Germination response to heat and smoke of 22 Poaceae species from grassy woodlands

2005 ◽  
Vol 53 (5) ◽  
pp. 445 ◽  
Author(s):  
S. Clarke ◽  
K. French
Keyword(s):  
Heat Treatment ◽  
Species Richness ◽  
Exotic Species ◽  
Fire Regime ◽  
Fire Regimes ◽  
Grass Species ◽  
Percentage Germination ◽  
Germination Response ◽  
Eastern Australia ◽  
Smoke Water

Grasses form an important component of grassy woodlands, although their response to fire has been understudied. In this study, fire germination responses of 22 Poaceae species from an endangered grassy-woodland community in eastern Australia were investigated. Seeds of 20 native and two exotic species were subjected to heat (no heat, 40, 80 and 120°C) and smoke treatment (10% dilution smoke water) and the percentage germination was compared. Germination response of species showed no consistent pattern to phylogeny and was highly variable. Germination in six species was unaffected by the application of heat or smoke. In five species, heat, irrespective of smoke application, influenced germination. Smoke, irrespective of heat treatment, influenced six species. For a further six species, the effect of smoke varied with temperature. These results suggest that fire regimes will influence the recruitment of grass species differentially and maintaining regional species richness is likely to require the maintenance of a heterogeneous fire regime across the landscape.

Effect of fire regime on the grass community of the humid savanna of Lamto, Ivory Coast

2018 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Kouamé Fulgence Koffi ◽  
Aya Brigitte N’Dri ◽  
Jean-Christophe Lata ◽  
Souleymane Konaté ◽  
Tharaniya Srikanthasamy ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Ivory Coast ◽  
Fire Regime ◽  
Fire Regimes ◽  
Abundant Species ◽  
Grass Species ◽  
The Third ◽  
Humid Savanna ◽  
The Impact ◽  
Tussock Grasses

AbstractThis study assesses the impact of four fire treatments applied yearly over 3 y, i.e. early fire, mid-season fire, late fire and no fire treatments, on the grass communities of Lamto savanna, Ivory Coast. We describe communities of perennial tussock grasses on three replicated 5 × 5-m or 10 × 5-m plots of each fire treatment. Tussock density did not vary with fire treatment. The relative abundance of grass species, the circumference of grass tussocks and the probability of having a tussock with a central die-back, varied with fire treatment. Mid-season fire had the highest proportion of tussocks with a central die-back while the late fire had the smallest tussocks. Tussock density, circumference, relative abundance and probability of having a central die-back varied with species. Andropogon canaliculatus and Hyparrhenia diplandra were the most abundant of the nine grass species. They had the largest tussocks and the highest proportion of tussock with a central die-back. Loudetia simplex was the third most abundant species but was very rare in no fire plots. The distribution of tussock circumferences was right skewed and dominated by small tussocks. The proportion of the tussocks with a central die-back strongly increased with circumference, which could lead to tussock fragmentation. Taken together, this study suggests that fire regimes impact grass demography and that this impact depends on grass species and tussock size.

Using simulation to map fire regimes: an evaluation of approaches, strategies, and limitations

2003 ◽  
Vol 12 (4) ◽  
pp. 309 ◽  
Author(s):  
Robert E. Keane ◽  
Geoffrey J. Cary ◽  
Russell Parsons
Keyword(s):  
Geographical Information Systems ◽  
Fire History ◽  
Fire Regime ◽  
Wildland Fire ◽  
Fire Regimes ◽  
Simulation Modelling ◽  
Fire Frequency ◽  
Geographical Information ◽  
Spatially Explicit ◽  
Eastern Australia

