Is resource change a useful predictor of carrion insect succession on pigs and humans?
- Dawson, Blake, Wallman, James, Evans, Maldwyn, Barton, Philip
- Authors: Dawson, Blake , Wallman, James , Evans, Maldwyn , Barton, Philip
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Medical Entomology Vol. 58, no. 6 (2021), p. 2228-2235
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- Description: Carrion is a dynamic and nutrient-rich resource that attracts numerous insect species that undergo succession due to the rapid change in the carrion resource. Despite this process being well-understood, few studies have examined resource change as a driver of carrion insect succession, and instead have focused on the effects of time per se, or on coarse, qualitative measures such as decay stage. Here we report on three field succession experiments using pig carcasses and human cadavers encompassing two winters and one summer. We quantified the effects of resource change (measured as total body score, TBS), carrion type, initial carrion mass, ambient temperature, and season on insect species richness and community composition. We found that all variables had an effect on different taxonomic or trophic components of the insect community composition, with the exception of initial carrion mass which had no effect. We found significant positive effects of TBS on beetle species richness and composition, while fly species richness was not significantly affected by TBS, but was by ambient temperature. TBS had a significant positive effect on all trophic groups, while ambient temperature also had a significant positive effect on the necrophages and predator/parasitoids. Our study indicates that resource change, as indicated by TBS, is an important driver of carrion insect species turnover and succession on carrion, and that TBS can provide information about insect ecological patterns on carrion that other temporal measures of change cannot.
- Authors: Dawson, Blake , Wallman, James , Evans, Maldwyn , Barton, Philip
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Medical Entomology Vol. 58, no. 6 (2021), p. 2228-2235
- Full Text:
- Reviewed:
- Description: Carrion is a dynamic and nutrient-rich resource that attracts numerous insect species that undergo succession due to the rapid change in the carrion resource. Despite this process being well-understood, few studies have examined resource change as a driver of carrion insect succession, and instead have focused on the effects of time per se, or on coarse, qualitative measures such as decay stage. Here we report on three field succession experiments using pig carcasses and human cadavers encompassing two winters and one summer. We quantified the effects of resource change (measured as total body score, TBS), carrion type, initial carrion mass, ambient temperature, and season on insect species richness and community composition. We found that all variables had an effect on different taxonomic or trophic components of the insect community composition, with the exception of initial carrion mass which had no effect. We found significant positive effects of TBS on beetle species richness and composition, while fly species richness was not significantly affected by TBS, but was by ambient temperature. TBS had a significant positive effect on all trophic groups, while ambient temperature also had a significant positive effect on the necrophages and predator/parasitoids. Our study indicates that resource change, as indicated by TBS, is an important driver of carrion insect species turnover and succession on carrion, and that TBS can provide information about insect ecological patterns on carrion that other temporal measures of change cannot.
Field succession studies and casework can help to identify forensically useful Diptera
- Dawson, Blake, Barton, Philip, Wallman, James
- Authors: Dawson, Blake , Barton, Philip , Wallman, James
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Forensic Sciences Vol. 66, no. 6 (2021), p. 2319-2328
- Full Text: false
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- Description: Fly development rates, and to a lesser extent succession data, can be used to provide an estimate of a minimum postmortem interval (mPMI). Yet, these data are most useful when a full account of species’ ecology, seasonality, and distribution is known. We conducted succession experiments on human cadavers over different seasons near Sydney, Australia, to document forensically useful information, including the pre-appearance interval for carrion flies. We also compiled a detailed record of flies identified in casework collected in 156 cases distributed across New South Wales, Australia. We then compared the occurrence of fly species from both field and casework datasets to identify any consistencies or gaps to determine how useful species might be for forensic investigations. In the field experiments, we found differences in species diversity and abundance between seasons, as well as yearly variation between two winter seasons. Most fly species we recorded ovipositing showed a 2- or 3-day delay between adult arrival and oviposition in summer, with a longer delay in winter. Species that were previously encountered in casework, such as Calliphora augur (Fabricius, 1775) and Calliphora ochracea Schiner, 1868, were confirmed as forensically useful, with their colonization behavior and seasonal preferences documented here. Although not encountered in casework, we confirmed Hemipyrellia fergusoni Patton, 1925 as a primary colonizer of human cadavers. Our study emphasizes the need to link field and casework data for a complete understanding of all aspects of a carrion fly's ecology to assist forensic investigators in mPMI estimations. © 2021 American Academy of Forensic Sciences
Temperature dynamics in different body regions of decomposing vertebrate remains
- Barton, Philip, Dawson, Blake, Barton, Andrew, Joshua, Sergio, Wallman, James
- Authors: Barton, Philip , Dawson, Blake , Barton, Andrew , Joshua, Sergio , Wallman, James
- Date: 2021
- Type: Text , Journal article
- Relation: Forensic Science International Vol. 325, no. (2021), p.
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- Description: The decomposition of vertebrates is controlled largely by external temperature, yet internal temperatures can also play an important role but are generally poorly documented. In this study, we compared continuous hourly temperature recordings from the mouth, under the head, right chest and right abdomen, and in the rectum of one refrigerated human and one fresh pig cadaver during 29 days of decomposition. Each cadaver differed in its internal starting temperature, thus providing two contrasting case studies for examining temperature dynamics among body regions. We used time-series analysis methods common to hydrology to reveal key differences in internal temperature dynamics. Within both cadavers, the chest region experienced the highest average temperatures, and the mouth experienced the highest maximum hourly temperature. Temperatures exceeded 30 °C inside the pig for between 40% (rectum) and 75% (chest) of the duration of the study, but for only 20% (rectum) and 35% (chest) of the time in the human. Our study provides evidence of the different thermal trajectories occurring in different body regions, and some similarities between two cadavers despite their different starting thermal conditions. These results improve our understanding of why decomposition occurs at different rates within the same cadaver, and that the location of blowfly larvae collections should be noted to improve estimates of the post-mortem interval. © 2021 Elsevier B.V.
