Effects of High Frequency Fire on Floristic Composition and Abundance in a Fire-prone Heathland near Sydney

1997 ◽  
Vol 45 (4) ◽  
pp. 641 ◽  
Author(s):  
R. A. Bradstock ◽  
M. G. Tozer ◽  
D. A. Keith
Keyword(s):  
High Frequency ◽  
Floristic Composition ◽  
Fire Regimes ◽  
Site Effect ◽  
Plant Community Composition ◽  
Site Factors ◽  
Shrub Species ◽  
Species Frequency ◽  
Constrained Ordination ◽  
Banksia Ericifolia

The effect of high frequency fire regimes on a coastal heathland north of Sydney was examined. Plant community composition and species frequency and density (of a subset of species) were compared among sites burnt by either one, two or three fires in the period 1988-1990 inclusive. Constrained ordination indicated that number of fires had a significant effect on floristic composition. Site variables also had a significant effect on floristics and frequency and accounted for a larger proportion of variation than did number of fires. Analyses of deviance indicated that frequency in 13 species was unaffected by fire regimes or site factors. Site factors significantly affected frequency in 42 species. Frequency in seven species was significantly affected by fire regimes (no site effect). In six of these, frequency was lower in areas subjected to either two or three fires compared to one fire. Three of these species were obligate seeders. Frequency in the other species (a herbaceous resprouter) was significantly higher in the area subjected to two fires. There was no significant effect of fire on species richness. Densities of seven out of a subset of eight species were also significantly affected by fire (two obligate seeder spp.) and site factors (four spp.), Significantly lower densities were related to multiple fires. The study indicated that regimes of frequent fire can deplete populations of some heathland species with the dominant shrub species, Banksia ericifolia L.f., being most affected.

Rehabilitating Downy Brome (Bromus tectorum)–Invaded Shrublands Using Imazapic and Seeding with Native Shrubs

2011 ◽  
Vol 4 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Suzanne M. Owen ◽  
Carolyn Hull Sieg ◽  
Catherine A. Gehring
Keyword(s):  
Community Composition ◽  
Plant Community ◽  
Native Species ◽  
Developmental Stages ◽  
Growth Stages ◽  
Plant Community Composition ◽  
Downy Brome ◽  
Invasive Grass ◽  
Shrub Species ◽  
Native Shrubs

AbstractRehabilitation of downy brome–infested shrublands is challenging once this invasive grass dominates native communities. The effectiveness of imazapic herbicide in reducing downy brome cover has been variable, and there is uncertainty about the impacts of imazapic on native species. We used a before-after-control-impact (BACI) field experiment and greenhouse studies to (1) determine if imazapic herbicide applied at 132 g ai ha−1 (8 oz/ac−1) and seeding with two native shrub species (Wyoming big sagebrush [Artemisia tridentata] and Mexican cliffrose [Purshia mexicana]) reduced downy brome cover and promoted shrub establishment, (2) assess potential effects of imazapic on nontarget plant species and plant community composition, and (3) determine if imazapic affected downy brome or seeded shrub species when applied at different developmental stages. Seeding shrubs, alone, or in combination with imazapic application, did not significantly increase shrub density, possibly because of droughty conditions. In the field, imazapic reduced downy brome cover by 20% and nontarget forb cover by 25% and altered plant community composition the first year after treatment. Imazapic was lethal to downy brome at all growth stages in the greenhouse and reduced shrub germination by 50 to 80%, but older shrub seedlings were more tolerant of the herbicide. We conclude that a one-time application of imazapic combined with seeding shrubs was only slightly effective in rehabilitating areas with high downy brome and thatch cover and resulted in short-term impacts to nontarget species. These results highlight the need to treat downy brome infestations before they become too large. Also, removing thatch prior to treating with imazapic, although likely lethal to the native shrubs we studied, could increase the effectiveness of imazapic.

scholarly journals Contribution of forest species to the floristic composition of a forested savanna in southeastern Brazil

2006 ◽  
Vol 49 (5) ◽  
pp. 763-774 ◽  
Author(s):  
Marcelo Henrique Ongaro Pinheiro ◽  
Reinaldo Monteiro
Keyword(s):  
Floristic Composition ◽  
Forest Tree ◽  
Sensu Stricto ◽  
Sao Paulo ◽  
Southeastern Brazil ◽  
São Paulo ◽  
Inclusion Criteria ◽  
Forest Species ◽  
Shrub Species ◽  
The City

Based on studies of floristic lists the contribution of forest tree and shrub species in a forested savanna area in the city of Bauru, State of São Paulo, and in 14 different places sheltering cerrado sensu stricto and cerradão in Brazil is defined as the evidence of forest species causing a change of cerrado heterogeneity. The percentages of occurrence of forest species in the locations analyzed varied from zero to 4.5%. The proximity of different forest matrices, the occurrence of fires and the inclusion criteria used were some of the factors that may have influenced such variation.

scholarly journals Is Anthropogenic Pyrodiversity Invisible in Paleofire Records?

