Fire-stimulated rainforest seedling recruitment and vegetative regeneration in a densely grassed wet sclerophyll forest of north-eastern Australia

2000 ◽  
Vol 48 (5) ◽  
pp. 651 ◽  
Author(s):  
Paul R. Williams
Keyword(s):  
Seedling Recruitment ◽  
Fire Regimes ◽  
Moderate Intensity ◽  
Complex Nature ◽  
Pioneer Species ◽  
Vegetative Regeneration ◽  
Eastern Australia ◽  
North Eastern ◽  
Sclerophyll Forest ◽  
Soil Seedbank

Details of plant regeneration, combined with soil seedbank data, are documented for a densely grassed wet sclerophyll forest in north-eastern Australia. The following two hypotheses were tested: (1) that established individuals of rainforest pioneer species are killed by low to moderate intensity fires and (2) that seedling recruitment of these species is evenly distributed throughout the intervals between fires. Both the sclerophyll and rainforest pioneer species displayed strong regenerative abilities as a response to low or moderate intensity fires. Most of the rainforest pioneer species were not killed by two recent fires but vegetatively regenerated. Alstonia muelleriana showed fire-enhanced vegetative expansion via root suckering. Both the sclerophyll and rainforest pioneer species were found to recruit seedlings primarily as a pulse in the first year or two after a fire, with limited recruitment after longer intervals between fires. This is consistent with suggestions that grass competition may limit tree recruitment. The germinable soil seedbank was dominated by rainforest pioneers, herbs and grasses, with heat treatment of the seedbank enhancing seed germination of two rainforest pioneer species. These results demonstrate the ability of rainforest pioneers to exploit the post-fire environment and indicate the complex nature of rainforest boundary dynamics. Further research into tropical rainforest expansion is required to examine the effects of fire regimes on vegetative and seedling regeneration across a range of sites.

Responses of Non-volant Mammals to Late Quaternary Climatic Changes in the Wet Tropics Region of North-eastern Australia

1997 ◽  
Vol 24 (5) ◽  
pp. 493 ◽  
Author(s):  
J. W. Winter
Keyword(s):  
Late Quaternary ◽  
Temperature Tolerance ◽  
Climatic Changes ◽  
Glacial Period ◽  
Profound Influence ◽  
Eastern Australia ◽  
North Eastern ◽  
Sclerophyll Forest ◽  
Wet Tropics ◽  
Glacial Periods

It is generally recognised that the distribution of vertebrates in rainforest and wet sclerophyll forest of the Wet Tropics region of north-eastern Australia is profoundly influenced by the formation of two rainforest refugia at the height of Pleistocene glacial periods. Anomalies in the distribution of non-volant mammals indicate that other events may be equally important. In this paper, past geographical occurrence of non-volant mammals is examined by equating the mammals’ known temperature tolerance with palaeoclimatic temperature zones. It is hypothesised that dispersal and vicariant phases taking place since the most recent glacial period have had a profound influence on current patterns of distribution. A major dispersal phase of cool-adapted species occurred after the glacial period, and continuous populations were subsequently fragmented into upland isolates by expansion of warm rainforest during the late post-glacial period. These upland isolates remain substantially unchanged to the present day. Species shared either with New Guinea or south-eastern Australia arrived in the region during the most recent post-glacial period. Clarification of periods of vicariance and dispersal provides a conceptual framework for testing relative divergences of populations within and between regions.

scholarly journals Subsoil constraints to grain production in the cropping soils of the north-eastern region of Australia: an overview

2006 ◽  
Vol 46 (1) ◽  
pp. 19 ◽  
Author(s):  
Y. P. Dang ◽  
R. C. Dalal ◽  
R. Routley ◽  
G. D. Schwenke ◽  
I. Daniells
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Soil Layer ◽  
Environmental Damage ◽  
Complex Nature ◽  
Eastern Region ◽  
Nutrient Deficiencies ◽  
Potential Yield ◽  
Eastern Australia ◽  
North Eastern

