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Methods for sampling ecological assemblages strive to be efficient, repeatable, and representative. Unknowingly, common methods may be limited in terms of revealing species function and so of less value for comparative studies. The global decline in pollination services has stimulated surveys of flower-visiting invertebrates, using pan traps and net sampling. We explore the relative merits of these two methods in terms of species discovery, quantifying abundance, function, and composition, and responses of species to changing floral resources. Using a spatially-nested design we sampled across a 5000 km(2) area of arid grasslands, including 432 hours of net sampling and 1296 pan trap-days, between June 2010 and July 2011. Net sampling yielded 22% more species and 30% higher abundance than pan traps, and better reflected the spatio-temporal variation of floral resources. Species composition differed significantly between methods; from 436 total species, 25% were sampled by both methods, 50% only by nets, and the remaining 25% only by pans. Apart from being less comprehensive, if pan traps do not sample flower-visitors, the link to pollination is questionable. By contrast, net sampling functionally linked species to pollination through behavioural observations of flower-visitation interaction frequency. Netted specimens are also necessary for evidence of pollen transport. Benefits of net-based sampling outweighed minor differences in overall sampling effort. As pan traps and net sampling methods are not equivalent for sampling invertebrate-flower interactions, we recommend net sampling of invertebrate pollinator assemblages, especially if datasets are intended to document declines in pollination and guide measures to retain this important ecosystem service.

Top predators are declining globally, in turn allowing populations of smaller predators, or mesopredators, to increase and potentially have negative effects on biodiversity. However, detection of interactions among sympatric predators can be complicated by fluctuations in the background availability of resources in the environment, which may modify both the numbers of predators and the strengths of their interactions. Here, we first present a conceptual framework that predicts how top-down and bottom-up interactions may regulate sympatric predator populations in environments that experience resource pulses. We then test it using 2 years of remote-camera trapping data to uncover spatial and temporal interactions between a top predator, the dingo Canis dingo, and the mesopredatory European red fox Vulpes vulpes and feral cat Felis catus, during population booms, declines and busts in numbers of their prey in a model desert system. We found that dingoes predictably suppress abundances of the mesopredators and that the effects are strongest during declines and busts in prey numbers. Given that resource pulses are usually driven by large yet infrequent rains, we conclude that top predators like the dingo provide net benefits to prey populations by suppressing mesopredators during prolonged bust periods when prey populations are low and potentially vulnerable.

Ecological forecasting provides a powerful set of methods for predicting short‐ and long‐term change in living systems. Forecasts are now widely produced, enabling proactive management for many applied ecological problems. However, despite numerous calls for an increased emphasis on prediction in ecology, the potential for forecasting to accelerate ecological theory development remains underrealized. Here, we provide a conceptual framework describing how ecological forecasts can energize and advance ecological theory. We emphasize the many opportunities for future progress in this area through increased forecast development, comparison and synthesis. Our framework describes how a forecasting approach can shed new light on existing ecological theories while also allowing researchers to address novel questions. Through rigorous and repeated testing of hypotheses, forecasting can help to refine theories and understand their generality across systems. Meanwhile, synthesizing across forecasts allows for the development of novel theory about the relative predictability of ecological variables across forecast horizons and scales. We envision a future where forecasting is integrated as part of the toolset used in fundamental ecology. By outlining the relevance of forecasting methods to ecological theory, we aim to decrease barriers to entry and broaden the community of researchers using forecasting for fundamental ecological insight.

