Biological invasions threaten biodiversity and ecosystem functions, often causing cascading effects across trophic levels. Yet how these impacts vary over the fundamental day–night cycle remains largely overlooked. On Barrow Island, a high-conservation-value reserve off northwestern Australia, we examined how infestations of the non-native scale insect Saissetia miranda (Hemiptera: Coccidae) on a dominant native tree species – the fig Ficus brachypoda – influenced native arboreal invertebrate communities and ant-mediated ecosystem functions in a natural matched-pairs experiment, comparing scale-infested versus uninfested sites. We observed the ecologically dominant native meat ant Iridomyrmex sanguineus collecting carbohydrate-rich honeydew from the non-native scale insects on fig trees. Although the meat ants are primarily diurnal, their nocturnal foraging activity increased by 164% at infested sites. Scale-infested sites supported higher abundances of arboreal invertebrates (~28% higher overall). In particular, scale infestations boosted the nighttime abundances of moth and cockroach species, which were observed feeding on excess honeydew, as well as spiders, possibly preying on these groups. Moreover, we uncovered knock-on effects on ant-mediated ecosystem functions in the brown and green food webs of infested sites. On the ground, the higher nocturnal ant activity contributed to a 207% increase in the mass of protein baits scavenged by ants during the night. In the canopy, there was a nearly fivefold increase in ant attacks on insect herbivores, as well as a 35% reduction in leaf damage across diel periods. Our findings show that non-native hemipterans can trigger carbohydrate-rich pulses in ecosystems, reshaping ant behaviour and amplifying both ant–herbivore interactions and higher-order effects on multitrophic communities. Critically, these impacts are not uniform across the diel cycle, but disproportionately affect nocturnal assemblages. Recognising the temporal dimension of invasion impacts is crucial for understanding and managing their full ecological consequences.

ABSTRACT Motivation The accelerated and widespread conversion of once continuous ecosystems into fragmented landscapes has driven ecological research to understand the response of biodiversity to local (fragment size) and landscape (forest cover and fragmentation) changes. This information has important theoretical and applied implications, but is still far from complete. We compiled the most comprehensive and updated database to investigate how these local and landscape changes determine species composition, abundance and trait diversity of multiple taxonomic groups in forest fragments across the globe. Main Types of Variables Contained We gathered data for 1472 forest fragments, providing information on the abundance and composition of 9154 species belonging to vertebrates, invertebrates, and plants. For 2703 of these species, we obtained more than 20 functional traits. We provided the spatial location and size of each fragment and metrics of landscape composition and configuration. Spatial Location and Grain The dataset includes 1472 forest fragments sampled in 121 studies from all continents except Antarctica. Most datasets (77%) are from tropical regions, 17% are from temperate regions, and 6% are from subtropical regions. Species abundance and composition were collected at the plot or fragment scale, whereas the landscape metrics were extracted with buffer size ranging from a radius of 200–2000 m. Time Period and Grain Data on the abundance of species and community composition were collected between 1994 and 2022, and the landscape metrics were extracted from the same year that a given study collected the abundance and composition data. Major Taxa and Level of Measurement The studied organisms included invertebrates (Arachnida, Insecta and Gastropoda; 41% of the datasets), vertebrates (Amphibia, Squamata, Aves and Mammalia; 44%), and vascular plants (19%), and the lowest level of identification was species or morphospecies. Software Format The dataset and code can be downloaded on Zenodo or GitHub.

Evidence is accumulating of declines in widespread, abundant insect species. The consequences of these losses for ecosystem functioning are predicted to be severe but remain poorly tested in real-world ecosystems. Here we tested the relative importance of functional redundancy versus complementarity in conferring stability of multifunctional performance in the face of dominant insect species decline. We conducted an experimental manipulation of functional trait-space occupancy within naturally occurring ant communities in Australia. Experimental suppression of dominant ant species in multiple trait groupings caused a counterintuitive increase in multifunctional performance, which was associated with an increase in species richness. The resident ant community had high functional redundancy, contributing to rapid compensatory dynamics following suppression. However, colonization by new species with increased trait complementarity drove higher multifunctional performance. This increased multifunctionality probably occurred via reduced interspecific competition but at the cost of increased sensitivity of ecosystem multifunctionality to further species loss. Our findings show that functional redundancy can buffer multifunctional performance of a community against decline of dominant insect species but suggest that future stability of ecosystem multifunctionality depends more on functional complementarity and altered competitive interactions.

