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David A Westcott - One of the best experts on this subject based on the ideXlab platform.
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Visual lures increase camera-trap detection of the southern cassowary (Casuarius casuarius johnsonii)
Wildlife Research, 2017Co-Authors: Wren R. Mclean, Ross L. Goldingay, David A WestcottAbstract:Context Monitoring is a key component in managing wildlife populations and is critical for revealing long-term population trends of endangered species. Cryptic or highly mobile species that occur in low densities and in remote terrain require the development of specific monitoring methods. The southern cassowary is an Australian endangered species that poses many challenges for conducting population surveys. Aims The aims of the present study were to determine the effectiveness of camera traps in detecting Cassowaries at a site, to determine whether visual lures increased detection rates, and to explore the potential of camera traps in population surveys. Methods Coloured lures (mimicking large blue and red fruit) were placed in front of a set of camera traps and compared with controls (no lures) at 29 survey sites on the Daintree coast, northern Queensland, Australia. Key results Camera traps with lures (1) detected more birds, (2) had a shorter detection latency, (3) had a marginally greater number of captures, (4) experienced a longer capture duration, (5) were more likely to have the cassowary stop in front of the camera, and (6) achieved a 95% probability of detecting Cassowaries in 12 trap days, compared with 28 trap days without lures. Conclusions An increase in the number of Cassowaries detected, the reduction in camera latency times and the ability to identify the birds enables a more efficient approach to estimating population sizes over existing methods. This is the first published study to use visual lures to conduct camera trapping of birds. Implications The use of camera traps with lures is a practical and cost-efficient technique for the rapid detection of Cassowaries at a site and lends itself to studies of population structure, size and trends.
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prioritising the protection of habitat utilised by southern Cassowaries casuarius casuarius johnsonii
Endangered Species Research, 2012Co-Authors: Hamish A Campbell, Ross G Dwyer, Sean Fitzgibbons, Carissa J Klein, Graham Lauridsen, Adam Mckeown, Annebelle Olsson, Scott Sullivan, Matthew E Watts, David A WestcottAbstract:The southern cassowary Casuarius casuarius johnsonii L. is an endangered flightless bird from northern Australia. The Cassowaries' rainforest habitat has been extensively cleared, and the population primarily exists within discrete protected areas. They do, however, venture outside the reserves into modified landscapes, and it is here they are exposed to threatening pro- cesses. We used GPS-based telemetry and the adaptive local convex hull (a-LoCoH) non-paramet- ric kernel method to define the relationship between cassowary home range (HR) and a protec- tion-area network. The study showed that: (1) females had a larger HR than males; (2) overlapping HR occurred between but not within the sexes; (3) HRs of the same sex partitioned along defined boundaries; and (4) the current protected areas only encompassed core HR for the inhabiting cas- sowaries. This information was incorporated within a spatial-conservation-prioritisation analysis to define the relative cost:benefit relationship for protecting the currently non-protected land utilised by the Cassowaries. The results showed that the current reserve system may accommodate up to 24 adult Cassowaries, only offering HR protection at the 40 to 60% a-LoCoH. This could be raised, relatively cheaply (1.2-fold the current costs), to 70% a-LoCoH for all birds by protecting adjacent forested areas on private land. Protection beyond the 70% a-LoCoH, however, required protection of large expanses of agricultural land, resulting in an exponential increase in monetary cost (5.1-fold). We argue that total HR protection for the Cassowaries was an unfeasible conserva- tion option, but protection of core habitat was achieved relatively cheaply. Combining core HS protection with target incentives to landowners of adjacent cleared land may be the most cost- effective conservation strategy for C.c. johnsonii.