Fire ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 42 ◽  
Author(s):  
Roos ◽  
Williamson ◽  
Bowman
Keyword(s):  
High Frequency ◽  
Landscape Heterogeneity ◽  
Fire Regime ◽  
Fire Regimes ◽  
Regime Shifts ◽  
Cultural Changes ◽  
Regime Changes ◽  
Other Information ◽  
Patch Burning ◽  
The Impact

Paleofire studies frequently discount the impact of human activities in past fire regimes. Globally, we know that a common pattern of anthropogenic burning regimes is to burn many small patches at high frequency, thereby generating landscape heterogeneity. Is this type of anthropogenic pyrodiversity necessarily obscured in paleofire records because of fundamental limitations of those records? We evaluate this with a cellular automata model designed to replicate different fire regimes with identical fire rotations but different fire frequencies and patchiness. Our results indicate that high frequency patch burning can be identified in tree-ring records at relatively modest sampling intensities. However, standard methods that filter out fires represented by few trees systematically biases the records against patch burning. In simulated fire regime shifts, fading records, sample size, and the contrast between the shifted fire regimes all interact to make statistical identification of regime shifts challenging without other information. Recent studies indicate that integration of information from history, archaeology, or anthropology and paleofire data generate the most reliable inferences of anthropogenic patch burning and fire regime changes associated with cultural changes.

Floristic and structural characteristics of a coastal heathland exhibiting symptoms of Phytophthora cinnamomi infestation in the eastern Otway Ranges, Victoria

2003 ◽  
Vol 51 (3) ◽  
pp. 283 ◽  
Author(s):  
W. Scott Laidlaw ◽  
Barbara A. Wilson
Keyword(s):  
Phytophthora Cinnamomi ◽  
Structural Characteristics ◽  
Floristic Composition ◽  
Shrub Species ◽  
Heathland Vegetation ◽  
Recovery Capacity ◽  
Structural Differences ◽  
Open Ground ◽  
Floristic Data

The floristics and structure of heathland vegetation exhibiting symptoms of Phytophthora cinnamomi Rands infestation was assessed at two sites in heathlands at Anglesea, Victoria. There were significant effects in both floristics and structure. Thirteen heathland species were significantly less abundant in diseased areas and 23 species were more abundant. Diseased (infested) vegetation, when compared with non-diseased areas, had less cover of Xanthorrhoea australis and shrub species and a greater cover of sedges, grasses and open ground. Structural differences were observed between heights 0 and 0.6 m, with a decline in cover recorded in diseased vegetation. Non-metric multidimensional scaling ordination of the floristic data showed a clear separation of diseased and non-diseased vegetation and that changes in floristic composition post-infestation were similar at both sites. Although there was some evidence of regeneration of X. australis, the recovery capacity of other susceptible species at Anglesea is unknown. The long-term consequences of loss of species and structure in the eastern Otways mean that the vegetation is unlikely to return to former status, especially if the pathogen continues to reinfect.

Imaging the rupture process of recent earthquakes using backprojection of local high frequency records

2020 ◽  
Author(s):  
Ioannis Fountoulakis ◽  
Christos Evangelidis ◽  
Olga-Joan Ktenidou
Keyword(s):  
High Frequency ◽  
A Priori ◽  
Strong Motion ◽  
Seismic Hazard Assessment ◽  
Seismic Source ◽  
Site Effect ◽  
Source Inversion ◽  
Waveform Data ◽  
Novel Approach ◽  
Spatio Temporal

<p>The seismic source spatio-temporal rupture processes of events in Japan, Greece and Turkey are imaged by backprojection of strong-motion waveforms. Normalized high-frequency (> 2Hz) S-waveforms from recordings on dense strong-motion networks are used to scan a predefined 3D source volume over time. </p><p>Backprojection is an alternative novel approach to image the spatio-temporal earthquake rupture. The method was first applied for large earthquakes at teleseismic distances, but is nowadays also used at local distances and over higher frequencies. The greatest advantage of the method is that processing is done without any a-priori constraints on the geometry, or size of the source. Thus, the spatio-temporal imaging of the rupture is feasible at higher frequencies (> 1Hz) than conventional source inversion studies, even when the examined fault geometry is complex. This high-frequency energy emitted during an earthquake is of great importance in seismic hazard assessment for certain critical infrastructures. The actual challenge in using high-frequency local recordings is to distinguish the local site effects from the true earthquake source content - otherwise, mapping the former incorrectly onto the latter limits the resolvability of the method. It is not straightforward to remove the site effect component or even to distinguish good reference stations from amid hard-soil and rock sites. In this study, the advantages and limitations of the method are explored using waveform data from well-recorded events in Japan (Kumamoto Mw7.1, 2016), Turkey (Marmara Mw6.4, 2019) and Greece (Antikythera Mw6.1, 2019). For each event and seismic array the resolution limits of the applied method are explored by performing various synthetic tests.</p>

