Stephen E Williams

• PhD
• Professor (Full) at James Cook University

Camera traps are widely used in wildlife research and monitoring, so it is imperative to understand their strengths, limitations, and potential for increasing impact. We investigated a decade of use of wildlife cameras (2012–2022) with a case study on Australian terrestrial vertebrates using a multifaceted approach. We (i) synthesised information...

Herbivore–plant interactions are fundamental processes shaping ecosystems, yet their study is challenged by their complex connections within broader ecosystem processes, requiring a nuanced understanding of ecosystem dynamics. This study investigated the relationship between nutrient availability and insect herbivory in the Australian Wet Tropics....

Climatic variation at local scales can influence both exposure and sensitivity of organisms and thereby scale up to influence population persistence and community composition across broader geographic extents. Tropical forest canopies are more climatically dynamic than the understorey. Consequently, the niche space of forest canopies has higher ove...

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 extinctio...

Climate‐driven biodiversity erosion is escalating at an alarming rate. The pressure imposed by climate change is exceptionally high in tropical ecosystems, where species adapted to narrow environmental ranges exhibit strong physiological constraints. Despite the observed detrimental effect of climate change on ecosystems at a global scale, our unde...

Aim The increasing frequency and intensity of extreme weather escalate the pressure of global warming on biodiversity. Globally, synergistic effects of multiple components of climate change have driven local extinctions and community collapses, raising concern about the irreversible deterioration of ecosystems. Here, we disentangle the pressure of...

Invasive mesopredators are responsible for the decline of many species of native mammals worldwide. Feral cats have been causally linked to multiple extinctions of Australian mammals since European colonization. While feral cats are found throughout Australia, most research has been undertaken in arid habitats, thus there is a limited understanding...

Aim Climate change is driving species to migrate to novel areas as current environments become unsuitable. As a result, species distributions have shifted uphill in montane ecosystems globally. Heterogeneous dispersal rates among shifting species could result in complex changes to community assemblages. For example, interspecific differences in dis...

Many authors have suggested that the vulnerability of montane biodiversity to climate change worldwide is significantly higher than in most other ecosystems. Despite the extensive variety of studies predicting severe impacts of climate change globally, few studies have empirically validated the predicted changes in distribution and population densi...

Determining how species thermal limits correlate with climate is important for understanding biogeographic patterns and assessing vulnerability to climate change. Such analyses need to consider thermal gradients at multiple spatial scales. Here we relate thermal traits of rainforest ants to microclimate conditions from ground to canopy (microgeogra...

Species are not uniformly distributed across the landscape. For every species, there should be few favoured sites where abundance is high and many other sites of lower suitability where abundance is low. Consequently, local abundance could be thought of as a natural expression of species response to local conditions. The correlation between abundan...

Many authors have suggested that the vulnerability of montane biodiversity to climate change worldwide is significantly higher than in most other ecosystems. Despite the extensive variety of studies predicting severe impacts of climate change globally, few studies have empirically validated the predicted changes in distribution and population densi...

Aim We propose that forest trees create a vertical dimension for ecological niche variation that generates different regimes of climatic exposure, which in turn drives species elevation distributions. We test this hypothesis by statistically modelling the vertical and elevation distributions and microclimate exposure of rainforest ants. Location W...

Anonychomyrma is a dolichoderine ant genus of cool-temperate Gondwanan origin with a current distribution that extends from the north of southern Australia into the Australasian tropics. Despite its abundance and ecological dominance, little is known of its species diversity and distribution throughout its range. Here, we describe the diversity and...

Species distribution models (SDMs) are widely used to predict and study distributions of species. Many different modeling methods and associated algorithms are used and continue to emerge. It is important to understand how different approaches perform, particularly when applied to species occurrence records that were not gathered in struc­tured sur...

Aim Regional diversity can increase owing to either the packing of species within regional niche space or the expansion of regional niche space. Yet, the primary factors dictating these dynamics remain poorly understood. Here, we assess the relative influence of current environmental conditions (net primary productivity, NPP) versus historic enviro...