Spatial depictions of fire regimes are indispensable to fire management because they portray important characteristics of wildland fire, such as severity, intensity, and pattern, across a landscape that serves as important reference for future treatment activities. However, spatially explicit fire regime maps are difficult and costly to create requiring extensive expertise in fire history sampling, multivariate statistics, remotely sensed image classification, fire behaviour and effects, fuel dynamics, landscape ecology, simulation modelling, and geographical information systems (GIS). This paper first compares three common strategies for predicting fire regimes (classification, empirical, and simulation) using a 51�000�ha landscape in the Selway-Bitterroot Wilderness Area of Montana, USA. Simulation modelling is identified as the best overall strategy with respect to developing temporally deep spatial fire patterns, but it has limitations. To illustrate these problems, we performed three simulation experiments using the LANDSUM spatial model to determine the relative importance of (1) simulation time span; (2) fire frequency parameters; and (3) fire size parameters on the simulation of landscape fire return interval. The model used to simulate fire regimes is also very important, so we compared two spatially explicit landscape fire succession models (LANDSUM and FIRESCAPE) to demonstrate differences between model predictions and limitations of each on a neutral landscape. FIRESCAPE was developed for simulating fire regimes in eucalypt forests of south-eastern Australia. Finally, challenges for future simulation and fire regime research are presented including field data, scale, fire regime variability, map obsolescence, and classification resolution.

scholarly journals Applying seed germination studies in fire management for biodiversity conservation in south-eastern Australia

Web Ecology ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 47-54 ◽  
Author(s):  
T. D. Auld ◽  
M. K. J. Ooi
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Fire Regimes ◽  
Functional Trait ◽  
Strong Response ◽  
South Eastern ◽  
Germination Response ◽  
Eastern Australia ◽  
The Impact ◽  
South Eastern Australia

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.

Fly and wasp diversity responds to elements of both the visible and invisible fire mosaic

2017 ◽  
Vol 26 (5) ◽  
pp. 434 ◽  
Author(s):  
Julian Brown ◽  
Alan York
Keyword(s):  
Species Richness ◽  
Fire History ◽  
Fire Regime ◽  
Empirical Test ◽  
Empirical Studies ◽  
Fire Regimes ◽  
Cumulative Effects ◽  
Wasp Species ◽  
Landscape Mosaics ◽  
The Invisible

It is increasingly recognised that fire management for biodiversity conservation must account for two kinds of landscape mosaics: 1) the ‘visible’ mosaic of post-fire age classes as it relates to organism responses to the most recent fire events; and 2) the ‘invisible’ mosaic of inter-fire intervals, frequencies and other components of the fire regime as they relate to the cumulative effects of multiple fires. Patch mosaic burning (PMB) aims to create landscape mosaics of fire ages to cater for the needs of a diversity of species differing in their age class preferences, but empirical studies often fail to detect a link between species richness and the visible mosaic. Empirical studies of cumulative effects have so far related species richness to the fire regimes of sample locations rather than the invisible mosaic, within which sample locations are embedded. Invertebrate responses to landscape fire mosaics are particularly poorly understood, so we investigated relationships between fire history heterogeneity and fly and wasp species richness. We find support for the PMB paradigm and the notion the invisible mosaic influences species richness. To the best of our knowledge, this is the first empirical test of the invisible mosaic’s influence on animal communities.

Divergent responses to long-term grazing exclusion among three plant communities in a flood pulsing wetland in eastern Australia.

2014 ◽  
Vol 20 (3) ◽  
pp. 237 ◽  
Author(s):  
Peter J Berney ◽  
G. Glenn Wilson ◽  
Darren S. Ryder ◽  
R.D.B Whalley ◽  
John Duggin ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Composition ◽  
Plant Community ◽  
Plant Communities ◽  
Dominant Species ◽  
Grass Species ◽  
Grazing Exclusion ◽  
Eastern Australia ◽  
Domestic Livestock ◽  
Over Time

We examined the effects of grazing exclusion over a period of 14 years on the species richness and community composition of three plant communities with different dominant species and water regimes in the Gwydir Wetlands in eastern Australia. Responses to grazing exclusion varied among the three plant communities, and were most likely to be evident during dry periods rather than during periods of inundation. In frequently flooded plant communities, there was an increase in phytomass following exclusion of domestic livestock, but changes in plant community composition and species richness due to livestock exclusion varied depending on the morphological attributes of the dominant plant species. In a plant community where tall sedge species were dominant, livestock exclusion further increased their dominance and overall species richness declined. In contrast, where a prostrate grass species such as Paspalum distichum was dominant, species richness increased following livestock exclusion, due to an increase in the abundance of taller dicotyledon species. However, livestock exclusion in a community where flooding was less frequent and native grass species have been largely replaced with the introduced species Phyla canescens, resulted in no significant changes to phytomass, species richness or community composition among the grazing exclusion treatments over time. Our results indicate responses to exclusion of domestic livestock are dependent upon the dominant species within the plant community and will likely vary over time with the extent of wetland inundation. Grazing exclusion alone, without increased flooding, is unlikely to restore floristically degraded floodplain plant communities.

