Output list
Journal article
Published 2023
PloS one, 18, 6, e0287659
As a case study of the responses of natural history museums to changing scientific and funding environments, we analysed research publications of Australia's Natural History Museums (ANHMs) 1981-2020. Using Scopus, 9,923 relevant documents 1981-2020 were identified, mainly research papers but with a growing proportion of reviews. The number of documents published increased over tenfold from 39 (1981) to 553 (2020), likely driven by collaborations (rising from 28.5% of documents 1981-1985 to 87.2% of documents 2016-2020), contributions from retired staff, and volunteer support. The mean length of documents (pages) ranged from a low of 15.3 in 2001-2005 to a high of 17.4 in 1991-1995, but this statistically significant result was trivial in practical terms. The sources (i.e., journals, book titles, conference proceedings) in which ANHM authors published changed over time, with growing proportions of publications in journals covering molecular ecology/phylogenetics and biological conservation. We identified the major areas of study canvassed within the corpus of publications by developing structural topic models based on patterns of word use in document titles, abstracts and keyword lists. The topics discovered included study subjects traditional for natural history museums (new taxa, phylogeny, systematics, animal morphology, palaeontology, minerals), new directions (molecular genetics, ecology, biological conservation) and marine biology (probably reflecting Australia's large coastline). Most citations came from Australia, USA and UK, although in 2016-2020 only 27.9% of citing documents included an Australian author. Growth in numbers of documents and collaborations, as well as use of documents internationally over a period of great change in scientific and funding environments, indicate an enduring legacy of ANHM research, grounded on the intrinsic value of the collections.
Journal article
Habitat element associations in the bird fauna of an Australian farmland landscape
Published 2022
Pacific conservation biology, 29, 6, 503 - 525
Context
The decline of birds in farmland is of global concern.
Aims
The aim of this paper was to provide a local-scale case study of the bird fauna of temperate inland eastern Australia’s sheep–wheat belt.
Methods
Relationships between species occurrence and various habitat elements in the landscape were examined in a 342 km2 area of agricultural countryside near Wagga Wagga in southern inland New South Wales, Australia. The pre-agricultural bird fauna of this area was also investigated by collating records from previous studies of nearby larger woodland remnants.
Key results
The study identified a bird fauna of 115 species compared to 160 species known from nearby woodland remnants. Significant relationships were found with the presence of farm dams, extent of local woodland cover and roadside woodland at the levels of individual species, guilds and total fauna. A small ephemeral wetland also contributed substantially to waterbird diversity.
Conclusion
Twenty commonly recorded species typical of the farmland matrix and 15 species considered at particular risk of local extinction were identified. At the guild level, frugivore/granivores, small insectivores and hollow-users were found to be associated with remaining woodland elements in the agricultural landscape.
Implications
Ecologically sustainable management of agricultural areas is essential to avoid further local extinctions. Hollow-using species are expected to be particularly affected by the anticipated widespread loss of trees in the landscape over the next century.
Journal article
Published 2022
Animals, 12, 17, 2301
Globally, unowned urban cats are a major concern because they may suffer from poor welfare and cause problems, including public health risks, nuisances, and urban wildlife predation. While management options are often presented as a choice between culling or trap–neuter–return (TNR), for 25 years, the Lonely Miaow (Inc.) charity in Auckland, New Zealand (hereafter LM), has used a third strategy—intensive adoption or trap–assess–resolve (TAR). As of 2019, of 14,611 unowned cats trapped, 64.2% were adopted, 22.2% were euthanized if unsocialised or in grave ill-health, 5.7% were neutered and returned to the site, and 7.9% had other outcomes, such as being transferred to other shelters. Adoption rates increased over this time, exceeding 80.0% in 2018 and 2019. The cost of processing each cat from capture to adoption rose from NZD 58 in 1999 to NZD 234 by 2017. Approximately 80% of colonies (sites where cats were trapped) were around residential areas. Approximately 22% of cats required veterinary treatment after capture; common ailments included respiratory infections, ringworm, dental problems, and trauma. Consistently, 52% of cats were young kittens (<10 weeks old), c. 80% of cats were <1 year old, and only c. 2% were estimated to be >5 years old. TAR avoids euthanasia where possible. Its effectiveness would be enhanced by fewer abandonments of owned cats and kittens, fitting within integrated strategies for the control of unowned cats involving community education. Cat adoptions improve the welfare of cats and, with appropriate husbandry, should alleviate concerns about nuisances, public health, and attacks on wildlife or the cats themselves, essentially benefitting the community and the cats. This case study is relevant to other cities around the world that are seeking to manage unowned cats.