Fauna communities respond to exotic plant invasions through multiple pathways, including via changes to habitat structure and food resources and depending on the scale at which fauna access these resources. To assess whether such multi‐dimensional impacts on fauna can be generalised across taxa, we developed and empirically tested a conceptual framework to predict how fauna communities respond to exotic grass invasion in open arid ecosystems. We predicted the greatest impact on combinations of lower trophic levels or diet‐specialists, ground‐active fauna, including open habitat specialists, and species that operate over smaller spatial scales. We further proposed that functional analysis would more readily detect impacts than total taxon abundance, diversity or taxonomic composition. Replicated across two regions of arid central Australia, we sampled birds, reptiles and ants at native sites and paired sites invaded by exotic buffel grass (Cenchrus ciliaris). Results largely validated our predictions. Bird and ant communities showed significant functional homogenisation or restructuring at invaded sites, respectively (PERMDISP or PERMANOVA p ≤ 0.005), with some functional differences also evident for reptiles (p = 0.02), despite low captures of this group with dry conditions. Ground‐active reptiles, birds and ecologically dominant ant groups, especially those that use open microhabitats, were less characteristic of invaded sites. Diet specialists were less associated with invaded sites, including insectivorous birds, and granivorous ants and birds, except where granivores operated at landscape scales. Whilst ant abundance was reduced by 50% (0.41 [0.25–0.68, 95% CI]) and bird communities showed taxonomic homogenisation in invaded sites (PERMDISP p = 0.005), no impacts on taxonomic diversity were detected. Functional responses provided the clearest and most consistent detection of community‐level impacts in a multi‐taxa context. This validates key aspects of our conceptual framework and offers a robust, transferrable approach for analysing exotic grass invasions and other drivers of ecological change. To assess whether the impacts of exotic plant invasion can be generalised across taxa, we developed a conceptual framework predicting faunal responses to grass invasion in open, arid ecosystems and tested our predictions using data on birds, reptiles and ants from sites invaded by buffel grass (Cenchrus ciliaris) and paired uninvaded sites. Diet specialists and ground‐active fauna were generally less associated with invaded sites, aligning with our predictions. Functional responses provided the most consistent signal of community‐level impacts of invasion on fauna, more so than abundance or diversity metrics. With validation of key aspects of our framework, this multi‐taxa and multi‐trait approach could be used for other invasions and environmental change.

Growth in the publication of scientific articles is occurring at an exponential rate, prompting a growing need to synthesise information in a timely manner to combat urgent environmental problems and guide future research. Here, we undertake a topic analysis of dryland literature over the last 75 years (8218 articles) to identify areas in arid ecology that are well studied and topics that are emerging. Four topics-wetlands, mammal ecology, litter decomposition and spatial modelling, were identified as 'hot topics' that showed higher than average growth in publications from 1940 to 2015. Five topics-remote sensing, climate, habitat and spatial, agriculture and soils-microbes, were identified as 'cold topics', with lower than average growth over the survey period, but higher than average numbers of publications. Topics in arid ecology clustered into seven broad groups on word-based similarity. These groups ranged from mammal ecology and population genetics, broad-scale management and ecosystem modelling, plant ecology, agriculture and ecophysiology, to populations and paleoclimate. These patterns may reflect trends in the field of ecology more broadly. We also identified two broad research gaps in arid ecology: population genetics, and habitat and spatial research. Collaborations between population genetics and ecologists and investigations of ecological processes across spatial scales would contribute profitably to the advancement of arid ecology and to ecology more broadly.

Plant invasions drive biodiversity loss, transform ecosystems, and promote positive‐feedback cycles between invasion and fire. However, the long‐term impacts of invasive grasses across landscapes with diverse plant communities and interactions with fire are poorly known. Our objectives were to examine whether buffel grass (Cenchrus ciliaris), a globally significant plant invader, altered the abundance of understory and overstory plants, homogenized plant composition, and shifted ecosystems from woodlands to grassland and to explore interrelationships between invasion and fire. We combined two methodological approaches to assess invasion spread and impacts of buffel grass in the Aṉangu Pitjantjatjara Yankunytjatjara (APY) Lands of arid central Australia: a before‐after‐control‐impact (BACI) experiment over 25 years at 15 sites and a paired‐plot (randomized‐block) experiment at 18 sites. Both experiments spanned two geographic regions and multiple vegetation communities situated on flat plains and rocky hills. We used generalized linear mixed models to analyze predictions about plant abundance and permutational multivariate ANOVA (PERMANOVA) and permutational multivariate analysis of dispersion (PERMDISP) to examine changes in community composition. Fire and invasion interactions were explored using fire history or the relative fire tolerance of plant species as covariates, predictors, or responses. Fire interacted with the invasion process in multiple ways. Invaded sites had burnt more frequently and recently than native sites in one region, and where propagules were present in 1995, buffel grass abundance increased most when fires ensued. Abundance of understory plant functional groups (native grasses, ferns, and vines) decreased with invasion, and understory shrubs decreased due to frequent fires in invaded sites. Overstory composition shifted from fire‐sensitive species toward fire‐tolerant species, but this was not directly attributable to invasion. Partial evidence for ecosystem regime shifts included homogenization of understory communities in invaded rocky hills, and an increase in woody shrub cover at native but not invaded sites over 25 years, resulting in a 5% cover difference by 2019. Impacts were detected across heterogeneous ecological communities at a scale not previously tested amongst high background community variability. Although invasion is not dependent on fire, the acceleration of invasion spread and impacts with fire is a critical consideration for future research and management of grass invaders.

