ORCID Profile
0000-0002-5040-3911
Current Organisations
University of Adelaide
,
Flinders University School of Biological Sciences
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Aboriginal and Torres Strait Islander history | Quaternary environments | Aboriginal and Torres Strait Islander archaeology | Aboriginal and Torres Strait Islander culture language and history | Wildlife and Habitat Management | Environmental Science and Management | Conservation and Biodiversity | Archaeological science | Population, Ecological and Evolutionary Genetics |
ANZSRC Socio-Economic Objective (SEO)
Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Ecosystem Assessment and Management of Forest and Woodlands Environments | Forest and Woodlands Flora, Fauna and Biodiversity |
Related Links
Publications
Climate-human interaction associated with southeast Australian megafauna extinction patterns
Publisher: Springer Science and Business Media LLC
Date: 22-11-2019
DOI: 10.1038/S41467-019-13277-0
Abstract: The mechanisms leading to megafauna ( kg) extinctions in Late Pleistocene (126,000—12,000 years ago) Australia are highly contested because standard chronological analyses rely on scarce data of varying quality and ignore spatial complexity. Relevant archaeological and palaeontological records are most often also biased by differential preservation resulting in under-representated older events. Chronological analyses have attributed megafaunal extinctions to climate change, humans, or a combination of the two, but rarely consider spatial variation in extinction patterns, initial human appearance trajectories, and palaeoclimate change together. Here we develop a statistical approach to infer spatio-temporal trajectories of megafauna extirpations (local extinctions) and initial human appearance in south-eastern Australia. We identify a combined climate-human effect on regional extirpation patterns suggesting that small, mobile Aboriginal populations potentially needed access to drinkable water to survive arid ecosystems, but were simultaneously constrained by climate-dependent net landscape primary productivity. Thus, the co-drivers of megafauna extirpations were themselves constrained by the spatial distribution of climate-dependent water sources.
Sahul’s megafauna were vulnerable to plant-community changes due to their position in the trophic network
Publisher: Cold Spring Harbor Laboratory
Date: 20-01-2021
DOI: 10.1101/2021.01.19.427338
Abstract: Extinctions stemming from environmental change often trigger trophic cascades and coextinctions. However, it remains unclear whether trophic cascades were a large contributor to the megafauna extinctions that swept across several continents in the Late Pleistocene. The pathways to megafauna extinctions are particularly unclear for Sahul (landmass comprising Australia and New Guinea), where extinctions happened earlier than on other continents. We investigated the role of bottom-up trophic cascades in Late Pleistocene Sahul by constructing pre-extinction (~ 80 ka) trophic network models of the vertebrate community of Naracoorte, south-eastern Australia. These models allowed us to predict vertebrate species’ vulnerability to cascading extinctions based on their position in the network. We tested whether the observed extinctions could be explained by bottom-up cascades, or if they should be attributed to other external causes. Species that disappeared from the community were more vulnerable, overall, to bottom-up cascades than were species that survived. The position of extinct species in the network – having few or no predators – also suggests they might have been particularly vulnerable to a new predator. These results provide quantitative evidence that trophic cascades and naivety to predators could have contributed to the megafauna extinction event in Sahul.
On the rise: Climate change in New Zealand will cause sperm and blue whales to seek higher latitudes
Publisher: Elsevier BV
Date: 09-2022
FosSahul 2.0, an updated database for the Late Quaternary fossil records of Sahul
Publisher: Springer Science and Business Media LLC
Date: 19-11-2019
DOI: 10.1038/S41597-019-0267-3
Abstract: The 2016 version of the FosSahul database compiled non-human vertebrate megafauna fossil ages from Sahul published up to 2013 in a standardized format. Its purpose was to create a publicly available, centralized, and comprehensive database for palaeoecological investigations of the continent. Such databases require regular updates and improvements to reflect recent scientific findings. Here we present an updated FosSahul (2.0) containing 11,871 dated non-human vertebrate fossil records from the Late Quaternary published up to 2018. Furthermore, we have extended the information captured in the database to include methodological details and have developed an algorithm to automate the quality-rating process. The algorithm makes the quality-rating more transparent and easier to reproduce, facilitating future database extensions and dissemination. FosSahul has already enabled several palaeoecological analyses, and its updated version will continue to provide a centralized organisation of Sahul’s fossil records. As an ex le of an application of the database, we present the temporal pattern in megafauna genus richness inferred from available data in relation to palaeoclimate indices over the past 180,000 years.
Demographic models predict end-Pleistocene arrival and rapid expansion of pre-agropastoralist humans in Cyprus
Publisher: Research Square Platform LLC
Date: 23-10-2023
Predicting predator–prey interactions in terrestrial endotherms using random forest
Publisher: Wiley
Date: 10-07-2023
DOI: 10.1111/ECOG.06619
Abstract: Species interactions play a fundamental role in ecosystems. However, few ecological communities have complete data describing such interactions, which is an obstacle to understanding how ecosystems function and respond to perturbations. Because it is often impractical to collect empirical data for all interactions in a community, various methods have been developed to infer interactions. Machine learning is increasingly being used for making interaction predictions, with random forest being one of the most frequently used of these methods. However, performance of random forest in inferring predator‐prey interactions in terrestrial vertebrates and its sensitivity to training data quality remain untested. We examined predator–prey interactions in two erse, primarily terrestrial vertebrate classes: birds and mammals. Combining data from a global interaction dataset and a specific community (Simpson Desert, Australia), we tested how well random forest predicted predator–prey interactions for mammals and birds using species' ecomorphological and phylogenetic traits. We also tested how variation in training data quality – manipulated by removing records and switching interaction records to non‐interactions – affected model performance. We found that random forest could predict predator–prey interactions for birds and mammals using ecomorphological or phylogenetic traits, correctly predicting up to 88 and 67% of interactions and non‐interactions in the global and community‐specific datasets, respectively. These predictions were accurate even when there were no records in the training data for focal species. In contrast, false non‐interactions for focal predators in training data strongly degraded model performance. Our results demonstrate that random forest can identify predator–prey interactions for birds and mammals that have few or no interaction records. Furthermore, our study provides guidance on how to prepare training data to optimise machine learning classifiers for predicting species interactions, which could help ecologists 1) address knowledge gaps and explore network‐related questions in data‐poor situations, and 2) predict interactions for range‐expanding species.
