Influence of panicle fragment size on ant seed-harvesting and seedling recruitment in Phalaris aquatica

2002 ◽  
Vol 42 (5) ◽  
pp. 571 ◽  
Author(s):  
W. M. Kelman ◽  
G. M. Lodge ◽  
R. A. Culvenor
Keyword(s):  
Seedling Recruitment ◽  
Fragment Size ◽  
New South ◽  
New South Wales ◽  
Sheep Grazing ◽  
Phalaris Aquatica ◽  
South Wales ◽  
Naked Seed ◽  
Seed Harvesting ◽  
Second Year

Successful seedling recruitment events in sparse stands of the grass Phalaris aquatica (phalaris) are rare. A major contributing factor to this situation is the seed-harvesting activity of ants. In recently developed cultivars of phalaris, the seed is retained within the glumes of the floret and is shed in a seed-retaining panicle fragment. We tested the hypothesis that seed contained in panicle fragments was less likely to be harvested by ants than naked seed and that this would be reflected in increased seedling recruitment. Observations of ant seed-harvesting activity and records of seedling recruitment following dispersal of seed and panicle fragments onto field plots were made at Canberra, Australian Capital Territory, and Tamworth, New South Wales, over 2 years. In the second year, the effects of 2 pasture renovation treatments (sheep-grazing and shallow-discing) on seedling recruitment from seed and panicle fragments were examined. Averaged over the 2 localities, 4% of large-sized (>10�florets), 13% of medium-sized (5-10 florets) and 27% of the small-sized (2 or 3 florets) panicle fragments were harvested in a 24 h period by ants (mainly Pheidole spp.), compared with 83% of the naked phalaris seed. The effects of panicle fragment size on recruitment were variable depending on site in the first year and the interaction of site and renovation treatments in the second year, but contrary to expectation, recruitment often was not higher in panicle fragment treatments than in seeded treatments. Seedling recruitment at Canberra (a hardsetting sandy loam) was lower (22 plants/m2 from naked seed and 15 plants/m2 from seed in panicle fragments) because of the competition from existing vegetation and germination of subterranean clover from the seedbank, than at Tamworth (a self-mulching red chromosol; 179 plants/m2 from naked seed and 118 plants/m2 from seed in panicle fragments), where seedling recruitment was also significantly increased by the sheep-grazing renovation treatment. At Tamworth, a larger seedbank was recovered from plots of oversown panicle fragments compared with plots oversown with naked phalaris seed. This suggested that protection of seeds in panicle fragments over the summer months on the Tablelands of New South Wales would increase the time over which phalaris seeds are available for recruitment. Further work is needed to test seedling recruitment in panicle shattering v. non-shattering phalaris populations and to define the conditions under which the seedbank contained in the panicle fragments can be exploited to improve stand persistence.

Establishing surface-sown pastures in a Poa labillardieri-Themeda australis association

1986 ◽  
Vol 26 (3) ◽  
pp. 331 ◽  
Author(s):  
MH Campbell ◽  
MJ Keys ◽  
RD Murison ◽  
JJ Dellow
Keyword(s):  
Festuca Arundinacea ◽  
New South ◽  
New South Wales ◽  
Ground Cover ◽  
Cost Effective ◽  
Phalaris Aquatica ◽  
South Wales ◽  
Before And After

The effects of time and rate of application of glyphosate, 2,2-DPA and tetrapion on Poa labillardieri and Themeda australis were measured in seven experiments carried out 55 km south of Braidwood, on the southern tablelands of New South Wales between 1980 and 1982. In an eighth experiment (1981) and in a 35-ha demonstration (1983), at the same site, the effects of applying herbicides (before and after the autumn break) and surface-sowing Phalaris aquatica, Festuca arundinacea and Trifiolium repens with fertiliser on the control of P. labillardieri were ascertained. All three herbicides proved effective in reducing the ground cover of P. labillardieri from applications at any time of the year. For T. australis, tetrapion proved effective when applied at any time of the year, while glyphosate and 2,2-DPA were effective in all seasons except winter. Glyphosate at rates between 0.72 and 1.44 kg/ha a.i. was more cost effective than 2,2-DPA (11.1 kg/ha a.i.) and tetrapion (3.75 kg/ha a.i.). Best establishment and development of sown grasses and legumes was attained by applying herbicides after the autumn break but before heavy frosts, and then surface-sowing 1-3 months later. Control of P. labillardieri was best where P. aquatica and F. arundinacea established most densely.

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.