Climate change poses significant emerging risks to biodiversity, ecosystem function and associated socioecological systems. Adaptation responses must be initiated in parallel with mitigation efforts, but resources are limited. As climate risks are not distributed equally across taxa, ecosystems and processes, strategic prioritization of research th...

The distributions of Nomascus annamensis, N. gabriellae and N. siki in Indochina are an interesting example of how species distributions are influenced by the interactions between bioclimatic gradients and evolutionary history. However, for these gibbon species, the biogeography and evolutionary relationships have not been fully resolved. We used E...

Increases in mean temperatures caused by anthropogenic climate change increase the frequency and severity of temperature extremes. Although extreme temperature events are likely to become increasingly important drivers of species' response to climate change, the impacts are poorly understood owing mainly to a lack of understanding of species’ physi...

Nomascus annamensis is a newly described gibbon endemic to the Indochina peninsula (Cambodia, Laos and Vietnam). We review the published and unpublished literature relevant to N. annamensis to clarify its distribution and help inform conservation management and policy related to this species. The best current distribution estimate for N. annamensis...

The effects of anthropogenic climate change on biodiversity are well known for some high‐profile Australian marine systems, including coral bleaching and kelp forest devastation. Less well‐published are the impacts of climate change being observed in terrestrial ecosystems, although ecological models have predicted substantial changes are likely. D...

According to a prevailing hypothesis, lowland tropical organisms are unlikely to successfully cross mountain passes because they have neither acclimated nor adapted to the colder temperatures found at higher elevations. However, this expectation assumes that changes in temperature are uniform across space and fails to account for the presence of di...

https://www.nccarf.edu.au/sites/default/files/attached_files/NARP_update_Terrestrial_Biodiversity-2017.pdf This document delivers a resource for research providers to identify critical gaps of information needed by sectoral decision-makers; set research priorities based on these gaps, and identify capacity across the network that could be harnesse...

Consequences of shifting species distributions Climate change is causing geographical redistribution of plant and animal species globally. These distributional shifts are leading to new ecosystems and ecological communities, changes that will affect human society. Pecl et al. review these current and future impacts and assess their implications for...

Aim Species that respond favourably to environmental change tend to be mobile or dispersive. Living within trees has some benefits over life on the ground. Species that move vertically within forest canopies can take advantage of increased complexity and resource availability, which should correspond to increased resilience to environmental variabi...

The effect of twenty-first-century climate change on biodiversity is commonly forecast based on modelled shifts in species ranges, linked to habitat suitability. These projections have been coupled with species-area relationships (SAR) to infer extinction rates indirectly as a result of the loss of climatically suitable areas and associated habitat...

The effect of twenty-first-century climate change on biodiversity is commonly forecast based on modelled shifts in species ranges, linked to habitat suitability. These projections have been coupled with species-area relationships (SAR) to infer extinction rates indirectly as a result of the loss of climatically suitable areas and associated habitat...

There is pressing urgency to understand how tropical ectotherms can behaviorally and physiologically respond to climate warming. We examine how basking behavior and thermal environment interact to influence evolutionary variation in thermal physiology of multiple species of lygosomine rainforest skinks from the Wet Tropics of northeastern Queenslan...

Predicting climate change impacts on biodiversity is a major scientific challenge, but doing so is important for assessing extinction risk, developing conservation action plans, providing guidance for laws and regulations, and identifying the mechanisms and patterns of impact to inform climate change adaptation. In the few decades since the threat...

Most terrestrial species on Earth are ectothermic and track temperature at small spatial scales, from sun flecks to cool shaded spots. Current assessments of thermal heterogeneity in complex environments are predominately characterized by ambient temperature. This omission of solar radiation may lead to inaccurate conclusions regarding thermoregula...