Habitat fragmentation generally reduces biodiversity at the patch scale (α diversity)1. However, there is ongoing debate about whether such negative effects can be alleviated at the landscape scale (γ diversity) if among-patch diversity (β diversity) increases as a result of fragmentation2-6. This controversial view has not been rigorously tested. Here we use a dataset of 4,006 taxa across 37 studies from 6 continents to test the effects of fragmentation on biodiversity across scales by explicitly comparing continuous and fragmented landscapes. We find that fragmented landscapes consistently have both lower α diversity and lower γ diversity. Although fragmented landscapes did tend to have higher β diversity, this did not translate into higher γ diversity. Our findings refute claims that habitat fragmentation can increase biodiversity at landscape scales, and emphasize the need to restore habitat and increase connectivity to minimize biodiversity loss at ever-increasing scales.

Anthelmintic residues in livestock dung can adversely affect beneficial organisms. Targeted selective treatment (TST) of a reduced proportion of livestock with anthelmintics can slow resistance development in gastrointestinal nematodes by providing residue-free dung which could also benefit non-target organisms. We tested effects of TST on survival and reproduction of the dung beetle Onthophagus taurus (Scarabaeidae) in a factorial glasshouse experiment (Experimental treatments: five TST levels, 0.00, 0.25, 0.50, 0.75, 1.00 x four ivermectin concentrations, 125, 250, 375, 500 ppb). Each mesocosm comprised a 60 L bin containing sand, four dung pats and six pairs of adult beetles (F0 generation). No effects of TST level and ivermectin concentration on mortality of F0 adults after one week were observed. F0 adult brood ball production was affected by TST level, particularly at high ivermectin concentrations. Brood ball production increased as more untreated pats became available, with greater increases at higher ivermectin concentrations. We tested for evidence of a reported attraction of dung beetles to ivermectin-treated dung using a novel glitter-marker to trace the origin of dung used in brood balls. Where mesocosms contained both dung types, the proportion of brood balls created from untreated dung showed no statistical difference from the null expectation based on untreated dung availability in the mesocosm. Emergence of F1 adults was affected by the increase in TST, with this effect dependent on concentration. Treatments with concentrations of 250-500 ppb had the lowest emergence rates (ca. 5-20 % in mesocosms where all dung pats were treated) but emergence rates increased with TST level, reaching 68-88 % emergence where no dung pats were treated with ivermectin. Ivermectin-induced mortality occurred predominantly at egg and first instar stages. TST can provide refuges for dung beetles offering a strategy for livestock producers to maintain livestock welfare whilst benefiting from ecosystem services provided by important insects.

The functional stability of ecosystems depends greatly on interspecific differences in responses to environmental perturbation. However, responses to perturbation are not necessarily invariant among populations of the same species, so intraspecific variation in responses might also contribute. Such inter-population response diversity has recently been shown to occur spatially across species ranges, but we lack estimates of the extent to which individual populations across an entire community might have perturbation responses that vary through time. We assess this using 524 taxa that have been repeatedly surveyed for the effects of tropical forest logging at a focal landscape in Sabah, Malaysia. Just 39 % of taxa – all with non-significant responses to forest degradation – had invariant responses. All other taxa (61 %) showed significantly different responses to the same forest degradation gradient across surveys, with 6 % of taxa responding to forest degradation in opposite directions across multiple surveys. Individual surveys had low power (< 80 %) to determine the correct direction of response to forest degradation for one-fifth of all taxa. Recurrent rounds of logging disturbance increased the prevalence of intra-population response diversity, while uncontrollable environmental variation and/or turnover of intraspecific phenotypes generated variable responses in at least 44 % of taxa. Our results show that the responses of individual species to local environmental perturbations are remarkably flexible, likely providing an unrealised boost to the stability of disturbed habitats such as logged tropical forests.### Competing Interest StatementThe authors have declared no competing interest.

