Toby Pak Nok Tsang

Dispersal enables species to track climate change by facilitating range shifts and colonization, yet successful post-dispersal establishment is often constrained by ecological niche mismatches. The mechanisms underlying this constraint remain poorly understood due to a lack of molecular evidence, limiting our ability to predict climate-induced range dynamics. Here, we integrate biogeographic analysis with macroecological insights to investigate how ecology shapes genomic divergence, local adaptation, and climate resilience in Debregeasia orientalis C. J. Chen, a dominant riparian shrub distributed across multiple biodiversity hotspots in southwestern China. Based on whole genome sequencing data from 332 individuals, we identify three genetically distinct groups: two diverged during the early Last Glacial period, and one originated through hybridization more recently. Despite both historical and ongoing opportunities for gene flow, strong genetic differentiation persists among the three groups. This differentiation is supported by clear niche divergence among the three groups and by genomic signatures of local adaptation, including selective sweeps related to hypoxia tolerance, thermal adaptation, and anthropogenic pressures. Together, these findings indicate that post-dispersal niche filtering limits the merging of these lineages. Genomic offset projections reveal asymmetric vulnerabilities to future climate scenarios, with one lineage particularly maladapted under projected shifts. These findings highlight niche-driven adaptation as a primary determinant of both historical divergence and contemporary resilience. Collectively, this study presents a framework linking post-dispersal ecological filtering to long-term genomic divergence, offering new insights into how niche filtering maintains genetic structure under rapid environmental change.

Migratory species worldwide face escalating anthropogenic pressures, yet effective conservation requires transboundary strategies across their ranges. This is particularly evident in the East Asian‐Australasian Flyway (EAAF), a region vital for migratory waterbirds and home to a third of the global human population. Despite its ecological importance and the numerous threats impacting waterbird populations, a systematic, evidence‐based assessment of conservation actions is lacking. We investigated the conservation actions implemented by reserve managers in the EAAF, focusing on their perceived threats and associated management strategies. We then compared these practitioner‐driven priorities with the scientific evidence available in the conservation evidence (CE), using a modified pressure–state–response (PSR) framework to structure the linkage between implemented actions and evidence. This comparison allowed us to identify potential gaps between conservation practice and scientific knowledge, highlighting key research areas for improved, evidence‐based species conservation along the flyway. Our results revealed discrepancies between perceived threats and the evidence in the CE to support management actions. Habitat loss and human disturbance were prioritized by the reserve managers, but evidence for the effectiveness of some management practices was limited. Biological invasions were a lower priority for managers, despite there is a comparable evidence base for justifying the action. This indicates a mismatch between research focus and on‐the‐ground needs. Furthermore, the existing CE database has limited evidence specific to the EAAF. Synthesis and application : The modified PSR framework proved valuable for assessing conservation effectiveness and identifying research gaps for waterbirds in the EAAF. Recognizing similar threats to other migratory species globally, we urge action to: (1) prioritize regionally relevant research validating frontline conservation actions, (2) enhance communication between researchers and practitioners and (3) expand evidence databases with relevant spatial and taxonomic representation. Implementing these steps will strengthen the evidence base, better align research with on‐the‐ground needs and improve the long‐term prospects for migratory species in Asia.

Statistical autocorrelation between sampling units violates independence assumptions in many analyses. Here, we used simulations and empirical analyses to demonstrate how shared evolutionary history between species and species overlap among communities leads to an insidious form of autocorrelation, termed compositional autocorrelation. We simulated compositionally autocorrelated ecosystem functions across communities and assessed the type I error, statistical power and accuracy of slope estimates from naïve linear regression models and mixed models accounting for compositional autocorrelation. Mixed models maintained lower type I error, similar or higher statistical power, and more accurate slope estimates compared to linear regression. Re‐analysing an empirical dataset, we found linear regression underestimated uncertainty in species richness effects for eight of 10 ecosystem functions. As species overlap and shared evolutionary history are common features in community data, our results highlight the need to explicitly consider compositional autocorrelation in statistical analyses to ensure correct inferences.

