Distribution of the Soil Seedbank and Influence of Fire on Seedling Emergence in Acacia saligna Growing on the Central Coast of New South Wales

1998 ◽  
Vol 46 (6) ◽  
pp. 743 ◽  
Author(s):  
M. G. Tozer
Keyword(s):  
New South ◽  
Seedling Emergence ◽  
New South Wales ◽  
Soil Surface ◽  
Seed Density ◽  
Acacia Saligna ◽  
Seedling Mortality ◽  
Central Coast ◽  
Seed Mortality ◽  
South Wales

The distribution of seed in the soil and its response to simulated fires were examined in a population of Acacia saligna (Labill.) H.L.Wendl. on the central coast of New South Wales (NSW). Soil seed density was measured by excavating and sieving soil samples, and was estimated to be 1389 ± 297 seeds m–2 and 3600 ± 279 seeds m–2 at two sites within the population. Seed density declined with depth, with 80% of the seedbank located in the upper 6 cm of soil. The passage of fire was simulated by heating the soil surface with a propane burner over an area of 0.25 m2 for durations of 2 or 4 min. A large percentage (88–94%) of the seedbank remained dormant following heating. Temperatures measured in the soil during heating showed that the 4-min treatment approximated the level of soil heating expected during a fire in which all fine ground fuel was consumed; therefore, the seedbank of A. saligna is unlikely to be significantly depleted following a single fire. A frequency distribution of the depths from which seedlings emerged was constructed using measurements of the distance between the soil surface and the hypocotyl–radical junction. A zone of lower than expected seedling emergence occurred from 0–2 cm, but the depth of this zone was not consistent with seed mortality due to excessive heating. Reduced emergence from 0–2 cm may be the result of seedling mortality due to temperature or water stress, which may be influenced by changes in the soil structure or chemistry caused by heating.

Effects of depth and time of sowing on emergence of Danthonia richardsonii Cashmore and Danthonia linkii Kunth

1993 ◽  
Vol 44 (6) ◽  
pp. 1311 ◽  
Author(s):  
GM Lodge ◽  
AJ Schipp
Keyword(s):  
New South ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Maximum Temperature ◽  
Sowing Time ◽  
Sand Mixture ◽  
South Wales ◽  
Seed Field ◽  
Dry Conditions ◽  
Soil Temperatures

Two experiments examined the effects of sowing time and depth (surface and 10, 25, 50 mm) on emergence of Danthonia richardsonii Cashmore and Danthonia linkii Kunth. Experiment 1 was conducted from January to December 1990 on a loam/sand mixture in boxes. Emergence was highest in both species for seeds sown onto the soil surface in summer and autumn (P < 0.05). Sowing at any depth at any time of the year, or surface sowing in winter and spring, markedly reduced emergence. Experiment 2 was conducted in the field at Tamworth, northern New South Wales from September 1991 to August 1992, on a red brown earth and a black earth. This study confirmed that emergence in both species was highest from surface sown seed. Field emergence was lowest in winter, but in contrast to experiment 1, it was higher in spring, particularly on the black earth. Seedling emergence appeared to be related to mean maximum temperature, decreasing in winter as it declined below 20�C, and increasing in spring when it was greater than 23�C. Differences in seed weight were reflected in emergence of D. richardsonii and D. linkii in experiment 1. Similar emergence was recorded for the loamlsand mixture and sand, indicating that there was little effect of texture. Phalaris aquatica L. cv. Sirosa surface sown in December had lower emergence ( P < 0.05) than both Danthonia spp., but emergence of this larger seeded cultivar was higher at depths of 10 and 25 mm. Laboratory studies to determine reasons for the low emergence of D. richardsonii and D. linkii from depth, indicated that neither had an obligate light requirement for germination. Depth, however, reduced germination (P < 0.05) compared with surface sowing of seed. Seedlings at depth also were observed to have slower rates of shoot and root elongation. In the field, the most successful establishments of D. richardsonii and D. linkii seedlings are likely to occur from surface sowings in April and May. Sowing in spring may also be possible if mean maximum soil temperatures exceed 23�C, and seedlings can establish before the onset of hot, dry conditions in summer.

Notes on the Birds of the Central Coast Area of New South Wales

1962 ◽  
Vol 61 (4) ◽  
pp. 295-300 ◽  
Author(s):  
J. N. Hobbs ◽  
M. Kaveney
Keyword(s):  
New South ◽  
New South Wales ◽  
Central Coast ◽  
South Wales

Some investigations into soil and vegetation relationships associated with alkaline-saline soil surfaces in the Walcha area, Northern Tablelands, New South Wales

1995 ◽  
Vol 46 (1) ◽  
pp. 209 ◽  
Author(s):  
KH Kreeb ◽  
RDB Whalley ◽  
JL Charley
Keyword(s):  
Cynodon Dactylon ◽  
New South ◽  
New South Wales ◽  
Soil Surface ◽  
Tree Planting ◽  
Soil Parameters ◽  
Alkali Cations ◽  
Grazing Land ◽  
South Wales ◽  
Wide Range

The characteristics of the soil, vegetation and groundwater at a dryland salinity site on Miramoona, a property near Walcha on the Northern Tablelands of New South Wales, were investigated. Soil parameters measured at 23 points along a 200 m transect were highly correlated with the pattern of vegetation. Of overriding significance was soil pH, which varied from a high of over 10 on bare areas delineated by Critesion marinum and Cynodon dactylon to a low of less than 5 on grazing land supporting the growth of a wide range of pasture species. The bare areas were characterized by alkalinity. While they were sodic at all depths measured, they were only marginally saline and then only at the soil surface. The chemical composition of the groundwater collected from three piezometer tubes varied quite markedly over the site. It is hypothesized that the presence of alkaline bare areas on the Northern Tablelands is not a new problem, but rather the natural result of alternating wet and dry periods which have induced accumulation of carbonates and bicarbonates of the alkali cations, notably sodium. Drainage of the original perched swamps by the early landholders, tree clearing and the grazing of domestic livestock would have accelerated the process since European settlement. However, tree planting would appear unlikely to have any impact on the reclamation process in the short term. A more viable option would be the recreation of the original swamps in suitable situations, although this solution would create problems for grazing management.

Saccocirridae (Annelida : Archiannelida) from the central coast of New South Wales

1981 ◽  
Vol 32 (3) ◽  
pp. 439 ◽  
Author(s):  
R Brown
Keyword(s):  
World Wide ◽  
New South ◽  
New South Wales ◽  
Ventral Surface ◽  
The Body ◽  
Coarse Grained ◽  
Pacific Region ◽  
Central Coast ◽  
South Wales ◽  
Turbulent Water

Saccocirrids (archiannelids) were collected from coarse-grained sediments in turbulent water from the central New South Wales coast. Saccocirrus jouinae, sp. nov., and S. tridentiger, sp, nov., are described, and S. krusadensis Alikunhi, 1948 newly recorded in Australia. In these species gonads occur only on the left side of the body and cilia are found on the ventral surface. Of the 17 species attributed to the Saccocirridae, seven species are known to have unilateral gonads and ventral ciliation. They occur only in the Indo-Pacific region. Species with gonads on both sides of the body have not been described with cilia on the ventral surface. Their distribution is world-wide.

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.

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