Hypotheses arising from a population recovery of the Western Ringtail PossumPseudocheirus occidentalis in fire regrowth patches in a stand ofAgonis flexuosa trees in south-western Australia

2004 ◽  
pp. 656-662
Author(s):  
Barbara A. Jones ◽  
Catherine E. Meathrel ◽  
Michael C. Calver
Keyword(s):  
Western Australia ◽  
Population Recovery ◽  
In Fire

Feral pigs in north-western Australia: population recovery after 1080 baiting and further control

2006 ◽  
Vol 33 (5) ◽  
pp. 417 ◽  
Author(s):  
Laurie E. Twigg ◽  
Tim Lowe ◽  
Michael Everett ◽  
Gary Martin
Keyword(s):  
Western Australia ◽  
Population Recovery ◽  
Feral Pigs ◽  
Muddy Water ◽  
Good Body Condition ◽  
Bait Station ◽  
Before And After ◽  
Bait Stations ◽  
North Western ◽  
Fitzroy River

The recovery rate of a population of feral pigs (Sus scrofa) in the west Kimberley in north-western Australia was determined 12 months after a 1080 (sodium fluoroacetate)-baiting program. An estimated 56 pigs were present in the 15 000-ha study area in August 2005 compared with the prebaiting levels of 250–275 pigs in 2004 (11 pigs were known to be alive on site after the 2004 baiting). This represents a population recovery of 20–23% of the 2004 prebaiting levels. Although most pigs were in good body condition, environmental conditions were quite different between the two years. In 2005, some waterholes were dry or comprised mainly muddy water with little associated shelter for feral pigs. Consequently, and in contrast to 2004, no pigs were seen, and no bait take could be attributed to feral pigs, at the four resurveyed waterholes. Most pig sightings, and activity, were close to the Fitzroy River. Fermented wheat, with blood and bone, was used to determine areas of pig activity, and also used as prefeed before 1080-baiting commenced in 2005. Using the same bait stations as for 2004, plus additional stations established in new areas of pig activity, 1080-treated wheat and malted barley again proved highly effective in reducing pig numbers. The daily sighting index before and after 1080-baiting indicated that pig numbers had been reduced by ~90% within four days. Estimated pre- and postpoisoning density, with and without an edge effect, was 0.12–1.7 pigs km–2 and 0.05–0.67 pigs km–2. Pig tracks decreased to zero on the six track plots within two days of baiting, but the number of macropod tracks remained constant over the four-day baiting period. Thirty-eight poisoned pigs were found after 1080-baiting, and these were generally in clustered groups within 200 m of an active bait station. Poisoned juvenile pigs were again found closer to the active bait stations than were adult or subadult pigs (P < 0.05).

Fire responses and survival strategies of mistletoes (Loranthaceae) in an arid environment in Western Australia

2011 ◽  
Vol 59 (6) ◽  
pp. 533 ◽  
Author(s):  
A. N. Start
Keyword(s):  
Host Specificity ◽  
Western Australia ◽  
Seed Storage ◽  
Fire Risk ◽  
Fire Regimes ◽  
Arid Environment ◽  
Survival Strategies ◽  
Fresh Seed ◽  
Acacia Aneura ◽  
In Fire

Between 1982 and 2008, data were collected on Loranthaceous mistletoes, their hosts and the fire responses of both, in and adjacent to the Pilbara, an arid region in Western Australia where hummock grasslands (dominated by Triodia sp. R.Br., Poaceae) and mulga woodlands (dominated by Acacia aneura Benth., Mimosaceae) are widespread. Hummock grasslands are fire prone and highly flammable. Mulga woodlands are less so, except in an inter-zone where Triodia in the understorey may be sufficiently dense to carry fire. The foliage (and fresh seed) of all mistletoe species was killed if scorched. Moreover, none had any means of long-term, in situ seed-storage. Three fire-survival strategies were observed across the 16 mistletoe taxa. One species (two varieties) was a resprouter. The other 14 were obligate seeders. Post-fire regeneration of those taxa depended on fresh seed being imported and deposited in suitable host canopies by birds. Twelve of them reduced fire risk by varying degrees of host specificity, favouring hosts that grew in fire-sheltered sites. However, two species had very low host specificity and grew on fire-vulnerable hosts in fire-prone hummock grasslands. Their low host specificity increased the likelihood that imported seed would be deposited on suitable hosts. Since pastoral settlement, fire regimes have changed and current regimes are eroding many mistletoe populations. None of the species occurring in the study area is threatened at bioregional or National levels. Nevertheless, the outlook is bleak for mistletoes growing in areas dominated by hummock grasslands, subregional extinction is likely and there are broader implications for biodiversity.

Conserving Australia’s threatened native mammals in predator-invaded, fire-prone landscapes

2020 ◽  
Vol 47 (1) ◽  
pp. 1 ◽  
Author(s):  
Bronwyn A. Hradsky
Keyword(s):  
Introduced Species ◽  
Statistical Power ◽  
Field Experiments ◽  
Prescribed Burning ◽  
Fire Regimes ◽  
Population Recovery ◽  
Red Foxes ◽  
Management Options ◽  
Introduced Predators ◽  
In Fire