Journal article
Effects of plant hydraulic traits on the flammability of live fine canopy fuels
Published 2021
Functional ecology, 35, 4, 835 - 846
1. Plant species vary in how they regulate moisture and this has implications for their flammability during wildfires. We explored how fuel moisture is shaped by variation within five hydraulic traits: saturated moisture content, cell wall rigidity, cell solute potential, symplastic water fraction and tissue capacitance.
2. Using pressure-volume curves, we measured these hydraulic traits in twigs and distal shoots (i.e. twigs + leaves) in 62 plant species across four wooded communities in south-eastern Australia. Moisture content of fine fuels was then estimated for circumstances typical of fire weather. These projections were made assuming that under the hot, dry, windy conditions typical of large wildfires, leaves and fine twigs would function at internal water pressures close to wilting point (i.e. turgor loss point, TLP). The effect of different moisture contents at TLP on ignition time was then modelled using a fully mechanistic, finite element model of biomass ignition based on standard principles of physical chemistry.
3. We also measured predawn water potential, an indication of plant access to soil water that is influenced by root architecture. These data were used to model how root traits influence fuel moisture and ignition time.
4. Most variation among species in fuel moisture under fire weather conditions arose from differences in saturated moisture content (3.4- to 3.6-fold variation). Twig capacitance was also an important driver of fuel moisture under these weather conditions (1.9- to 2.2-fold variation in moisture content). A suite of other leaf and root traits influencing how much shoots dry out as they approach wilting point each contributed 1.0- to 1.6-fold variation in projected fuel moisture during fire weather. Fuel moisture variation in turn drove variation in flammability by modifying predicted ignition time.
5. Two main life-history types in fire-prone habitats are obligate seeders and resprouters. There were no significant differences between these species groups in estimated fuel moisture during fire weather, nor in any measured hydraulic traits.
6. Live fuel moisture is an important determinant of wildfire activity. Our data show that variation in tissue saturated moisture content among co-occurring species represents an important ecological store of variation in flammability in the study communities.
Journal article
Diet of the critically endangered woylie (Bettongia penicillata ogilbyi) in south-western Australia
Published 2017
Australian Journal of Zoology, 65, 5, 302 - 312
To assist the management of the critically endangered woylie (Bettongia penicillata ogilbyi), a quantitative study of its diet was conducted across five of the larger subpopulations in south-Western Australia. There was a close match between dietary composition established from foregut contents and faecal pellets. Woylies were predominantly mycophagous in all subpopulations, but consumed a broad diet including invertebrates, seeds and other plant material. Individuals in a high-density, fenced subpopulation ate significantly less fungi than free-ranging animals from lower-density subpopulations. Dietary composition did not vary significantly amongst subpopulations in the Upper Warren region, where a range of population densities was observed. Altogether, 79 fungal spore classes were identified, including at least 15 genera from 14 families. Sampling across one year showed that fungi made up a larger fraction of the diet in autumn or winter, and greater diversities of fungi were consumed at these times than at other times of year. This information is essential to provide valuable ecological context for effective population management of woylies, as well as identification and conservation of important habitats.
Journal article
Exploring phosphate effects on leaf flammability using a physical chemistry model
Published 2012
International journal of wildland fire, 21, 8, 1042 - 1051
Some plants have traits that cause them to be more flammable than others, influencing wildfire spread and fire regimes. Some of these plant traits have been identified through laboratory-scale experiments. We built a numerical model that could quantify the extent of these effects on flammability. Here we present that model and use it to investigate the effect of phosphate content on the flammability of leaves. The model used finite-element methods and was based on heat transfer and thermal decomposition kinetics. Predictions were compared with three laboratory experiments involving ignition of leaf or cellulose samples. We then ran simulations of two situations through which leaf phosphate could influence wildfire spread: horizontal fire spread and crowning. The ignition time and maximum fuel gap that could be bridged by a flame front was predicted. Two key results emerged. (1) The importance of leaf phosphate in laboratory studies of ignition depends on the rate of sample heating, with the strongest effect under slow heating. (2) In the context of wildfires, phosphate was predicted to have modest effects compared with other plant traits influencing moisture content, leaf construction and angle of display.
Journal article
Plant traits and wood fates across the globe: Rotted, burned, or consumed?