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Consequences of southern cassowary (Casuarius casuarius, L.) gut passage and deposition pattern on the germination of rainforest seeds
Austral Ecology, 2010Co-Authors: Matt Bradford, David A WestcottAbstract:In Australia's tropical rainforests the endangered southern cassowary, Casuarius casuarius, L., is the largest native frugivore and many plant species, because of the size of their fruits or seeds, are thought to be largely dependent on Cassowaries for their dispersal. In this study we asked whether the contribution of Cassowaries to plant recruitment extends beyond removing seeds from the vicinity of the parent. To do this we conducted germination trials involving 17 rainforest plant species to test whether cassowary consumption and seed deposition pattern alter germination probability or time to germination. Twenty-four per cent of species showed changed germination probabilities, with one species showing no germination without cassowary consumption, and 35% showed changed time to germination. However these differences did not translate into any significant effects when considered across all species. We examined gut scarification, fruit pulp removal (de-inhibition) and deposition in faecal material as mechanisms for changing germination success; each contributed to the changed success of individual species. There was a negative effect of seed clumping on five species. We conclude that cassowary consumption can modify germination performance in a minority of rainforest plants and that the effect is generally positive. Although the effect on large seeded species was small it is most likely to be important as the cassowary is the only animal in Australia able to internally process large numbers of these seeds.
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Diet and Dietary Preferences of the Southern Cassowary (Casuarius casuarius) in North Queensland, Australia
Biotropica, 2008Co-Authors: Matt Bradford, A. J. Dennis, David A WestcottAbstract:We investigated the diet of the southern cassowary (Casuarius casuarius) by identifying the seeds and fruits in fecal droppings encountered on a set of transects over 2 yr in upland rain forest in the wet tropics of North Queensland. A total of 198 droppings containing 56 plant species were found. We surveyed fleshy fruit availability over the subsequent 68 mo on transects in the same area to ascertain fruiting patterns in the study area. The number of droppings found each month did not correspond to the pattern of available fruit biomass. There was no relationship between the fruit traits of moisture content, flesh to seed mass ratio, color, or crop size to contribution of a species to the diet. During the lean fruiting season (May-July) Cassowaries relied more on species that fruited continuously throughout the year as they were significantly over-represented in droppings, while annual fruiting species were under-represented. During months of high fruit availability (October-December), continuously fruiting species were still over-represented in the diet but became less important while annual and biennial species became more important. Significantly more species with large fruit and large seeds appeared in the diet than expected and we confirm that the cassowary contributes to the continued dispersal of these species over long distances and in large quantities.
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Cassowary dispersal of the invasive pond apple in a tropical rainforest: the contribution of subordinate dispersal modes in invasion
Diversity and Distributions, 2007Co-Authors: David A Westcott, Adam Mckeown, Matt Bradford, Melissa J. Setter, Stephen D. SetterAbstract:Dispersal is a significant determinant of the pattern and process of invasions; however, weed dispersal distances are rarely described and descriptions of dispersal kernels are completely lacking for vertebrate-dispersed weeds. Here, we describe dispersal kernels generated by a native disperser, the endangered southern cassowary (Casuarius casuarius, L.) for an invasive, tropical rainforest plant, pond apple (Annona glabra, L.). Pond apple is primarily water-dispersed and is managed as such. We consider whether cassowary dispersal, as a numerically subordinate dispersal mode, provides an additional dispersal service that may modify the invasion process. In infested areas, pond apple seed was common in cassowary dung. Gut passage had no effect on the probability of single seed germination but deposition in clumps or as whole fruits reduced the probability of germination below that of single seeds. Gut passage times ranged from 65 to 1675 min. Combined with cassowary movement data, this resulted in estimated dispersal distances of 12.5-5212 m, with a median distance of 387 m (quartile range 112-787 m). Native frugivores can be effective dispersers of weeds in rainforest and even terrestrial dispersers can provide long-distance dispersal. Importantly, though pond apple might be expected to be almost entirely dispersed downstream and along the margins of aquatic and marine habitats, Cassowaries provide dispersal upstream and between drainages, leading to novel dispersal outcomes. Even through the provision of small quantities of novel dispersal outcomes, subordinate dispersal modes can play a significant role in determining invasion pattern and influence the ultimate success of control programs by providing dispersal to locations unattainable via the primary mode.
