Suchergebnisse

Ecological fire management in Australia is often built on an assumption that meeting the needs of plant species will automatically meet the needs of animal species. However, the scarcity of ecological data on the needs of fauna in relation to fire undermines the confidence managers should place in current popular frameworks for planning ecological burning. Such frameworks are built almost entirely around the goal of maintaining plant community diversity. They provide little guidance to managers regarding the characteristics of desirable 'mosaics' (e.g. patch size, connectivity or composition of age-since-burnt classes) or the timing of fires in relation to faunal population trends linked to other cycles (e.g. El Niño events). Claims by agencies of adopting an adaptive management approach ('learning by doing') to cope with a dearth of knowledge are credible only if monitoring and evaluation are carried out and future actions are modified in light of new evidence. Much monitoring of fauna is of such a small scale and short duration that the statistical likelihood of detecting a positive or negative effect of the management regime is minute. Such shortcomings will only be overcome through broad-scale and/or long-term studies of fauna. The funding for such research is unlikely to be forthcoming if fire ecologists and land managers convey the impression that the current data are adequate for the implementation of the current planning frameworks.

The noisy miner (Manorina melanocephala) is a large, communally breeding colonial native honeyeater renowned for aggressively excluding virtually all other bird species from areas they occupy. In the woodlands of southern and eastern Australia, numerous studies have identified the domination of remnants by noisy miners as having a profound negative effect on woodland bird communities. Despite this, very little is known about the habitat characteristics that make domination of a site by noisy miners more likely. This study investigated the depth from edges that noisy miners penetrated into large woodland remnants (>48 ha) within Victoria and attempted to identify habitat characteristics that influenced the depth to which they penetrated. Penetration depth differed significantly across four broad habitat types but commonly ranged from 150 m to more than 300 m from the remnant edge. If noisy miners colonise a site, their capacity to penetrate in from a remnant edge has implications for the size that remnants need to be (>36 ha) to contain any core 'noisy-miner-free' habitat and the width that habitat corridors need to be to avoid domination by noisy miners (>600 m). Broad differences in habitat type and the abundance of noisy miners at a site were the most powerful predictors of penetration distance. The density of canopy trees on a site was the only other habitat variable contributing to the most parsimonious model of penetration depth. Decreasing density of trees was associated with increasing penetration depth by noisy miners.

We tested the hypothesis that predation rates increase near habitat edges and can cause low reproductive success in forest bird species living in a fragmented habitat. We constructed artificial yellow-faced honeyeater (Lichenostomus chrysops) nests and placed them 5 m, 20 m, 50 m and 200 m from the forest edge. We also monitored natural yellow-faced honeyeater nests at varying distances from the forest edge. Artificial nests experienced 43% predation over the 14-day exposure period, while natural yellow-faced honeyeater nests experienced 28% during the incubation period and 47% during the nestling period. No negative edge effect was detected for artificial or natural nests. In fact, natural nests experienced higher nest success closer to the forest edge. There was no increase in the number of avian predators recorded at the forest edge, even though birds were identified as the main predators at artificial nests (49%). The lack of support for both the 'ecological trap' and 'predator influx' hypotheses contributes to a growing body of evidence that suggests that not all species surviving in highly fragmented environments are negatively affected by edge effects.

Context
Competition for space and resources within a fragmented landscape may change interspecific interactions within the remaining available habitat. These changes may inhibit the persistence of one species but facilitate the success of another. The yellow-throated miner (Manorina flavigula) is an example of a successful species, reportedly more common in the landscape as a result of fragmentation yet the consequences of its success are still relatively unknown.

Aims
To investigate whether the yellow-throated miner had negative impacts on bird community assemblages, particularly small insectivorous species, and whether its presence resulted in higher psyllid abundances and lower tree health, similar to impacts noted for other miner species.

Methods
We undertook this study near Walpeup in Victoria's Mallee region, a highly fragmented, agriculture-dominated, semiarid landscape. Yellow-throated miner colonies and control sites free of miners were identified and surveyed for bird species present, psyllid abundance and measures of tree health.

Conclusions
The presence of the yellow-throated miner was associated with a significant reduction in bird species richness, lower abundance of small birds and a dissimilar community composition. Psyllid abundance was higher in miner colonies and tree health was significantly lower. Small insectivorous birds compete directly with miners for resources and, as such, are likely targeted by interspecific aggressive behaviour. The absence of small species from miner colonies most likely caused a trend in increased psyllid abundance and subsequently reduced tree health.

