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Macropod habitat use and response to management interventions in an agricultural - forest mosaic in north-eastern Tasmania as inferred by scat surveys
In: Wildlife research, Volume 38, Issue 2, p. 103
ISSN: 1448-5494, 1035-3712
Context Native pest herbivores often require population numbers to be controlled in landscape settings where agricultural, plantation forests and native forests are juxtaposed. The Tasmanian pademelon Thylogale billardierii and the red-necked wallaby Macropus rufogriseus rufogriseus are among the most abundant native pest herbivore species in Tasmania. Aims We aimed to determine the habitat use of pademelons and wallabies in response to (i) environmental and seasonal variation, and (ii) two different wildlife management interventions (shooting and fencing) in an agricultural–forest mosaic in north-eastern Tasmania. Methods Macropod abundance before and after shooting and fencing management interventions were estimated by changes in the rate of deposition of faecal pellets (scats per unit area per time interval) on an array of permanent transects that were stratified across three habitat types (agricultural land, plantation forest, and native forest). An experiment was also conducted to determine the endurance of fresh scats in the three habitats. Key results More than 90% of scats remained undecomposed for over five months, and more than 50% of scats remained undecomposed for over 11 months across the study site. Decomposition rates were significantly influenced by habitat type, specifically, highest in agricultural land and lowest in native forest for both species. Scat deposition rates showed that species abundance was influenced by habitat type and season. Macropod abundance was highest in agricultural land and lowest in native forest. Compared with summer and early autumn, pademelon scat abundance significantly decreased in late autumn and spring on agricultural land but showed no change for plantation forest or native forest. Wallaby scats showed similar seasonal trends for all three habitats, lower in late autumn and spring compared with summer and early autumn. Following each of the management interventions, macropod scat deposition rates decreased predominantly on agricultural land. This effect decreased with increasing distance from intervention loci. Conclusions We demonstrate that scat monitoring provides a useful survey technique for the assessment of macropod habitat use, and show that macropods select for agricultural habitats. Shooting and fencing interventions reduced the use of agricultural habitats, but this effect was localised. Implications A whole-landscape perspective is required when assessing the impacts of management interventions on pest populations. Results highlight the formidable challenges in controlling native herbivores in habitat mosaics, given the localised effects of management interventions and the importance of environmental and seasonal factors as drivers of habitat use.
Evolution of a pyrocumulonimbus event associated with an extreme wildfire in Tasmania, Australia
In: Natural hazards and earth system sciences: NHESS, Volume 20, Issue 5, p. 1497-1511
ISSN: 1684-9981
Abstract. Extreme fires have substantial adverse effects on society and
natural ecosystems. Such events can be associated with the intense coupling of
fire behaviour with the atmosphere, resulting in extreme fire
characteristics such as pyrocumulonimbus cloud (pyroCb) development. Concern
that anthropogenic climate change is increasing the occurrence of pyroCbs
globally is driving more focused research into these meteorological
phenomena. Using 6 min scans from a nearby weather radar, we describe the
development of a pyroCb during the afternoon of 4 January 2013 above the
Forcett–Dunalley fire in south-eastern Tasmania. We relate storm development
to (1) near-surface weather using the McArthur forest fire danger index
(FFDI) and the C-Haines index, the latter of which is a measure of the vertical atmospheric
stability and dryness, both derived from gridded weather reanalysis for
Tasmania (BARRA-TA); and (2) a chronosequence of fire severity derived from
remote sensing. We show that the pyroCb rapidly developed over a 24 min
period on the afternoon of 4 January, with the cloud top reaching a height
of 15 km. The pyroCb was associated with a highly unstable lower atmosphere
(C-Haines value of 10–11) and severe–marginally extreme (FFDI 60–75) near-surface
fire weather, and it formed over an area of forest that was severely burned
(total crown defoliation). We use spatial patterns of elevated fire weather
in Tasmania and fire weather during major runs of large wildfires in
Tasmania for the period from 2007 to 2016 to geographically and historically
contextualise this pyroCb event. Although the Forcett–Dunalley fire is the
only known record of a pyroCb in Tasmania, our results show that eastern and
south-eastern Tasmania are prone to the conjunction of high FFDI and
C-Haines values that have been associated with pyroCb development. Our
findings have implications for fire weather forecasting and wildfire
management, and they highlight the vulnerability of south-east Tasmania to extreme
fire events.