Water consumption and water turnover of sheep grazing semiarid pasture communities in New South Wales

1974 ◽  
Vol 25 (2) ◽  
pp. 339 ◽  
Author(s):  
AD Wilson
Keyword(s):  
Water Consumption ◽  
Mineral Content ◽  
New South ◽  
New South Wales ◽  
Supplementary Data ◽  
Sheep Grazing ◽  
Water Turnover ◽  
Merino Sheep ◽  
South Wales ◽  
Reduced Water

The water consumption and water turnover of Merino sheep grazing on three natural pastures of south-western New South Wales were recorded throughout 1 year, and supplementary data on the water consumption of sheep on some pastures were collected for a further 2–4 years. On Danthonia caespitosa grassland, water was consumed for up to 7 months each year over the summer months. Maximum intakes were 3–3.5 litres per sheep per day, but this was reduced for 1–2 weeks after falls of rain of less than 25 mm and for longer periods after heavier falls. The provision of shade reduced water turnover by a maximum of 0.3–0.5 litre per day on some occasions only, which indicates that shade is of little importance to woolled sheep. On the saltbush (Atriplex vesicaria) and belah-rosewood (Casuarina cristata-Heterodendrum oleifolium) communities, water intakes were up to 6–7 litres per day in summer. In the particularly dry summer of 1972–73, water intakes of the sheep on saltbush rose to 12 litres per day for several months. The higher water intakes of these sheep were attributed mainly to the high mineral content of the Atriplex and Bassia spp. eaten by them, although the sheep on the belah-rosewood community were also in a hotter environment. In contrast to the sheep on Danthonia, those on the bush communities consumed significant amounts of water throughout the winter in years of low rainfall.

Use of herbicides for selective removal of Eragrostis curvula (Schrad.) Nees from a Phalaris aquatica pasture

1985 ◽  
Vol 25 (3) ◽  
pp. 665 ◽  
Author(s):  
MH Campbell ◽  
JJ Dellow ◽  
MJ Keys ◽  
AR Gilmour
Keyword(s):  
Maximum Rate ◽  
New South ◽  
New South Wales ◽  
Ground Cover ◽  
Trifolium Subterraneum ◽  
Selective Removal ◽  
Main Experiment ◽  
Phalaris Aquatica ◽  
Eragrostis Curvula ◽  
South Wales

In the main experiment, the effectiveness of tetrapion, glyphosate and 2,2-DPA in selectively removing Eragrostis curvula from a Phalaris aquatica pasture was determined by applying each at three rates in July 1980, September 1980, December 1980 and March 1981 near Braidwood, New South Wales. Auxiliary experiments were conducted from April 1981 to April 1983 to determine the reliability of herbicide effect on E. curvula. Tetrapion (2.25 and 3.375 kg/ha a.i.) was the most effective herbicide in killing E. curvula and promoting P. aquatica and Trifolium subterraneum. It was more selective when applied in September 1980 and December 1980 than when applied in July 1980 or March 198 1. Re-infestation by E. curvula seedlings in the 3 years after spraying with tetrapion amounted to a maximum of 3% of ground cover. In the auxiliary experiments, tetrapion was effective on all nine occasions of application, which demonstrated its reliability and effectiveness at any time of the year. Glyphosate (1.08 and 1.62 kg/ha a.i.) was effective in killing E. curvula in March 1981 but this result could not be repeated in March 1982 or March 1983 or in nine other applications at other times in these years. 2,2-DPA (maximum rate 22.2 kg/ha a.i.) was ineffective in killing E. curvula at four times of application. Recovery of the P. aquatica pasture after treatment declined in the order: tetrapion >2,2-DPA>glyphosate.

Studies of soil seedbanks in native and sown pastures in northern New South Wales

2001 ◽  
Vol 23 (2) ◽  
pp. 204 ◽  
Author(s):  
G. M. Lodge
Keyword(s):  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Subterranean Clover ◽  
Summer Rainfall ◽  
Perennial Grasses ◽  
Soil Core ◽  
Phalaris Aquatica ◽  
South Wales ◽  
Native Pasture