Abstract Inappropriate fire regimes and predation by introduced species each pose a major threat to Australia’s native mammals. They also potentially interact, an issue that is likely to be contributing to the ongoing collapse of native mammal communities across Australia. In the present review, I first describe the mechanisms through which fire could create predation pinch points, exacerbating the impacts of predators, including red foxes, Vulpes vulpes, and feral cats, Felis catus, on their native mammalian prey. These mechanisms include a localised increase in predator activity (a numerically mediated pathway) and higher predator hunting success after fire (a functionally moderated pathway), which could both increase native mammal mortality and limit population recovery in fire-affected landscapes. Evidence for such interactions is growing, although largely based on unreplicated experiments. Improving native mammal resilience to fire in predator-invaded landscapes requires addressing two key questions: how can the impacts of introduced predators on native mammals in fire-affected areas be reduced; and, does a reduction in predation by introduced species result in higher native mammal survival and population recovery after fire? I then examine potential management options for reducing predator impacts post-fire. The most feasible are landscape-scale predator control and the manipulation of fire regimes to create patchy fire scars. However, robust field experiments with adequate statistical power are required to assess the effectiveness of these approaches and preclude null (e.g. compensatory mortality) or adverse (e.g. mesopredator or competitor release) outcomes. Ongoing predator management and prescribed burning programs provide an opportunity to learn through replicated natural experiments as well as experimental manipulations. Standardised reporting protocols and cross-jurisdiction monitoring programs would help achieve necessary spatial and environmental replication, while multi-trophic, spatially explicit simulation models could help synthesise findings from disparate study designs, predict management outcomes and generate new hypotheses. Such approaches will be key to improving management of the complex mechanisms that drive threatened native mammal populations in Australia’s predator-invaded, fire-prone landscapes.

Variation in fire interval sequences has minimal effects on species richness and composition in fire-prone landscapes of south-west Western Australia

2011 ◽  
Vol 261 (6) ◽  
pp. 965-978 ◽  
Author(s):  
Roy S. Wittkuhn ◽  
Lachie McCaw ◽  
Allan J. Wills ◽  
Richard Robinson ◽  
Alan N. Andersen ◽  
...  
Keyword(s):  
Species Richness ◽  
Western Australia ◽  
South West ◽  
In Fire

Germination characteristics and the relationship between population structure, soil seed bank density and fire response in the rare endemic Stachystemon vinosus (Halford & R.J.F.Hend.) (Euphorbiaceae) from southern Western Australia

2019 ◽  
Vol 29 (2) ◽  
pp. 124-134
Author(s):  
Brian J. Vincent ◽  
Sarah Barrett ◽  
Anne Cochrane ◽  
Michael Renton
Keyword(s):  
Population Structure ◽  
Western Australia ◽  
Seed Bank ◽  
Fire Regime ◽  
Soil Seed Bank ◽  
Fire Response ◽  
Germination Characteristics ◽  
In Fire ◽  
Rare Endemic ◽  
The Relationship

AbstractThe regeneration niche defines the specific environmental requirements of the early phases of a plant's life cycle. It is critical for the long-term persistence of plant populations, particularly for obligate seeders that are highly vulnerable to stochastic events in fire-prone ecosystems. Here, we assessed germination characteristics and the relationship between population structure, soil seed bank density and fire response in Stachystemon vinosus (Euphorbiaceae), a rare endemic shrub from Western Australia, from burnt and long unburnt habitats. Many plants in long unburnt habitat were similar in size to those in recently burnt habitat. Soil seed bank density was related to plant abundance and fire history with density lower in burnt than unburnt sites. Thus, inter-fire recruitment may play a critical role in the requirements of the study species. To assess the dormancy status and germination requirements we used a ‘move-along’ experiment with temperatures from six seasonal phases of the year. Seeds were incubated under light and dark conditions, with and without smoked water, and with and without dry after-ripening. Germination was most effective when seeds were treated with smoked water and incubated in the dark at temperatures resembling autumn/winter conditions. After-ripening increased germination in light and dark incubated seeds in the absence of smoked water but was unnecessary for optimal germination in smoked water treated seeds. Irrespective of treatment, seeds showed a requirement for cooler temperatures for germination. These results suggest that rising temperatures and changes in fire regime associated with global warming may alter future germination responses of Stachystemon vinosus.

Seed germination and unusual serotiny in two species of Conospermum from fire-prone vegetation in Western Australia

2014 ◽  
Vol 62 (6) ◽  
pp. 511 ◽  
Author(s):  
Xiaoying Zhao ◽  
P. G. Ladd
Keyword(s):  
Western Australia ◽  
Growth Form ◽  
Cortical Cells ◽  
Aerial Parts ◽  
Plant Body ◽  
Inflorescence Axis ◽  
Whole Plant ◽  
Germination Trial ◽  
Morphological Modification ◽  
In Fire

Serotiny is a mechanism for storing propagules on plants, so that seed dispersal can be maximised after the death of aerial parts of plants or to take advantage of conditions beneficial to establishment. In fire-prone vegetation, regeneration of new plants after fire is mostly from seeds that are stored in the soil or on the plant. These traits are generally consistent within a genus. However, in Conospermum, a genus of shrubs that mostly occur in fire-prone vegetation and in which most species have soil-stored seeds, two species exhibit an unusual serotinous structure. We examined the morphology and anatomy of inflorescences and infructescences of C. capitatum and C. petiolare that were collected from natural vegetation in south-western Western Australia. Inflorescence and infructescence axes were sectioned and examined microscopically, fresh infructescences were heated in an oven to various temperatures for 2 min and the fruits from them sown in a germination trial. Some fruits were also treated with smoke chemicals. Both species have a low, dense growth form and retain the seed-like fruits in a serotinous structure formed by enlargement of the cortical cells of the inflorescence axis after flowering. The fruits can be effectively released from the plant only if the foliage is removed by a fire. For both species, the infructescence protects the fruits from heat up to 200°C for 2 min and this is similar to protection afforded by woody cones in other serotinous species. C. capitatum requires either heat or smoke to cue germination, whereas C. petiolare requires no cue, as is found in most other serotinous species. A combination of morphological modification associated with allometry of the whole plant body and physiological changes to germination requirements shows that a series of complex changes may be needed to develop serotiny from non-serotinous antecedents.

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