Many broad‐scale studies along spatial and habitat gradients show that organisms' traits can strongly influence community assembly by facilitating dispersal and environmental filtering. Nonetheless, how traits structure local faunal communities within habitats remains poorly understood. In particular, the often‐assumed role of traits in affecting the outcome of competition among animal species is rarely tested. We coupled a field study with a mesocosm experiment to explore how arboreal ant species' traits shaped competition and community structure, leveraging a small mangrove ecosystem which conceivably imposed minimal dispersal and environmental filtering effects on ant community assembly. We first surveyed the ant communities inhabiting 115 mangrove trees using >2000 carbohydrate and protein baits, and measured multiple morphological, physiological (critical thermal maximum) and dietary (stable isotope trophic position) traits of all ant species. We then coupled co‐occurrence network analyses with meta‐analytical models to uncover the trait‐based mechanisms structuring species co‐occurrences in the field. Finally, in a mesocosm experiment, we reared 87 colonies of eight ant species from the mangrove over 30 days under different competition treatments to investigate trait‐mediated effects of competition on ant colony performance. Patterns of ant species co‐occurrences and bait recruitment indicated strong competition for limited protein‐rich resources. Accordingly, dissimilarities in three traits—eye size, pronotum width and antennal scape length—consistently explained species co‐occurrences, suggesting that the communities were competitively assembled by a partitioning of resource acquisition strategies among species. Species co‐occurrences were also, to a lesser extent, explained by similarities in critical thermal limits, suggesting mild environmental filtering. In the mesocosm experiment, increasing directional differences in eye size and pronotum width between neighbouring ant colonies exacerbated interspecific competitive effects on colony survival and growth. Our results empirically demonstrate that traits linked to resource acquisition shape both coexistence and exclusion in ants. More broadly, by contrasting field patterns of niche partitioning with experimentally measured competitive effects, we show that the same traits can underpin stabilising processes that promote coexistence through limiting similarity, or equalising processes that drive exclusion through hierarchical differences, with their relative importance shifting across spatial scales and environmental contexts. Read the free Plain Language Summary for this article on the Journal blog.

Plant invasion is a significant driver of species loss in ecological communities. However, projecting its impact on multispecies coexistence remains a challenge. Here, we conducted pairwise experiments with five native and five non‐native species, using the Ricker model to estimate interaction coefficients and population growth rates. We assessed the impact of non‐native species on community persistence potential through a structural approach that integrates multispecies interactions and estimates coexistence probabilities. We found that community persistence potential generally declined after invasion, with the feasibility domain (i.e., the probability that all species co‐occur simultaneously) becoming more asymmetric as more native species were replaced by non‐native ones. Interestingly, non‐native species were more likely to be excluded first under random environmental perturbations in communities where they were dominant. Our findings highlight the importance of clarifying species interaction structure under random disturbances in shaping community persistence and suggest tailored invasion management strategies to optimise resource allocation.

Aim: Thousands of non‐native species have established populations and spread in outdoor environments (i.e., Naturalised), yet some populations or species only occur indoors, potentially due to unsuitable climates. We assessed the hypothesis that non‐native ants are more often restricted to indoor environments when they invade regions with climates dissimilar from their native regions. Furthermore, we forecasted how climate change could influence the naturalisation of indoor‐restricted non‐native ants. Location: Global. Methods: Using a global database of 323 non‐native ant taxa across 477 regions, we modelled how average climatic conditions in the native and invaded regions of each taxon determined whether they naturalised or were restricted indoors. We then modelled regional climatic suitability for the naturalisation of indoor‐restricted non‐native ants and projected future changes under climate change scenarios. We further assessed if climate change would facilitate the naturalisation of impactful non‐native ants using a global database describing their known impacts. Results: Non‐native ants originating from warm regions were more likely restricted indoors when introduced to cold regions. Under 2°C and 4°C of warming, the number of indoor‐restricted non‐native ant species projected to find suitable regional climates for naturalisation increased by an average of 0.08 (maximum = 1.2) and 0.27 (maximum = 3.7) taxa per region, respectively. These anticipated naturalisations include high‐impact non‐native ants, such as the Argentine ant Linepithema humile and are expected to increase socioeconomic and environmental impacts under both warming scenarios, particularly in European regions. Main Conclusions: Our findings suggest that indoor environments serve as microclimatic beachheads for biological invasions, especially in cold regions in the Northern Hemisphere. Failure to limit climate warming and inadequate biosecurity management in indoor environments may facilitate the naturalisation of non‐native ants, with costly repercussions on nature and society.