How climate, migration ability and habitat fragmentation affect the projected future distribution of European beech.
Publisher: Wiley
Date: 03-12-2015
DOI: 10.1111/GCB.12771
Abstract: Recent efforts to incorporate migration processes into species distribution models (SDMs) are allowing assessments of whether species are likely to be able to track their future climate optimum and the possible causes of failing to do so. Here, we projected the range shift of European beech over the 21st century using a process-based SDM coupled to a phenomenological migration model accounting for population dynamics, according to two climate change scenarios and one land use change scenario. Our model predicts that the climatically suitable habitat for European beech will shift north-eastward and upward mainly because (i) higher temperature and precipitation, at the northern range margins, will increase survival and fruit maturation success, while (ii) lower precipitations and higher winter temperature, at the southern range margins, will increase drought mortality and prevent bud dormancy breaking. Beech colonization rate of newly climatically suitable habitats in 2100 is projected to be very low (1-2% of the newly suitable habitats colonised). Unexpectedly, the projected realized contraction rate was higher than the projected potential contraction rate. As a result, the realized distribution of beech is projected to strongly contract by 2100 (by 36-61%) mainly due to a substantial increase in climate variability after 2050, which generates local extinctions, even at the core of the distribution, the frequency of which prevents beech recolonization during more favourable years. Although European beech will be able to persist in some parts of the trailing edge of its distribution, the combined effects of climate and land use changes, limited migration ability, and a slow life-history are likely to increase its threat status in the near future.
Estimating co‐extinction threats in terrestrial ecosystems
Publisher: Wiley
Date: 29-06-2023
DOI: 10.1111/GCB.16836
Abstract: The biosphere is changing rapidly due to human endeavour. Because ecological communities underlie networks of interacting species, changes that directly affect some species can have indirect effects on others. Accurate tools to predict these direct and indirect effects are therefore required to guide conservation strategies. However, most extinction‐risk studies only consider the direct effects of global change—such as predicting which species will breach their thermal limits under different warming scenarios—with predictions of trophic cascades and co‐extinction risks remaining mostly speculative. To predict the potential indirect effects of primary extinctions, data describing community interactions and network modelling can estimate how extinctions cascade through communities. While theoretical studies have demonstrated the usefulness of models in predicting how communities react to threats like climate change, few have applied such methods to real‐world communities. This gap partly reflects challenges in constructing trophic network models of real‐world food webs, highlighting the need to develop approaches for quantifying co‐extinction risk more accurately. We propose a framework for constructing ecological network models representing real‐world food webs in terrestrial ecosystems and subjecting these models to co‐extinction scenarios triggered by probable future environmental perturbations. Adopting our framework will improve estimates of how environmental perturbations affect whole ecological communities. Identifying species at risk of co‐extinction (or those that might trigger co‐extinctions) will also guide conservation interventions aiming to reduce the probability of co‐extinction cascades and additional species losses.
Predicting predator-prey interactions in terrestrial endotherms using random forest
Publisher: Cold Spring Harbor Laboratory
Date: 05-09-2022
DOI: 10.1101/2022.09.02.506446
Abstract: Species interactions play a fundamental role in ecosystems. However, few ecological communities have complete data describing such interactions, which is an obstacle to understanding how ecosystems function and respond to perturbations. Because it is often impractical to collect empirical data for all interactions in a community, various methods have been developed to infer interactions. Machine learning is increasingly being used for making interaction predictions, with random forest being one of the most frequently used of these methods. However, performance of random forest in inferring predator-prey interactions in terrestrial vertebrates and its sensitivity to training data quality remain untested. We examined predator-prey interactions in two erse, primarily terrestrial vertebrate classes: birds and mammals. Combining data from a global interaction dataset and a specific community (Simpson Desert, Australia), we tested how well random forest predicted predator-prey interactions for mammals and birds using species’ ecomorphological and phylogenetic traits. We also tested how variation in training data quality—manipulated by removing records and switching interaction records to non-interactions—affected model performance. We found that random forest could predict predator-prey interactions for birds and mammals using ecomorphological or phylogenetic traits, correctly predicting up to 88% and 67% of interactions and non-interactions in the global and community-specific datasets, respectively. These predictions were accurate even when there were no records in the training data for focal species. In contrast, false non-interactions for focal predators in training data strongly degraded model performance. Our results demonstrate that random forest can identify predator-prey interactions for birds and mammals that have few or no interaction records. Furthermore, our study provides guidance on how to prepare training data to optimise machine-learning classifiers for predicting species interactions, which could help ecologists ( i ) address knowledge gaps and explore network-related questions in data-poor situations, and ( ii ) predict interactions for range-expanding species.