Extreme climatic events, such as flooding rains, extended decadal droughts and heat waves have been identified increasingly as important regulators of natural populations. Climate models predict that global warming will drive changes in rainfall and increase the frequency and severity of extreme events. Consequently, to anticipate how organisms will respond we need to document how changes in extremes of temperature and rainfall compare to trends in the mean values of these variables and over what spatial scales the patterns are consistent. Using the longest historical weather records available for central Australia – 100 years – and quantile regression methods, we investigate if extreme climate events have changed at similar rates to median events, if annual rainfall has increased in variability, and if the frequency of large rainfall events has increased over this period. Specifically, we compared local (individual weather stations) and regional (Simpson Desert) spatial scales, and quantified trends in median (50th quantile) and extreme weather values (5th, 10th, 90th, and 95th quantiles). We found that median and extreme annual minimum and maximum temperatures have increased at both spatial scales over the past century. Rainfall changes have been inconsistent across the Simpson Desert; individual weather stations showed increases in annual rainfall, increased frequency of large rainfall events or more prolonged droughts, depending on the location. In contrast to our prediction, we found no evidence that intra‐annual rainfall had become more variable over time. Using long‐term live‐trapping records (22 years) of desert small mammals as a case study, we demonstrate that irruptive events are driven by extreme rainfalls (>95th quantile) and that increases in the magnitude and frequency of extreme rainfall events are likely to drive changes in the populations of these species through direct and indirect changes in predation pressure and wildfires. Increases in extreme rainfall events at regional scales were not consistent at local scales and differed from trends in the median values. Rodent irruptions will likely increase as they show a threshold relationship with rainfall; responding to extreme rainfall events. Temperature increases were similar across scales and quantiles.

Species afflicted by multiple threats are thought to face greater extinction risk. However, it is not known whether multiple threats operate antagonistically, additively, or synergistically, or whether they vary across different taxonomic and spatial scales. We addressed these questions by analyzing threats to 10,378 species in six vertebrate classes at global and regional spatial scales using network analysis. The total number of threats was a poor predictor of extinction risk, and particular combinations of threats did not predict extinction risk in the same way at different spatial scales. The exception was cartilaginous fishes, which faced increased extinction risk with increasing numbers of threats. Except for cartilaginous fishes, our findings indicate that species facing more threats than others do not face a higher risk of extinction and suggest that effective conservation will require more investment in identifying how threats and different ecosystem stressors operate together at local scales.

Understanding the temporal and spatial dynamics of species populations remains a key focus of population biology, providing vital insight into the drivers that influence demography and into sub‐populations that are vulnerable to extinction. Across regional landscapes, spatially separated sub‐populations may fluctuate in synchrony, or exhibit sub‐structuring due to subtle differences in local intrinsic and extrinsic factors. Using a long‐term data set (17–22 yr) obtained from a large (8000 km 2 ) study region in arid central Australia, we tested firstly for regional synchrony in annual rainfall and the dynamics of five small mammal species across nine widely separated sites. Using Moran's theorem, we predicted that the spatial correlation between the regional sub‐populations of these species would equal that between local density‐independent conditions (annual rainfall). For species that showed synchronous spatial dynamics, we then used multivariate state‐space ( MARSS ) models to predict that regional rainfall would be positively associated with their populations, whereas species with asynchronous sub‐populations would be influenced largely by other factors. For these latter species, we used MARSS models to test four hypotheses. These were that sub‐population structures: (1) were asynchronous and governed by local site‐specific factors, (2) differed between oasis and non‐oasis sites, (3) differed between burnt and unburnt sites, and (4) differed between three sub‐regions with different rainfall gradients. We found that the spatial population dynamics of our study small mammals differed between and within families. Two species of insectivorous dasyurid marsupials showed asynchronous dynamics, which most likely tracked local conditions, whereas a larger carnivorous marsupial and two species of rodents had strongly synchronous dynamics. These latter species exhibited similar spatial correlations to local and regional rainfall events, providing evidence that the Moran effect operates for some, but not all, species in this arid system. Our results suggest that small mammal populations do not respond in similar ways to shared environmental drivers in arid regions, and hence will vary in their responses to climate change. As arid lands globally are predicted to face climatic shifts that will exacerbate rainfall‐drought cycles, we suggest that future work focuses on exploring these responses at different spatial scales across multiple dryland taxa.

Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence how native biota respond to grazing.