Land use change threatens global biodiversity and compromises ecosystem functions, including pollination and food production. Reduced taxonomic α‐diversity is often reported under land use change, yet the impacts could be different at larger spatial scales (i.e., γ‐diversity), either due to reduced β‐diversity amplifying diversity loss or increased β‐diversity dampening diversity loss. Additionally, studies often focus on taxonomic diversity, while other important biodiversity components, including phylogenetic diversity, can exhibit differential responses. Here, we evaluated how agricultural and urban land use alters the taxonomic and phylogenetic α‐, β‐, and γ‐diversity of an important pollinator taxon—bees. Using a multicontinental dataset of 3117 bee assemblages from 157 studies, we found that taxonomic α‐diversity was reduced by 16%–18% in both agricultural and urban habitats relative to natural habitats. Phylogenetic α‐diversity was decreased by 11%–12% in agricultural and urban habitats. Compared with natural habitats, taxonomic and phylogenetic β‐diversity increased by 11% and 6% in urban habitats, respectively, but exhibited no systematic change in agricultural habitats. We detected a 22% decline in taxonomic γ‐diversity and a 17% decline in phylogenetic γ‐diversity in agricultural habitats, but γ‐diversity of urban habitats was not significantly different from natural habitats. These findings highlight the threat of agricultural expansions to large‐scale bee diversity due to systematic γ‐diversity decline. In addition, while both urbanization and agriculture lead to consistent declines in α‐diversity, their impacts on β‐ or γ‐diversity vary, highlighting the need to study the effects of land use change at multiple scales.

Urban areas are foci for the introduction of non‐native plant species, and they often act as launching sites for invasions into the wider environment. Although interest in biological invasions in urban areas is growing rapidly, and the extent and complexity of problems associated with invasions in these systems have increased, data on the composition and numbers of non‐native plants in urbanized areas remain scattered and idiosyncratic. We assembled data from multiple sources to create the Global Urban Biological Invasions Compendium (GUBIC) for vascular plants representing 553 urban centres from 61 countries across every continent except Antarctica. The GUBIC repository includes 8140 non‐native plant species from 253 families. The number of urban centres in which these non‐native species occurred had a log‐normal distribution, with 65.2% of non‐native species occurring in fewer than 10 urban centres. Practical implications: The dataset has wider applications for urban ecology, invasion biology, macroecology, conservation, urban planning and sustainability. We hope this dataset will stimulate future research in invasion ecology related to the diversity and distributional patterns of non‐native flora across urban centres worldwide. Further, this information should aid the early detection and risk assessment of potential invasive species, inform policy development and assist in setting management priorities.

Plant invasion is a significant driver of species loss in ecological communities. However, projecting its impact on the coexistence potential of multi-species communities and their persistence under random environmental perturbations remains challenging. Here, we conducted pairwise experiments with five native and five non-native species using the Ricker model to estimate interaction coefficients and assessed the impact of non-native species on community persistence through feasibility domains (i.e., the probability that all species can coexist simultaneously), and species exclusion probabilities. At the community level, we found that community persistence generally declined after non-native species invasion, with the feasibility domain becoming more asymmetric as more native species were replaced by non-native ones. At the species level, non-native species are likely to be excluded first under strong perturbations. Our findings highlight the importance of clarifying species interactions in shaping community persistence, and tailoring invasion management strategies to local environments to optimize resource allocation.

Identifying the drivers that promote unique species compositions (i.e. ecological uniqueness) is crucial to understanding the mechanisms underpinning diversity patterns and for effective conservation planning. Environmental conditions are often sampled differentially in datasets, which can lead to rarer environments having unique species compositions, provided that environmental differences increase compositional differences. This effect, however, will be undesirable when a study aims to test the direct impact of environments rather than their availability. We developed an approach to reduce the effects of environmental availability in ecological uniqueness analyses through calculating expected pairwise compositional dissimilarities for each unique environmental condition. We further used simulations to assess the performance of our methods by randomly generating communities from two hypothetical environments with non‐overlapping species pools. Additionally, we used a dataset of 50 tree communities to demonstrate how environmental availability could impact relationships between environmental conditions and ecological uniqueness in empirical studies. Our simulations revealed that uniqueness metrics based on observed values are sensitive to environmental availability, while our approach correctly concluded that there were no differences among environments under the unbalanced design. Our analysis of tree communities produced divergent conclusions between the two approaches, as increasing slope reduced ecological uniqueness after controlling for their low availability in the dataset only. This suggests that low environmental availability inflated the ecological uniqueness of sites with high slope, which opposed its direct negative effects on ecological uniqueness, leading to a weak relationship based on observed values. To achieve a more mechanistic understanding of ecological uniqueness patterns, the effects of environmental availability must be considered. We recommend that studies use both uncorrected and corrected analyses to identify not only the direct effects of environmental conditions but also the degree to which their availability influences the observed relationships between ecological uniqueness and environment conditions. Our approach should be most necessary and applicable in unbalanced designs, which is a common characteristic in empirical studies.