Since 1968, the Australian Dung Beetle Project has carried out field releases of 43 deliberately introduced dung beetle species for the biological control of livestock dung and dung-breeding pests. Of these, 23 species are known to have become established. For most of these species, sufficient time has elapsed for population expansion to fill the extent of their potential geographic range through both natural and human-assisted dispersal. Consequently, over the last 20 years, extensive efforts have been made to quantify the current distribution of these introduced dung beetles, as well as the seasonal and spatial variation in their activity levels. Much of these data and their associated metadata have remained unpublished, and they have not previously been synthesized into a cohesive dataset. Here, we collate and report data from the three largest dung beetle monitoring projects from 2001 to 2022. Together, these projects encompass data collected from across Australia, and include records for all 23 species of established dung beetles introduced for biocontrol purposes. In total, these data include 22,718 presence records and 213,538 absence records collected during 10,272 sampling events at 546 locations. Most presence records (97%) include abundance data. In total, 1,752,807 dung beetles were identified as part of these data. The distributional occurrence and abundance data can be used to explore questions such as factors influencing dung beetle species distributions, dung beetle biocontrol, and insect-mediated ecosystem services. These data are provided under a CC-BY-NC 4.0 license and users are encouraged to cite this data paper when using the data.

Insect activity powers ecosystems and food production globally. Although insect activity is known to vary with the rise and setting of the sun, there is surprisingly limited empirical information on how insect abundance and richness varies across the 24-hour day-night (diel) cycle. Moreover, commonly used methods for sampling insects such as light traps do not provide suitable comparisons of community properties between diel periods. We present a dataset of 1512 observations of abundance and richness during diurnal and nocturnal periods in insect communities worldwide. The data were collected from 99 studies that systematically sampled insect communities during day and night, using sampling methods minimally influenced by diel variation, such as movement-based interception traps. Spanning six continents, 41 countries and 16 insect orders, the data can support investigations into the factors influencing insect diel preferences as well as the causes and consequences of temporal changes in insect biodiversity. The data also provides key baseline information on the diel activity patterns of insect communities for long-term ecological monitoring. These pursuits take on added significance considering contemporary 'insect declines' and increasing anthropogenic impacts on diurnal and nocturnal biodiversity.

Logged and disturbed forests are often viewed as degraded and depauperate environments compared with primary forest. However, they are dynamic ecosystems(1) that provide refugia for large amounts of biodiversity2,3, so we cannot afford to underestimate their conservation value4. Here we present empirically defined thresholds for categorizing the conservation value of logged forests, using one of the most comprehensive assessments of taxon responses to habitat degradation in any tropical forest environment. We analysed the impact of logging intensity on the individual occurrence patterns of 1,681 taxa belonging to 86 taxonomic orders and 126 functional groups in Sabah, Malaysia. Our results demonstrate the existence of two conservation-relevant thresholds. First, lightly logged forests (<29% biomass removal) retain high conservation value and a largely intact functional composition, and are therefore likely to recover their pre-logging values if allowed to undergo natural regeneration. Second, the most extreme impacts occur in heavily degraded forests with more than two-thirds (>68%) of their biomass removed, and these are likely to require more expensive measures to recover their biodiversity value. Overall, our data confirm that primary forests are irreplaceable5, but they also reinforce the message that logged forests retain considerable conservation value that should not be overlooked.