Hamish A Campbell - One of the best experts on this subject based on the ideXlab platform.
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Using citizen-collected wildlife sightings to predict traffic strike hot spots for threatened species: a case study on the southern cassowary
Journal of Applied Ecology, 2016Co-Authors: Ross G Dwyer, Luke Carpenter‐bundhoo, Craig E. Franklin, Hamish A CampbellAbstract:Assessing the causal factors underpinning the distribution and abundance of wildlife road-induced mortality can be challenging. This is particularly ubiquitous for rare or elusive species, because traffic strikes occur infrequently for these populations and information about localized abundance, distribution and movements are generally lacking. Here, we assessed whether citizen-collected sightings data may serve as a low cost and efficient means of gathering long-term animal roadside presence and road-crossing information, which could then be used to assess the causative factors and direct mitigation actions aimed at reducing wildlife traffic strike frequency. We explored this principle using two decades of traffic strike records and citizen-collected sightings of the southern cassowary Casuarius casuarius johnsonii. Roads have bisected the Cassowaries' rain forest habitat and despite considerable investment into mitigation strategies for this species, road-induced mortality is considered one of the primary threatening processes affecting the population. Using a Bayesian approach and controlling for spatial autocorrelation with conditional autoregressive models, we demonstrate that traffic strikes are primarily a density-dependent process in the southern cassowary. That is, traffic strike clusters occurred along stretches of road where Cassowaries were most frequently sighted. There were, however, road stretches where traffic strike frequency was greater than predicted by the number of roadside sightings, illustrating when and where density-independent processes increased the mortality potential for a road-crossing cassowary.Synthesis and applications. This is the first time that citizen-collected sightings data have been used to systematically inform upon the abundance and distribution of wildlife traffic strike. The technique not only predicts where incidents are likely to occur but also helps us to understand the factors responsible for strike clustering. While not a replacement for systematic surveys, we highlight citizen-collected sightings data as a low-cost option when assessing contributing factors to vehicle-induced mortality. Accounting for density-dependent and density-independent processes will ensure the most effective allocation of resources when implementing wildlife traffic strike mitigation.
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chemical immobilisation and satellite tagging of free living southern Cassowaries
Australian Veterinary Journal, 2014Co-Authors: Hamish A Campbell, Ross G Dwyer, Scott Sullivan, D Mead, G LauridsenAbstract:Background: The southern cassowary (Casuarius casuarius johnsonii) attains 1.8m in height and over 80kg in weight. These large birds are equipped with large claws and, although not a direct threat to humans, they have caused serious injury to handlers and members of the public. Methods and results: This study describes chemical immobilisation, restraint, transport and post-monitoring (satellite tracking) methodologies for adult and juvenile southern Cassowaries, captured and released from their natural environment. Conclusions: The described methods have improved the management and research opportunities for the southern cassowary and may be transferable to other species of large ratite.