Total and germinable soil seedbanks (litter and soil) were studied for a native pasture and three sown pastures (dominated by Phalaris aquatica L. cv. Sirosa) in northern New South Wales from 1993 to 1996. Soil core samples were taken from continuously grazed plots for both pasture types and two oversown treatments in the native pasture and from a spring-autumn rest treatment at the sown pasture sites. At each site above ground herbage mass was also estimated regularly as part of the Temperate Pasture Sustainability Key Program. For all sites and treatments, the proportion of germinable seeds as a percentage of the total (dormant and germinable) seedbank ranged from 1–26% for the native pasture and 1–39% for the sown pastures. Germinable seed numbers ranged from 280 to 26,110 seeds per m2, while total seedbank numbers were from 6700 to 178,360 seeds per m2. Native pasture herbage mass was dominated by native perennial grasses, but seeds of these species were less than 20% of the total seed bank in all treatments in 1994 and 1995. At the sown pasture sites, most of the germinable (51–92%) and total (65–97%) seedbanks were either barnyard grass (Echinochloa crus-galli (L.) Beauv, annual ryegrass (Lolium rigidum Gaudin), subterranean clover (Trifolium subterraneum L.) or wireweed (Polygonum aviculare L.). Since seeds of annuals and other forbs generally dominated both the total and germinable seedbanks of these perennial grass-based pastures, these species were likely to increase over time. Seeds of the sown perennial grass Phalaris aquatica L, cv. Sirosa were less than 1% of the total seedbanks in pastures sown in 1990 and less than 3% of those sown in 1979. With above average summer rainfall at the native pasture site in 1996 and prolific growth of redgrass, seeds of this species were 38–63% of the total and 11–29% of the germinable seedbank in May 1996. Except at this site and time, the species composition of the total and germinable seedbanks did not generally reflect the dominance of the above ground herbage mass of these pastures by perennial grasses.

Incidence of Phomopsis phaseoli (Desm.) Sacc. in crops and seed of soybean in New South Wales

1987 ◽  
Vol 27 (2) ◽  
pp. 317
Author(s):  
GE Stovold ◽  
A Francis
Keyword(s):  
Climatic Factors ◽  
New South ◽  
New South Wales ◽  
First Year ◽  
North West ◽  
The North ◽  
South Wales ◽  
Second Year ◽  
Phomopsis Phaseoli ◽  
Harvest Maturity

The pod and stem blight and seed decay fungus Phomopsis phaseoli was detected in soybean crops in coastal districts of New South Wales as a symptomless infection in the lowest petioles at flowering. Up to 90% of petioles from a second year crop yielded the fungus compared with 17% from a first year crop. Similar effects of paddock history were evident during pod fill when 43% of pods from a first year crop were infected compared with 76% in a second year crop. Visible symptoms of infection only appeared after crops reached harvest maturity. Crops in the North West of the state were infected at a much lower level. As in coastal districts the highest levels of infection occurred in fields which had been sown previously to soybeans. Only negligible levels of infection were detected in crops grown in the Riverina district. Only seed from coastal crops carried significant infection with P. phaseoli. The level of infection varied within and between seasons and was determined by prevailing climatic factors, especially atmospheric humidity and rainfall during pod fill and after maturity. Humidity and rainfall are greater for coastal than for inland districts, but prevailing temperatures in coastal and inland districts are only slightly different.

Establishment and Survival of Pasture Grasses Surface-Sown Into Wheat Stubble in North-Western New South Wales.

1995 ◽  
Vol 17 (1) ◽  
pp. 37 ◽  
Author(s):  
MH Campbell ◽  
AM Bowman ◽  
WD Bellotti ◽  
JJ Friend ◽  
HI Nicol
Keyword(s):  
Plant Density ◽  
Seedling Recruitment ◽  
New South ◽  
New South Wales ◽  
Climatic Conditions ◽  
Factors Affecting ◽  
South Wales ◽  
Pasture Grasses ◽  
Order Of Magnitude ◽  
Wheat Stubble

In four experiments near Walgett, New South Wales, between 1987 and 1990, the establishment and survival of Astrebla lappacea, Setaria incrassata, Panicurn coloraturn var. rnakarikariense and Cenchrus ciliaris were determined when surface-sown into low, reduced or heavy stubble just before or after harvesting wheat (November or December). Despite external deleterious factors affecting three experiments, grasses established in the first six months after sowing in all experiments unde; above average rainfall. Best establishment (8 to 31 plants/m2 in the 1990 experiment) occurred in response to 166 mm in 12 rain days over a 29 day period in December-January 1990-91, followed by 10 dry days and then a further 60 mm of rain in February; plants flowered by May and thus survived winter well. Under non-flood conditions (1987, 1988 and 1990 experiments) the order of magnitude of establishment was: C. ciliaris, A. lappacea > S. incrassata > P. coloraturn. Under flood conditions (1989 experiment) establishment of S. incrassata was highest and that of A. lappacca was lowest. In the 1987 and 1988 experiments full stubble (1.5 and 3.4 t/ha) did not improve the establishment of surface-sown grasses over that on low stubble (0.1 and 1.4 tlha). In the 1989 and 1990 experiments establishment was lower on full stubble (5 and 7 tlha) than on low stubble (0.1 and 0.1 tlha) owing to, respectively, flooding and competition from volunteer wheat. After the six months establishment period grass density declined over the two to five year survival period with plants self- thinning due to interspecific competition. Allowing mature plants to seed increased plant density due to seedling recruitment under favourable climatic conditions.