Fire, humans and climate as drivers of environmental change on Broughton Island, New South Wales, Australia

The Holocene ◽  
2020 ◽  
Vol 30 (11) ◽  
pp. 1528-1539
Author(s):  
Scott D. Mooney ◽  
Geoffrey Hope ◽  
Dylan Horne ◽  
Johan Kamminga ◽  
Alan N. Williams
Keyword(s):  
Fire Regime ◽  
New South ◽  
Climatic Variability ◽  
Fire Regimes ◽  
Anthropogenic Activity ◽  
South Wales ◽  
Arboreal Pollen ◽  
Eastern Australia ◽  
Near Shore ◽  
Obvious Feature

In Australia, the drivers of precolonial fire regimes remain contentious, with some advocating an anthropogenic-dominated regime, and others highlighting the importance of climate, climatic variability or alternatively some nexus between climate and human activity. Here, we explore the inter-relationships between fire, humans and vegetation using macroscopic charcoal, archaeology and palynology over the last ~5430 cal. year BP from Broughton Island, a small, near-shore island located in eastern Australia. We find a clear link between fire and the reduction of arboreal pollen and rainforest indicators on the island, especially at ~4.0 ka and in the last ~1000 years. Similarities with comparable palaeoenvironmental records of fire in the region and a record of strong El Niño (dry, fire-prone) events supports the contention that climate was a significant influence on the fire regimes of Broughton Island. However, two periods of enhanced fire activity, at ~4000 years BP and ~<600 years BP have weaker links to climate, and perhaps reflect anthropogenic activity. Changes to the fire regime in the last ~600 years corresponds with the earliest evidence of Indigenous archaeology on the island, and coincides with implications that Polynesian people were present in the region. After the mid-Twentieth Century a human-dominated fire regime is also an obvious feature of the reconstructed fire record on Broughton Island.

Dormancy release in Australian fire ephemeral seeds during burial increases germination response to smoke water or heat

2005 ◽  
Vol 15 (4) ◽  
pp. 339-348 ◽  
Author(s):  
Katherine S. Baker ◽  
Kathryn J. Steadman ◽  
Julie A. Plummer ◽  
David J. Merritt ◽  
Kingsley W. Dixon
Keyword(s):  
Heat Treatment ◽  
Ex Situ ◽  
Dormancy Release ◽  
Soil Burial ◽  
Germination Response ◽  
Ephemeral Species ◽  
Smoke Water ◽  
Germination Cues ◽  
Over Time

Fire ephemerals are short-lived plants that primarily germinate after fire. Fresh and laboratory-stored seeds are difficult to germinateex situ, even in response to fire-related cues such as heat and smoke. Seeds of eight Australian fire ephemeral species were buried in unburnt and recently burnt sites of natural bushland during autumn. Seeds were exhumed after 6 and 12 months and incubated in water and smoke water, either with or without a heat treatment at 70°C for 1 h. Generally, germination did not increase after 6 months of burial, but after 12 months of burial germination was enhanced in seven of the eight species.Actinotus leucocephalusproduced higher germination following 12 months of burial without any further treatment, and smoke water and heat further improved germination. The fourGyrostemonaceaespecies,Codonocarpus cotinifolius,Gyrostemon racemiger,Gyrostemon ramulosusandTersonia cyathiflora, only germinated in the presence of smoke water, and their germination was enhanced by burial. Burial improved germination in response to a heat treatment inGrevillea scapigeraandAlyogyne huegeliiseeds, but did not enhanceAlyogyne hakeifoliagermination. During concurrent dry laboratory storage of seeds at 15°C, onlyActinotus leucocephalusproduced increased germination in response to smoke water and heat over time. In summary, soil burial can alter the dormancy status of a number of Australian fire ephemeral seeds, rendering them more responsive to germination cues such as smoke water and heat. The requirement for a period of burial before seeds become responsive to smoke and/or heat would ensure that seeds persist in the soil until a subsequent fire, when there is an increase in nutrients available for growth and reduced competition from other plants.