Uncertainties in dating constrain model choice for inferring extinction time from fossil records
Publisher: Elsevier BV
Date: 03-2015
Climate change not to blame for late Quaternary megafauna extinctions in Australia
Publisher: Springer Science and Business Media LLC
Date: 29-01-2016
DOI: 10.1038/NCOMMS10511
Abstract: Late Quaternary megafauna extinctions impoverished mammalian ersity worldwide. The causes of these extinctions in Australia are most controversial but essential to resolve, because this continent-wide event presaged similar losses that occurred thousands of years later on other continents. Here we apply a rigorous metadata analysis and new ensemble-hindcasting approach to 659 Australian megafauna fossil ages. When coupled with analysis of several high-resolution climate records, we show that megafaunal extinctions were broadly synchronous among genera and independent of climate aridity and variability in Australia over the last 120,000 years. Our results reject climate change as the primary driver of megafauna extinctions in the world’s most controversial context, and instead estimate that the megafauna disappeared Australia-wide ∼13,500 years after human arrival, with shorter periods of coexistence in some regions. This is the first comprehensive approach to incorporate uncertainty in fossil ages, extinction timing and climatology, to quantify mechanisms of prehistorical extinctions.
A Facile Route to Homogeneous High Density Networks of Metal Nanoparticles
Publisher: American Chemical Society (ACS)
Date: 09-09-2009
DOI: 10.1021/LA9026915
Abstract: In this communication, we report an inexpensive and simple-to-implement method using self-assembly properties of surfactants onto solid substrates for patterning square centimeter surfaces with a high density of catalyst metal nanoparticles with narrow size distributions. This method, which uses patterns of hemimicelles of partially fluorinated alkanes as masks and over metal evaporation, leads to typical particle sizes and spacings of 2 and 25 nm, respectively, arranged in a hexagonal network with a density of about 10(11) particles/cm2. Using gold as the metal, we show the ability of such material to catalyze the oxidation reaction of carbon monoxide into carbon dioxide at low temperature.
Author response: Relative demographic susceptibility does not explain the extinction chronology of Sahul’s megafauna
Publisher: eLife Sciences Publications, Ltd
Date: 19-03-2021
Minimum founding populations for the first peopling of Sahul
Publisher: Springer Science and Business Media LLC
Date: 17-06-2019
DOI: 10.1038/S41559-019-0902-6
Abstract: The timing, context and nature of the first people to enter Sahul is still poorly understood owing to a fragmented archaeological record. However, quantifying the plausible demographic context of this founding population is essential to determine how and why the initial peopling of Sahul occurred. We developed a stochastic, age-structured model using demographic rates from hunter-gatherer societies, and relative carrying capacity hindcasted with LOVECLIM's net primary productivity for northern Sahul. We projected these populations to determine the resilience and minimum sizes required to avoid extinction. A census founding population of between 1,300 and 1,550 in iduals was necessary to maintain a quasi-extinction threshold of ≲0.1. This minimum founding population could have arrived at a single point in time, or through multiple voyages of ≥130 people over ~700-900 years. This result shows that substantial population amalgamation in Sunda and Wallacea in Marine Isotope Stages 3-4 provided the conditions for the successful, large-scale and probably planned peopling of Sahul.
Predicting and mitigating future biodiversity loss using long-term ecological proxies
Publisher: Springer Science and Business Media LLC
Date: 28-09-2016
DOI: 10.1038/NCLIMATE3086
Using Holocene fossils to model the future: Distribution of climate suitability for tuatara, the last rhynchocephalian
Publisher: Wiley
Date: 19-03-2021
DOI: 10.1111/JBI.14092
Abstract: Correlative species distribution models (SDMs) are typically trained using only the contemporary distribution of species however, recent records might reflect an incomplete description of a species' niche, limiting the reliability of predictions. SDMs linking fossil records have the potential to improve conservation decisions under human‐induced climate change. Here, we built SDMs using presence records from contemporary and Holocene records to enable estimations of climatically suitable area under current and future climate scenarios. Aotearoa New Zealand Tuatara, Sphenodon punctatus For an evolutionary relict found in Aotearoa New Zealand, the tuatara ( Sphenodon punctatus ), we built SDMs using presence records from contemporary and Holocene records to estimate climatically suitable area under current and future climate scenarios. We also use our detailed knowledge of the Holocene distribution and remnant populations to examine niche shifts following the arrival of humans and associated introduction of mammalian predators. To build SDMs, we use presence records from four sources: (a) remnant populations, (b) radiocarbon‐dated fossil deposits from the Holocene, (c) other fossil deposits containing tuatara bones of Holocene age and iv) islands from which tuatara are known or highly likely to have become extinct. We found shifts in the niche of tuatara due to niche unfilling. Incorporating locations of Holocene deposits and/or all past locations in SDMs led to larger areas of climatically suitable area being identified compared to SDMs derived from remnant populations only. Using all presence records, under climate change projections for 2090, climatically suitable area increased slightly. However, many areas retain potential as translocation sites (e.g. northern South Island), some areas become unsuitable (e.g. inland Canterbury) and/or involve extrapolation into novel climates (e.g. Northland). SDMs incorporating locations of Holocene deposits and/or all past locations identified areas of critical habitat for tuatara under current and future climate scenarios, that would not have been identified using contemporary occurrences only. Our results highlight the need to consider past locations when assessing habitat suitability for conservation translocations, both for tuatara and other relict species.