- Authors: Barton, Philip , Dawson, Blake , Barton, Andrew , Joshua, Sergio , Wallman, James
- Date: 2021
- Type: Text , Journal article
- Relation: Forensic Science International Vol. 325, no. (2021), p.
- Full Text:
- Reviewed:
- Description: The decomposition of vertebrates is controlled largely by external temperature, yet internal temperatures can also play an important role but are generally poorly documented. In this study, we compared continuous hourly temperature recordings from the mouth, under the head, right chest and right abdomen, and in the rectum of one refrigerated human and one fresh pig cadaver during 29 days of decomposition. Each cadaver differed in its internal starting temperature, thus providing two contrasting case studies for examining temperature dynamics among body regions. We used time-series analysis methods common to hydrology to reveal key differences in internal temperature dynamics. Within both cadavers, the chest region experienced the highest average temperatures, and the mouth experienced the highest maximum hourly temperature. Temperatures exceeded 30 °C inside the pig for between 40% (rectum) and 75% (chest) of the duration of the study, but for only 20% (rectum) and 35% (chest) of the time in the human. Our study provides evidence of the different thermal trajectories occurring in different body regions, and some similarities between two cadavers despite their different starting thermal conditions. These results improve our understanding of why decomposition occurs at different rates within the same cadaver, and that the location of blowfly larvae collections should be noted to improve estimates of the post-mortem interval. © 2021 Elsevier B.V.
Priority effects and density promote coexistence between the facultative predator Chrysomya rufifacies and its competitor Calliphora stygia
- Dawson, Blake, Wallman, James, Evans, Maldwyn, Butterworth, Nathan, Barton, Philip
- Authors: Dawson, Blake , Wallman, James , Evans, Maldwyn , Butterworth, Nathan , Barton, Philip
- Date: 2022
- Type: Text , Journal article
- Relation: Oecologia Vol. 199, no. 1 (2022), p. 181-191
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- Description: Highly competitive ephemeral resources like carrion tend to support much greater diversity relative to longer-lived resources. The coexistence of diverse communities on short-lived carrion is a delicate balance, maintained by several processes including competition. Despite this balance, few studies have investigated the effect of competition on carrion, limiting our understanding of how competition drives coexistence. We investigated how priority effects and larval density influence coexistence between two blowfly species, the facultative predator Chrysomya rufifacies and its competitor Calliphora stygia, which occupy broadly similar niches but differ in their ecological strategies for exploiting carrion. We examined how adult oviposition, larval survival, developmental duration, and adult fitness were affected by the presence of differently aged heterospecific larval masses, and how these measures varied under three larval densities. We found C. rufifacies larval survival was lowest in conspecific masses with low larval densities. In heterospecific masses, survival increased, particularly at high larval density, with priority effects having minimal effect, suggesting a dependency on collective exodigestion. For C. stygia, we found survival to be constant across larval densities in a conspecific mass. In heterospecific masses, survival decreased drastically when C. rufifacies arrived first, regardless of larval density, suggesting C. stygia is temporally constrained to avoid competition with C. rufifacies. Neither species appeared to completely outcompete the other, as they were either constrained by density requirements (C. rufifacies) or priority effects (C. stygia). Our results provide new mechanistic insights into the ecological processes allowing for coexistence on a competitively intense, ephemeral resource such as carrion. © 2022, The Author(s).
- Authors: Dawson, Blake , Wallman, James , Evans, Maldwyn , Butterworth, Nathan , Barton, Philip
- Date: 2022
- Type: Text , Journal article
- Relation: Oecologia Vol. 199, no. 1 (2022), p. 181-191
- Full Text:
- Reviewed:
- Description: Highly competitive ephemeral resources like carrion tend to support much greater diversity relative to longer-lived resources. The coexistence of diverse communities on short-lived carrion is a delicate balance, maintained by several processes including competition. Despite this balance, few studies have investigated the effect of competition on carrion, limiting our understanding of how competition drives coexistence. We investigated how priority effects and larval density influence coexistence between two blowfly species, the facultative predator Chrysomya rufifacies and its competitor Calliphora stygia, which occupy broadly similar niches but differ in their ecological strategies for exploiting carrion. We examined how adult oviposition, larval survival, developmental duration, and adult fitness were affected by the presence of differently aged heterospecific larval masses, and how these measures varied under three larval densities. We found C. rufifacies larval survival was lowest in conspecific masses with low larval densities. In heterospecific masses, survival increased, particularly at high larval density, with priority effects having minimal effect, suggesting a dependency on collective exodigestion. For C. stygia, we found survival to be constant across larval densities in a conspecific mass. In heterospecific masses, survival decreased drastically when C. rufifacies arrived first, regardless of larval density, suggesting C. stygia is temporally constrained to avoid competition with C. rufifacies. Neither species appeared to completely outcompete the other, as they were either constrained by density requirements (C. rufifacies) or priority effects (C. stygia). Our results provide new mechanistic insights into the ecological processes allowing for coexistence on a competitively intense, ephemeral resource such as carrion. © 2022, The Author(s).
- Cairncross, Rhys, Barton, Philip, Bonat, Stefanie, Crowther, Matthew, Dickman, Christopher, Vandersteen, James, Newsome, Thomas
- Authors: Cairncross, Rhys , Barton, Philip , Bonat, Stefanie , Crowther, Matthew , Dickman, Christopher , Vandersteen, James , Newsome, Thomas
- Date: 2022
- Type: Text , Journal article
- Relation: Food Webs Vol. 31, no. (2022), p.
