scholarly journals Simulating the effect of environmental flow duration on seedling emergence from riparian seed banks of the Upper Hunter River, New South Wales

2018 ◽  
Vol 36 (4) ◽  
pp. 607-619 ◽  
Author(s):  
Luke Stone ◽  
Kirstie Fryirs ◽  
Michelle Leishman
Keyword(s):  
New South ◽  
Seedling Emergence ◽  
New South Wales ◽  
Seed Banks ◽  
Environmental Flow ◽  
Flow Duration ◽  
South Wales

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.

Ecology of Nassella neesiana, Chilean needle grass, in pastures on the Northern Tablelands of New South Wales. II. Seedbank dynamics, seed germination, and seedling recruitment

2003 ◽  
Vol 54 (6) ◽  
pp. 621 ◽  
Author(s):  
M. R. Gardener ◽  
R. D. B. Whalley ◽  
B. M. Sindel
Keyword(s):  
Seed Production ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
New South ◽  
Seedling Emergence ◽  
New South Wales ◽  
Separate Experiment ◽  
Bare Ground ◽  
Total Percentage ◽  
South Wales

This is the second in a series of papers investigating the ecology of Nassella neesiana (Trin. & Rupr.) Barkworth (Chilean needle grass) in pastures on the Northern Tablelands of New South Wales. The reasons for its success as a pasture weed are discussed. Nassella neesiana has a large and persistent soil seedbank. After 3 years without seed input, the seedbank declined from 4676 to 1323 seeds/m2. When an exponential decay curve was fitted to the data it was predicted that the seedbank would reach 10 seeds/m2 after 12.4 years. When seed production was large in 1996, 41.6% of seeds produced were incorporated into the seedbank, whereas in 1995 and 1997 the smaller seed production was only sufficient to maintain seedbank numbers. Furthermore, it is likely that the seedbank numbers were underestimated because they did not include basal cleistogenes. In a separate experiment, basal cleistogenes were found to contribute a further 20% to the seedbank.A small proportion of the viable seeds in a natural seedbank emerged from bare ground over 2 years. Seedling survival was high, with 78% of those germinating from bare ground surviving for at least 20 months. Several experiments were designed to investigate the mechanisms of this germination and survival. It appears that the seeds of N. neesiana have an after-ripening requirement of between 3 months and 1 year for maximum germination. Lemma removal from seeds stored for 8 months increased germination from 49 to 82%. The rate of germination and the total percentage of seeds germinating also increased with time of burial in the ground. Of seeds that had been buried for 2 years, 90% germinated after laboratory incubation compared with 48% of seeds stored in the laboratory as controls. Depth of seed burial appears to affect seedling emergence and survival. A smaller number of seedlings emerged from 0–10 mm and they had lower survival than those from seed buried at 10–20 mm.

Seedling emergence and survival of annual pasture legumes in northern New South Wales

1996 ◽  
Vol 47 (4) ◽  
pp. 559 ◽  
Author(s):  
GM Lodge
Keyword(s):  
New South ◽  
Seedling Emergence ◽  
New South Wales ◽  
Survival Rates ◽  
Trifolium Subterraneum ◽  
Survival Curves ◽  
Vicia Villosa ◽  
Pasture Legumes ◽  
South Wales ◽  
Seedling Emergence And Survival

Seedling emergence and survival of 15 annual pasture legumes was studied in the field at Tamworth, northern New South Wales. Emergence was measured in permanent quadrats (0.09 m2) in covered and uncovered areas approximately every 15 days from 30 November 1983 to 30 November 1984. Survival of seedlings was estimated from 15 December 1983 to 31 August 1984, before plants senesced. Emergence was generally highest in summer and autumn following seed set and lowest in winter and spring. Two legumes, Medicago scutellata cv. Sava and Trifolium subterraneum cv. Seaton Park, had high emergence in winter (mid July). Total seedling emergence was highest ( P < 0.05) in covered areas of cv. Seaton Park and uncovered areas of T. hirtum cv. Hykon. All T. subterraneum cultivars, M. minima, Astragalus hamosus cv. Ioman, Vicia villosa cv. Namoi, and M. truncatula cv. Paraggio had higher total emergence in covered compared with uncovered areas. In contrast, total emergence of M. aculeata, M. truncatula cv. Jemalong, Sava, and Hykon was lowest in covered areas. Cover had little effect on the total emergence of M. truncatula cv. Sephi and T. glomeratum. Of the 7700 individual seedlings marked from November 1983 to August 1984, a mean of only 31% (covered) and 41% (uncovered) survived until 31 August 1984. For each emergence time, highest ( P < 0.05) survival rate coincided with the highest (P < 0.05) number of emerged seedlings in 4 of the legumes in covered areas (cv. Namoi, 31 January; cv. Ioman, 31 March; cv. Hykon, 15 April; cv. Sava, 15 July; Table 4) and 9 in uncovered areas (cvv. Nungarin, Seaton Park, and Namoi, 31 January; M. aculeata and cv. Sephi, 28 February; cvv. Jemalong and Ioman, 31 March; T. glomeratum, 15 April; cv. Sava, 15 July). In all other legumes there was no optimum time for emergence, since the highest (P < 0.05) survival rates were associated with seedling survivals <50%. Generally, survival curves with a mortality constant rather than a mortality rate were a better fit ( P < 0.05) for most legumes and times. This implied that these survival curves were determined at the time of recruitment, and declined at a constant rate, despite below-average post-emergence rainfall in May-June. Low rates of survival at times of highest ( P < 0.05) emergence indicated that there may have been some density-dependent regulation in some of the legumes.