Fire Studies in Mallee (Eucalyptus Spp.) Communities of Western New South Wales: Grass Fuel Dynamics and Associated Weather Patterns.

1993 ◽  
Vol 15 (2) ◽  
pp. 270 ◽  
Author(s):  
JC Noble ◽  
RG Vines
Keyword(s):  
Seedling Recruitment ◽  
New South ◽  
New South Wales ◽  
Field Studies ◽  
Major Elements ◽  
Rainfall Data ◽  
Rainfall Regime ◽  
Balance Study ◽  
South Wales ◽  
Average Rainfall

The probability of wildfires, or prescribed fires, occurring in mallee rangelands, is strongly dependent on availability of adequate grass fuel loads. Grass fuels comprise two major elements, a perennial component dominated by the hummock species Triodia scariosa (porcupine grass) and an ephemeral component dominated by the annual/biemial tussock species Stipa nitida (speargrass). Population dynamics and abundance of both fuel elements are, in turn, strongly influenced by rainfall regime, particularly during the seedling recruitment phase. This paper records data on the spatial distributions of different fuels, plant architecture and post-fire seedling recruitment and survivorship of T. scariosa, obtained during field studies on contrasting mallee sites in western New South Wales. In addition, rainfall data extending over c. 100 years were used in a water balance study at one mallee site (Pooncarie); while similar rainfall data were analysed for three mallee sites (Pooncarie, Ivanhoe and Mount Hope) using a filter technique to examine quasi- periodicities of rainfall and potential correlations with known wildfire seasons in the past. Precipitation records from the Meteorological Districts of western New South Wales, and from various towns in the area, were analysed as well. All data sets exhibited strong coherence and the resulting filter curves resembled each other closely, with peaks reflecting 'above-average rainfall' and troughs 'below-average rainfall or drought'- the latter often being associated with El NiiiolSouthern Oscillation events. The management implications of these phenomena, particularly as they relate to major drought events, are discussed in the context of vegetation manipulation based on prescribed fire.

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.

Eragrostis curvula (Schrad.) Nees. complex pastures in southern New South Wales, Australia: a comparison with Medicago sativa L. and Phalaris aquatica L. pastures under rotational grazing

2005 ◽  
Vol 45 (4) ◽  
pp. 401 ◽  
Author(s):  
W. H. Johnston ◽  
P. S. Cornish ◽  
V. F. Shoemark
Keyword(s):  
Medicago Sativa ◽  
New South ◽  
New South Wales ◽  
The Other ◽  
Wagga Wagga ◽  
Rotational Grazing ◽  
Phalaris Aquatica ◽  
Eragrostis Curvula ◽  
South Wales ◽  
Wide Range

A grazing experiment conducted in Wagga Wagga (New South Wales) from September 1993 to September 1998 compared the productivity of pastures containing 3 palatable types of summer-active Eragrostis curvula complex, with pastures containing either Medicago sativa or Phalaris aquatica. Issues relating to the management of E. curvula pastures were also investigated. Herbage growth rates of the P. aquatica and M. sativa pastures were highest in winter and spring; E. curvula pastures were most productive in summer and autumn. Stocking rates equivalent to 30–40 dry sheep were carried by the pastures during their growing seasons. Throughout the study, the pastures were dominated by their respective sown perennial species, however, a suite of desirable and undesirable annual grasses and annual legumes usually contributed >20% of total herbage mass in spring. The P. aquatica pasture contained a higher proportion of weedy species than the other pastures, especially C4 grasses and broadleafed species, and towards the end of the experiment it was also invaded by several native perennial grasses. Overall, the wool yield from the M. sativa pasture was 0.5–1.0 kg/animal.year higher than the other pastures. Management to minimise herbage accumulation on the E. curvula pastures was a key issue, and provided that pastures were grazed heavily, this was achieved by the rotational grazing strategy used in the experiment. It was concluded that palatable varieties of E. curvula have a useful and complementary role as perennial pastures in southern Australia. By increasing herbage availability in summer and autumn, E. curvula may improve management flexibility for a wide range of pastures that are commonly grown on farms.

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