- Full Text: false
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- Description: Carrion is a vital resource in terrestrial ecosystems, supporting complex networks of interacting consumer organisms. The insect community attending carrion forms a vital part of this food web, but the functional roles of insects as scavengers can be altered by invasive species via the effects of predation and competition. European wasps (Vespula germanica) have invaded many parts of Australia and have been documented to directly kill native insect scavengers, especially necrophilous flies. Yet, little is known about the factors that influence predation rates by European wasps on flies at carcasses. The aim of this study was to determine how carcass state and altitude influences the occurrence and predatory impacts of wasps on flies. We placed 18 kangaroo carcasses along an altitudinal gradient in an Australian alpine ecosystem and manipulated half of the carcasses by splitting them open to simulate the wounds created by vertebrate scavengers present at the time of death. We found that carcasses with open wounds exacerbated already severe predation on flies from wasps, as well as intense scavenging activity, even though wasp abundance remained the same across both treatments. Meanwhile, densities of wasps declined and their impact on flies lessened with higher altitude. We suggest that the suppressive effect of wasps on flies may interrupt key processes triggered by carrion and cause shifts in energy flow through scavenger food webs. Further, under climate change, we predict that wasps will continue to spread into new areas at altitudes the species currently find unhospitable and conclude that carcass management practices must recognise the potential threat that wasps pose to ecosystem stability. © 2022 Elsevier Inc.
Insect abundance patterns on vertebrate remains reveal carrion resource quality variation
- Dawson, Blake, Wallman, James, Evans, Maldwyn, Barton, Philip
- Authors: Dawson, Blake , Wallman, James , Evans, Maldwyn , Barton, Philip
- Date: 2022
- Type: Text , Journal article
- Relation: Oecologia Vol. 198, no. 4 (2022), p. 1043-1056
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- Description: Resource quality is a key driver of species abundance and community structure. Carrion is unique among resources due to its high nutritional quality, rapidly changing nature, and the diverse community of organisms it supports. Yet the role resource quality plays in driving variation in abundance patterns of carrion-associated species remains poorly studied. Here we investigate how species abundances change with a measure of resource change, and interpret these findings to determine how species differ in their association with carrion that changes in quality over time. We conducted field succession experiments using pigs and humans over two winters and one summer. We quantified the effect of total body score, an objective measure of resource change, on adult insect abundance using generalised additive models. For each species, phases of increasing abundance likely indicated attraction to a high-quality resource, and length of abundance maxima indicated optimal oviposition and feeding time. Some species such as the beetle Necrobia rufipes had a rapid spike in abundance, suggesting a narrow window of opportunity for carrion resource exploitation, while species like the wasp Nasonia vitripennis had a gradual change in abundance, indicating a wide window of resource exploitation. Different abundance patterns were also observed between species occurring on pigs and humans, suggesting cadaver type is an important aspect of resource quality. Our findings show that species abundances, unlike species occurrences, can reveal additional detail about species exploitation of carrion and provide information about how resource quality may drive competition and variation in insect community succession. © 2022, The Author(s).
- Authors: Dawson, Blake , Wallman, James , Evans, Maldwyn , Barton, Philip
- Date: 2022
- Type: Text , Journal article
- Relation: Oecologia Vol. 198, no. 4 (2022), p. 1043-1056
- Full Text:
- Reviewed:
- Description: Resource quality is a key driver of species abundance and community structure. Carrion is unique among resources due to its high nutritional quality, rapidly changing nature, and the diverse community of organisms it supports. Yet the role resource quality plays in driving variation in abundance patterns of carrion-associated species remains poorly studied. Here we investigate how species abundances change with a measure of resource change, and interpret these findings to determine how species differ in their association with carrion that changes in quality over time. We conducted field succession experiments using pigs and humans over two winters and one summer. We quantified the effect of total body score, an objective measure of resource change, on adult insect abundance using generalised additive models. For each species, phases of increasing abundance likely indicated attraction to a high-quality resource, and length of abundance maxima indicated optimal oviposition and feeding time. Some species such as the beetle Necrobia rufipes had a rapid spike in abundance, suggesting a narrow window of opportunity for carrion resource exploitation, while species like the wasp Nasonia vitripennis had a gradual change in abundance, indicating a wide window of resource exploitation. Different abundance patterns were also observed between species occurring on pigs and humans, suggesting cadaver type is an important aspect of resource quality. Our findings show that species abundances, unlike species occurrences, can reveal additional detail about species exploitation of carrion and provide information about how resource quality may drive competition and variation in insect community succession. © 2022, The Author(s).
Ant community responses to farmland use and revegetation in a fragmented agricultural landscape
- Ng, Katherine, Nowrouzi, Somayeh, Staunton, Kyran, Barton, Philip, Driscoll, Don
- Authors: Ng, Katherine , Nowrouzi, Somayeh , Staunton, Kyran , Barton, Philip , Driscoll, Don
- Date: 2021
- Type: Text , Journal article
- Relation: Agriculture Ecosystems & Environment Vol. 311, no. (May 2021), p. 8
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- Description: Recent alarming losses of insects from agricultural landscapes in multiple countries around the world have brought into sharp focus the urgent need to identify ways to manage these landscapes to avoid further biodiversity decline. Identifying the drivers of insect declines, such as land use change, is critical to this effort. We examined ant communities at the interface between remnant vegetation patches and three adjoining farmland types (wheat crop, rested from cropping and restoration plantings) in a fragmented landscape in temperate Australia. We asked: do ant communities and occurrence of individual species differ between remnant patches and farmlands with more intensive farmland use (restoration plantings < rested farmlands < wheat crop)? We recorded 13,283 ants belonging to 102 species from 30 genera. Excluding 21 singletons, 27 species only occurred in remnant patches compared to ten species found only in farmlands. Ant community composition in wheat crop and rested farmlands significantly differed from their adjacent remnant patches and were more homogeneous. In contrast, ant communities from restoration plantings in farmland were not significantly different in composition from those in the adjacent remnant patch. The large, aggressive Australian meat ant (Iridomyrmex purpureus) showed significantly higher occurrence in the remnant patch than all farmland types, and we suggest that the absence of this strongly interacting species from farmlands may have contributed to biotic homogenisation. Our findings show that native vegetation provides crucial habitat resources for many ant species that are not provided by farmlands, and native plantings can, in some cases, ameliorate negative effects of farmland clearing over relatively short time scales (<7 years). Agricultural intensification that involves loss of remnant native vegetation or reduced revegetation will contribute to ongoing losses and changes to ant biodiversity in farming landscapes. However, replanting native vegetation can lead to rapid restoration, signifying a possible simple remedy to insect declines.
