Assessing the impact of drought and forestry on streamflows in south-eastern Australia using a physically based hydrological model

Abstract. We examine the patterns of germination response to fire in the fire-prone flora of the Sydney basin, south-eastern Australia, using examples from several decades of research. The flora shows a strong response to fire-related germination cues. Most species show an interaction between heat and smoke, a number respond only to heat, whilst a few are likely to respond only to smoke. Many recruit in the first 12 months after fire and show no obvious seasonal patterns of recruitment, whilst several species have a strong seasonal germination requirement, even in this essentially aseasonal rainfall region. Key challenges remaining include designing future seed germination studies within the context of informing the germination response surface to smoke and heat interactions, and incorporation of the impact of varying soil moisture on seed germination post-fire, including its affect on resetting of seed dormancy. An understanding of the resilience of species to frequent fire also requires further work, to identify species and functional types most at risk. This work must ideally be integrated within the framework of the management of fire regimes that will change under a changing climate. We suggest that the functional classification of plant types in relation to fire could be enhanced by a consideration of both the type of germination response to fire (type of cues required) and the timing of the response (seasonally driven in response to seed dormancy characteristics, or independent of season). We provide a simplified version of such an addition to functional trait classification in relation to fire.

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Crop damage caused by residual acetolactate synthase herbicides in the soils of south-eastern Australia

Australian Journal of Experimental Agriculture ◽

10.1071/ea05053 ◽

2006 ◽

Vol 46 (10) ◽

pp. 1323 ◽

Cited By ~ 9

Author(s):

K. L. Hollaway ◽

R. S. Kookana ◽

D. M. Noy ◽

J. G. Smith ◽

N. Wilhelm

Keyword(s):

Acetolactate Synthase ◽

Clay Soils ◽

Alkaline Soil ◽

Alkaline Soils ◽

Metsulfuron Methyl ◽

Herbicide Residues ◽

South Eastern ◽

Eastern Australia ◽

The Impact ◽

South Eastern Australia

Grain growers in south-eastern Australia have reported unexpected crop failures with theoretically safe recropping periods for acetolactate synthase herbicides in alkaline soils. This experience has led to the concern that these herbicides may degrade very slowly in alkaline soils, and herbicide residues have at times been blamed for unexplained crop losses. To address this issue, we established 5 recropping trials across Victoria and South Australia with 5 acetolactate synthase herbicides (chlorsulfuron, triasulfuron, metsulfuron-methyl, imazethapyr, and flumetsulam). The herbicides were applied to separate plots in years 1, 2 or 3, and sensitive crop species were sown in year 4 to measure the impact of herbicide residues. We observed that the persistence of the sulfonylureas (chlorsulfuron, triasulfuron, metsulfuron-methyl) varied between herbicides, but all persisted longer in alkaline soils than in acid soils, and were, therefore, more likely to damage crops in alkaline soil. Imazethapyr persisted longer in clay soils than in sandy soils and was, therefore, more likely to damage crops in clay soils. All herbicides persisted longer when rainfall was below average. Canola was more sensitive to imazethapyr than either pea, lentil or medic, but was less sensitive to the sulfonylureas. In contrast, lentil and medic were the most sensitive to sulfonylureas. Despite some damage, we found that safe recropping periods could be predicted from the product labels in all but one situation. The sole exception was that metsulfuron-methyl reduced dry matter and yield of lentil and medic sown 10 months after application in a soil with pH 8.5. We hypothesise that the real cause of crop failure in many situations is not unusual herbicide persistence, but failure to take full account of soil type (pH and clay content including variation in the paddock) and rainfall when deciding to recrop after using acetolactate synthase herbicides.

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Determining the impact of the Holocene highstand at the coastal-fluvial interface, Shoalhaven River, south-eastern Australia

Earth Surface Processes and Landforms ◽

10.1002/esp.3382 ◽

2013 ◽

pp. n/a-n/a ◽

Cited By ~ 1

Author(s):

Stephanie J. Kermode ◽

Martin R. Gibling ◽

Brian G. Jones ◽

Tim J. Cohen ◽

David M. Price ◽

...

Keyword(s):

The Holocene ◽

South Eastern ◽

Eastern Australia ◽

The Impact ◽

South Eastern Australia

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Effects of fire retardant on heathland soils in south-eastern Australia

Soil Research ◽

10.1071/sr07040 ◽

2007 ◽

Vol 45 (8) ◽

pp. 607 ◽

Cited By ~ 5

Author(s):

P. Hopmans ◽

N. Collett ◽

R. Bickford

Keyword(s):