scholarly journals High-severity wildfires in temperate Australian forests have increased in extent and aggregation in recent decades

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242484
Author(s):  
Bang Nguyen Tran ◽  
Mihai A. Tanase ◽  
Lauren T. Bennett ◽  
Cristina Aponte
Keyword(s):  
Fire Regime ◽  
Fire Severity ◽  
Fire Regimes ◽  
Ecosystem Dynamics ◽  
Burned Area ◽  
Burned Areas ◽  
South Eastern ◽  
High Severity ◽  
Eastern Australia ◽  
South Eastern Australia

Wildfires have increased in size and frequency in recent decades in many biomes, but have they also become more severe? This question remains under-examined despite fire severity being a critical aspect of fire regimes that indicates fire impacts on ecosystem attributes and associated post-fire recovery. We conducted a retrospective analysis of wildfires larger than 1000 ha in south-eastern Australia to examine the extent and spatial pattern of high-severity burned areas between 1987 and 2017. High-severity maps were generated from Landsat remote sensing imagery. Total and proportional high-severity burned area increased through time. The number of high-severity patches per year remained unchanged but variability in patch size increased, and patches became more aggregated and more irregular in shape. Our results confirm that wildfires in southern Australia have become more severe. This shift in fire regime may have critical consequences for ecosystem dynamics, as fire-adapted temperate forests are more likely to be burned at high severities relative to historical ranges, a trend that seems set to continue under projections of a hotter, drier climate in south-eastern Australia.

scholarly journals A reconstruction of the recent fire regimes of Majete Wildlife Reserve, Malawi, using remote sensing

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Willem A. Nieman ◽  
Brian W. van Wilgen ◽  
Alison J. Leslie
Keyword(s):  
Remote Sensing ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Dry Season ◽  
Annual Rainfall ◽  
Vegetation Types ◽  
Local Evidence ◽  
Hot Dry Season ◽  
Wildlife Reserve

Abstract Background Fire is an important process that shapes the structure and functioning of African savanna ecosystems, and managers of savanna protected areas use fire to achieve ecosystem goals. Developing appropriate fire management policies should be based on an understanding of the determinants, features, and effects of prevailing fire regimes, but this information is rarely available. In this study, we report on the use of remote sensing to develop a spatially explicit dataset on past fire regimes in Majete Wildlife Reserve, Malawi, between 2001 and 2019. Moderate Resolution Imaging Spectroradiometer (MODIS) images were used to evaluate the recent fire regime for two distinct vegetation types in Majete Wildlife Reserve, namely savanna and miombo. Additionally, a comparison was made between MODIS and Visible Infrared Imager Radiometer Suite (VIIRS) images by separately evaluating selected aspects of the fire regime between 2012 and 2019. Results Mean fire return intervals were four and six years for miombo and savanna vegetation, respectively, but the distribution of fire return intervals was skewed, with a large proportion of the area burning annually or biennially, and a smaller proportion experiencing much longer fire return intervals. Variation in inter-annual rainfall also resulted in longer fire return intervals during cycles of below-average rainfall. Fires were concentrated in the hot-dry season despite a management intent to restrict burning to the cool-dry season. Mean fire intensities were generally low, but many individual fires had intensities of 14 to 18 times higher than the mean, especially in the hot-dry season. The VIIRS sensors detected many fires that were overlooked by the MODIS sensors, as images were collected at a finer scale. Conclusions Remote sensing has provided a useful basis for reconstructing the recent fire regime of Majete Wildlife Reserve, and has highlighted a current mismatch between intended fire management goals and actual trends. Managers should re-evaluate fire policies based on our findings, setting clearly defined targets for the different vegetation types and introducing flexibility to accommodate natural variation in rainfall cycles. Local evidence of the links between fires and ecological outcomes will require further research to improve fire planning.

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