- Authors: Ng, Katherine , Nowrouzi, Somayeh , Staunton, Kyran , Barton, Philip , Driscoll, Don
- Date: 2021
- Type: Text , Journal article
- Relation: Agriculture Ecosystems & Environment Vol. 311, no. (May 2021), p. 8
- Full Text:
- Reviewed:
- Description: Recent alarming losses of insects from agricultural landscapes in multiple countries around the world have brought into sharp focus the urgent need to identify ways to manage these landscapes to avoid further biodiversity decline. Identifying the drivers of insect declines, such as land use change, is critical to this effort. We examined ant communities at the interface between remnant vegetation patches and three adjoining farmland types (wheat crop, rested from cropping and restoration plantings) in a fragmented landscape in temperate Australia. We asked: do ant communities and occurrence of individual species differ between remnant patches and farmlands with more intensive farmland use (restoration plantings < rested farmlands < wheat crop)? We recorded 13,283 ants belonging to 102 species from 30 genera. Excluding 21 singletons, 27 species only occurred in remnant patches compared to ten species found only in farmlands. Ant community composition in wheat crop and rested farmlands significantly differed from their adjacent remnant patches and were more homogeneous. In contrast, ant communities from restoration plantings in farmland were not significantly different in composition from those in the adjacent remnant patch. The large, aggressive Australian meat ant (Iridomyrmex purpureus) showed significantly higher occurrence in the remnant patch than all farmland types, and we suggest that the absence of this strongly interacting species from farmlands may have contributed to biotic homogenisation. Our findings show that native vegetation provides crucial habitat resources for many ant species that are not provided by farmlands, and native plantings can, in some cases, ameliorate negative effects of farmland clearing over relatively short time scales (<7 years). Agricultural intensification that involves loss of remnant native vegetation or reduced revegetation will contribute to ongoing losses and changes to ant biodiversity in farming landscapes. However, replanting native vegetation can lead to rapid restoration, signifying a possible simple remedy to insect declines.
Climate‐driven divergent long‐term trends of forest beetles in Japan
- Evans, Maldwyn, Barton, Philip, Niwa, Shigeru, Soga, Masashi, Seibold, Sebastian, Tsuchiya, Kazuaki, Hisano, Masumi
- Authors: Evans, Maldwyn , Barton, Philip , Niwa, Shigeru , Soga, Masashi , Seibold, Sebastian , Tsuchiya, Kazuaki , Hisano, Masumi
- Date: 2022
- Type: Text , Journal article
- Relation: Ecology letters Vol. 25, no. 9 (2022), p. 2009-2021
- Full Text: false
- Reviewed:
- Description: Concerning declines in insect populations have been reported from Europe and the United States, yet there are gaps in our knowledge of the drivers of insect trends and their distribution across the world. We report on our analysis of a spatially extensive, 14‐year study of ground‐dwelling beetles in four natural forest biomes spanning Japan's entire latitudinal range (3000 km). Beetle species richness, abundance and biomass declined in evergreen coniferous forests but increased in broadleaf‐coniferous mixed forests. Further, beetles in evergreen coniferous forests responded negatively to increased temperature and precipitation anomalies, which have both risen over the study's timespan. These significant changes parallel reports of climate‐driven changes in forest tree species, providing further evidence that climate change is altering forest ecosystems fundamentally. Given the enormous biodiversity and ecosystem services that forests support globally, the implications for biodiversity change resulting from climate change could be profound. With recent concerns about catastrophic insect declines in the US and Europe, research that provides evidence for insect trends in other regions and in forest ecosystems is crucial. We report on data of forest beetles collected over a 14‐year period in forest plots across the whole latitudinal range of Japan (3000 km). Using these data, we show declines in evergreen coniferous forests accompanied with community changes in other forest biomes.
How does mass loss compare with total body score when assessing decomposition of human and pig cadavers?
- Dawson, Blake, Wallman, James, Barton, Philip
- Authors: Dawson, Blake , Wallman, James , Barton, Philip
- Date: 2022
- Type: Text , Journal article
- Relation: Forensic Science, Medicine, and Pathology Vol. 18, no. 3 (2022), p. 343-351
- Full Text:
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- Description: Providing accurate and reliable measures of decomposition is paramount for forensic research where decomposition progress is used to estimate time of death. Mass loss is routinely used as a direct measure of biomass decomposition in ecological studies, yet few studies have analysed mass loss in a forensic context on human cadavers to determine its usefulness for modelling the decomposition process. Mass loss was examined in decomposing human and pig cadavers, and compared with other common decomposition metrics, such as total body score (TBS). One summer and one winter field decomposition experiment was conducted using human and pig cadavers, as pigs are often used as proxies for human cadavers in forensic research. The two measures of decomposition revealed two contrasting patterns of decomposition on pigs and humans, particularly in winter where TBS stabilised at similar values, but mass loss differed greatly. Mass loss was found to be faster in pigs than humans during early decomposition. Pigs lost 75% of their mass in winter, while humans lost less than 50%; however, in summer, both lost around 80% of their mass. TBS displayed similar patterns in both experiments, with TBS increasing more rapidly in pigs compared with humans but both eventually reaching similar TBS values in late decomposition. Measuring mass loss can provide additional information about decomposition progress that is missed if using TBS only. Key differences in decomposition progress between cadaver types were also observed, suggesting caution when extrapolating data from pigs to humans for forensic research and decomposition modelling. © 2022, The Author(s).