Surface Soil ◽

Fire Retardant ◽

Total Carbon ◽

Rapid Decline ◽

Surface Soils ◽

South Eastern ◽

Eastern Australia ◽

Pre Treatment ◽

The Impact ◽

South Eastern Australia

A study was undertaken to assess the effects of fire retardant application, unmodified by heat of fire, on soil properties in 2 fire-prone heathland communities at Marlo and the Grampians in south-eastern Australia. Fire retardant (Phos-Chek D75-R at 0.144 g/L) was applied at rates of 0.5, 1.0, and 1.5 L/m2 and compared with control treatments of nil and 1.0 L/m2 of water. Monitoring of surface soils showed that pH at both sites decreased while soil salinity increased immediately after application followed by a rapid decline to pre-treatment values within 12 months. The impact of retardant on total carbon and nitrogen was minor and within the range of natural variation of C and N in surface soils at both sites. Levels of readily available or labile forms of N increased at both sites but declined rapidly to background values after 12 months. Applications of retardant progressively increased extractable P in the surface soil at Marlo, in contrast to the Grampians where a rapid increase was observed after two months followed by a decline after 12 months. These results showed a significant increase in labile P in the surface soil after 12 months and also indicated that a large proportion of the phosphate applied had leached into the subsoil. Likewise, fire retardant applied at the highest rate caused increases in labile sulfate after 2 months at both sites, followed by a rapid decline to background levels. It is expected that the elevated levels of soil phosphate in particular could have a long-term impacts on growth and composition of heathland vegetation known to be sensitive to elevated levels of phosphate in soil.

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Contrasting impacts of environmental variability on the breeding biology of two sympatric small procellariiform seabirds in south-eastern Australia

10.1101/2021.04.19.440428 ◽

2021 ◽

Author(s):

Yonina H Eizenberg ◽

Aymeric Fromant ◽

Arnaud Lec'hvien ◽

John P Y Arnould

Keyword(s):

Breeding Success ◽

Environmental Variability ◽

Marine Ecosystems ◽

Breeding Biology ◽

South Eastern ◽

Eastern Australia ◽

The Common ◽

The Impact ◽

Diving Petrel ◽

South Eastern Australia

Seabirds play a vital role in marine ecosystems and are determinant sentinels of the productivity of their environments. The long-term study of their breeding biology and their responses to environmental variations can be used to monitor the effects of climate change on marine fauna. However, the ecological and physiological differences among seabirds induce a large range of responses complicating our understanding of the effects of environmental changes on marine ecosystems. The present study investigated the impact of environmental variability on breeding biology in two sympatric small Procellariiform species, the fairy prion ( Pachyptila turtur ) ) and the common diving petrel ( Pelecanoides urinatrix ), over four reproductive seasons (2017-2020) in Bass Strait, south-eastern Australia. Marine heatwaves had a negative effect on chick growth, breeding success, and induced a delay in laying dates in both species. While fairy prions maintained a relatively high breeding success and broadly constant breeding phenology, common diving petrels delayed the start of the breeding season by up to 50 days and experienced dramatic collapses in breeding success in years of high marine heat wave occurrence. The high wing loading and absence of stomach oils in the common diving petrel are likely to have limited the capacity of this species to increase foraging effort in years of low food availability.

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The impact of wildfire on an endangered reptile (Eulamprus leuraensis) in Australian montane swamps

International Journal of Wildland Fire ◽

10.1071/wf17048 ◽

2018 ◽

Vol 27 (7) ◽

pp. 447 ◽

Cited By ~ 1

Author(s):

Sarsha Gorissen ◽

Matthew Greenlees ◽

Richard Shine

Keyword(s):

Direct Effect ◽

Fire Regime ◽

Ground Vegetation ◽

Blue Mountains ◽

South Eastern ◽

Eastern Australia ◽

Before And After ◽

Transitory Effect ◽

The Impact ◽

South Eastern Australia

Intense fire is a key threatening process for the endangered Blue Mountains water skink, Eulamprus leuraensis. This species is restricted to isolated, densely vegetated and waterlogged peat swamps in montane south-eastern Australia. We surveyed 11 swamps (5 unburnt, 6 burnt) over 2 years, before and after the intense spring bushfires of 2013, to quantify the fires’ impacts on these skinks, other lizards and the habitat upon which they depend. Trapping revealed no direct effect of fire on E. leuraensis populations, with skinks persisting in all burnt swamps. Fire modified ground vegetation, virtually eliminating live plants and the dense understorey. Despite the conflagration, vegetation regrowth was rapid with swamp habitat largely recovering in just over 1 year post-fire. Fire thus had only a transitory effect on lizard habitat and a non-significant impact on E. leuraensis numbers. Nonetheless, broader-scale analyses suggest a different story: skinks were more abundant in swamps that had experienced a longer time since major fire. Although the ability of this endangered reptile to survive even intense wildfires is encouraging, fire during prolonged dry periods or an intensified fire regime might imperil skink populations.