There is strong trait dependence in species-level responses to environmental change and their cascading effects on ecosystem functioning. However, there is little understanding of whether intraspecific trait variation (ITV) can also be an important mechanism mediating environmental effects on ecosystem functioning. This is surprising, given that global change processes such as habitat fragmentation and the creation of forest edges drive strong trait shifts within species. On 20 islands in the Thousand Island Lake, China, we quantified intraspecific leaf trait shifts of a widely distributed shrub species, Vaccinium carlesii, in response to habitat fragmentation. Using a reciprocal transplant decomposition experiment between forest edge and interior on 11 islands with varying areas, we disentangled the relative effects of intraspecific leaf trait variation versus altered environmental conditions on leaf decomposition rates in forest fragments. We found strong intraspecific variation in leaf traits in response to edge effects, with a shift toward recalcitrant leaves with low specific leaf area and high leaf dry matter content from forest interior to the edge. Using structural equation modeling, we showed that such intraspecific leaf trait response to habitat fragmentation had translated into significant plant afterlife effects on leaf decomposition, leading to decreased leaf decomposition rates from the forest interior to the edge. Importantly, the effects of intraspecific leaf trait variation were additive to and stronger than the effects from local environmental changes due to edge effects and habitat loss. Our experiment provides the first quantitative study showing that intraspecific leaf trait response to edge effects is an important driver of the decrease in leaf decomposition rate in fragmented forests. By extending the trait-based response-effect framework toward the individual level, intraspecific variation in leaf economics traits can provide the missing functional link between environmental change and ecological processes. These findings suggest an important area for future research on incorporating ITV to understand and predict changes in ecosystem functioning in the context of global change.

The ecosystem services provided by dung beetles are well known and valued. Dung beetles bury dung for feeding and breeding, and it is generally thought that the process of burying dung increases nutrient uptake by plant roots, which promotes plant growth. Many studies have tested the effects of dung beetles on plant growth, but there has been no quantitative synthesis of these studies. Here we use a multi-level meta-analysis to estimate the average effect of dung beetles on plant growth and investigate factors that moderate this effect. We identified 28 publications that investigated dung beetle effects on plant growth. Of these, 24 contained the minimum quantitative data necessary to include in a meta-analysis. Overall, we found that dung beetles increased plant growth by 17%; the 95% CI for possible values for the true increase in plant growth that were most compatible with our data, given our statistical model, ranged from 1% to 35%. We found evidence that the dung beetle-plant growth relationship is influenced by the plant measurement type and the number of beetles accessing the dung. However, beetles did not increase plant growth in all quantitative trials, as individual effect sizes ranged from -72% to 806%, suggesting important context-dependence in the provision of ecosystem services.

AbstractInsects sustain key ecosystem functions, but how their activity varies across the day–night cycle and the underlying drivers are poorly understood. Although entomologists generally expect that more insects are active at night, this notion has not been tested with empirical data at the global scale. Here, we assemble 331 quantitative comparisons of the abundances of insects between day and night periods from 78 studies worldwide and use multi-level meta-analytical models to show that insect activity is on average 31.4% (CI: −6.3%–84.3%) higher at night than in the day. We reveal diel preferences of major insect taxa, and observe higher nocturnal activity in aquatic taxa than in terrestrial ones, as well as in warmer environments. In a separate analysis of the small subset of studies quantifying diel patterns in taxonomic richness (31 comparisons from 13 studies), we detect preliminary evidence of higher nocturnal richness in tropical than temperate communities. The higher overall (but variable) nocturnal activity in insect communities underscores the need to address threats such as light pollution and climate warming that may disproportionately impact nocturnal insects.

Land use change alters floral resource availability, thereby contributing to declines in important pollinators. However, the severity of land use impact varies by species, influenced by factors such as dispersal ability and resource specialization, both of which can correlate with body size. Here. we test whether floral resource availability in the surrounding landscape (the ‘matrix’) influences bee species’ abundance in isolated remnant woodlands, and whether this effect varies with body size. We sampled quantitative flower-visitation networks within woodland remnants and quantified floral energy resources (nectar and pollen calories) available to each bee species both within the woodland and the matrix. Bee abundance in woodland increased with floral energy resources in the surrounding matrix, with strongest effects on larger-bodied species. Our findings suggest important but size-dependent effects of declining matrix floral resources on the persistence of bees in remnant woodlands, highlighting the need to incorporate landscape-level floral resources in conservation planning for pollinators in threatened natural habitats.

