Stephen A. Murphy

The short-term effects of an extensive and high-intensity fire on vertebrates in the tropical savannas of the central Kimberley, northern Australia

We report the effects of an extensive (>7000 km 2 ), high-intensity late-dry-season fire in the central Kimberley, Western Australia, on the species richness and abundance of mammals, reptiles and birds. Five weeks after the fire we surveyed 12 sites (six burnt, six unburnt); each pair of sites was closely matched for soil type and vegetation. The species richness and abundance of mammals and reptiles was greater at unburnt sites, especially for mammals (with a 4-fold difference in abundance between burnt and unburnt sites). There was an indication that reptiles immigrated into unburnt patches, but mammals did not. There were also species-specific responses to the fire: Rattus tunneyi and Pseudomys nanus were much more abundant in unburnt sites, whereas Pseudomys delicatulus was caught in equal numbers at burnt and unburnt sites. Diurnal reptiles were more abundant at unburnt sites, but nocturnal reptiles were equally common at burnt and unburnt sites. Avian species richness and overall abundance was similar between burnt and unburnt patches, although a few species showed preferences for one state or the other. The overall high trapping success for mammals (18% across all sites; 28% in unburnt patches) contrasts with the well documented mammal collapse in parts of northern Australia and seems paradoxical given that our study area has experienced the same increase in fire frequency and extent that is often blamed for species collapse. However, our study area has fewer pressures from other sources, including grazing by large herbivores, suggesting that the effects of these pressures, and their interaction with fire, may have been underestimated in previous studies.

Overlap and competition for nest holes among eclectus parrots, palm cockatoos and sulphur-crested cockatoos

We examined the extent of overlap in the characteristics of nest holes used by eclectus parrots (Eclectus roratus), palm cockatoos (Probosciger aterrimus) and sulphur-crested cockatoos (Cacatua galerita) in patches of rainforest and woodland in and around Iron Range National Park, Cape York Peninsula, Australia. Eclectus parrots nested only in rainforest and palm cockatoos nested mostly in eucalypt woodland adjacent to rainforest. Sulphur-crested cockatoos nested in both habitats. Nest holes of eclectus parrots and rainforest sulphur-crested cockatoos were in trees of larger DBH (diameter at breast height) and higher off the ground than those of palm cockatoos and sulphur-crested cockatoos in woodland. Palm cockatoos differed from the other parrots in their use of deeper holes with entrances that faced skywards rather than sideways. Both palm cockatoos and woodland sulphur-crested cockatoos used nests with smaller entrances than eclectus parrots and rainforest sulphur-crested cockatoos. All species showed intraspecific competition for nest holes. Behavioural conflict was also common between sulphur-crested cockatoos and the other two species. Each year 9.7-25.8% of eclectus parrot nests were taken over either permanently or temporarily by sulphur-crested cockatoos. Only one palm cockatoo nest was taken over by sulphur-crested cockatoos. Nest-holes were destroyed by natural causes at similar rates in rainforest (3.8% per annum over 174 nest-years) and woodland (5.4% per annum over 93 nest-years). Four nest trees fell over, and the floor of the nest collapsed at a further four holes. Three woodland nest trees burnt down during dry-season fires (August-October). New eclectus parrot and rainforest sulphur-crested cockatoo holes originated from incipient hollows on the tree that were modified by the parrots. We discuss the intense competition between these large parrots in light of the apparent shortage of appropriate nest holes in Cape York rainforest and eucalypt woodland.

The effects of early and late-season fires on mortality, dispersal, physiology and breeding of red-backed fairy-wrens (Malurus melanocephalus)

Context. Mismanaged fire is one of the main processes threatening biodiversity in northern Australian savannas. While the suite of species adversely affected by fire has been quite well documented, empirical studies that seek to identify the ecological mechanisms that underpin these declines are rare. This dearth of mechanistic knowledge is hindering the refinement and development of conservation management practices and policy, such as early dry-season prescribed burning programmes. Aims. Our aim was to describe why red-backed fairy-wrens (RBWs; Malurus melanocephalus) decline after fire, as shown by previous studies. Methods. We examined the effects of early and late dry-season fire (and an unburnt control) on the mortality, dispersal, physiology and breeding of colour-marked RBWs. We also tested whether the early fire area became an important refuge after the late fire. Key results. Neither fire treatment caused a detectable increase in mortality. Individuals relocated short distances to unburnt habitat following both fires. Some individuals used the early fire area after the late fire, but only if they were already living nearby and most also relied on adjacent unburnt habitat. Blood-parasite infection and pectoral-muscle attrition were unaffected by the treatments. The early fire caused loss of body mass at a time when the control population gained mass after breeding, whereas the late fire had no effect on mass. Blood haemoglobin concentrations in birds affected by the late fire deviated from the levels observed in the control population, presumably because of disruption of behaviours associated with the onset of the breeding season. Mayfield estimations of daily egg-survival probability showed no difference among the treatments, whereas the daily probability of nestling survival was significantly lower in the late fire area. Pairs affected by the late fire also had a shorter breeding season and none attempted multiple broods after earlier successes. Conclusions. Our results suggest that the reproductive output of RBWs is low following late dry-season fire, and that this is the main mechanism that explains their decline. Implications. This study provides support for the value of using early dry-season prescribed burning to limit the effects of late dry-season wildfire. However, there are important caveats to this, such as the retention of near-by unburnt habitat, and the consideration of variable regeneration rates for different vegetation types.