Published 2009
Global change biology, 15, 10, 2431 - 2449
Wood represents the defining feature of forest systems, and often the carbon in woody debris has a long residence time. Globally, coarse dead wood contains 36-72 Pg C, and understanding what controls the fate of this C is important for predicting C cycle responses to global change. The fate of a piece of wood may include one or more of the following: microbial decomposition, combustion, consumption by insects, and physical degradation. The probability of each fate is a function of both the abiotic environment and the wood traits of the species. The wood produced by different species varies substantially in chemical, micro- and macro-morphological traits; many of these characteristics of living species have 'afterlife' effects on the fate and turnover rate of dead wood. The colonization of dead wood by microbes and their activity depends on a large suite of wood chemical and anatomical traits, as well as whole-plant traits such as stem-diameter distributions. Fire consumption is driven by a slightly narrower range of traits with little dependence on wood anatomy. Wood turnover due to insects mainly depends on wood density and secondary chemistry. Physical degradation is a relatively minor loss pathway for most systems, which depends on wood chemistry and environmental conditions. We conclude that information about the traits of woody plants could be extremely useful for modeling and predicting rates of wood turnover across ecosystems. We demonstrate how this trait-based approach is currently limited by oversimplified treatment of dead wood pools in several leading global C models and by a lack of quantitative empirical data linking woody plant traits with the probability and rate of each turnover pathway. Explicitly including plant traits and woody debris pools in global vegetation climate models would improve predictions of wood turnover and its feedback to climate.
Journal article
The influence of tissue phosphate on plant flammability: A kinetic study
Published 2008
Polymer degradation and stability, 93, 10, 1930 - 1934
The concentration of phosphate (P) in leaves is an important indicator of the ecological strategy of a plant species. P is also a fire retardant, which if effective at the low concentrations typical of plant tissue may influence wildfire behaviour, but the size of such effects is unknown.
We studied two mechanisms of P fire retardance, gas-phase and solid-phase, using samples of pure cellulose with controlled quantities of added P. The gas-phase mechanism was not detectable at P concentrations found in plants. However, significant solid-phase effects led to increased charring and reduced supply of flammable tars to the flame. Activation energies were not significantly altered, but pre-exponential constants for charring and tar production were significantly increased and decreased, respectively. These data provide a basis for mechanistically modelling the influence of ecological variation in P on the behaviour of wildfires around individual plants and across vegetation boundaries.
Journal article
Published 2006
Australian Journal of Zoology, 54, 5, 335 - 341
The bark of trees is an important foraging substrate for a range of vertebrate insectivores. This study aimed to investigate the distribution of food resources available to the bark-foraging insectivore Phascogale tapoatafa, and to compare prey biomass on bark versus the litter layer. We conducted nocturnal sampling for arthropods on tree trunks and litter in a forest in south-western Australia. The bark fauna biomass was dominated by spiders, with cockroaches, beetles and ants also well represented. In contrast, the litter was dominated by orthopterans. Invertebrate biomass was much greater in the litter layer than on tree trunks. Prey items in bark were more plentiful in Melaleuca swamps than in the surrounding dry sclerophyll woodland. Within swamps, trees with the highest invertebrate densities had thin trunks or loose bark, whilst in woodland it was trees with thick bark. Water availability may increase the prey resource used by bark-foraging insectivores.
Journal article
Leaf litter flammability in some semi-arid Australian woodlands
Published 2006
Functional ecology, 20, 5, 745 - 752
Wildfires strongly influence the biotic composition and carbon cycle of many ecosystems. Plant species provide the fuel for wildfires, but vary widely in their flammability. This study aimed to determine what plant characteristics control leaf litter flammability and to clarify how they are related to other functional traits.
Litter flammability varied across 14 tree species occurring in a mosaic of five floristic associations.
Differences in heat-release rate between species were driven by leaf size, from small-leaved conifers, casuarinas and acacias to large-leaved eucalypts and Brachychiton.
Large leaves created an open litter-bed structure that burned more rapidly because it was better ventilated. The results on heat-release rate were partitioned according to fundamental principles for the transport of oxygen through a packed fuel bed, showing that heat-release rate scaled linearly with estimated gas-flow rates, as expected in ventilation-controlled fires.
Species that were able to resprout after fire had litter that burned more intensely and was more likely to sustain a spreading fire than litter from obligate seeders, and were correspondingly larger-leaved.
Many fire-prone wooded ecosystems in the region consist of large-leaved resprouting tree species co-occurring with small-leaved obligate seeders.