Between 1972 and 1999 the clearance of Tasmanian runs for crops, improved pasture and dams declin... more Between 1972 and 1999 the clearance of Tasmanian runs for crops, improved pasture and dams declined dramatically, although, since then, there has been clearance of some of the least-protected vegetation types. During a six-year period in the 1990s some vegetation remnants in wool-growing country were cleared or partially cleared and a substantial number of properties changed ownership. Change in ownership was often associated with changes in management of the remnants. Some changes were positive; more were negative. The vegetation characteristics of the edges and centres of the uncleared remnants did not change very much over the six years. Edge effects in remnants are shown to be very limited in penetration and largely related to ingress of nutrients from surrounding developed country. Mosses and liverworts, vascular plants and birds respond very differently to the characteristics and management of remnants. Small remnants in poor condition may, in some cases, be more important for the maintenance of native biodiversity than large remnants in good condition. The management of remnants for nature conservation should be primarily directed towards the maintenance of populations of threatened species, not improvement in condition.
Ecological Management and Restoration, Apr 1, 2005
ABSTRACT Summary An important conservation question for grazed areas of lowland subhumid Tasmania... more ABSTRACT Summary An important conservation question for grazed areas of lowland subhumid Tasmania is ‘what effects do different, practical disturbance regimes have on native vegetation?’ An experiment designed to determine the single and interactive effects of fire and sheep grazing was established at four sites with distinct vegetation types. There were significant interactive effects of fire and sheep grazing on vegetation attributes at all sites. An analysis of published and new data indicated that there were several vascular plant species that appeared dependent on sheep grazing for their persistence in the present landscape, while there were others that were intolerant of this disturbance but required other types of disturbance, such as mowing. However, most native species appeared to survive in a wide variety of disturbance regimes short of ploughing and fertilization. The implications of these results are that a variety of disturbance regimes is necessary to maintain biological diversity in this environment, and that the naturalness of the regime is not necessarily relevant to its use for conservation.
Natural temperate grasslands are endangered throughout their range, largely because of their almo... more Natural temperate grasslands are endangered throughout their range, largely because of their almost complete conversion to agriculture, and by changes in fire and grazing regimes. Woody encroachment by shrubs is a global threat to the structure, function and composition of grasslands. We wished to determine the characteristics of fire regimes that prevent or reverse woody plant encroachment, maintain native species richness and minimise exotic plant invasion in temperate grassland at the Surrey Hills Tasmania, where a fire management plan with variable prescriptions had been implemented for two decades. We collected floristic, fire regime and environmental data from 105 quadrats (1 × 10 m) in 2016/2017, and compared the data from 2016/2017 to that from a 1994 survey using the same methods. A high frequency and cover of native shrubs characterised areas unburned for at least 20 years before 2017, but not those unburned in the 20 years before 1994. Shrub cover began to strongly increa...
Acacia axillaris Benth. had been recommended for downgrading from a conservation status of vulner... more Acacia axillaris Benth. had been recommended for downgrading from a conservation status of vulnerable to one of rare in response to changed knowledge of its distribution. Ecological investigations of its phytosociology, stand structure, germination requirements, soil seed store and response to fire and disturbance indicate, however, that it is susceptible to elimination by fire regimes that allow the survival of most of its co-occurring species and most other Australian species of Acacia. The species is also vulnerable to land clearance and weed competition in the lowland part of its range, which is largely on private land.A. axillaris may be a refugial species, better suited to glacial Tasmania than to interglacial Tasmania. On ecological evidence, the species should retain its conservation status of vulnerable to extinction.
Although being possibly widespread on the mainland of Australia, where it is recognised as part o... more Although being possibly widespread on the mainland of Australia, where it is recognised as part of the Stackhousia monogyna Labill. complex, S. gunnii Hook.f. is an endangered species in Tasmania, with only 10 known extant populations, all in the drier parts of the southern Midlands. These populations occur largely on roadsides or lightly grazed paddocks in vegetation that was originally either Themeda triandra grassland or Eucalyptus pauciflora woodland. An ordination of floristic data from sites with and without S. gunnii showed that the species occupies a floristically distinct environment. The floristic differences between stands of S. gunnii relate partly to the presence or absence of tree cover and substantially to precipitation. The groups of species that preferentially occur with S. gunnii are geophytes, non-geophytic herbs and exotic plants, while those that are concentrated elsewhere include shrubs, grasses and non-geophytic graminoids. Permanent transects were monitored o...