PaleoView: a tool for generating continuous climate projections spanning the last 21 000 years at regional and global scales
Publisher: Wiley
Date: 12-05-2017
DOI: 10.1111/ECOG.03031
Predicting targets and costs for feral-cat reduction on large islands using stochastic population models
Publisher: Cold Spring Harbor Laboratory
Date: 14-06-2020
DOI: 10.1101/2020.06.12.149393
Abstract: Feral cats are some of the most destructive invasive predators worldwide, particularly in insular environments hence, density-reduction c aigns are often applied to alleviate the predation mortality they add to native fauna. Density-reduction and eradication efforts are costly procedures with important outcomes for native fauna recovery, so they require adequate planning to be successful. These plans need to include empirical density-reduction models that can guide yearly culling quotas, and resource roll-out for the duration of the culling period. This ensures densities are reduced over the long term and that no resources are wasted. We constructed a stochastic population model with cost estimates to test the relative effectiveness and cost-efficiency of two main culling scenarios for a 10-year eradication c aign of cats on Kangaroo Island, Australia: (1) constant proportional annual cull (one-phase), and (2) high initial culling followed by a constant proportional maintenance cull (two-phase). A one-phase cull of at least 0.35 of the annual population size would reduce the final population to 0.1 of its original size, while a two-phase cull with an initial cull of minimum 0.6 and minimum 0.5 maintenance cull would reduce the final population to 0.01 of its initial size by 2030. Cost estimates varied widely depending on the methods applied (shooting, trapping, aerial poison baits, Felixer ™ poison-delivery system), but using baiting, trapping and Felixers with additional shooting to meet culling quotas was the most cost-effective combination (minimum cost: AU$19.56 million range: AU$16.87 million–AU$20.69 million). Our model provides an adaptable and general assessment tool for cat reductions in Australia and potentially elsewhere, and provides relative culling costs for the Kangaroo Island programme specifically.
The Australian National Rabbit Database: 50 yr of population monitoring of an invasive species.
Publisher: Wiley
Date: 20-05-2019
DOI: 10.1002/ECY.2750
Abstract: With ongoing introductions into Australia since the 1700s, the European rabbit (Oryctolagus cuniculus) has become one of the most widely distributed and abundant vertebrate pests, adversely impacting Australia's bio ersity and agroeconomy. To understand the population and range dynamics of the species and its impacts better, occurrence and abundance data have been collected by researchers and citizens from sites covering a broad spectrum of climatic and environmental conditions in Australia. The lack of a common and accessible repository for these data has, however, limited their use in determining important spatiotemporal drivers of the structure and dynamics of the geographical range of rabbits in Australia. To meet this need, we created the Australian National Rabbit Database, which combines more than 50 yr of historical and contemporary survey data collected from throughout the range of the species in Australia. The survey data, obtained from a suite of complementary monitoring methods, were combined with high-resolution weather, climate, and environmental information, and an assessment of data quality. The database provides records of rabbit occurrence (689,265 records) and abundance (51,241 records, >120 distinct sites) suitable for identifying the spatiotemporal drivers of the rabbit's distribution and for determining spatial patterns of variation in its key life-history traits, including maximum rates of population growth. Because all data are georeferenced and date st ed, they can be coupled with information from other databases and spatial layers to explore the potential effects of rabbit occurrence and abundance on Australia's native wildlife and agricultural production. The Australian National Rabbit Database is an important tool for understanding and managing the European rabbit in its invasive range and its effects on native bio ersity and agricultural production. It also provides a valuable resource for addressing questions related to the biology, success, and impacts of invasive species more generally. No copyright or proprietary restrictions are associated with the use of this data set other than citation of this Data Paper.
Sahul's megafauna were vulnerable to plant‐community changes due to their position in the trophic network
Publisher: Wiley
Date: 13-12-2021
DOI: 10.1111/ECOG.06089
Abstract: Extinctions stemming from environmental change often trigger trophic cascades and coextinctions. Bottom–up cascades occur when changes in the primary producers in a network elicit flow‐on effects to higher trophic levels. However, it remains unclear what determines a species' vulnerability to bottom–up cascades and whether such cascades were a large contributor to the megafauna extinctions that swept across several continents in the Late Pleistocene. The pathways to megafauna extinctions are particularly unclear for Sahul (landmass comprising Australia and New Guinea), where extinctions happened earlier than on other continents. We investigated the potential role of bottom–up trophic cascades in the megafauna extinctions in Late Pleistocene Sahul by first developing synthetic networks that varied in topology to identify how network position (trophic level, diet breadth, basal connections) influences vulnerability to bottom–up cascades. We then constructed pre‐extinction (~80 ka) network models of the ecological community of Naracoorte, south‐eastern Sahul, to assess whether the observed megafauna extinctions could be explained by bottom–up cascades. Synthetic networks showed that node vulnerability to bottom–up cascades decreased with increasing trophic level, diet breadth and basal connections. Extinct species in the Naracoorte community were more vulnerable overall to these cascades than were species that survived. The position of extinct species in the network – tending to be of low trophic level and therefore having relatively narrow diet breadths and fewer connections to plants – made them vulnerable. However, these species also tended to have few or no predators, a network‐position attribute that suggests they might have been particularly vulnerable to new predators. Together, these results suggest that trophic cascades and naivety to predators could have contributed to the megafauna extinction event in Sahul.
A comprehensive database of quality-rated fossil ages for Sahul’s Quaternary vertebrates
Publisher: Springer Science and Business Media LLC
Date: 19-07-2016
Abstract: The study of palaeo-chronologies using fossil data provides evidence for past ecological and evolutionary processes, and is therefore useful for predicting patterns and impacts of future environmental change. However, the robustness of inferences made from fossil ages relies heavily on both the quantity and quality of available data. We compiled Quaternary non-human vertebrate fossil ages from Sahul published up to 2013. This, the FosSahul database, includes 9,302 fossil records from 363 deposits, for a total of 478 species within 215 genera, of which 27 are from extinct and extant megafaunal species (2,559 records). We also provide a rating of reliability of in idual absolute age based on the dating protocols and association between the dated materials and the fossil remains. Our proposed rating system identified 2,422 records with high-quality ages (i.e., a reduction of 74%). There are many applications of the database, including disentangling the confounding influences of hypothetical extinction drivers, better spatial distribution estimates of species relative to palaeo-climates, and potentially identifying new areas for fossil discovery.