- Authors: Dawson, Blake , Wallman, James , Barton, Philip
- Date: 2022
- Type: Text , Journal article
- Relation: Forensic Science, Medicine, and Pathology Vol. 18, no. 3 (2022), p. 343-351
- Full Text:
- Reviewed:
- Description: Providing accurate and reliable measures of decomposition is paramount for forensic research where decomposition progress is used to estimate time of death. Mass loss is routinely used as a direct measure of biomass decomposition in ecological studies, yet few studies have analysed mass loss in a forensic context on human cadavers to determine its usefulness for modelling the decomposition process. Mass loss was examined in decomposing human and pig cadavers, and compared with other common decomposition metrics, such as total body score (TBS). One summer and one winter field decomposition experiment was conducted using human and pig cadavers, as pigs are often used as proxies for human cadavers in forensic research. The two measures of decomposition revealed two contrasting patterns of decomposition on pigs and humans, particularly in winter where TBS stabilised at similar values, but mass loss differed greatly. Mass loss was found to be faster in pigs than humans during early decomposition. Pigs lost 75% of their mass in winter, while humans lost less than 50%; however, in summer, both lost around 80% of their mass. TBS displayed similar patterns in both experiments, with TBS increasing more rapidly in pigs compared with humans but both eventually reaching similar TBS values in late decomposition. Measuring mass loss can provide additional information about decomposition progress that is missed if using TBS only. Key differences in decomposition progress between cadaver types were also observed, suggesting caution when extrapolating data from pigs to humans for forensic research and decomposition modelling. © 2022, The Author(s).
Climate-driven animal mass mortality events : is there a role for scavengers?
- Barton, Philip, Reboldi, Anna, Bonat, Stefanie, Mateo-Tomás, Patricia, Newsome, Thomas
- Authors: Barton, Philip , Reboldi, Anna , Bonat, Stefanie , Mateo-Tomás, Patricia , Newsome, Thomas
- Date: 2023
- Type: Text , Journal article
- Relation: Environmental conservation Vol. 50, no. 1 (2023), p. 1-6
- Full Text: false
- Reviewed:
- Description: Summary Animal mass mortality events (MMEs) will increase with weather and climate extremes. MMEs can add significant stress to ecosystems through extraordinary nutrient pulses or contribute to potential disease transmission risks. Given their efficient removal of carrion biomass from landscapes, we argue here for the potential of scavenger guilds to be a key nature-based solution to mitigating MME effects. However, we caution that scavenger guilds alone will not be a silver bullet. It is critical for further research to identify how the composition of scavenger guilds and the magnitude of MMEs will determine when scavengers will buffer the impacts of such events on ecosystems and when intervention might be required. Some MMEs are too large for scavengers to remove efficiently, and there is a risk of MMEs subsidizing pest species, altering nutrient cycling or leading to disease spread. Prioritizing native scavenger taxa in conservation management policies may help to boost ecosystem resilience through preserving their key ecological services. This should be part of a multi-pronged approach to MME mitigation that combines scavenger conservation with practices such as carcass dispersal or removal when exceeding a threshold quantity. Policymakers are urged to identify such thresholds and to recognize both the insects and the vertebrate scavengers that could act as allies for mitigating the emerging problem of climate-driven MMEs.
Responses of necrophilous beetles to animal mass mortality in the Australian Alps
- Stone, Rebecca, Bonat, Stefanie, Newsome, Thomas, Barton, Philip
- Authors: Stone, Rebecca , Bonat, Stefanie , Newsome, Thomas , Barton, Philip
- Date: 2023
- Type: Text , Journal article
- Relation: Journal of Insect Conservation Vol. 27, no. 6 (2023), p. 865-877
- Full Text:
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- Description: A diversity of insects can be found at the remains of dead animals (carrion) and they play a vital role in its decomposition and recycling. An emerging global problem with carrion is animal mass mortality events – the sudden, rapid die-off of many animals resulting in a large increase to the localised carrion resource pool. Yet, little is known about how insects respond to sudden and large inputs of carrion. We conducted an experiment in a mountainous alpine region of south-eastern Australia and compared beetle assemblages found at single carcass and mass mortality sites. We also examined the effects of vertebrate exclusion, and decomposition stage on beetles. We found 4,774 beetles representing 146 different species/morphospecies from 17 families. The most abundant species was Saprinus cyaneus cyaneus (Histeridae), and species of Staphylinidae and Silphidae also dominated the fauna, which is typical for necrophilous beetles in Australia. We also found a clear temporal change in beetle assemblages, with abundance and richness peaking during the active decay stage. We found that beetle abundance was greater at single carcasses than mass mortality sites, possibly as an artifact of sampling, and that species richness was similar among these two carcass treatment types. We found no significant effect of vertebrate exclusion on beetles, suggesting that large scavengers in the study system may not influence necrophilous insect communities around carrion. Implications for insect conservation: Our study highlights the diversity of beetles that can be found at carrion and their similar composition to the fauna found in other areas in the south-east of the Australian continent. Beetles may have reduced abundance at mass mortality sites which could affect their ability to contribute to carrion removal relative to smaller carrion quantities. Further research is required to quantify the role of other insects in carrion removal under a range of natural and mass mortality scenarios. © 2023, The Author(s).