Between 1972 and 1999 the clearance of Tasmanian runs for crops, improved pasture and dams declin... more Between 1972 and 1999 the clearance of Tasmanian runs for crops, improved pasture and dams declined dramatically, although, since then, there has been clearance of some of the least-protected vegetation types. During a six-year period in the 1990s some vegetation remnants in wool-growing country were cleared or partially cleared and a substantial number of properties changed ownership. Change in ownership was often associated with changes in management of the remnants. Some changes were positive; more were negative. The vegetation characteristics of the edges and centres of the uncleared remnants did not change very much over the six years. Edge effects in remnants are shown to be very limited in penetration and largely related to ingress of nutrients from surrounding developed country. Mosses and liverworts, vascular plants and birds respond very differently to the characteristics and management of remnants. Small remnants in poor condition may, in some cases, be more important for the maintenance of native biodiversity than large remnants in good condition. The management of remnants for nature conservation should be primarily directed towards the maintenance of populations of threatened species, not improvement in condition.
Ecological Management and Restoration, Apr 1, 2005
ABSTRACT Summary An important conservation question for grazed areas of lowland subhumid Tasmania... more ABSTRACT Summary An important conservation question for grazed areas of lowland subhumid Tasmania is ‘what effects do different, practical disturbance regimes have on native vegetation?’ An experiment designed to determine the single and interactive effects of fire and sheep grazing was established at four sites with distinct vegetation types. There were significant interactive effects of fire and sheep grazing on vegetation attributes at all sites. An analysis of published and new data indicated that there were several vascular plant species that appeared dependent on sheep grazing for their persistence in the present landscape, while there were others that were intolerant of this disturbance but required other types of disturbance, such as mowing. However, most native species appeared to survive in a wide variety of disturbance regimes short of ploughing and fertilization. The implications of these results are that a variety of disturbance regimes is necessary to maintain biological diversity in this environment, and that the naturalness of the regime is not necessarily relevant to its use for conservation.
Natural temperate grasslands are endangered throughout their range, largely because of their almo... more Natural temperate grasslands are endangered throughout their range, largely because of their almost complete conversion to agriculture, and by changes in fire and grazing regimes. Woody encroachment by shrubs is a global threat to the structure, function and composition of grasslands. We wished to determine the characteristics of fire regimes that prevent or reverse woody plant encroachment, maintain native species richness and minimise exotic plant invasion in temperate grassland at the Surrey Hills Tasmania, where a fire management plan with variable prescriptions had been implemented for two decades. We collected floristic, fire regime and environmental data from 105 quadrats (1 × 10 m) in 2016/2017, and compared the data from 2016/2017 to that from a 1994 survey using the same methods. A high frequency and cover of native shrubs characterised areas unburned for at least 20 years before 2017, but not those unburned in the 20 years before 1994. Shrub cover began to strongly increa...
Acacia axillaris Benth. had been recommended for downgrading from a conservation status of vulner... more Acacia axillaris Benth. had been recommended for downgrading from a conservation status of vulnerable to one of rare in response to changed knowledge of its distribution. Ecological investigations of its phytosociology, stand structure, germination requirements, soil seed store and response to fire and disturbance indicate, however, that it is susceptible to elimination by fire regimes that allow the survival of most of its co-occurring species and most other Australian species of Acacia. The species is also vulnerable to land clearance and weed competition in the lowland part of its range, which is largely on private land.A. axillaris may be a refugial species, better suited to glacial Tasmania than to interglacial Tasmania. On ecological evidence, the species should retain its conservation status of vulnerable to extinction.
Although being possibly widespread on the mainland of Australia, where it is recognised as part o... more Although being possibly widespread on the mainland of Australia, where it is recognised as part of the Stackhousia monogyna Labill. complex, S. gunnii Hook.f. is an endangered species in Tasmania, with only 10 known extant populations, all in the drier parts of the southern Midlands. These populations occur largely on roadsides or lightly grazed paddocks in vegetation that was originally either Themeda triandra grassland or Eucalyptus pauciflora woodland. An ordination of floristic data from sites with and without S. gunnii showed that the species occupies a floristically distinct environment. The floristic differences between stands of S. gunnii relate partly to the presence or absence of tree cover and substantially to precipitation. The groups of species that preferentially occur with S. gunnii are geophytes, non-geophytic herbs and exotic plants, while those that are concentrated elsewhere include shrubs, grasses and non-geophytic graminoids. Permanent transects were monitored o...
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Papers by Louise Gilfedder