Morphology mediates the relationship between an organism's body temperature and its environment. Dark organisms, for example, tend to absorb heat more quickly than lighter individuals, which could influence their responses to temperature. Therefore, temperature-related traits such as morphology may affect patterns of species abundance, richness, an...

Understanding how the environment influences patterns of diversity is vital for effective conservation management, especially in a changing global climate. While assemblage structure and species richness patterns are often correlated with current environmental factors, historical influences may also be considerable, especially for taxa with poor di...

Coverage-based rarefaction and extrapolation curves for each subregion. (DOCX)

Summary of flightless ground beetle species. (DOCX)

Pearson correlation coefficients and P values of the 17 predictor variables. (DOCX)

Individual-based rarefaction and extrapolation curves for each subregion. (DOCX)

There is broad consensus that the diversity of functional traits within species assemblages drives several ecological processes. It is also widely recognized that rare species are the first to become extinct following human-induced disturbances. Surprisingly, however, the functional importance of rare species is still poorly understood, particularl...

Understanding how the environment influences patterns of diversity is vital for effective conservation management, especially in a changing global climate. While assemblage structure and species richness patterns are often correlated with current environmental factors, historical influences may also be considerable, especially for taxa with poor di...

Extinction risk for frogs in the Australian wet tropics under a baseline ‘no climate change’ scenario

Extinction risk for frogs in the Australian wet tropics simulated using an extreme Allee effect

Extinction risk for frogs in the Australian wet tropics simulated using an extreme Allee effect

Extinction risk for frogs in the Australian wet tropics under a baseline ‘no climate change’ scenario

Detailed description of the methods

Sensitivity analysis for niche-population models

Sensitivity analysis for niche-population models

Detailed description of the methods

Indices of relative abundance do not control for variation in detectability, which can bias density estimates such that ecological processes are difficult to infer. Distance sampling methods can be used to correct for detectability, but in rainforest, where dense vegetation and diverse assemblages complicate sampling, information is lacking about f...

AHTEENSUU ET AL. highlight four issues with our proposed framework for guiding decisions to conserve species under climate change and suggest some ways forward. From the outset we stress that we presented a framework. By their very nature, frameworks are for building on and elaborating. We thus welcome the contribution of Ahteensuu et al.. Here we...

The effects of climate change on biodiversity are increasingly well documented, and many methods have been developed to assess species' vulnerability to climatic changes, both ongoing and projected in the coming decades. To minimize global biodiversity losses, conservationists need to identify those species that are likely to be most vulnerable to...

While gradual changes in climate means will have numerous effects on a range of environmental, social, and economic sectors, emerging evidence shows that many of the environmental, social, and economic impacts of anthropogenic climate change will arise from shifts in the regimes of extreme weather and climatic events, including heat waves, fires, f...

Vegetated habitats contain a variety of fine-scale features that can ameliorate temperate extremes. These buffered microhabitats may be used by species to evade extreme weather and novel climates in the future. Yet, the magnitude and extent of this buffering on a global scale remains unknown. Across all tropical continents and using 36 published st...

To assess a species' vulnerability to climate change, we commonly use mapped environmental data that are coarsely resolved in time and space. Coarsely resolved temperature data are typically inaccurate at predicting temperatures in microhabitats used by an organism and may also exhibit spatial bias in topographically complex areas. One consequence...

The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm) months in the region, but othe...

We model the occurrence of biodiversity as a function of environmental variables to estimate its distribution. This is an alternative to close the gaps of species occurrence information, and to support decision-making. Herein we’ve evaluated the distribution patterns of two dimensions of biodiversity: community composition and species richness for...

The seasonality of litter inputs in forests has important implications for understanding ecosystem processes and biogeochemical cycles. We quantified the drivers of seasonality in litterfall and leaf decomposability using plots throughout the Australian wet tropical region. Litter fell mostly in the summer (wet, warm) months in the region, but othe...