- Authors: Stone, Rebecca , Bonat, Stefanie , Newsome, Thomas , Barton, Philip
- Date: 2023
- Type: Text , Journal article
- Relation: Journal of Insect Conservation Vol. 27, no. 6 (2023), p. 865-877
- Full Text:
- Reviewed:
- Description: A diversity of insects can be found at the remains of dead animals (carrion) and they play a vital role in its decomposition and recycling. An emerging global problem with carrion is animal mass mortality events – the sudden, rapid die-off of many animals resulting in a large increase to the localised carrion resource pool. Yet, little is known about how insects respond to sudden and large inputs of carrion. We conducted an experiment in a mountainous alpine region of south-eastern Australia and compared beetle assemblages found at single carcass and mass mortality sites. We also examined the effects of vertebrate exclusion, and decomposition stage on beetles. We found 4,774 beetles representing 146 different species/morphospecies from 17 families. The most abundant species was Saprinus cyaneus cyaneus (Histeridae), and species of Staphylinidae and Silphidae also dominated the fauna, which is typical for necrophilous beetles in Australia. We also found a clear temporal change in beetle assemblages, with abundance and richness peaking during the active decay stage. We found that beetle abundance was greater at single carcasses than mass mortality sites, possibly as an artifact of sampling, and that species richness was similar among these two carcass treatment types. We found no significant effect of vertebrate exclusion on beetles, suggesting that large scavengers in the study system may not influence necrophilous insect communities around carrion. Implications for insect conservation: Our study highlights the diversity of beetles that can be found at carrion and their similar composition to the fauna found in other areas in the south-east of the Australian continent. Beetles may have reduced abundance at mass mortality sites which could affect their ability to contribute to carrion removal relative to smaller carrion quantities. Further research is required to quantify the role of other insects in carrion removal under a range of natural and mass mortality scenarios. © 2023, The Author(s).
Conserving focal insect groups in woodland remnants : the role of landscape context and habitat structure on cross-taxonomic congruence
- Yong, Ding, Barton, Philip, Okada, Sachiko, Crane, Mason, Cunningham, Saul, Lindenmayer, David
- Authors: Yong, Ding , Barton, Philip , Okada, Sachiko , Crane, Mason , Cunningham, Saul , Lindenmayer, David
- Date: 2020
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 115, no. (2020), p.
- Full Text:
- Reviewed:
- Description: Determining the shared responses of different taxa to landscape modification is a key step for identifying which groups of species are good surrogates for other groups. Yet, surprisingly little is known about the spatial processes that drive cross-taxonomic congruence of diversity and how this knowledge can be used to improve the management of modified landscapes for biodiversity, especially insects. We investigated how assemblages of two ecologically important insect groups, wild bees and beetles, respond to different landscape contexts and habitat structure in an Australian agricultural landscape, and how this, in turn, influenced either group's potential as a surrogate for the other. Bee and ground-active beetle assemblages were sampled in remnant woodland patches in two landscape contexts: woodland patches surrounded by pine plantation and woodland patches surrounded by open grazing land. Bee species richness, and the richness of functionally-defined bee groups did not differ between landscape contexts, in contrast to beetles. We found that landscape context exerted a stronger effect on species composition than species richness of both groups. Although some landscape and habitat variables were useful in predicting the diversity of both insect groups, few were shared. Our findings showed that bee and beetles are poor surrogates for each other in landscapes that are highly modified. Our study highlighted the need to consider: (1) taxon-specific responses to landscape context, (2) the influence of different metrics of cross-taxonomic surrogacy and, (3) dissimilar ecological attributes among insect taxa when selecting insects as biodiversity surrogates. It should not be assumed that agricultural landscapes managed to conserve specific insects (e.g. bees) will necessarily benefit other insects. © 2020
- Authors: Yong, Ding , Barton, Philip , Okada, Sachiko , Crane, Mason , Cunningham, Saul , Lindenmayer, David
- Date: 2020
- Type: Text , Journal article
- Relation: Ecological Indicators Vol. 115, no. (2020), p.
- Full Text:
- Reviewed:
- Description: Determining the shared responses of different taxa to landscape modification is a key step for identifying which groups of species are good surrogates for other groups. Yet, surprisingly little is known about the spatial processes that drive cross-taxonomic congruence of diversity and how this knowledge can be used to improve the management of modified landscapes for biodiversity, especially insects. We investigated how assemblages of two ecologically important insect groups, wild bees and beetles, respond to different landscape contexts and habitat structure in an Australian agricultural landscape, and how this, in turn, influenced either group's potential as a surrogate for the other. Bee and ground-active beetle assemblages were sampled in remnant woodland patches in two landscape contexts: woodland patches surrounded by pine plantation and woodland patches surrounded by open grazing land. Bee species richness, and the richness of functionally-defined bee groups did not differ between landscape contexts, in contrast to beetles. We found that landscape context exerted a stronger effect on species composition than species richness of both groups. Although some landscape and habitat variables were useful in predicting the diversity of both insect groups, few were shared. Our findings showed that bee and beetles are poor surrogates for each other in landscapes that are highly modified. Our study highlighted the need to consider: (1) taxon-specific responses to landscape context, (2) the influence of different metrics of cross-taxonomic surrogacy and, (3) dissimilar ecological attributes among insect taxa when selecting insects as biodiversity surrogates. It should not be assumed that agricultural landscapes managed to conserve specific insects (e.g. bees) will necessarily benefit other insects. © 2020
Incorporating regional-scale ecological knowledge to improve the effectiveness of large-scale conservation programmes
- Kay, G., Barton, Philip, Driscoll, D., Cunningham, S., Blanchard, Wade
- Authors: Kay, G. , Barton, Philip , Driscoll, D. , Cunningham, S. , Blanchard, Wade
- Date: 2016
- Type: Text , Journal article
- Relation: Animal Conservation Vol. 19, no. 6 (2016), p. 515-525
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- Reviewed:
