The germination of some shrub species may be enhanced following fire in shrublands and woodlands. This paper reports the germination response of Acacia aneura, Cassia nemophila and Dodonaea viscosa common shrub species in semi-arid and arid woodlandsto laboratory fires over a range of intensities and durations.Seeds were subjected to fires of different intensities in the controlled environment of a glasshouse. Depth of seed placement in the soil, soil moisture level and amount and type of fuel influenced the percentage of seeds that germinated. Amounts of shredded paper fuel, equivalent to typical grass fuel levels in semi-arid woodlands did not enhance the germinability of seeds of any of the species, except for A. aneura on a moist or wet soil surface. A high, dense fuel load (simulating slow burning, lowintensity litter fires) either increased or decreased the germinability of surface and buried seeds of all species, depending upon soil moisture level and depth of seeds. The germination response to the heat of fires differed significantly between species: A . aneura germination increased substantially at low levels of peak temperature up to 60 "C whereas germination of C. nemophila increased to a lesser extent and D. viscosa was not affected at all over this low temperature range. Seeds of all species were killed by slow burning litter fires when the temperature exceeded 80 "C. These results confirm the view that firepromoted germination does not result from the burning of fine fuels perse but occurs only where there is litter buildup and when the soil temperature does not exceed the lethal threshold of 70-8O0C.
This article outlines the exploration and settlement of poplar box lands which followed the European occupation of the Australian continent in the mid-19th century, draws attention to the various fragments of historical information on substantial changes in the soils, vegetation and biota, and describes the role of European livestock (sheep, cattle, goats, rabbits) and fire in these changes.
Methods for measuring long-term changes in vegetation and soil condition were evaluated in terms of recording error, efficiency and value in meeting management objectives. The evaluation was made on 4-5 sites for each of six vegetation types across the semi-arid rangelands of South Australia and New South Wales. In the semi-arid woodlands the lowest errors of measurement (C.V. = 12-14%) were associated with point measures of canopy cover, while in the chenopod shrublands the most precise measure in most situations was the density of shrub clumps (C.V. = 12-16%). Measures of herbaceous and litter cover had a high error of measurement (e.g. C.V. = 60%) and observers were significantly different. The point measurement of the area of degraded soil surface was reliable on duplex soils, but not on gradational soils. The results are discussed in terms of their application for the monitoring of change in range condition. It is concluded that the most appropriate measure of the shrub layer is foliar cover in woodlands and clump density in chenopod shrublands.
This article combines data from historical records, recently published maps and a field survey to document changes in the vegetation of a pastoral
area in south-western Queensland. Examples are given where wildfire, ringbarking,clearing and grazing by both rabbits anddomestic stock have had
major influences on the vegetation.
The greatest change to the trees and inedible shrubs has been one of density. Evidence for changes in the herbaceous layer is less conclusive but it
is likely that there has been a reduction in density of desirable perennial grasses and an increase in less palatable species.
This article examines historical records of a grazing property in south-westem Queensland to analyse various aspects of station improvements, pasture and sheep productivity. The drought at about the turn of the century was the catalyst that led to a permanent loss of pasture and canying capacity. Competition from rabbits and the full utilisation of grazing land by about 1914 exacerbated the situation. The station was able to cope with early localised degradation because new land was constantly becoming available due to improvements in fencing and stock watering facilities. Summer rainfall was of utmost importance in providing sufficient perennial grass for the maintenance of stock numbers. Annual sheep losses and average fleece weights were highly correlated with the amount of summer rainfall. A high lambing percentage was dependent on good seasonal conditions-over the 18 months.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.