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prioritising the protection of habitat utilised by southern Cassowaries casuarius casuarius johnsonii
Endangered Species Research, 2012Co-Authors: Hamish A Campbell, Ross G Dwyer, Sean Fitzgibbons, Carissa J Klein, Graham Lauridsen, Adam Mckeown, Annebelle Olsson, Scott Sullivan, Matthew E Watts, David A WestcottAbstract:The southern cassowary Casuarius casuarius johnsonii L. is an endangered flightless bird from northern Australia. The Cassowaries' rainforest habitat has been extensively cleared, and the population primarily exists within discrete protected areas. They do, however, venture outside the reserves into modified landscapes, and it is here they are exposed to threatening pro- cesses. We used GPS-based telemetry and the adaptive local convex hull (a-LoCoH) non-paramet- ric kernel method to define the relationship between cassowary home range (HR) and a protec- tion-area network. The study showed that: (1) females had a larger HR than males; (2) overlapping HR occurred between but not within the sexes; (3) HRs of the same sex partitioned along defined boundaries; and (4) the current protected areas only encompassed core HR for the inhabiting cas- sowaries. This information was incorporated within a spatial-conservation-prioritisation analysis to define the relative cost:benefit relationship for protecting the currently non-protected land utilised by the Cassowaries. The results showed that the current reserve system may accommodate up to 24 adult Cassowaries, only offering HR protection at the 40 to 60% a-LoCoH. This could be raised, relatively cheaply (1.2-fold the current costs), to 70% a-LoCoH for all birds by protecting adjacent forested areas on private land. Protection beyond the 70% a-LoCoH, however, required protection of large expanses of agricultural land, resulting in an exponential increase in monetary cost (5.1-fold). We argue that total HR protection for the Cassowaries was an unfeasible conserva- tion option, but protection of core habitat was achieved relatively cheaply. Combining core HS protection with target incentives to landowners of adjacent cleared land may be the most cost- effective conservation strategy for C.c. johnsonii.
Andrew L. Mack - One of the best experts on this subject based on the ideXlab platform.
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The Frugivore Community and the Fruiting Plant Flora in a New Guinea Rainforest: Identifying Keystone Frugivores
Tropical Fruits and Frugivores, 2005Co-Authors: Andrew L. Mack, Debra D. WrightAbstract:The flora at Crater Mountain Biological Research Station in Papua New Guinea is very diverse: 228 tree species ( 10 cm DBH) on a single hectare. However, the vertebrate fauna (169 bird and 31 mammal species) is less diverse than many tropical sites. At least 47% of bird species and 29% of mammal species are partially frugivorous. Using data on relative abundance, mass, and degree of frugivory for all frugivorous vertebrates at Crater, we generated a crude “index of importance” for each species. Using the fruit size and mass data from 400 plant species, we exclude fruits either too large or too heavy for each frugivore to disperse, yielding a “possible diet” for each species. Four species (a cassowary, a hornbill, a h fruit pigeon and a flying fox) stand out as being crucial dispersers for a large subset of the plant community. The frugivore with the highest importance ranking, Casuarius bennetti, is highly effective as a disperser. Cassowaries appear to be a keystone frugivore, especially for large-fruited plant species (67 species > 50 g at our study site). The method employed is fairly simple and quickly identifies candidates for keystone frugivore status. However, further life history studies are recommended for confirmation of f importance when using this method.
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low frequency vocalizations by Cassowaries casuarius spp
The Auk, 2003Co-Authors: Andrew L. Mack, Josh JonesAbstract:Abstract Although some birds can detect wavelengths in the infrasound range, there has been litle evidence that birds produce very low frequencies. We made nine recordings of a captive Dwarf Cassowary (Casuarius benneti) and one recording of a wild Southern Cassowary (C. casuarius) near Crater Mountain, Papua New Guinea. Both species produced sounds near the floor of the human hearing range in their pulsed booming notes: down to 32 Hz for C. casuarius and 23 Hz in C. benneti. Recordings of C. benneti indicate four levels of harmonics with the 23 Hz fundamental frequency. Such low frequencies are probably ideal for communication among widely dispersed, solitary Cassowaries in dense rainforest. The discovery of very low-frequency communication by Cassowaries creates new possibilities for studying those extremely secretive birds and for learning more about the evolution of avian vocalizations.
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a non intrusive method for measuring movements and seed dispersal in Cassowaries
Journal of Field Ornithology, 2003Co-Authors: Andrew L. Mack, Gretchen DrulinerAbstract:Abstract We describe a method for measuring gut passage time and seed dispersal distance for a large terrestrial frugivore. We attached temperature data loggers to radio transmitters in baits that were ingested by free-ranging Cassowaries. The resulting data yielded information on how fast the unit passed through the gut (3–4 h) and how far they were moved (240–325 m), an analog for dispersed seeds. Additionally, the data loggers revealed that Cassowaries reingest fecal matter, the first observation of coprophagy in wild Cassowaries.