Identifying refugia is a critical component of effective conservation of biodiversity under anthropogenic climate change. However, despite a surge in conceptual and practical interest, identifying refugia remains a significant challenge across diverse continental landscapes. We provide an overview of the key properties of refugia that promote speci...

Understanding the spatial variability in plant litter processes is essential for accurate comprehension of biogeochemical cycles and ecosystem function. We assessed spatial patterns in litter processes from local to regional scales, at sites throughout the wet tropical rain forests of northern Australia. We aimed to determine the controls (e.g., cl...

With the impending threat of climate change, greater understanding of patterns of species distributions and richness and the environmental factors driving them are required for effective conservation efforts. Species distribution models enable us to not only estimate geographic extents of species and subsequent patterns of species richness, but als...

Global climate change is expected to cause major loss of biodiversity in the next century in both terrestrial and marine systems. Climate change impacts, including warming and extreme weather events, on life history, physiology, ecology and community and ecosystem interactions will increase the extinction risks for a variety of taxonomic groups.

Biodiversity is spatially organized by climatic gradients across elevation and latitude. But do other gradients exist that might drive biogeographic patterns? Here, we show that rainforest's vertical strata provide climatic gradients much steeper than those offered by elevation and latitude, and biodiversity of arboreal species is organized along t...

Extreme weather events, such as unusually hot or dry conditions, can cause death by exceeding physiological limits, and so cause loss of population. Survival will depend on whether or not susceptible organisms can find refuges that buffer extreme conditions. Microhabitats offer different microclimates to those found within the wider ecosystem, but...

Aim Correlative species distribution models ( SDM s) combined with spatial layers of climate and species' localities represent a frequently utilized and rapid method for generating spatial estimates of species distributions. However, an SDM is only as accurate as the inputs upon which it is based. Current best‐practice climate layers commonly utili...

Species may circumvent the impacts of climate warming if the habitats they use reduce ambient temperature. In this study, we identified which frog species from a tropical montane rain forest in the Philippines may be vulnerable to climate warming. To do so, we selected five anuran species that utilize four breeding habitats and identified the sensi...

Among birds, tropical montane species are likely to be among the most vulnerable to climate change, yet little is known about how climate drives their distributions, nor how to predict their likely responses to temperature increases. Correlative models of species' environmental niches have been widely used to predict changes in distribution, but di...

Example fitted Gaussian curves. Gaussian curves (dashed lines) are shown fitted to the elevational density profiles for the remaining species examined for elevational difference in their estimated density optima between southern AWT (filled circles) and northern AWT (unfilled circles). Data are the estimated densities calculated with Distance analy...

AIC scores for competing models in HOF [30] analysis. Shown are competing models in a hierarchical Huissman-Olff-Frescoe [30] model selection analysis for elevational density responses across the 88 Australian Wet Tropics rainforest bird species (those with sufficient sampling in this study). Models were selected using the approach implemented in t...

Results of the Huisman-Olff-Frescoe (HOF) hierarchical model fitting process. Models are shown for rainforest bird density responses across the temperature gradient in the study region. Models tested were flat (light blue), plateau (green), monotonic (dark blue), unimodal (Gaussian) (red) and skewed (black). AIC values (upper right of each plot) we...

Scatter plots of the relationship between temperature parameters and elevation in the study area for accuCLIM. Results are shown for MAT, Tmax and Tmin derived from microclimate measured across the range of elevations present in the southern AWT (filled circles) and northern AWT (unfilled circles). Solid lines are simple linear models of the effect...

Severe impacts on biodiversity are predicted to arise from climate change. These impacts may not be adequately addressed by conventional approaches to conservation. As a result, additional management actions are now being considered. However, there is currently limited guidance to help decision makers choose which set of actions (and in what order)...

Climate change is expected to have significant influences on terrestrial biodiversity at all system levels, including species-level reductions in range size and abundance, especially amongst endemic species1, 2, 3, 4, 5, 6. However, little is known about how mitigation of greenhouse gas emissions could reduce biodiversity impacts, particularly amon...