Traditional and ecological fires and effects of bushfire laws in north Australian savannas

2007 ◽  
Vol 16 (4) ◽  
pp. 378 ◽  
Author(s):  
Noel Preece
Keyword(s):  
Land Management ◽  
High Frequency ◽  
Prescribed Burning ◽  
Fire Management ◽  
Management Strategies ◽  
Fire Regimes ◽  
Ecosystem Dynamics ◽  
Traditional Practices ◽  
The North ◽  
In Fire

Landscape fires are common and frequent across the north Australian savannas, and are arguably an essential component of regional ecosystem dynamics. Seasonal biases in fire regimes and the high frequency of late dry season fires in a large proportion of the region have been presented as an impediment to appropriate land management. Legislation regulating the lighting of fires applies to the whole of the savannas. The legislation seeks to control the lighting of fires, provides for permit systems to operate in each jurisdiction, and is supported by policies and guidance manuals. The present paper argues that the legislation fails to address prescribed burning, the biophysical and social realities of contemporary regimes, and management needs. The policies and legislation are in need of some fundamental changes, including recognition of the concept of prescribed burning, mechanisms to promote regional fire management strategies and plans, and recognition of indigenous traditional practices.

Site Effects of the 2003 Bam, Iran, Earthquake

2005 ◽  
Vol 21 (1_suppl) ◽  
pp. 125-136 ◽  
Author(s):  
Mohammad Kazem Jafari ◽  
Mohammad Reza Ghayamghamian ◽  
Mohammad Davoodi ◽  
Mohsen Kamalian ◽  
Abdollah Sohrabi-Bidar
Keyword(s):  
High Frequency ◽  
Site Effects ◽  
Site Effect ◽  
Site Amplification ◽  
Frequency Characteristics ◽  
Ground Conditions ◽  
A Site ◽  
The City

The site amplification characteristics of the 2003 Bam, Iran, earthquake were investigated based on geological studies as well as geophysical, microtremor and aftershock measurements conducted by IIEES in the study area. A site effect microzonation map was prepared classifying the ground conditions of the city into five distinct categories, based on their stiffness, thickness, and frequency characteristics. The highest percentage of damage was concentrated in sites with stiff shallow and medium depth soils, which possessed considerable amplification potentials in high frequency ranges.

scholarly journals High-Frequency Site Effect of Hard Rocks at Ashio, Central Japan.

1993 ◽  
Vol 41 (5) ◽  
pp. 327-335 ◽  
Author(s):  
Kazuo Yoshimoto ◽  
Haruo Sato ◽  
Shigeo Kinoshita ◽  
Masakazu Ohtake
Keyword(s):  
High Frequency ◽  
Site Effect ◽  
Central Japan ◽  
Hard Rocks

scholarly journals THE OCCURRENCE OF BROWNTOP, IN THE MANAWATU

1973 ◽  
pp. 86-94
Author(s):  
R.W. Brougham ◽  
D.A. Grant ◽  
V.C. Goodall
Keyword(s):  
Species Composition ◽  
White Clover ◽  
High Frequency ◽  
Dairy Farms ◽  
Early Spring ◽  
Frequency Of Occurrence ◽  
Botanical Composition ◽  
Farming Practices ◽  
Species Frequency ◽  
Hill Country

Results are presented from a survey of the frequency of occurrence of pasture species in the different topographical and soil type areas of the Manawatu. It was carried out in the early spring of 1967 and again in the summer of 1968. The survey indicated a high frequency of occurrence of browntop on hill country (81 and 87% in early spring and summer, respectively) and terrace country (46 and 40%, respectively) and moderate amounts on flat land and sand country. Lowest occurrence was recorded on flat country dairy farms (15 and 17%, respectively). Marked differences in species frequency of occurrence were recorded between farms on hill country. These ranged from farms in which pastures were dominantly browntop, sweet vernal, and moss, to farms where relatively high amounts of white clover, ryegrass, and dogstail occurred in association with other less productive species. These differences have been related to produotivity levels possible from such extremes in species composition. Results are discussed in relation to current hill country farming practices. Factors considered to be significant in altering hill country botanical composition and hence levels of productivity are also discussed.

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