Implications
Our findings suggest that management of these miners is likely required to prevent further loss of biodiversity in this fragmented landscape. The loss of bird species and reduced tree health due to the influence of the yellow-throated miner presents one of the greatest threats to these communities nationally and a challenging conservation problem.

Abstract Context Species translocations are used in conservation globally. Although harvest for translocation may have negative impacts on source populations, translocation programs rarely explore ways of minimising those impacts. In fluctuating source populations, harvest timing may affect its impact because population size and trajectory vary among years. Aims We explored whether the timing and scale of harvest can be altered to reduce its impact on a fluctuating source population of Mallee Emu-wrens, Stipiturus mallee; an endangered passerine in south-eastern Australia. Mallee Emu-wren populations fluctuate with ~5–10-year drought–rain cycles. Methods We used population viability analysis (PVA) to compare the impact of five harvest scales (no harvest, 100, 200, 300 or 500 individuals) under three population trajectories (increasing, stable or decreasing) and two initial population sizes (our model-based estimate of the population size and the lower 95% confidence interval of that estimate). To generate a model-based estimate of the population size, we surveyed 540 sites (9 ha), stratified according to environmental variables known to affect Mallee Emu-wren occurrence. We used an information-theoretic approach with N-mixture models to estimate Mallee Emu-wren density, and extrapolated results over all potential habitat. Key Results We estimate that in spring 2019, the source population consisted of 6449 individuals, with a minimum of 1923 individuals (lower 95% confidence interval). Of 48 harvest scenarios, only seven showed no impact of harvest within 5 years (15%). Those seven all had increasing population trajectories and carrying capacity set to equal initial population size. Twenty-six populations showed no impact of harvest within 25 years (54%). These were either increasing populations that had reached carrying capacity or decreasing populations nearing extinction. Conclusions Initial population size, carrying capacity, harvest scale and population trajectory were all determinants of harvest impact. Given the importance of carrying capacity, further research is required to determine its role in the Mallee Emu-wren source population. Implications Harvesting Mallee Emu-wrens after high-rainfall years will have the least impact because source populations are likely to be large with increasing trajectories. For fluctuating source populations, flexibility in the timing of harvest can reduce its impact and should be considered during translocation planning.

Bell miner (Manorina melanophrys) colonies are closely associated with decreased avian abundance and diversity and an apparently associated increase in psyllid abundance. However, a causative link between the presence of bell miners and increased psyllid abundance has yet to be established. We took advantage of the movement of bell miners into two new areas to investigate the ecological consequences of bell miner occupation on both avian and psyllid abundance. We monitored the number of bell miners and other avian species, using area searches, and psyllid abundance by monthly counts of lerp on leaves. Bell miner presence alone had limited effect on either bird diversity or abundance. However, when miners were also giving their distinctive 'tink' vocalisation, a significant decrease in avian abundance and diversity was observed. This evidence supports the hypothesis that 'tink' vocalisations are used by interspecific competitors to detect bell miner colonies. At the time of initial occupation, new sites did not have significantly elevated levels of psyllids compared with surrounding areas unoccupied by bell miners. Six months later one of the two newly occupied sites had significantly more Cardiaspina spp. than either the long-established colony or an unoccupied control site. In contrast, infestations of Glycaspis spp. remained significantly lower at both new sites when compared with the long-established colony, but equivalent to unoccupied areas. Given this, we conclude that bell miner occupation does not necessarily lead to an increase in psyllid abundance, characteristic of tree dieback in some colonies, and that a causative link between bell miner presence and declining tree health remains to be demonstrated.

It has been postulated that aggressive honeyeaters like the noisy miner,
Manorina melanocephala, may contribute to rural tree
decline by excluding small insectivorous birds from remnant patches of
woodland, thereby reducing the level of predation upon defoliating insects.
Previous studies provide correlational evidence that avian diversity and
abundance is lower in remnant patches of woodland occupied by noisy miners
than in those without noisy miners. Noisy miners were removed from three small
remnant patches of woodland in north-eastern Victoria. The removal of the
majority of noisy miners from a site, or even the removal of only part of a
noisy miner colony from a site, resulted in a major influx of honeyeaters and
other insectivorous birds to these sites in the following three months. Such
major invasions were not observed on matching control sites. At two of the
three removal sites, this led to an increase in both the abundance and
diversity of birds on the site. At the third site, there was an increase in
the diversity, but not the abundance of birds. These experiments are the first
to demonstrate that noisy miners affect avian diversity and abundance by
aggressive exclusion of small birds. They also showed that if domination by
noisy miners is reduced, small, degraded woodland remnants can support
significant populations of some small insectivorous birds and honeyeaters.
Noisy miners did not reinvade the experimental sites during the following 16
months and avian diversity and abundance remained higher at the experimental
sites than at the paired control sites. Long-term monitoring is needed to
determine whether the small invading bird species have a lasting effect upon
insect populations and tree health.