Do Palm Cockatoos (Probosciger aterrimus) have long enough lifespans to support their low reproductive success

Abstract As an order, Parrots (Psittaciformes) are both the longest lived birds and among the most endangered. Palm Cockatoos (Probosciger aterrimus) have an extremely slow life history, including one of the lowest rates of breeding success reported for parrots. Here we use population viability analysis (PVA) to examine whether populations of Palm Cockatoos are viable in the long term with such low rates of reproduction. We built PVA models for two field sites with robust data on reproductive success and availability of nest-hollows: Iron Range on Cape York Peninsula (Queensland, Australia) and Crater Mountain (Eastern Highlands Province, Papua New Guinea). Our Iron Range models incorporate a fluctuating resource base of nest-hollows resulting from natural losses from fire, wind and tree decay and natural replenishment through tree breakages in tropical cyclones. The number of females allowed to breed each year in the simulations was limited by the availability of hollows. Our Iron Range models suggest that the population is only viable if juvenile and adult mortality rates are very low, and that at least some birds in the population live to 100 years old. Based on known maximum lifespans in the Cacatuidae, we conclude that Palm Cockatoos at Iron Range are unlikely to live for long enough on average to support their low rates of reproduction, and highlight the possibility that the population may be in decline. At Crater Mountain, where nestlings are harvested for food by local people, the models suggest that the reported current rate of 40% of nestlings taken is not sustainable.

A Landscape-Scale, Applied Fire Management Experiment Promotes Recovery of a Population of the Threatened Gouldian Finch, Erythrura gouldiae, in Australia’s Tropical Savannas

Fire is an integral part of savanna ecology and changes in fire patterns are linked to biodiversity loss in savannas worldwide. In Australia, changed fire regimes are implicated in the contemporary declines of small mammals, riparian species, obligate-seeding plants and grass seed-eating birds. Translating this knowledge into management to recover threatened species has proved elusive. We report here on a landscape-scale experiment carried out by the Australian Wildlife Conservancy (AWC) on Mornington Wildlife Sanctuary in northwest Australia. The experiment was designed to understand the response of a key savanna bird guild to fire, and to use that information to manage fire with the aim of recovering a threatened species population. We compared condition indices among three seed-eating bird species–one endangered (Gouldian finch) and two non-threatened (long-tailed finch and double-barred finch)—from two large areas (> 2,830 km2) with initial contrasting fire regimes (‘extreme’: frequent, extensive, intense fire; versus ‘benign’: less frequent, smaller, lower intensity fires). Populations of all three species living with the extreme fire regime had condition indices that differed from their counterparts living with the benign fire regime, including higher haematocrit levels in some seasons (suggesting higher levels of activity required to find food), different seasonal haematocrit profiles, higher fat scores in the early wet season (suggesting greater food uncertainty), and then lower muscle scores later in the wet season (suggesting prolonged food deprivation). Gouldian finches also showed seasonally increasing stress hormone concentrations with the extreme fire regime. Cumulatively, these patterns indicated greater nutritional stress over many months for seed-eating birds exposed to extreme fire regimes. We tested these relationships by monitoring finch condition over the following years, as AWC implemented fire management to produce the ‘benign’ fire regime throughout the property. The condition indices of finch populations originally living with the extreme fire regime shifted to resemble those of their counterparts living with the benign fire regime. This research supports the hypothesis that fire regimes affect food resources for savanna seed-eating birds, with this impact mediated through a range of grass species utilised by the birds over different seasons, and that fire management can effectively moderate that impact. This work provides a rare example of applied research supporting the recovery of a population of a threatened species.