- Description: Land-stewardship programmes are a major focus of investment by governments for conserving biodiversity in agricultural landscapes. These programmes are generally large-scale (e.g. >1000 km) spanning multiple biogeographic regions but developed using spatially limited (e.g. landscape-scale; <100 km) ecological data interpolated across broad areas for one, or a few, well-studied taxonomic groups. Information about how less-studied taxa respond to regional differences in management and environmental effects has potential to further inform land-stewardship conservation programmes, but suitable data sets are rarely available. In this study, we sought to enhance planning of large-scale conservation programmes by quantifying relationships between reptile assemblages and key environmental attributes at regional scales within a large-scale (>172 000 km2) Australian land-stewardship programme. Using 234 remnant woodland monitoring sites spanning four distinct biogeographic regions, we asked: Do reptile assemblages show different environmental associations across biogeographically distinct regions? We found that environmental features important to reptile diversity differed over each region. Abundance and rare species richness of reptiles responded at regional-scales to elevation, native groundcover and aspect. We identified four implications from our study: (1) large-scale conservation schemes can achieve better outcomes for reptiles using regional-scale knowledge of environmental associations; (2) regional-scale knowledge is particularly valuable for conservation of rare reptile taxa; (3) consideration of abiotic environmental features which cannot be directly managed (e.g. aspect, elevation) is important; (4) programmes can be tailored to better support reptile groups at higher conservation risk. Our study shows that reptile-environment associations differ among biogeographic regions, and this presents opportunity for tailoring stronger policy and management strategies for conserving large-scale agricultural landscapes globally. © 2016 The Zoological Society of London. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
- Authors: Kay, G. , Barton, Philip , Driscoll, D. , Cunningham, S. , Blanchard, Wade
- Date: 2016
- Type: Text , Journal article
- Relation: Animal Conservation Vol. 19, no. 6 (2016), p. 515-525
- Full Text:
- Reviewed:
- Description: Land-stewardship programmes are a major focus of investment by governments for conserving biodiversity in agricultural landscapes. These programmes are generally large-scale (e.g. >1000 km) spanning multiple biogeographic regions but developed using spatially limited (e.g. landscape-scale; <100 km) ecological data interpolated across broad areas for one, or a few, well-studied taxonomic groups. Information about how less-studied taxa respond to regional differences in management and environmental effects has potential to further inform land-stewardship conservation programmes, but suitable data sets are rarely available. In this study, we sought to enhance planning of large-scale conservation programmes by quantifying relationships between reptile assemblages and key environmental attributes at regional scales within a large-scale (>172 000 km2) Australian land-stewardship programme. Using 234 remnant woodland monitoring sites spanning four distinct biogeographic regions, we asked: Do reptile assemblages show different environmental associations across biogeographically distinct regions? We found that environmental features important to reptile diversity differed over each region. Abundance and rare species richness of reptiles responded at regional-scales to elevation, native groundcover and aspect. We identified four implications from our study: (1) large-scale conservation schemes can achieve better outcomes for reptiles using regional-scale knowledge of environmental associations; (2) regional-scale knowledge is particularly valuable for conservation of rare reptile taxa; (3) consideration of abiotic environmental features which cannot be directly managed (e.g. aspect, elevation) is important; (4) programmes can be tailored to better support reptile groups at higher conservation risk. Our study shows that reptile-environment associations differ among biogeographic regions, and this presents opportunity for tailoring stronger policy and management strategies for conserving large-scale agricultural landscapes globally. © 2016 The Zoological Society of London. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Philip Barton” is provided in this record**
The ephemeral resource patch concept
- Butterworth, Nathan, Benbow, M., Barton, Philip
- Authors: Butterworth, Nathan , Benbow, M. , Barton, Philip
- Date: 2023
- Type: Text , Journal article
- Relation: Biological Reviews Vol. 98, no. 3 (2023), p. 697-726
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- Reviewed:
- Description: Ephemeral resource patches (ERPs) – short lived resources including dung, carrion, temporary pools, rotting vegetation, decaying wood, and fungi – are found throughout every ecosystem. Their short-lived dynamics greatly enhance ecosystem heterogeneity and have shaped the evolutionary trajectories of a wide range of organisms – from bacteria to insects and amphibians. Despite this, there has been no attempt to distinguish ERPs clearly from other resource types, to identify their shared spatiotemporal characteristics, or to articulate their broad ecological and evolutionary influences on biotic communities. Here, we define ERPs as any distinct consumable resources which (i) are homogeneous (genetically, chemically, or structurally) relative to the surrounding matrix, (ii) host a discrete multitrophic community consisting of species that cannot replicate solely in any of the surrounding matrix, and (iii) cannot maintain a balance between depletion and renewal, which in turn, prevents multiple generations of consumers/users or reaching a community equilibrium. We outline the wide range of ERPs that fit these criteria, propose 12 spatiotemporal characteristics along which ERPs can vary, and synthesise a large body of literature that relates ERP dynamics to ecological and evolutionary theory. We draw this knowledge together and present a new unifying conceptual framework that incorporates how ERPs have shaped the adaptive trajectories of organisms, the structure of ecosystems, and how they can be integrated into biodiversity management and conservation. Future research should focus on how inter- and intra-resource variation occurs in nature – with a particular focus on resource × environment × genotype interactions. This will likely reveal novel adaptive strategies, aid the development of new eco-evolutionary theory, and greatly improve our understanding of the form and function of organisms and ecosystems. © 2022 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
- Authors: Butterworth, Nathan , Benbow, M. , Barton, Philip
- Date: 2023
- Type: Text , Journal article
- Relation: Biological Reviews Vol. 98, no. 3 (2023), p. 697-726
- Full Text:
- Reviewed:
- Description: Ephemeral resource patches (ERPs) – short lived resources including dung, carrion, temporary pools, rotting vegetation, decaying wood, and fungi – are found throughout every ecosystem. Their short-lived dynamics greatly enhance ecosystem heterogeneity and have shaped the evolutionary trajectories of a wide range of organisms – from bacteria to insects and amphibians. Despite this, there has been no attempt to distinguish ERPs clearly from other resource types, to identify their shared spatiotemporal characteristics, or to articulate their broad ecological and evolutionary influences on biotic communities. Here, we define ERPs as any distinct consumable resources which (i) are homogeneous (genetically, chemically, or structurally) relative to the surrounding matrix, (ii) host a discrete multitrophic community consisting of species that cannot replicate solely in any of the surrounding matrix, and (iii) cannot maintain a balance between depletion and renewal, which in turn, prevents multiple generations of consumers/users or reaching a community equilibrium. We outline the wide range of ERPs that fit these criteria, propose 12 spatiotemporal characteristics along which ERPs can vary, and synthesise a large body of literature that relates ERP dynamics to ecological and evolutionary theory. We draw this knowledge together and present a new unifying conceptual framework that incorporates how ERPs have shaped the adaptive trajectories of organisms, the structure of ecosystems, and how they can be integrated into biodiversity management and conservation. Future research should focus on how inter- and intra-resource variation occurs in nature – with a particular focus on resource × environment × genotype interactions. This will likely reveal novel adaptive strategies, aid the development of new eco-evolutionary theory, and greatly improve our understanding of the form and function of organisms and ecosystems. © 2022 The Authors. Biological Reviews published by John Wiley & Sons Ltd on behalf of Cambridge Philosophical Society.