Context
The superb lyrebird Menura novaehollandiae is thought to be an important ecosystem engineer that, through its foraging, accelerates the decomposition of litter in Eucalyptus forests. Lyrebird foraging is therefore likely to affect forest fuel loads and hence fire behaviour in these fire-prone forests. In turn, fire is likely to reduce the abundance and influence the distribution of lyrebirds.

Aims
Our goal was to determine the impacts of a major bushfire on the habitat and food sources for the superb lyrebird and the effects of foraging activities of lyrebirds on litter fuel and potential fire behaviour in gullies of herb-rich foothill forests.

Methods
The effect of fire on lyrebirds and their habitat in the post-fire environment was examined at the landscape-scale, 2 years after fire; and at the patch-scale, 3 years after fire. Paired exclusion and control plots were also used over a 9-month period to assess the effects of foraging by the lyrebird on litter accumulation and fuel connectivity. Fire-behaviour models were used to determine the potential influence of lyrebird scratchings on fire behaviour.

Key results
At the landscape scale, lyrebirds were present in both unburnt and ground-burnt sites, but not in canopy-burnt sites. Within patchily burnt sites, lyrebirds favoured foraging in unburnt patches. On average, lyrebird foraging reduced litter fuel loads by 25% (1.66 t ha–1) in plots in which they were free to forage, compared with plots from which they were excluded, over a 9-month period. Fire-behaviour modelling showed that lyrebird foraging led to a lower likelihood of fire occurring and less intense fire.

Conclusions
Distinctly different vegetation structure and composition between burnt and unburnt patches appears to influence both the foraging patterns and distribution of lyrebirds. Additionally, foraging by lyrebirds reduces surface fuel loads and fuel connectivity such that fire spread is likely to be inhibited.

Implications
We propose that alternative stable states may emerge in Eucalyptus forests as a result of feedback mechanisms among lyrebirds, vegetation and fuel accumulation. Therefore, the ecological role of lyrebirds is an important consideration in forest fuel management and conservation in these extensive, fire-prone forests in south-eastern Australia.

We critically evaluated population-monitoring programs for three endangered species of Australian honeyeater: the helmeted honeyeater, Lichenostomus melanops cassidix, the black-eared miner, Manorina melanotis, and the regent honeyeater, Xanthomyza phrygia (Meliphagidae). Our results challenge the common assumption that meaningful monitoring is possible in all species within the five-year lifetime of recovery plans. We found that the precision achievable from monitoring programs not only depends on the monitoring technique applied but also on the species' biology. Relevant life-history attributes include a species' pattern of movement, its home-range size and its distribution. How well understood and predictable these attributes are will also influence monitoring precision. Our results highlight the large degree of variability in precision among monitoring programs and the value of applying power analysis before continuing longer-term studies. They also suggest that managers and funding agencies should be mindful that more easily monitored species should not receive preferential treatment over species that prove more difficult to monitor.