Edge effects often exacerbate the negative effects of habitat loss on biodiversity. In forested ecosystems, however, many pollinators actually prefer open sunny conditions created by edge disturbances. We tested the hypothesis that forest edges have a positive buffering effect on plant-pollinator interaction networks in the face of declining forest area. In a fragmented land-bridge island system, we recorded ~20,000 plant-pollinator interactions on 41 islands over 3 yr. We show that plant richness and floral resources decline with decreasing forest area at both interior and edge sites, but edges maintain 10-fold higher pollinator abundance and richness regardless of area loss. Edge networks contain highly specialized species, with higher nestedness and lower modularity than interior networks, maintaining high robustness to extinction following area loss while forest interior networks collapse. Anthropogenic forest edges benefit community diversity and network robustness to extinction in the absence of natural gap-phase dynamics in small degraded forest remnants.

Context Germination is a vulnerable life stage for plants, therefore understanding the dynamics of seed ecology is essential to guiding management recommendations for highly invasive weeds. Aim We addressed the knowledge gap for how seeds contribute to the invasion process for European blackberry (Rubus anglocandicans), a threatening weed across the riparian ecosystems of south-western Australia. Methods We performed mechanical, chemical and thermal treatments on seeds to test for changes in germination success and conducted seed-burial trials to monitor seed viability over time in the soil seedbank. Key results In germination trials, freshly picked and frugivore egested seeds failed to germinate with the endocarp intact. With the endocarp removed, germination remained lower at 4–6 months compared with 10–28 months after collection, indicating a significant after-ripening period. Seeds in intact endocarps survived water immersion for more than 2 months, indicating an ability to survive winter flooding. Acid immersion did not improve germination. The germination success of seeds with endocarp removed increased linearly above 11°C, was greatest at 30°C and thereafter declined rapidly (no survival at 40°C). In a 5-year seed-burial trial, germination varied from 7.6 to 48.4% and was significantly lower closer to a river, and in areas where ‘blackberry decline’ syndrome was present. Conclusions While germination of seed without its pyrene coat occurred over a range of controlled conditions, the natural processes needed to break the pyrene remain unknown. Implications High germination success and the long-term survival of seeds in soil clarifies that the management of blackberry remains a difficult challenge in Australia.

Current methods for identifying resource preferences in dung beetles are based on above‐ground trials. Although useful, these methods do not directly investigate resource provisioning of offspring below ground, missing an important part of dung beetle ecology. We tested the potential for UV‐fluorescent and non‐fluorescent coloured glitters to be used as markers for tracing the origin of dung incorporated into brood balls (dung shaped by parental beetles enclosing an egg), and so aid in a more complete understanding of resource use in dung beetles. We tested the effect of glitter addition on brood ball production in two species of tunnelling dung beetles, Onthophagus taurus and Euoniticellus fulvus . There was no effect of glitter addition on brood ball production during no‐choice tests for each species: both species made a similar number of brood balls, regardless of glitter presence or glitter colour. In a separate choice trial, O. taurus showed no preference for dung when presented with four dung pats containing four unique glitter colours. Here we show that glitter can be used as an effective marker of individual brood ball origin in tunnelling dung beetles. This method provides a useful tool for tracking below ground resource use and larval provisioning experiments in dung beetles.