Current and future threats from non-indigenous animal species in northern Australia: a spotlight on World Heritage Area Kakadu National Park
In: Wildlife research, Volume 34, Issue 6, p. 419
ISSN: 1448-5494, 1035-3712
Non-indigenous animal species threaten biodiversity and ecosystem stability by damaging or transforming habitats, killing or out-competing native species and spreading disease. We use World Heritage Area Kakadu National Park, northern Australia, as a focal region to illustrate the current and potential threats posed by non-indigenous animal species to internationally and nationally recognised natural and cultural values. Available evidence suggests that large feral herbivores such as Asian swamp buffalo, pigs and horses are the most ecologically threatening species in this region. This may reflect the inherent research bias, because these species are highly visible and impact primary production; consequently, their control has attracted the strongest research and management efforts. Burgeoning threats, such as the already established cane toad and crazy ant, and potentially non-indigenous freshwater fish, marine invertebrates and pathogens, may cause severe problems for native biodiversity. To counter these threats, management agencies must apply an ongoing, planned and practical approach using scientifically based and well funded control measures; however, many stakeholders require direct evidence of the damage caused by non-indigenous species before agreeing to implement control. To demonstrate the increasing priority of non-indigenous species research in Australia and to quantify taxonomic and habitat biases in research focus, we compiled an extensive biography of peer-reviewed articles published between 1950 and 2005. Approximately 1000 scientific papers have been published on the impact and control of exotic animals in Australia, with a strong bias towards terrestrial systems and mammals. Despite the sheer quantity of research on non-indigenous species and their effects, management responses remain largely ad hoc and poorly evaluated, especially in northern Australia and in high-value areas such as Kakadu National Park. We argue that improved management in relatively isolated and susceptible tropical regions requires (1) robust quantification of density–damage relationships, and (2) the delivery of research findings that stimulate land managers to develop cost-effective control and monitoring programs.
Fertility partially drives the relative success of two introduced bovines (Bubalus bubalis and Bos javanicus) in the Australian tropics
In: Wildlife research, Volume 38, Issue 5, p. 386
ISSN: 1448-5494, 1035-3712
Context Some large herbivores introduced to Australia have achieved population densities so high as to cause considerable ecological damage. Intriguingly, others have been relatively less successful and have correspondingly perturbed their new environments less. An excellent example is two similar-sized bovine species that established feral populations in the Northern Territory of Australia in the mid-19th century. Asian swamp buffalo (Bubalus bubalis) rapidly colonised the tropical savannas, causing ecological degradation, especially on freshwater swamps. In contrast, banteng (Bos javanicus) are restricted to their point of introduction and have caused relatively negligible ecological damage. Understanding the reasons of this differential success is of theoretical and applied interest and contributes to managing large herbivore populations for ex situ conservation and feral-animal control. Aims To compare the population structure of buffalo and banteng on the basis of shot samples, so as to construct life tables for four contemporary (low-density) buffalo populations, and collated data from previous work from three historical (high-density) buffalo populations and one banteng population (the only extant ex situ population in existence). Further, to provide a validation of age estimation with and without informed priors in a Bayesian model comparing horn length and ages estimated from tooth cementum annuli. Finally, to interpret our results in the context of relative invasion potential of the two bovid species. Key Results For both species, survival of juveniles was the most important demographic component influencing deterministic population growth. However, buffalo have the demographic capacity to recover swiftly after control because of high survival and fertility rates across a range of population densities. Fertility of buffalo was historically greater than that of banteng, and buffalo fertility increased as their populations were reduced. Conclusions These findings highlight how subtle differences in demographic rates and feeding ecology can influence the success (high population growth and range expansion) of large herbivores, knowledge which is increasingly important for managing invasive species effectively. Implications We show that that individual life-history traits and demographic performance, especially fertility, play an important role in determining the spread of invasive bovids in a novel environment.