We are currently facing the likelihood of severe climate change before the close of the century. In the face of such a global driver of species loss, we urgently need to identify refugia that will shelter species from the worst impacts of climate change. This will be a critical component of successful conservation and management of our biodiversity...

Assisted colonisation has received considerable attention recently, and the risks and benefits of introducing taxa to sites beyond their historical range have been vigorously debated. The debate has primarily focused on using assisted colonization to enhance the persistence of taxa that would otherwise be stranded in unsuitable habitat as a consequ...

The known range of Eulamprus frerei is extended approximately 110 km north-northwest to Mt Lewis (16.510°S, 145.269°E) on the Mt Carbine Tableland, North Queensland. This record is from 200 m lower than the reported minimum elevation for the species. Despite extensive surveys throughout the Australian Wet Tropics, this is the frst record for E. fre...

Future climates have the potential to alter decomposition rates in tropical forest with implications for carbon emissions, nutrient cycling and retention of standing litter. However, our ability to predict impacts, particularly for seasonally wet forests in the old world, is limited by a paucity of data, a limited understanding of the relative impo...

Aim To measure the effects of including biotic interactions on climate‐based species distribution models ( SDM s) used to predict distribution shifts under climate change. We evaluated the performance of distribution models for an endangered marsupial, the northern bettong ( B ettongia tropica ), comparing models that used only climate variables wi...

Background/Question/Methods Tropical rainforests are among the most biologically rich communities on Earth, but their canopies and subcanopies are largely unstudied. Here we present the first comprehensive study of arboreal habitat use by amphibians and reptiles in the tropics. From February-October 2011, we conducted ground-to-canopy surveys and...

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to hu...

This is the Endnote Library of the peer-reviewed and the grey literature on biodiversity research in the Australian Wet Tropics (N > 2500 references, as per 2011), that accompanies the "Gap analysis of environmental research needs in the Australian Wet Tropics".

Montane tropical rainforests are critically important areas for global bird diversity, but are projected to be highly vulnerable to contemporary climate change. Upslope shifts of lowland species may partially offset declines in upland species but also result in a process of lowland biotic attrition. This latter process is contingent on the absence...

A recently developed integrative framework proposes that the vulnerability of a species to environmental change depends on the species' exposure and sensitivity to environmental change, its resilience to perturbations and its potential to adapt to change. These vulnerability criteria require behavioural, physiological and genetic data. With this in...

Tropical ectotherms are regarded as being especially threatened by global warming, but the extent to which populations vary in key thermal physiological traits is little known. In general, central and peripheral populations are most likely to differ where divergent selection pressures are un-opposed by gene flow. This leads to the prediction that p...

The rising global temperature is predicted to expand the distribution of vector-borne diseases both in latitude and altitude. Many host communities could be affected by increased prevalence of disease, heightening the risk of extinction for many already threatened species. To understand how host communities could be affected by changing parasite di...

Primer sequences used for the two PCR step reactions to detect blood parasites. Primers used to amplify Cytochrome b (Cyt-b) in Plasmodium (Pla), Haemoproteus (Hae) and Leucocytozoon (Leu), and 18 S rRNA (18 S) in Trypanosoma (Try). (DOC)

The full list of frequency of detection of blood parasites. Haemoproteus (Hae), Plasmodium (Pla), Leucocytozoon (Leu) and Trypanosoma (Try) in all the avian species presented alphabetically by family. Number of infected individuals/number of individuals sampled are shown. (DOC)

Regressions between Parasite prevalence and host ecological variables. Relationships between Parasite prevalence and host: a) Geographic range size, b) Body mass and c) Body size. All regressions are low and none significant. (DOC)

The full list of parasite lineages and host species. MalAvi lineage names (http://mbio-serv4.mbioekol.lu.se/avianmalaria), GenBank accession numbers, Parasite genus, Host Family and Host species. (DOC)