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Distance and non-randomness of seed dispersal by the dwarf cassowary Casuarius bennetti
Ecography, 1995Co-Authors: Andrew L. MackAbstract:To determine the sources of dispersed seeds I inserted unique tags in fallen Aglaia aff. flavida seeds before dwarf Cassowaries (Casuarius bennetti) ate the fruits containing the seeds. Thirty naturally-dispersed, marked seeds were re-located in cassowary droppings in a 400 ha study area. The distribution of seed dispersal distances did not differ significantly from a normal distribution with a mean dispersal distance of 388 m, SD=196.8. Mean distance of dispersed seeds to nearest mature conspecific tree was 170 m, SD=108.4 ; dispersed seeds usually landed closer to other conspecifics than their parent. The estimated distribution of all seeds (including many undispersed seeds) was leptokurtic, creating high densities near source trees (> 0.035 seeds m -2 within 100 m of bole) that quickly tapered off ( 100 m from the bole) ; any density dependent effects are liable to be manifest only near parent trees. Cassowary movement patterns and resting behavior caused non-random dispersal of seeds. Seeds were preferentially moved to level sites uphill from their source trees along routes that did not cross steep terrain. Undispersed seeds generally landed downhill from source trees. This population of Aglaia would probably contract downhill into smaller, fragmented populations in the absence of cassowary-mediated dispersal.
Ross G Dwyer - One of the best experts on this subject based on the ideXlab platform.
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Using citizen-collected wildlife sightings to predict traffic strike hot spots for threatened species: a case study on the southern cassowary
Journal of Applied Ecology, 2016Co-Authors: Ross G Dwyer, Luke Carpenter‐bundhoo, Craig E. Franklin, Hamish A CampbellAbstract:Assessing the causal factors underpinning the distribution and abundance of wildlife road-induced mortality can be challenging. This is particularly ubiquitous for rare or elusive species, because traffic strikes occur infrequently for these populations and information about localized abundance, distribution and movements are generally lacking. Here, we assessed whether citizen-collected sightings data may serve as a low cost and efficient means of gathering long-term animal roadside presence and road-crossing information, which could then be used to assess the causative factors and direct mitigation actions aimed at reducing wildlife traffic strike frequency. We explored this principle using two decades of traffic strike records and citizen-collected sightings of the southern cassowary Casuarius casuarius johnsonii. Roads have bisected the Cassowaries' rain forest habitat and despite considerable investment into mitigation strategies for this species, road-induced mortality is considered one of the primary threatening processes affecting the population. Using a Bayesian approach and controlling for spatial autocorrelation with conditional autoregressive models, we demonstrate that traffic strikes are primarily a density-dependent process in the southern cassowary. That is, traffic strike clusters occurred along stretches of road where Cassowaries were most frequently sighted. There were, however, road stretches where traffic strike frequency was greater than predicted by the number of roadside sightings, illustrating when and where density-independent processes increased the mortality potential for a road-crossing cassowary.Synthesis and applications. This is the first time that citizen-collected sightings data have been used to systematically inform upon the abundance and distribution of wildlife traffic strike. The technique not only predicts where incidents are likely to occur but also helps us to understand the factors responsible for strike clustering. While not a replacement for systematic surveys, we highlight citizen-collected sightings data as a low-cost option when assessing contributing factors to vehicle-induced mortality. Accounting for density-dependent and density-independent processes will ensure the most effective allocation of resources when implementing wildlife traffic strike mitigation.