In dryland agricultural systems of the subtropical, semi-arid region of north-eastern Australia, water is the most limiting resource. Crop productivity depends on the efficient use of rainfall and available water stored in the soil during fallow. Agronomic management practices including a period of fallow, stubble retention, and reduced tillage enhance reserves of soil water. However, access to stored water in these soils may be restricted by the presence of growth-limiting conditions in the rooting zone of the crop. These have been termed as subsoil constraints. Subsoil constraints may include compacted or gravel layers (physical), sodicity, salinity, acidity, nutrient deficiencies, presence of toxic elements (chemical) and low microbial activity (biological). Several of these constraints may occur together in some soils. Farmers have often not been able to obtain the potential yield determined by their prevailing climatic conditions in the marginal rainfall areas of the northern grains region. In the past, the adoption of soil management practices had been largely restricted to the top 100 mm soil layer. Exploitation of the subsoil as a source of water and nutrients has largely been overlooked. The key towards realising potential yields would be to gain better understanding of subsoils and their limitations, then develop options to manage them practically and economically. Due to the complex nature of the causal factors of these constraints, efforts are required for a combination of management approaches rather than individual options, with the aim to combat these constraints for sustainable crop production, managing natural resources and avoiding environmental damage.

Acid frogs can stand the heat: amphibian resilience to wildfire in coastal wetlands of eastern Australia

2013 ◽  
Vol 22 (7) ◽  
pp. 947 ◽  
Author(s):  
Katrin Lowe ◽  
J. Guy Castley ◽  
Jean-Marc Hero
Keyword(s):  
Strong Predictor ◽  
Fire Regimes ◽  
Species Traits ◽  
Landscape Scale ◽  
Moderate Intensity ◽  
Adaptive Responses ◽  
Coastal Heath ◽  
Eastern Australia ◽  
Temperature Ranges ◽  
In Fire

Fire has varying effects on species ecology. Knowledge of amphibian responses to fire is particularly limited, with variable responses reported amongst studies. Variability is attributed to differences in fire regimes, sampling methodologies, historical exposure to fire and species traits. Acid frogs, a group of amphibians restricted to acidic coastal heath wetlands of eastern Australia, occupy a discrete ecological niche that is exposed to regular and intense fires. Visual encounter surveys conducted monthly over 2 years revealed different short- and long-term responses to fire in three threatened acid frog species (Litoria olongburensis, Litoria freycineti and Crinia tinnula). Fires altered the thermal properties of habitats by increasing substrate temperature and widening daily temperature ranges. Acid frog populations did not suffer adversely from moderate intensity fires as suitable refuges, including standing water, were available. All species were present shortly after fire with subsequent successful reproduction occurring once wetlands were sufficiently inundated. Time since fire was a strong predictor of landscape scale differences in average relative abundance of acid frogs, yet the relationships varied among species. This highlights the importance of assessing community-wide responses to fire at the landscape scale. The dynamic and adaptive responses observed within acid frog populations demonstrate substantial resilience to fire processes in these fire prone environments.

scholarly journals Preliminary assessment of gidgee (Acacia cambagei) woodland thickening in the Longreach district, Queensland

2005 ◽  
Vol 27 (2) ◽  
pp. 159 ◽  
Author(s):  
R. J. Fensham ◽  
R. J. Fairfax
Keyword(s):  
Seedling Recruitment ◽  
Research Priorities ◽  
Fire Retardant ◽  
Extreme Rainfall ◽  
Preliminary Assessment ◽  
Eastern Australia ◽  
North Eastern ◽  
Other Information ◽  
The 1950S

Gidgee (Acacia cambagei) forms woodlands and forests on moderately fertile clay soils throughout semi-arid areas of north-eastern Australia. Analysis of soil data from Queensland indicates that gidgee’s environmental domain has a broad overlap with treeless Mitchell grassland although a preference for slightly coarser soils with higher phosphorus and lower potassium content. Mapping of woody cover change for an area of central Queensland suggests that gidgee thickening and spread has occurred between 1951 and 1994. However, this increase has been more than offset by loss of gidgee cover by clearing in other areas. Gidgee thickening and encroachment onto grassland is a problem for graziers because the trees suppress grass and are unpalatable except when very young. Landholder surveys and other information indicate that gidgee has recruited sporadically and that thickening occurred with a massive seedling recruitment in the 1950s with a smaller recruitment wave in the 1970s. These waves coincide with relatively wet times and the extreme rainfall abundance in the 1950s has a multi-century expected recurrence. There are historical records describing gidgee death during the extreme droughts in the first part of the 20th century. Young gidgee plants are fire sensitive but well-established gidgee stands are fire retardant, and the importance of fire for control of gidgee thickening is unknown. One scenario explaining gidgee dynamics emphasises the role of environment (mostly climate and soil), while another emphasises management (mostly fire). Research priorities are presented and may contribute to appropriate management of gidgee woodlands.