Context. Designing an appropriate survey protocol requires understanding of how capture rates of target species may be influenced by factors other than on-ground abundance, such as weather conditions or seasonality. This is particularly relevant for ectotherms such as reptiles, as activity can be affected by environmental conditions such as ambient temperature.
Aims. The present study examines factors affecting capture success of reptiles in semi-arid environments of southern Australia, and addresses the following two main questions: (1) what is the influence of weather and seasonal factors on capture rates of reptiles, and (2) what are the implications for developing an effective protocol for reptile surveys?
Methods. We surveyed reptiles using pitfall traps in spring and summer of 2006/07 and 2007/08 at sites (n = 280) throughout the Murray Mallee region of south-eastern Australia. We used mixed-effect regression models to investigate the influence of seasonal and weather-related variables on species' capture success.
Key results. Total captures of reptiles, and the likelihood of capture of 15 reptile species, increased with rising daily temperature. Greater numbers of individual species were captured during spring than in summer, even though temperatures were cooler. This probably reflects greater levels of activity associated with breeding. Several species were more likely to be captured when maximum or minimum daily temperatures exceeded a certain level (e.g. Lerista labialis, Delma australis, Nephrurus levis). Other factors, such as rainfall and moon phase, also influenced capture success of some species.
Conclusions. Surveys for reptiles in semi-arid environments are likely to capture the greatest diversity of species on warm days in late spring months, although surveys on hot days in summer will enhance detection of particular species (e.g. Morethia boulengeri, Varanus gouldii). We recommend trapping during periods with maximum temperatures exceeding 25–30°C and minimum overnight temperatures of 15°C. Finally, trapping during rainfall and full-moon events will maximise chances of encountering species sensitive to these variables (blind snakes and geckoes).
Implications. Selecting the most favourable seasonal and weather conditions will help ensure that reptile surveys maximise the likelihood of capturing the greatest diversity of reptiles, while minimising trap-effort required.

Context. Wildfire is a major driver of the structure and function of mallee eucalypt- and spinifex-dominated landscapes. Understanding how fire influences the distribution of biota in these fire-prone environments is essential for effective ecological and conservation-based management.
Aims. We aimed to (1) determine the effects of an extensive wildfire (118 000 ha) on a small mammal community in the mallee shrublands of semiarid Australia and (2) assess the hypothesis that the fire-response patterns of small mammals can be predicted by their life-history characteristics.
Methods. Small-mammal surveys were undertaken concurrently at 26 sites: once before the fire and on four occasions following the fire (including 14 sites that remained unburnt). We documented changes in small-mammal occurrence before and after the fire, and compared burnt and unburnt sites. In addition, key components of vegetation structure were assessed at each site.
Key results. Wildfire had a strong influence on vegetation structure and on the occurrence of small mammals. The mallee ningaui, Ningaui yvonneae, a dasyurid marsupial, showed a marked decline in the immediate post-fire environment, corresponding with a reduction in hummock-grass cover in recently burnt vegetation. Species richness of native small mammals was positively associated with unburnt vegetation, although some species showed no clear response to wildfire.
Conclusions. Our results are consistent with the contention that mammal responses to fire are associated with their known life-history traits. The species most strongly affected by wildfire, N. yvonneae, has the most specific habitat requirements and restricted life history of the small mammals in the study area. The only species positively associated with recently burnt vegetation, the introduced house mouse, Mus domesticus, has a flexible life history and non-specialised resource requirements.
Implications. Maintaining sources for recolonisation after large-scale wildfires will be vital to the conservation of native small mammals in mallee ecosystems.

Fire has been a source of global biodiversity for millions of years. However, interactions with anthropogenic drivers such as climate change, land use, and invasive species are changing the nature of fire activity and its impacts. We review how such changes are threatening species with extinction and transforming terrestrial ecosystems. Conservation of Earth's biological diversity will be achieved only by recognizing and responding to the critical role of fire. In the Anthropocene, this requires that conservation planning explicitly includes the combined effects of human activities and fire regimes. Improved forecasts for biodiversity must also integrate the connections among people, fire, and ecosystems. Such integration provides an opportunity for new actions that could revolutionize how society sustains biodiversity in a time of changing fire activity. ; The workshop leading to this paper was funded by the Centre Tecnològic Forestal de Catalunya and the ARC Centre of Excellence for Environmental Decisions. L.T.K. was supported by a Victorian Postdoctoral Research Fellowship (Victorian Government), a Centenary Fellowship (University of Melbourne), and an Australian Research Council Linkage Project Grant (LP150100765). A.R. was supported by the Xunta de Galicia (Postdoctoral Fellowship ED481B2016/084-0) and the Foundation for Science and Technology under the FirESmart project (PCIF/MOG/0083/2017). A.L.S. was supported by a Marie Skłodowska-Curie Individual Fellowship (746191) under the European Union Horizon 2020 Programme for Research and Innovation. L.R. was supported by the Australian Government's National Environmental Science Program through the Threatened Species Recovery Hub. L.B. was partially supported by the Spanish Government through the INMODES (CGL2014-59742-C2-2-R) and the ERANET-SUMFORESTS project FutureBioEcon (PCIN-2017-052). This research was supported in part by the U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station.