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chemical immobilisation and satellite tagging of free living southern Cassowaries
Australian Veterinary Journal, 2014Co-Authors: Hamish A Campbell, Ross G Dwyer, Scott Sullivan, D Mead, G LauridsenAbstract:Background: The southern cassowary (Casuarius casuarius johnsonii) attains 1.8m in height and over 80kg in weight. These large birds are equipped with large claws and, although not a direct threat to humans, they have caused serious injury to handlers and members of the public. Methods and results: This study describes chemical immobilisation, restraint, transport and post-monitoring (satellite tracking) methodologies for adult and juvenile southern Cassowaries, captured and released from their natural environment. Conclusions: The described methods have improved the management and research opportunities for the southern cassowary and may be transferable to other species of large ratite.
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prioritising the protection of habitat utilised by southern Cassowaries casuarius casuarius johnsonii
Endangered Species Research, 2012Co-Authors: Hamish A Campbell, Ross G Dwyer, Sean Fitzgibbons, Carissa J Klein, Graham Lauridsen, Adam Mckeown, Annebelle Olsson, Scott Sullivan, Matthew E Watts, David A WestcottAbstract:The southern cassowary Casuarius casuarius johnsonii L. is an endangered flightless bird from northern Australia. The Cassowaries' rainforest habitat has been extensively cleared, and the population primarily exists within discrete protected areas. They do, however, venture outside the reserves into modified landscapes, and it is here they are exposed to threatening pro- cesses. We used GPS-based telemetry and the adaptive local convex hull (a-LoCoH) non-paramet- ric kernel method to define the relationship between cassowary home range (HR) and a protec- tion-area network. The study showed that: (1) females had a larger HR than males; (2) overlapping HR occurred between but not within the sexes; (3) HRs of the same sex partitioned along defined boundaries; and (4) the current protected areas only encompassed core HR for the inhabiting cas- sowaries. This information was incorporated within a spatial-conservation-prioritisation analysis to define the relative cost:benefit relationship for protecting the currently non-protected land utilised by the Cassowaries. The results showed that the current reserve system may accommodate up to 24 adult Cassowaries, only offering HR protection at the 40 to 60% a-LoCoH. This could be raised, relatively cheaply (1.2-fold the current costs), to 70% a-LoCoH for all birds by protecting adjacent forested areas on private land. Protection beyond the 70% a-LoCoH, however, required protection of large expanses of agricultural land, resulting in an exponential increase in monetary cost (5.1-fold). We argue that total HR protection for the Cassowaries was an unfeasible conserva- tion option, but protection of core habitat was achieved relatively cheaply. Combining core HS protection with target incentives to landowners of adjacent cleared land may be the most cost- effective conservation strategy for C.c. johnsonii.
Allan J Baker - One of the best experts on this subject based on the ideXlab platform.
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multiple nuclear genes and retroposons support vicariance and dispersal of the palaeognaths and an early cretaceous origin of modern birds
Proceedings of The Royal Society B: Biological Sciences, 2012Co-Authors: Oliver Haddrath, Allan J BakerAbstract:The origin and timing of the diversification of modern birds remains controversial, primarily because phylogenetic relationships are incompletely resolved and uncertainty persists in molecular estimates of lineage ages. Here, we present a species tree for the major palaeognath lineages using 27 nuclear genes and 27 archaic retroposon insertions. We show that rheas are sister to the kiwis, emu and Cassowaries, and confirm ratite paraphyly because tinamous are sister to moas. Divergence dating using 10 genes with broader taxon sampling, including emu, cassowary, ostrich, five kiwis, two rheas, three tinamous, three extinct moas and 15 neognath lineages, suggests that three vicariant events and possibly two dispersals are required to explain their historical biogeography. The age of crown group birds was estimated at 131 Ma (95% highest posterior density 122–138 Ma), similar to previous molecular estimates. Problems associated with gene tree discordance and incomplete lineage sorting in birds will require much larger gene sets to increase species tree accuracy and improve error in divergence times. The relatively rapid branching within neoaves pre-dates the extinction of dinosaurs, suggesting that the genesis of the radiation within this diverse clade of birds was not in response to the Cretaceous–Paleogene extinction event.