Shifts in macropod home ranges in response to wildlife management interventions
In: Wildlife research, Volume 37, Issue 5, p. 379
ISSN: 1448-5494, 1035-3712
Context. Understanding how the individual movement patterns and dispersion of a population change following wildlife management interventions is crucial for effective population management.
Aims. We quantified the impacts of two wildlife management strategies, a lethal intervention and a subsequent barrier intervention, on localised populations of the two most common macropod species in Tasmania, the Tasmanian pademelon (Thylogale billardierii) and the red-necked wallaby (Macropus rufogriseus rufogriseus). This manipulation allowed us to examine two competing hypotheses concerning the distribution of individuals in animal populations – the Ideal Free Distribution (IFD) hypothesis and the Rose Petal (RP) hypothesis. We predicted that the RP would be supported if individuals maintained their previous home ranges following intervention, whereas the IFD would be supported if individuals redistributed following the management interventions.
Methods. The movement patterns of T. billardierii and M. r. rufogriseus were tracked using GPS technology before and after the two management interventions.
Key results. Following lethal intervention, pademelons and wallabies (1) maintained their home-range area, (2) increased their utilisation of agricultural habitat and (3) shifted their mean centroid locations compared with the pre-intervention period. Following barrier intervention, pademelons and wallabies (1) maintained their home-range area, (2) decreased their utilisation of agricultural habitat and (3) shifted their mean centroid locations compared with the pre-intervention period.
Conclusions. On the basis of the individual responses of macropods to the management strategies (1) lethal intervention appeared to induce small shifts in home-range distributions of those remaining individuals in the population with home ranges overlapping the areas of lethal intervention and (2) barrier intervention is likely to induce whole-scale population movements of the animals that survive the lethal intervention in their search of an alternative food source. Both species displayed spatial and temporal shifts in their home-range distributions in response to lethal and barrier interventions that appear to conform broadly to predictions of IFD, at least in the timeframe of the present experiment.
Implications. Wildlife management strategies, which are increasingly constrained by ethical, socio-political and financial considerations, should be based on ecological and behavioural data regarding the likely responses of the target population.
Monitoring Contrasting Land Management in the Savanna Landscapes of Northern Australia
In: Environmental management: an international journal for decision makers, scientists, and environmental auditors, Volume 41, Issue 4, p. 501-515
ISSN: 1432-1009
Managing an Endangered Asian Bovid in an Australian National Park: The Role and Limitations of Ecological-Economic Models in Decision-Making
In: Environmental management: an international journal for decision makers, scientists, and environmental auditors, Volume 38, Issue 3, p. 463-469
ISSN: 1432-1009
Small mammal diversity is higher in infrequently compared with frequently burnt rainforest–savanna mosaics in the north Kimberley, Australia
In: Wildlife research
ISSN: 1448-5494, 1035-3712
A systematic review of the impacts and management of introduced deer (family Cervidae) in Australia
In: Wildlife research, Volume 43, Issue 6, p. 515
ISSN: 1448-5494, 1035-3712
Deer are among the world's most successful invasive mammals and can have substantial deleterious impacts on natural and agricultural ecosystems. Six species have established wild populations in Australia, and the distributions and abundances of some species are increasing. Approaches to managing wild deer in Australia are diverse and complex, with some populations managed as 'game' and others as 'pests'. Implementation of cost-effective management strategies that account for this complexity is hindered by a lack of knowledge of the nature, extent and severity of deer impacts. To clarify the knowledge base and identify research needs, we conducted a systematic review of the impacts and management of wild deer in Australia. Most wild deer are in south-eastern Australia, but bioclimatic analysis suggested that four species are well suited to the tropical and subtropical climates of northern Australia. Deer could potentially occupy most of the continent, including parts of the arid interior. The most significant impacts are likely to occur through direct effects of herbivory, with potentially cascading indirect effects on fauna and ecosystem processes. However, evidence of impacts in Australia is largely observational, and few studies have experimentally partitioned the impacts of deer from those of sympatric native and other introduced herbivores. Furthermore, there has been little rigorous testing of the efficacy of deer management in Australia, and our understanding of the deer ecology required to guide deer management is limited. We identified the following six priority research areas: (i) identifying long-term changes in plant communities caused by deer; (ii) understanding interactions with other fauna; (iii) measuring impacts on water quality; (iv) assessing economic impacts on agriculture (including as disease vectors); (v) evaluating efficacy of management for mitigating deer impacts; and (vi) quantifying changes in distribution and abundance. Addressing these knowledge gaps will assist the development and prioritisation of cost-effective management strategies and help increase stakeholder support for managing the impacts of deer on Australian ecosystems.