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Subsoil constraints to crop production on neutral and alkaline soils in south-eastern Australia: a review of current knowledge and management strategies

Australian Journal of Experimental Agriculture ◽

10.1071/ea06250 ◽

2007 ◽

Vol 47 (11) ◽

pp. 1245 ◽

Cited By ~ 57

Author(s):

D. Adcock ◽

A. M. McNeill ◽

G. K. McDonald ◽

R. D. Armstrong

Keyword(s):

Crop Production ◽

Rooting Depth ◽

Nutrient Deficiencies ◽

Alkaline Soils ◽

Management Options ◽

Deep Placement ◽

South Eastern ◽

Eastern Australia ◽

The Impact ◽

South Eastern Australia

Crop yield variability and productivity below potential yield on neutral and alkaline soils in the semiarid Mediterranean-type environments of south-eastern Australia have been attributed, in part, to variable rooting depth and incomplete soil water extraction caused by physical and chemical characteristics of soil horizons below the surface. In this review these characteristics are referred to as subsoil constraints. This document reviews current information concerning subsoil constraints typical of neutral and alkaline soils in south-eastern Australia, principally salinity, sodicity, dense soils with high penetration resistance, waterlogging, nutrient deficiencies and ion toxicities. The review focuses on information from Australia (published and unpublished), using overseas data only where no suitable Australian data is available. An assessment of the effectiveness of current management options to address subsoil constraints is provided. These options are broadly grouped into three categories: (i) amelioration strategies, such as deep ripping, gypsum application or the use of polyacrylamides to reduce sodicity and/or bulk density, deep placement of nutrients or organic matter to overcome subsoil nutrient deficiencies or the growing of ‘primer’ crops to naturally ameliorate the soil; (ii) breeding initiatives for increased crop tolerance to toxicities such as salt and boron; and (iii) avoidance through appropriate agronomic or agro-engineering solutions. The review highlights difficulties associated with identifying the impact of any single subsoil constraint to crop production on neutral and alkaline soils in south-eastern Australia, given that multiple constraints may be present. Difficulty in clearly ranking the relative effect of particular subsoil constraints on crop production (either between constraints or in relation to other edaphic and biological factors) limits current ability to develop targeted solutions designed to overcome these constraints. Furthermore, it is recognised that the task is complicated by spatial and temporal variability of soil physicochemical properties and nutrient availability, as well as other factors such as disease and drought stress. Nevertheless, knowledge of the relative importance of particular subsoil constraints to crop production, and an assessment of impact on crop productivity, are deemed critical to the development of potential management solutions for these neutral to alkaline soils.

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‘Haying-off' in wheat is predicted to increase under a future climate in south-eastern Australia

Crop and Pasture Science ◽

10.1071/cp12062 ◽

2012 ◽

Vol 63 (7) ◽

pp. 593 ◽

Cited By ~ 15

Author(s):

J. G. Nuttall ◽

G. J. O'Leary ◽

N. Khimashia ◽

S. Asseng ◽

G. Fitzgerald ◽

...

Keyword(s):

Grain Filling ◽

Future Climate ◽

Maximum Temperature ◽

Wheat Crop ◽

Semiarid Regions ◽

South Eastern ◽

Eastern Australia ◽

Biomass Ratio ◽

The Impact ◽

South Eastern Australia

Under a future climate for south-eastern Australia there is the likelihood that the net effect of elevated CO2, (eCO2) lower growing-season rainfall and high temperature will increase haying-off thus limit production of rain-fed wheat crops. We used a modelling approach to assess the impact of an expected future climate on wheat growth across four cropping regions in Victoria. A wheat model, APSIM-Nwheat, was performance tested against three datasets: (i) a field experiment at Wagga Wagga, NSW; (ii) the Australian Grains Free Air Carbon dioxide Enrichment (AGFACE) experiment at Horsham, Victoria; and (iii) a broad-acre wheat crop survey in western Victoria. For down-scaled climate predictions for 2050, average rainfall during October, which coincides with crop flowering, decreased by 32, 29, 26, and 18% for the semiarid regions of the northern Mallee, the southern Mallee, Wimmera, and higher rainfall zone, (HRZ) in the Western District, respectively. Mean annual minimum and maximum temperature over the four regions increased by 1.9 and 2.2°C, respectively. A pair-wise comparison of the yield/anthesis biomass ratio across climate scenarios, used for assessing haying-off response, revealed that there was a 39, 49 and 47% increase in frequency of haying-off for the northern Mallee, southern Mallee and Wimmera, respectively, when crops were sown near the historically optimal time (1 June). This translated to a reduction in yield from 1.6 to 1.4 t/ha (northern Mallee), 2.5 to 2.2 t/ha (southern Mallee) and 3.7 to 3.6 t/ha (Wimmera) under a future climate. Sowing earlier (1 May) reduced the impact of a future climate on haying-off where decreases in yield/anthesis biomass ratio were 24, 28 and 23% for the respective regions. Heavy textured soils exacerbated the impact of a future climate on haying-off within the Wimmera. Within the HRZ of the Western District crops were not water limited during grain filling, so no evidence of haying-off existed where average crop yields increased by 5% under a future climate (6.4–6.7 t/ha). The simulated effect of eCO2 alone (FACE conditions) increased average yields from 18 to 38% for the semiarid regions but not in the HRZ and there was no evidence of haying-off. For a future climate, sowing earlier limited the impact of hotter, drier conditions by reducing pre-anthesis plant growth, grain set and resource depletion and shifted the grain-filling phase earlier, which reduced the impact of future drier conditions in spring. Overall, earlier sowing in a Mediterranean-type environment appears to be an important management strategy for maintaining wheat production in semiarid cropping regions into the future, although this has to be balanced with other agronomic considerations such as frost risk and weed control.

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