Invasive European wasps alter scavenging dynamics around carrion
- Spencer, Emma, Barton, Philip, Ripple, William, Newsome, Thomas
- Authors: Spencer, Emma , Barton, Philip , Ripple, William , Newsome, Thomas
- Date: 2020
- Type: Text , Journal article
- Relation: Food Webs Vol. 24, no. (2020), p.
- Full Text: false
- Reviewed:
- Description: European wasps (Vespula germanica) have invaded parts of North and South America, Australia and New Zealand. They are opportunistic predators and scavengers that can disrupt food webs and species interactions, but their role in food webs associated with carrion is poorly understood. In this study we examined wasp abundance at 20 vertebrate carcasses in south-eastern Australia. We also collected data on the abundance of blowflies and the occurrence and behavior of vertebrate scavengers at the same carcasses. Wasps arrived within minutes of deploying fresh carcasses and were approximately 4.3 times more abundant in forest compared with grassland habitats. Wasps killed and mutilated native blowflies and may have prevented them from ovipositing on carcasses, as we subsequently found that these carcasses were devoid of fly larvae. European wasps also appeared to interfere with dingoes (Canis dingo) feeding on carcasses, based on observations from cameras showing dingoes snapping their heads in the air and then retreating from the carcasses suddenly. The other major vertebrate scavenger in the system, feral pigs (Sus scrofa), did not show similar behavioral responses. Although we observed European wasps feeding on carcasses, carcass mass loss was slow. This could be a direct result of European wasps suppressing flies and potentially excluding dingoes from accessing carcasses. We conclude that European wasps may alter the way energy flows through scavenging food webs, which could have cascading impacts on ecosystem dynamics and services, although manipulative experiments would help to further evaluate these possibilities. © 2020 Elsevier Inc.
Traits reveal ecological strategies driving carrion insect community assembly
- Evans, Maldwyn, Wallman, James, Barton, Philip
- Authors: Evans, Maldwyn , Wallman, James , Barton, Philip
- Date: 2020
- Type: Text , Journal article
- Relation: Ecological Entomology Vol. 45, no. 5 (2020), p. 966-977
- Full Text:
- Reviewed:
- Description: 1. The succession of carrion-associated (necrophilous) insects on decomposing carrion is well documented. To exploit the changing nutritious and dynamic resources available throughout the carrion decomposition process, different species colonise and consume carrion in a predictable temporal sequence. The traits of these necrophilous insects should reflect their ecological strategies. Morphological traits of these insects, such as body size and wing size, however, have not previously been examined during active and advanced decomposition. 2. We used fourth-corner multivariate generalised linear models to identify insect community morphological trait patterns and to quantify their change through time on decomposing rabbit carcasses in grassland and woodland environments. 3. We found that larger-bodied species of flies and carrion-specialist beetles were associated with the early stages of decomposition. The morphological traits of ants, in contrast, showed no changes at carcasses through time and instead showed body size differences between grassland and woodland environments. 4. Our findings indicate that specialist flies and beetles that arrive early in the decomposition process possess traits that enable rapid discovery of carrion at a large scale. Generalist beetles and ants do not share this same trait and are instead adapted to locate and consume a wider variety of resources in their preferred habitat type at their local scale. 5. Our results provide insights into the morphological adaptations linked to the ecological strategies of distinct components of carrion insect communities. Further, our results offer insights into the community assembly dynamics that structure the communities of necrophilous insect species. © 2020 The Royal Entomological Society
- Authors: Evans, Maldwyn , Wallman, James , Barton, Philip
- Date: 2020
- Type: Text , Journal article
- Relation: Ecological Entomology Vol. 45, no. 5 (2020), p. 966-977
- Full Text:
- Reviewed:
- Description: 1. The succession of carrion-associated (necrophilous) insects on decomposing carrion is well documented. To exploit the changing nutritious and dynamic resources available throughout the carrion decomposition process, different species colonise and consume carrion in a predictable temporal sequence. The traits of these necrophilous insects should reflect their ecological strategies. Morphological traits of these insects, such as body size and wing size, however, have not previously been examined during active and advanced decomposition. 2. We used fourth-corner multivariate generalised linear models to identify insect community morphological trait patterns and to quantify their change through time on decomposing rabbit carcasses in grassland and woodland environments. 3. We found that larger-bodied species of flies and carrion-specialist beetles were associated with the early stages of decomposition. The morphological traits of ants, in contrast, showed no changes at carcasses through time and instead showed body size differences between grassland and woodland environments. 4. Our findings indicate that specialist flies and beetles that arrive early in the decomposition process possess traits that enable rapid discovery of carrion at a large scale. Generalist beetles and ants do not share this same trait and are instead adapted to locate and consume a wider variety of resources in their preferred habitat type at their local scale. 5. Our results provide insights into the morphological adaptations linked to the ecological strategies of distinct components of carrion insect communities. Further, our results offer insights into the community assembly dynamics that structure the communities of necrophilous insect species. © 2020 The Royal Entomological Society