Early human settlement of Sahul was not an accident
Publisher: Springer Science and Business Media LLC
Date: 17-06-2019
DOI: 10.1038/S41598-019-42946-9
Abstract: The first peopling of Sahul (Australia, New Guinea and the Aru Islands joined at lower sea levels) by anatomically modern humans required multiple maritime crossings through Wallacea, with at least one approaching 100 km. Whether these crossings were accidental or intentional is unknown. Using coastal-viewshed analysis and ocean drift modelling combined with population projections, we show that the probability of randomly reaching Sahul by any route is % until ≥40 adults are ‘washed off’ an island at least once every 20 years. We then demonstrate that choosing a time of departure and making minimal headway (0.5 knots) toward a destination greatly increases the likelihood of arrival. While drift modelling demonstrates the existence of ‘bottleneck’ crossings on all routes, arrival via New Guinea is more likely than via northwestern Australia. We conclude that anatomically modern humans had the capacity to plan and make open-sea voyages lasting several days by at least 50,000 years ago.
Climate refugia: joint inference from fossil records, species distribution models and phylogeography
Publisher: Wiley
Date: 16-07-2014
DOI: 10.1111/NPH.12929
Abstract: Climate refugia, locations where taxa survive periods of regionally adverse climate, are thought to be critical for maintaining bio ersity through the glacial–interglacial climate changes of the Q uaternary. A critical research need is to better integrate and reconcile the three major lines of evidence used to infer the existence of past refugia – fossil records, species distribution models and phylogeographic surveys – in order to characterize the complex spatiotemporal trajectories of species and populations in and out of refugia. Here we review the complementary strengths, limitations and new advances for these three approaches. We provide case studies to illustrate their combined application, and point the way towards new opportunities for synthesizing these disparate lines of evidence. Case studies with E uropean beech, Q inghai spruce and D ouglas‐fir illustrate how the combination of these three approaches successfully resolves complex species histories not attainable from any one approach. Promising new statistical techniques can capitalize on the strengths of each method and provide a robust quantitative reconstruction of species history. Studying past refugia can help identify contemporary refugia and clarify their conservation significance, in particular by elucidating the fine‐scale processes and the particular geographic locations that buffer species against rapidly changing climate. Contents Summary 38 I. Climate refugia: biogeographical and conservation significance 38 II. Approaches for reconstructing refugia: strengths, limitations and recent advances 39 III. Climate refugia of the past: three case studies 46 IV. New integrative approaches to reconstructing refugia 47 V. How can historical refugia inform us about future refugia? 48 VI. Concluding thoughts 49 Acknowledgements 49 References 49
Differential developmental rates and demographics in Red Kangaroo (Osphranter rufus) populations separated by the dingo barrier fence
Publisher: Oxford University Press (OUP)
Date: 31-05-2023
Abstract: Decommissioning the dingo barrier fence has been suggested to reduce destructive dingo control and encourage a free transfer of biota between environments in Australia. Yet the potential impacts that over a century of predator exclusion might have had on the population dynamics and developmental biology of prey populations has not been assessed. We here combine demographic data and both linear and geometric morphometrics to assess differences in populations among 166 red kangaroos (Osphranter rufus)—a primary prey species of the dingo—from two isolated populations on either side of the fence. We also quantified the differences in aboveground vegetation biomass for the last 10 years on either side of the fence. We found that the age structure and growth patterns, but not cranial shape, differed between the two kangaroo populations. In the population living with a higher density of dingoes, there were relatively fewer females and juveniles. These in iduals were larger for a given age, despite what seems to be lower vegetation biomass. However, how much of this biomass represented kangaroo forage is uncertain and requires further on-site assessments. We also identified unexpected differences in the ontogenetic trajectories in relative pes length between the sexes for the whole s le, possibly associated with male competition or differential weight-bearing mechanics. We discuss potential mechanisms behind our findings and suggest that the impacts of contrasting predation pressures across the fence, for red kangaroos and other species, merit further investigation.
Climate or migration: what limited E uropean beech post‐glacial colonization?
Publisher: Wiley
Date: 05-06-2013
DOI: 10.1111/GEB.12085
Dredging activity in a highly urbanised estuary did not affect the long-term occurrence of Indo-Pacific bottlenose dolphins and long-nosed fur seals
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.MARPOLBUL.2022.114183
Abstract: Dredging is an excavation activity used worldwide in marine and freshwater environments to create, deepen, and maintain waterways, harbours, channels, locks, docks, berths, river entrances, and approaches to ports and boat r s. However, dredging impacts on marine life, including marine mammals (cetaceans, pinnipeds, and sirenians), remain largely unknown. Here we quantified the effect of dredging operations in 2005 and 2019 on the occurrence of Indo-Pacific bottlenose dolphins (Tursiops aduncus) and long-nosed fur seals (Arctocephalus forsteri) in the Port River estuary, a highly urbanized estuary in Adelaide, South Australia. We applied generalised linear models to two long-term sighting datasets (dolphins: 1992-2020, fur seals: 2010-2020), to analyse changes in sighting rates as a function of dredging operations, season, rainfall, and sea surface temperature. We showed that the fluctuations in both dolphin and fur seal occurrences were not correlated with dredging operations, whereas sea surface temperature and season were stronger predictors of both species sighting rates (with seals more prevalent during the colder months, and dolphins in summer). Given the highly industrial environment of the Port River estuary, it is possible that animals in this area are habituated to high noise levels and therefore were not disturbed by dredging operations. Future research would benefit from analysing short-term effects of dredging operations on behaviour, movement patterns and habitat use to determine effects of possible habitat alteration caused by dredging.
