherapy) tended to have a nihilistic view of psychiatric intervention in this setting. Trainees generally felt ill-prepared to talk to dying patients and felt there was an educational “famine” in this area of psychiatry. They expressed a desire for more training and thought that increased mentorship and case-based learning, including input from palliative care clinicians, would be most helpful.Significance of Results:Participants generally feel unprepared to care for patients with a life-limiting physical illness and have contrasting views on the role of psychiatry in this setting. Targeted education is required for psychiatry trainees in order to equip them to care for these patients.

scholarly journals Similarity between seed bank and herb layer in a natural deciduous temperate lowland forest

2011 ◽  
Vol 79 (2) ◽  
pp. 157-166 ◽  
Author(s):  
Maciej Wódkiewicz ◽  
Anna Justyna Kwiatkowska-Falińska
Keyword(s):  
Seed Bank ◽  
Soil Seed Bank ◽  
Similarity Index ◽  
Seed Banks ◽  
Herb Layer ◽  
Managed Forests ◽  
Lowland Forest ◽  
Soil Seed Banks ◽  
Dominance Structure ◽  
Species Similarity

Forest seed banks mostly studied in managed forests proved to be small, species poor and not reflecting aboveground species composition. Yet studies conducted in undisturbed communities indicate a different seed bank characteristic. Therefore we aimed at describing soil seed bank in an undisturbed forest in a remnant of European lowland temperate forests, the Białowieża Forest. We compared similarity between the herb layer and seed bank, similarity of seed bank between different patches, and dominance structure of species in the herb layer and in the seed bank of two related oak-hornbeam communities. We report relatively high values of Sorensen species similarity index between herb layer and seed bank of both patches. This suggests higher species similarity of the herb layer and soil seed bank in natural, unmanaged forests represented by both plots than in fragmented communities influenced by man. Although there was a set of core seed bank species present at both plots, yielding high Sorensen species similarity index values, considerable differences between plots in seed bank size and dominance structure of species were found, indicating spatial variability of studied seed bank generated by edaphic conditions. Dominance structure of species in the herb layer was not reflected in the underlying seed bank. This stresses, that natural forest regeneration cannot rely only on the seed bank, although some forest species are capable of forming soil seed banks. While forest seed banks may not reflect vegetation composition of past successional stages, they may inform on history and land use of a specific plot.

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