In social animals, success can depend on the outcome of group battles. Theoretical models of warfare predict that group fighting ability is proportional to two key factors: the strength of each soldier in the group and group size. The relative importance of these factors is predicted to vary across environments [F. W. Lanchester, Aircraft in Warfare, the Dawn of the Fourth Arm (1916)]. Here, we provide an empirical validation of the theoretical prediction that open environments should favor superior numbers, whereas complex environments should favor stronger soldiers [R. N. Franks, L. W. Partridge, Anim. Behav. 45, 197-199 (1993)]. We first demonstrate this pattern using simulated battles between relatively strong and weak soldiers in a computer-driven algorithm. We then validate this result in real animals using an ant model system: In battles in which the number of strong native meat ant Iridomyrmex purpureus workers is constant while the number of weak non-native invasive Argentine ant Linepithema humile workers increases across treatments, fatalities of I. purpureus are lower in complex than in simple arenas. Our results provide controlled experimental evidence that investing in stronger soldiers is more effective in complex environments. This is a significant advance in the empirical study of nonhuman warfare and is important for understanding the competitive balance among native and non-native invasive ant species.

Altered microclimatic conditions and higher disturbance at forest edges create environmental stress and modify resource gradients from edge to interior, changing the selection pressures acting on individuals. Although community‐weighted trait‐mean (CWM) shifts along edge gradients have been widely documented at the species level, it is unclear how edge effects act at the individual level, and whether the direction of intraspecific trait shifts mirrors that of CWM shifts in response to edge effects. On 20 islands in the Thousand Island Lake, China, we established 484 plots (2 × 2 m) in a stratified random design across distances of 0–128 m from the forest edge. Within each plot, we sampled leaves (n = 34 768) from within and among all 2993 individuals of 68 species and measured five leaf traits (leaf area, LA; specific leaf area, SLA; leaf dry matter content, LDMC; thickness, LT; chlorophyll content, LCC). Using generalized linear mixed models, we found that different leaf traits exhibited contrasting shifts in inter‐ versus intraspecific trait variation in response to edge effects. For SLA, LT and LCC, negative covariance between inter‐ and intraspecific trait shifts resulted in dampening of community‐wide trends compared to CWM response to edge effects. In contrast, the community‐wide trend for LDMC was reinforced due to positive covariance between inter‐ and intraspecific trait shifts, while for LA the direction of covariance shifted from negative to positive on small versus large islands. Together, edge effects alter selection regimes in reassembling plant communities. Predicting the community‐wide consequences depends on the degree to which there is negative versus positive covariance between species sorting and within‐species adaptation. The widely‐used CWM approach can mask contrasting trait selection pressures acting on individuals within local populations. Individual‐level trait variation can improve understanding of community re‐assembly trajectories in response to global environmental change.

Aim Mounting global pressure on bird populations from invasive predators and habitat loss has driven a rapid growth in restorative and protective conservation action around the world, yet the efficacy of such actions is still not well understood. We investigated the relative effects of invasive predator control and habitat fragmentation on the abundance of native birds and invasive mammalian predators in native forest fragments. Location Waikato region, New Zealand Methods We sampled invasive mammalian predator and native bird abundances using camera traps and bird counts at 26 sites in 15 forest fragments across New Zealand’s Waikato region. Fragment area, shape complexity, and surrounding land cover of exotic and native forest were determined in ArcMap. We further created two composite gradients reflecting predator control intensity and temporal distribution of control based on seven quantitative variables recorded in each of the five years preceding native bird data collection. Finally, we estimated the relative influence of these drivers on invasive mammals and functional groups of native birds using model averaging. Results Of the two invasive predator control variables, only control intensity significantly affected invasive predator abundance and was also a more important driver than landscape or fragment structure, but responses varied among invasive mammal species. In contrast, both invasive predator control intensity and fragment structure were similarly important drivers of native bird abundance, though bird community responses varied markedly between functional groups. Main conclusions Our findings suggest that spatial extent of invasive mammal control is important for controlling mammal numbers and enhancing bird abundance, especially for small insectivorous species, and that habitat fragmentation is less important for invasive mammals but at least as important for native bird communities. Consequently, both drivers should be given strong consideration when undertaking landscape-scale conservation and restoration of bird communities in human-altered landscapes threatened by invasive predators.