Relative demographic susceptibility does not explain the extinction chronology of Sahul’s megafauna
Publisher: Cold Spring Harbor Laboratory
Date: 19-10-2020
DOI: 10.1101/2020.10.16.342303
Abstract: The causes of Sahul’s megafauna extinctions remain uncertain, although multiple, interacting factors were likely responsible. To test hypotheses regarding plausible ecological mechanisms underlying these extinctions, we constructed the first stochastic, age-structured models for 13 extinct megafauna species from five functional/taxonomic groups, as well as 8 extant species within these groups for comparison. Perturbing specific demographic rates in idually, we tested which species were more demographically susceptible to extinction, and then compared these relative sensitivities to the fossil-derived extinction chronology. Here we show that the macropodiformes were the most resilient to extinction, followed by carnivores, monotremes, vombatiform herbivores, and large birds. Five of the eight extant species were as or more susceptible than were the extinct species. There was no clear relationship between extinction susceptibility and the extinction chronology for any perturbation scenario, but body mass and generation length explained much of the variation in relative risk. Our models reveal that the actual mechanisms leading to extinction were unlikely related to variation in demographic susceptibility per se , but were driven instead by finer-scale variation in climate change and/or human prey choice and relative hunting success.
Commentary: Underestimating the Challenges of Avoiding a Ghastly Future
Publisher: Frontiers Media SA
Date: 13-05-2021
What caused extinction of the Pleistocene megafauna of Sahul?
Publisher: The Royal Society
Date: 10-02-2016
Abstract: During the Pleistocene, Australia and New Guinea supported a rich assemblage of large vertebrates. Why these animals disappeared has been debated for more than a century and remains controversial. Previous synthetic reviews of this problem have typically focused heavily on particular types of evidence, such as the dating of extinction and human arrival, and have frequently ignored uncertainties and biases that can lead to misinterpretation of this evidence. Here, we review erse evidence bearing on this issue and conclude that, although many knowledge gaps remain, multiple independent lines of evidence point to direct human impact as the most likely cause of extinction.
Why decadal to century timescale palaeoclimate data are needed to explain present‐day patterns of biological diversity and change
Publisher: Wiley
Date: 30-10-2017
DOI: 10.1111/GCB.13932
Abstract: The current distribution of species, environmental conditions and their interactions represent only one snapshot of a planet that is continuously changing, in part due to human influences. To distinguish human impacts from natural factors, the magnitude and pace of climate shifts, since the Last Glacial Maximum, are often used to determine whether patterns of ersity today are artefacts of past climate change. In the absence of high-temporal resolution palaeoclimate reconstructions, this is generally done by assuming that past climate change occurred at a linear pace between widely spaced (usually, ≥1,000 years) climate snapshots. We show here that this is a flawed assumption because regional climates have changed significantly across decades and centuries during glacial-interglacial cycles, likely causing rapid regional replacement of biota. We demonstrate how recent atmosphere-ocean general circulation model (AOGCM) simulations of the climate of the past 21,000 years can provide credible estimates of the details of climate change on decadal to centennial timescales, showing that these details differ radically from what might be inferred from longer timescale information. High-temporal resolution information can provide more meaningful estimates of the magnitude and pace of climate shifts, the location and timing of drivers of physiological stress, and the extent of novel climates. They also produce new opportunities to directly investigate whether short-term climate variability is more important in shaping bio ersity patterns rather than gradual changes in long-term climatic means. Together, these more accurate measures of past climate instability are likely to bring about a better understanding of the role of palaeoclimatic change and variability in shaping current macroecological patterns in many regions of the world.
High-quality fossil dates support a synchronous, Late Holocene extinction of devils and thylacines in mainland Australia
Publisher: The Royal Society
Date: 2018
Abstract: The last large marsupial carnivores—the Tasmanian devil ( Sarcophilis harrisii ) and thylacine ( Thylacinus cynocephalus )—went extinct on mainland Australia during the mid-Holocene. Based on the youngest fossil dates (approx. 3500 years before present, BP), these extinctions are often considered synchronous and driven by a common cause. However, many published devil dates have recently been rejected as unreliable, shifting the youngest mainland fossil age to 25 500 years BP and challenging the synchronous-extinction hypothesis. Here we provide 24 and 20 new ages for devils and thylacines, respectively, and collate existing, reliable radiocarbon dates by quality-filtering available records. We use this new dataset to estimate an extinction time for both species by applying the Gaussian-res led, inverse-weighted McInerney (GRIWM) method. Our new data and analysis definitively support the synchronous-extinction hypothesis, estimating that the mainland devil and thylacine extinctions occurred between 3179 and 3227 years BP.
Predicting targets and costs for feral‐cat reduction on large islands using stochastic population models
Publisher: Wiley
Date: 15-05-2021
DOI: 10.1111/CSP2.448
Abstract: Feral cats are some of the most destructive invasive predators worldwide, particularly in insular environments hence, density‐reduction c aigns are often applied to alleviate the predation mortality they add to native fauna. Density‐reduction and eradication efforts are costly procedures with important outcomes for native fauna recovery, so they require adequate planning to be successful. These plans should include empirical density‐reduction models that can guide yearly culling quotas, and resource roll‐out for the duration of the culling period. This ensures densities are reduced over the long term and that resources are not wasted. We constructed a stochastic population model with cost estimates to test the relative effectiveness and cost‐efficiency of two main culling scenarios for a 10‐year eradication c aign of cats on Kangaroo Island, Australia: (a) constant proportional annual cull (one‐phase), and (b) high initial culling followed by a constant proportional maintenance cull (two‐phase). A one‐phase cull of at least 0.35 of the annual population size would reduce the final population to 0.1 of its original size, while a two‐phase cull with an initial cull of minimum 0.6 and minimum 0.5 maintenance cull would reduce the final population to 0.01 of its initial size within the 10‐year time frame. Cost estimates varied widely depending on the methods applied (shooting, trapping, aerial poison baits, Felixer ™ poison‐delivery system), but using baiting, trapping and Felixers with additional shooting to meet culling quotas was the most cost‐effective combination (minimum cost: AU$19.56 million range: AU$16.87 million–AU$20.69 million). Our model provides an adaptable and general assessment tool for cat reductions in Australia and potentially elsewhere, and provides relative culling costs for the Kangaroo Island c aign specifically.