Emergence and early seedling growth of Phalaris tuberosa

1969 ◽  
Vol 9 (39) ◽  
pp. 422 ◽  
Author(s):  
A Lazenby ◽  
JMA Schiller
Keyword(s):  
Seedling Growth ◽  
New South ◽  
Seedling Emergence ◽  
New South Wales ◽  
Hydrogen Phosphate ◽  
Early Seedling Growth ◽  
South Wales ◽  
Early Seedling ◽  
Red Earth ◽  
Made In

A study was made in seed boxes at Armidale, New South Wales, on a red earth soil, of the effects of two soil tilths (particles<0.3 cm and between 0.6 and 1.25 cm), three seeding depths (surface seeding, 1.25 cm and 2.5 cm), and three levels of applied phosphorus (the equivalents of phosphorus in nil, 378 kg/ha and 756 kg/ha superphosphate, applied as sodium di-hydrogen phosphate) on emergence and early seedling growth of Phalaris tuberosa. Water was made non-limiting as far as practicable. Seedling counts were made every four days until the first harvest, 32 days after sowing. Four fortnightly destructive harvests were made to examine treatment effects on post-emergence seedling growth. Seeding into the fine tilth at a depth of 1.25 cm on the high phosphorus treatment gave the fastest and highest total seedling emergence. Conditions most favourable to immediate post-emergence seedling growth were sowing into a fine seedbed at a depth of 1.25 cm or 2.5 cm in combination with phosphorus ; the rate of seedling growth increased with rate of phosphorus applied.

Charophyte Occurrence, Seed Banks and Establishment in Farm Dams in New South Wales

1999 ◽  
Vol 47 (3) ◽  
pp. 437 ◽  
Author(s):  
Michelle T. Casanova ◽  
Margaret A. Brock
Keyword(s):  
New South ◽  
New South Wales ◽  
Water Clarity ◽  
High Water ◽  
Seed Banks ◽  
Water Bodies ◽  
Dissolved Phosphorus ◽  
South Wales ◽  
High Turbidity ◽  
Chara Australis

Farm dams are an important and common water resource in rural Australia. They provide relatively permanent surface water for stock and wildlife. They typically have high turbidity and high levels of disturbance by stock. The occurrence of charophytes in these water bodies was examined, as well as the conditions under which they germinated and established. Charophytes were found in 15% of 65 farm dams surveyed in two regions in New South Wales, Australia. However, charophytes germinated from 64.5% of farm dam seed banks sampled (n = 17). Species found were Chara australis R.Br., C. fibrosa Agardh ex Bruzelius, C. globularis Thuillier, C. muelleri A.Br., Nitella cristata A.Br. and N. tasmanica A.Br. Farm dams in which charophytes were found both in the survey and in the seed bank had lower turbidity, lower dissolved phosphorus levels and more extensive submerged plant communities than average. Charophytes established from the seed banks under experimentally induced water regimes when high water clarity was maintained and the disturbance of stock grazing was removed. Farm dams can support populations of perennial and annual charophyte species, and provide a habitat that is less available in naturally occurring shallow water bodies of the regions.

The influence of fire and rainfall upon seedling recruitment in sand-mass (wallum) heathland of north-eastern New South Wales

2004 ◽  
Vol 52 (1) ◽  
pp. 93 ◽  
Author(s):  
S. J. Griffith ◽  
C. Bale ◽  
P. Adam
Keyword(s):  
Field Experiments ◽  
Seedling Recruitment ◽  
New South ◽  
Seedling Emergence ◽  
New South Wales ◽  
Temporal Trends ◽  
Plant Resource ◽  
South Wales ◽  
Fire Environment ◽  
North Eastern

Wallum heathland is extensive on coastal sand masses in north-eastern New South Wales and south-eastern Queensland. Here the climate is subtropical, although monthly rainfall is highly variable and unreliable. We examined the influence of fire and rainfall on seedling recruitment in bradysporous dry-heathland [Banksia aemula R.Br., Melaleuca nodosa (Sol. ex Gaertn.) Sm.] and wet-heathland [Banksia oblongifolia Cav., B.�ericifolia L.f. subsp. macrantha (A.S.George) A.S.George, Leptospermum liversidgei R.T.Baker and H.G. Sm.] species. Two specific questions were addressed: (1) do elevated levels of soil moisture facilitate seedling recruitment; (2) is the post-fire environment superior for seedling recruitment? Field experiments demonstrated that heathland species studied here are capable of successful recruitment in atypical habitat, and this proceeds irrespective of fire and unreliable rainfall. Conditions for growth and reproduction were found to be adequate if not more favourable in dry heathland, and this outcome included species usually associated with wet heathland. Spatial and temporal trends in seedling emergence and survival were examined in relation to post-fire predation and plant resource availability. Existing ideas about wallum management and conservation are evaluated, in particular the role of fire.

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