Another piece in an Australian ornithological puzzle - a second Night Parrot is found dead in Queensland

Abstract We report on a specimen of the Night Parrot (Pezoporus occidentalis) found dead in Diamantina National Park, in western Queensland. It was found on a low dissected tableland near the head of a small creek, in an area vegetated by sparse shrubland of Gidgee (Acacia cambagei), Crimson Turkey Bush (Eremophila latrobei) and Blunt-leaf Cassia (Senna artemisioides var. helmsii.) Conditions were dry and the vegetation was not flowering or seeding. It is the second such specimen to be found dead in the region since 1990. The two specimens were found less than 200 km apart. Molecular analysis showed that both specimens are female. The latest specimen appears to be an immature undergoing post-juvenile moult. The specimen confirms a breeding event by Night Parrots in the region less than two years before its discovery in September 2006. Together with the 1990 specimen and other recent reports, it can be inferred that a population of Night Parrots exists in the region and that this is an encouraging sign that the species is not simply senescing to extinction. Diamantina National Park likely provides excellent opportunities to further study the ecology and management requirements of this enigmatic species.

Analysis of mitochondrial DNA clarifies the taxonomy and distribution of the Australian snubfin dolphin (Orcaella heinsohni) in northern Australian waters

Conservation management relies on being able to identify and describe species. Recent morphological and molecular analyses of the dolphin genus Orcaella show a species-level disjunction between eastern Australia and South-east Asia. However, because of restricted sampling, the taxonomic affinities of the geographically intermediate populations in the Northern Territory and Western Australia remained uncertain. We sequenced 403 base pairs of the mitochondrial control region from five free-ranging Orcaella individuals sampled from north-western Western Australia and the Northern Territory. Low net nucleotide divergence (0.11–0.67%) among the Australian Orcaella populations show that populations occurring in the Northern Territory and Western Australia belong to the Australian snubfin (O. heinsohni) rather than the Asian Irrawaddy dolphin (O. brevirostris). Clarifying the distribution of Orcaella is an important first step in the conservation and management for both species; however, an understanding of the metapopulation structure and patterns of dispersal among populations is now needed.

Understanding and managing the threats to Night Parrots in south-western Queensland

ABSTRACT South-western Queensland supports a suite of threatened native species, including Night Parrots. We investigated why this species has persisted in the region and discovered low prevalence of the typical factors that are thought to explain fauna attrition elsewhere in central Australia. Foxes appear to be completely absent. Feral cats were recorded relatively infrequently and showed a significant preference for habitats less commonly used by Night Parrots, a partition that may be driven by the presence of dogs that were detected twice as frequently as cats. Our study area has had a long history of moderate grazing pressure, which is concentrated mostly in productive alluvial habitats. We detected very few herbivores, and dog scat analyses suggest that macropod populations are regulated by predation. Archival imagery shows that large fires are not a feature of this landscape, resulting in the long-term, stable availability of patchy Triodia habitats separated by natural no-fuel areas. Based on these empirical data, we postulate that low non-native predator pressure, long-term stable availability of Triodia cover and a productive landscape that has had only moderate grazing pressure are the interacting factors that may explain why Night Parrots have persisted in south-western Queensland. We present practical management actions that could enhance the suitability of this landscape for Night Parrots.

Observations on breeding Night Parrots (Pezoporus occidentalis) in western Queensland

ABSTRACT A population of Night Parrots (Pezoporus occidentalis) was discovered in 2013 in western Queensland and has become the primary focus of efforts aimed at conserving habitat and protecting the species from extinction. Critical information on nesting habitat and location, breeding season and behaviour, clutch size and breeding success is currently limited to anecdotal 19th-century observations and accounts by early natural historians. Here we describe several breeding attempts at Pullen Pullen Reserve. Our observations include nest and fledgling descriptions, habitat and clutch characteristics, breeding seasonality, adult breeding behaviour and vocalisations. We also identify a King Brown Snake (Pseudechis australis) as the predator responsible for one nesting failure. Our observations confirm historical reports of nesting habitat, egg and clutch size and breeding seasonality and provide important new information on vocalisations and adult behaviour around an active nest. These new data provide a basis for future studies and conservation management of this enigmatic threatened species.

Social landscape of the night parrot in western Queensland, Australia

The attitudes of the owners or managers of properties potentially supporting populations of night parrot (Pezoporus occidentalis) in western Queensland, Australia, were explored using interviews to understand whether they would be sympathetic to the species’ conservation. Eighteen interviews were carried out by a former member of the local grazing community and found a high level of support for conservation, especially if it did not unduly disrupt existing grazing management practices and there was compensation in the event property management needed to change. This included trying to limit burning and not overgrazing habitat in which the parrot might occur. It also included the cessation of wild dog baiting, which is conducted to reduce calf losses, although concern about wild dogs was deeply entrenched. While some graziers were indifferent, none were openly antagonistic to parrot conservation that might involve their property. The results suggest that collaborative management with local graziers can contribute substantially to conservation of the night parrot in the region and any fears that graziers might be antagonistic to night parrot conservation are ill-founded.