Modeling the effects of water regulation on the population viability of a threatened amphibian
Publisher: Wiley
Date: 2023
DOI: 10.1002/ECS2.4379
Abstract: The regulation of river systems alters hydrodynamics and often reduces lateral connectivity between river channels and floodplains. For taxa such as frogs that rely on floodplain wetlands to complete their life cycle, decreasing inundation frequency can reduce recruitment and increase the probability of local extinction. We virtually reconstructed the inundation patterns of wetlands under natural and regulated flow conditions and built stochastic population models to quantify the probability of local extinction under different inundation scenarios. Specifically, we explored the interplay of habitat size, inundation frequency, and successive dry years on the local extinction probability of the threatened southern bell frog Litoria raniformis in the Murray River floodplains of South Australia. We hypothesized that the changes to wetland inundation resulting from river regulation are driving L. raniformis declines in this semiarid system. Regulation has reduced the inundation frequency of essential habitats below critical thresholds for the persistence of many fresh water‐dependent species. Successive dry years raise the probability of local extinction, and these effects are strongest in smaller wetlands. Larger wetlands and those with more frequent average inundation are less susceptible to these effects. Elucidating these trends informs the prioritization of intervention sites and the frequency of conservation interventions. Environmental water provision (through pumping or the operation of flow‐regulating structures) is a promising tool to reduce the probability of breeding failure and local extinction. Our modeling approach can be used to prioritize the delivery of environmental water to L. raniformis and potentially many other frog species.
Relative demographic susceptibility does not explain the extinction chronology of Sahul’s megafauna
Publisher: eLife Sciences Publications, Ltd
Date: 30-03-2021
DOI: 10.7554/ELIFE.63870
Abstract: The causes of Sahul’s megafauna extinctions remain uncertain, although several interacting factors were likely responsible. To examine the relative support for hypotheses regarding plausible ecological mechanisms underlying these extinctions, we constructed the first stochastic, age-structured models for 13 extinct megafauna species from five functional/taxonomic groups, as well as 8 extant species within these groups for comparison. Perturbing specific demographic rates in idually, we tested which species were more demographically susceptible to extinction, and then compared these relative sensitivities to the fossil-derived extinction chronology. Our models show that the macropodiformes were the least demographically susceptible to extinction, followed by carnivores, monotremes, vombatiform herbivores, and large birds. Five of the eight extant species were as or more susceptible than the extinct species. There was no clear relationship between extinction susceptibility and the extinction chronology for any perturbation scenario, while body mass and generation length explained much of the variation in relative risk. Our results reveal that the actual mechanisms leading to the observed extinction chronology were unlikely related to variation in demographic susceptibility per se, but were possibly driven instead by finer-scale variation in climate change and/or human prey choice and relative hunting success.
Underestimating the Challenges of Avoiding a Ghastly Future
Publisher: Frontiers Media SA
Date: 13-01-2021
DOI: 10.3389/FCOSC.2020.615419
Abstract: We report three major and confronting environmental issues that have received little attention and require urgent action. First, we review the evidence that future environmental conditions will be far more dangerous than currently believed. The scale of the threats to the biosphere and all its lifeforms—including humanity—is in fact so great that it is difficult to grasp for even well-informed experts. Second, we ask what political or economic system, or leadership, is prepared to handle the predicted disasters, or even capable of such action. Third, this dire situation places an extraordinary responsibility on scientists to speak out candidly and accurately when engaging with government, business, and the public. We especially draw attention to the lack of appreciation of the enormous challenges to creating a sustainable future. The added stresses to human health, wealth, and well-being will perversely diminish our political capacity to mitigate the erosion of ecosystem services on which society depends. The science underlying these issues is strong, but awareness is weak. Without fully appreciating and broadcasting the scale of the problems and the enormity of the solutions required, society will fail to achieve even modest sustainability goals.
A phenomenological model without dispersal kernel to model species migration
Publisher: Elsevier BV
Date: 12-2009
Landscape rules predict optimal superhighways for the first peopling of Sahul.
Publisher: Springer Science and Business Media LLC
Date: 29-04-2021
DOI: 10.1038/S41562-021-01106-8
Abstract: Archaeological data and demographic modelling suggest that the peopling of Sahul required substantial populations, occurred rapidly within a few thousand years and encompassed environments ranging from hyper-arid deserts to temperate uplands and tropical rainforests. How this migration occurred and how humans responded to the physical environments they encountered have, however, remained largely speculative. By constructing a high-resolution digital elevation model for Sahul and coupling it with fine-scale viewshed analysis of landscape prominence, least-cost pedestrian travel modelling and high-performance computing, we create over 125 billion potential migratory pathways, whereby the most parsimonious routes traversed emerge. Our analysis revealed several major pathways-superhighways-transecting the continent, that we evaluated using archaeological data. These results suggest that the earliest Australian ancestors adopted a set of fundamental rules shaped by physiological capacity, attraction to visually prominent landscape features and freshwater distribution to maximize survival, even without previous experience of the landscapes they encountered.