Stability of nest range, home range and movement of the northern bettong (Bettongia tropica) following moderate-intensity fire in a tropical woodland, north-eastern Queensland

2001 ◽  
Vol 28 (2) ◽  
pp. 141 ◽  
Author(s):  
Karl Vernes ◽  
Lisa Claire Pope
Keyword(s):  
Home Range ◽  
Radio Telemetry ◽  
Ground Cover ◽  
Home Range Size ◽  
Moderate Intensity ◽  
Home Ranges ◽  
Eastern Australia ◽  
North Eastern ◽  
Before And After ◽  
Materials Used

Nest use, home-range characteristics and nightly movements by the northern bettong (Bettongia tropica) were examined before and after a low- to moderate-intensity fire in sclerophyll woodland in north-eastern Australia using radio-telemetry. In all, 23 animals were radio-tracked at three-month intervals between February 1995 and May 1996. During November 1995 a low-intensity experimental fire burned the entire home range of most animals. The northern bettong appeared fairly catholic in choice of nest site, with a variety of nest locations and nesting materials used. Prior to the fire, nests were generally located in areas of dense cover, such as the skirts of grass trees (46%) or grass close to a log (29%). After fire removed most ground cover in the nesting areas of most animals, bettongs used remaining shelter such as boulder piles (45%), recently fallen trees (8%) and patches of unburnt vegetation (21%). Nest areas (10.1 ha) of males were significantly larger than those of females (5.4 ha). Home ranges of both sexes were large (59 ha) and most ranges lacked distinct core areas, suggesting that bettongs used all parts of their home ranges equally. High mean rates of nightly movement by the northern bettong indicated that large distances were moved within home ranges during nightly foraging. No significant fire-related changes were detected in home-range size, home-range location, nest-area location or mean rates of nightly movement, suggesting that the northern bettong is well adapted to the low- and medium-intensity fires that characterise its habitat.

scholarly journals Seed bank dynamics in five Panamanian forests

2005 ◽  
Vol 21 (2) ◽  
pp. 223-226 ◽  
Author(s):  
D. A. Fornara ◽  
J. W. Dalling
Keyword(s):  
Seed Bank ◽  
Seedling Recruitment ◽  
Fruit Production ◽  
Pioneer Species ◽  
Seasonal Fluctuations ◽  
Annual Fluctuation ◽  
Soil Seed Banks ◽  
Successful Recruitment ◽  
Seed Bank Dynamics ◽  
Lowland Forests

Many tropical pioneer species depend on the presence of high seed densities in the soil for successful recruitment following canopy disturbance (Cheke et al. 1979, Dalling & Hubbell 2002, Guevara Sada & Gómez Pompa 1972, Whitmore 1983). However determinants of variation in the composition and abundance of soil seed banks remain poorly understood. Seed bank densities can be affected by rates of seed predation and pathogen infection on the surface and in the soil, by intrinsic rates of loss in viability following dispersal, and by variation in the timing and duration of fruit production (Dalling et al. 1997, Garwood 1983, Murray & Garcia 2002). Here we compare seasonal fluctuations in seed bank density in five Panamanian forests varying in elevation and seasonality of precipitation (Table 1). We predict that lowland forests should show stronger intra-annual fluctuation in seed bank densities than montane forests because seed production and loss rates should be higher under conditions of greater resource availability, and where consistent high temperatures support greater abundance or activity of seed predators and pathogens (Brühl et al. 1999). Secondly, among lowland sites, we predict greater fluctuations in seed bank densities at drier, more seasonal sites where seasonally favourable conditions for seedling recruitment may select for interspecific synchrony in fruit production (Daubenmire 1972, Garwood 1983).

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