Differences in grass pollen allergen exposure across Australia
OBJECTIVE Allergic rhinitis and allergic asthma are important chronic diseases posing serious public health issues in Australia with associated medical, economic, and societal burdens. Pollen are significant sources of clinically relevant outdoor aeroallergens, recognised as both a major trigger for, and cause of, allergic respiratory diseases. This study aimed to provide a national, and indeed international, perspective on the state of Australian pollen data using a large representative sample. METHODS Atmospheric grass pollen concentration is examined over a number of years within the period 1995 to 2013 for Brisbane, Canberra, Darwin, Hobart, Melbourne, and Sydney, including determination of the 'clinical' grass pollen season and grass pollen peak. RESULTS The results of this study describe, for the first time, a striking spatial and temporal variability in grass pollen seasons in Australia, with important implications for clinicians and public health professionals, and the Australian grass pollen-allergic community. CONCLUSIONS These results demonstrate that static pollen calendars are of limited utility and in some cases misleading. This study also highlights significant deficiencies and limitations in the existing Australian pollen monitoring and data. IMPLICATIONS Establishment of an Australian national pollen monitoring network would help facilitate advances in the clinical and public health management of the millions of Australians with asthma and allergic rhinitis. ; Funding support for the Working Group came from the Australian Centre for Ecological Analysis and Synthesis (ACEAS), Terrestrial Ecosystem Research Network (TERN), which is supported by the Australian Government through the National Collaborative Research Infrastructure Strategy and the Super Science Initiative. MSD provided additional independent untied co-sponsorship for the Working Group. Alison Jaggard has been assisted by the New South Wales Government through its Environmental Trust (project reference number 2011/RD/0049).
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AusTraits, a curated plant trait database for the Australian flora
We introduce the AusTraits database - a compilation of values of plant traits for taxa in the Australian flora (hereafter AusTraits). AusTraits synthesises data on 448 traits across 28,640 taxa from field campaigns, published literature, taxonomic monographs, and individual taxon descriptions. Traits vary in scope from physiological measures of performance (e.g. photosynthetic gas exchange, water-use efficiency) to morphological attributes (e.g. leaf area, seed mass, plant height) which link to aspects of ecological variation. AusTraits contains curated and harmonised individual- and species-level measurements coupled to, where available, contextual information on site properties and experimental conditions. This article provides information on version 3.0.2 of AusTraits which contains data for 997,808 trait-by-taxon combinations. We envision AusTraits as an ongoing collaborative initiative for easily archiving and sharing trait data, which also provides a template for other national or regional initiatives globally to fill persistent gaps in trait knowledge. ; Funding Agencies|Australian Research CouncilAustralian Research Council [FT160100113, DE170100208, FT100100910]; National Collaborative Research Infrastructure Strategy (NCRIS)Australian GovernmentDepartment of Industry, Innovation and Science
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