Stochastic models support rapid peopling of Late Pleistocene Sahul
Publisher: Springer Science and Business Media LLC
Date: 29-04-2021
DOI: 10.1038/S41467-021-21551-3
Abstract: The peopling of Sahul (the combined continent of Australia and New Guinea) represents the earliest continental migration and settlement event of solely anatomically modern humans, but its patterns and ecological drivers remain largely conceptual in the current literature. We present an advanced stochastic-ecological model to test the relative support for scenarios describing where and when the first humans entered Sahul, and their most probable routes of early settlement. The model supports a dominant entry via the northwest Sahul Shelf first, potentially followed by a second entry through New Guinea, with initial entry most consistent with 50,000 or 75,000 years ago based on comparison with bias-corrected archaeological map layers. The model’s emergent properties predict that peopling of the entire continent occurred rapidly across all ecological environments within 156–208 human generations (4368–5599 years) and at a plausible rate of 0.71–0.92 km year −1 . More broadly, our methods and approaches can readily inform other global migration debates, with results supporting an exit of anatomically modern humans from Africa 63,000–90,000 years ago, and the peopling of Eurasia in as little as 12,000–15,000 years via inland routes.
Modelling range dynamics under global change: which framework and why?
Publisher: Wiley
Date: 15-12-2015
Abstract: To conserve future bio ersity, a better understanding of the likely effects of climate and land‐use change on the geographical distributions of species and the persistence of ecological communities is needed. Recent advances have integrated population dynamic processes into species distribution models ( SDM s), to reduce potential biases in predictions and to better reflect the demographic nuances of incremental range shifts. However, there is no clear framework for selecting the most appropriate demographic‐based model for a given data set or scientific question. We review the computer‐based modelling platforms currently used for the development of either population‐ or in idual‐based species range dynamics models. We describe the features and requirements of 20 software platforms commonly used to generate simulations of species ranges and abundances. We classify the platforms according to particular capabilities or features that account for user requirements and constraints, such as (i) ability to simulate simple to complex population dynamics, (ii) organism specificity or (iii) their computational capacities. Using this classification, we develop a protocol for choosing the most appropriate framework for modelling species range dynamics based in data availability and research requirements. We find that the main differences between modelling platforms are related to the way in which they simulate population dynamics, the type of organisms they are able to model and the ecological processes they incorporate. We show that some platforms can be used as generic modelling software to investigate a broad range of ecological questions related to the range dynamics of most species, and how these are likely to change in the future in response to forecast climate and land‐use change. We argue that model predictions will be improved by reducing usage to a smaller number of highly flexible freeware platforms. Our approach provides ecologists and conservation biologists with a clear method for selecting the most appropriate software platform that meets their needs when developing SDM s coupled with population‐dynamic processes. We argue that informed tool choice will translate to better predictions of species responses to climate and land‐use change and improved conservation management.
Modeling the distribution of a wide‐ranging invasive species using the sampling efforts of expert and citizen scientists
Publisher: Wiley
Date: 19-09-2019
DOI: 10.1002/ECE3.5609
Criteria for assessing the quality of Middle Pleistocene to Holocene vertebrate fossil ages
Publisher: Elsevier BV
Date: 10-2015
Addendum: FosSahul 2.0, an updated database for the Late Quaternary fossil records of Sahul
Publisher: Springer Science and Business Media LLC
Date: 13-05-2021
Stochastic population models to identify optimal and cost-effective harvest strategies for feral pig eradication
Publisher: Cold Spring Harbor Laboratory
Date: 12-03-2023
DOI: 10.1101/2023.03.08.531659
Abstract: Eradicating feral pigs from island ecosystems can assist in restoring damaged bio ersity values and protect commercial industries such as agriculture. Although many feral pig eradications have been attempted, management decisions are often led by practitioner experience rather than empirical evidence. Few interventions have been guided by population models to identify harvest rates necessary to achieve eradication within a specified time frame, nor have they applied data on control effort and cost to evaluate the relative cost-effectiveness of proposed control strategies. We used effort and cost data from a feral pig-control program on Kangaroo Island, South Australia over 17 months to derive functional-response relationships between control effort (hours pig -1 ) and pig abundance for four control methods: ( i ) ground-based shooting, ( ii ) trapping with remote triggers, ( iii ) poison baiting, and ( iv ) thermal-assisted aerial culling. We developed a stochastic Leslie matrix with compensatory density feedback on survival and fertility to project population trajectories from an initial population ( N 0 ) of 250 female pigs with an estimated island-wide carrying capacity ( K ) of 2500 over 3 and 10 years for populations subjected to an annual harvest of 35% to 95%. We built functional-response models to calculate annual effort and cost for six cull scenarios across all harvest rates. We derived total cost and effort over 3- and 10-year projections from the sum of annual cost and effort within the projection intervals. Pig populations were reduced to 10% N 0 based on harvest rates 70% and 50% for culls of 3- and 10-year duration, respectively. In all scenarios except ‘trapping only’, the total cost to reduce population to ≤ 10% of N 0 decreased with increasing harvest proportion, with lower total costs incurred over 3 years compared to 10 years. The simulations suggest that the most cost-effective approach for most scenarios is to maximise annual harvest and complete eradication effort over the shortest periods.
The role of temperature on treeline migration for an eastern African mountain during the Last Glacial Maximum
Publisher: Springer Science and Business Media LLC
Date: 08-01-2013
Where to Dig for Fossils: Combining Climate-Envelope, Taphonomy and Discovery Models
Publisher: Public Library of Science (PLoS)
Date: 30-03-2016
Climate‐driven shifts in the distribution of koala‐browse species from the Last Interglacial to the near future
Publisher: Wiley
Date: 27-06-2019
DOI: 10.1111/ECOG.04530
Related Organisations
Flinders University School Of Biological Sciences
Location: Australia
Related Funding Activities
Linkage Projects - Grant ID: LP210100450
Start Date: 09-2022
End Date: 09-2026
Amount: $770,622.00
Funder: Australian Research Council
View Funded ActivityARC Centres Of Excellence - Grant ID: CE230100009
Start Date: 07-2024
End Date: 06-2031
Amount: $35,000,000.00
Funder: Australian Research Council
View Funded Activity