Phylogenetic composition of native island floras influences naturalized alien species richness

Islands are hotspots of plant endemism and are particularly vulnerable to the establishment (naturalization) of alien plant species. Naturalized species richness on islands depends on several biogeographical and socioeconomic factors, but especially on remoteness. One potential explanation for this is that the phylogenetically imbalanced composition of native floras on remote islands leaves unoccupied niche space for alien species to colonize. Here, we tested whether the species richness of naturalized seed plants on 249 islands worldwide is related to the phylogenetic composition of their native floras. To this end, we calculated standardized effect size (ses) accounting for species richness for three phylogenetic assemblage metrics (Faith's phylogenetic diversity (PD), PDses; mean pairwise distance (MPD), MPDses; and mean nearest taxon distance (MNTD), MNTDses) based on a phylogeny of 42 135 native island plant species and related them to naturalized species richness. As covariates in generalized linear mixed models, we included native species richness and biogeographical, climatic and socioeconomic island characteristics known to affect naturalized species richness. Our analysis showed an increase in naturalized species richness with increasing phylogenetic clustering of the native assemblages (i.e. native species more closely related than expected by chance), most prominently with MPDses. This effect, however, was smaller than the influence of native species richness and biogeographical factors, e.g. remoteness. Further, the effect of native phylogenetic structure (MPDses) on naturalized species richness was stronger for smaller islands, but this pattern was not consistent across all phylogenetic assemblage metrics. This finding suggests that the phylogenetic composition of native island floras may affect naturalized species richness, particularly on small islands where species are more likely to co-occur locally. Overall, we conclude that the composition of native island assemblages affects their susceptibility to plant naturalizations in addition to other socioeconomic and biogeographical factors, and should be considered when assessing invasion risks on islands

Phylogenetic composition of native island floras influences naturalized alien species richness

Islands are hotspots of plant endemism and are particularly vulnerable to the establishment (naturalization) of alien plant species. Naturalized species richness on islands depends on several biogeographical and socioeconomic factors, but especially on remoteness. One potential explanation for this is that the phylogenetically imbalanced composition of native floras on remote islands leaves unoccupied niche space for alien species to colonize. Here, we tested whether the species richness of naturalized seed plants on 249 islands worldwide is related to the phylogenetic composition of their native floras. To this end, we calculated standardized effect size (ses) accounting for species richness for three phylogenetic assemblage metrics (Faith’s phylogenetic diversity (PD), PDses; mean pairwise distance (MPD), MPDses; and mean nearest taxon distance (MNTD), MNTDses) based on a phylogeny of 42 135 native island plant species and related them to naturalized species richness. As covariates in generalized linear mixed models, we included native species richness and biogeographical, climatic and socioeconomic island characteristics known to affect naturalized species richness. Our analysis showed an increase in naturalized species richness with increasing phylogenetic clustering of the native assemblages (i.e. native species more closely related than expected by chance), most prominently with MPDses. This effect, however, was smaller than the influence of native species richness and biogeographical factors, e.g. remoteness. Further, the effect of native phylogenetic structure (MPDses) on naturalized species richness was stronger for smaller islands, but this pattern was not consistent across all phylogenetic assemblage metrics. This finding suggests that the phylogenetic composition of native island floras may affect naturalized species richness, particularly on small islands where species are more likely to co-occur locally. Overall, we conclude that the composition of native island assemblages affects their susceptibility to plant naturalizations in addition to other socioeconomic and biogeographical factors, and should be considered when assessing invasion risks on islands

Beyond the Imitation Game: Quantifying and extrapolating the capabilities of language models

Language models demonstrate both quantitative improvement and new qualitative capabilities with increasing scale. Despite their potentially transformative impact, these new capabilities are as yet poorly characterized. In order to inform future research, prepare for disruptive new model capabilities, and ameliorate socially harmful effects, it is vital that we understand the present and near-future capabilities and limitations of language models. To address this challenge, we introduce the Beyond the Imitation Game benchmark (BIG- bench). BIG-bench currently consists of 204 tasks, contributed by 450 authors across 132 institutions. Task topics are diverse, drawing problems from linguistics, childhood develop- ment, math, common-sense reasoning, biology, physics, social bias, software development, and beyond. BIG-bench focuses on tasks that are believed to be beyond the capabilities of current language models. We evaluate the behavior of OpenAI's GPT models, Google- internal dense transformer architectures, and Switch-style sparse transformers on BIG-bench, across model sizes spanning millions to hundreds of billions of parameters. In addition, a team of human expert raters performed all tasks in order to provide a strong baseline. Findings include: model performance and calibration both improve with scale, but are poor in absolute terms (and when compared with rater performance); performance is remarkably similar across model classes, though with benefits from sparsity; tasks that improve gradually and predictably commonly involve a large knowledge or memorization component, whereas tasks that exhibit "breakthrough" behavior at a critical scale often involve multiple steps or components, or brittle metrics; social bias typically increases with scale in settings with ambiguous context, but this can be improved with prompting

TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Life‐history dimensions indicate non‐random assembly processes in tropical island tree communities

Community assembly processes on islands are often non‐random. The mechanisms behind non‐random assembly, however, are generally difficult to disentangle. Functional diversity in combination with a null model approach that accounts for differences in species richness among islands can be used to test for non‐random assembly processes, but has been applied rarely to island communities. By linking functional diversity of trees on islands with a null model approach, we bridge this gap and test for the role of stochastic versus non‐random trait‐mediated assembly processes in shaping communities by studying functional diversity–area relationships. We measured 11 plant functional traits linked to species dispersal and resource acquisition strategies of 57 tree species on 40 tropical islands. We grouped traits into four life‐history dimensions representing 1) dispersal ability, 2) growth strategy, 3) light acquisition and 4) nutrient acquisition. To test for non‐random assembly processes, we used null models that account for differences in species richness among the islands. Our results reveal contrasting responses of the four life‐history dimensions to island area. The dispersal and the growth strategy dimensions were underdispersed on smaller islands, whereas the light acquisition dimension was overdispersed. The nutrient acquisition dimension did not deviate from null expectations. With increasing island area, shifts in the strength of non‐random assembly processes increased the diversity of dispersal and acquisition strategies in island communities. Our results suggest that smaller islands may be more difficult to colonize and provide more limited niche space compared to larger islands, whose tree communities are likely determined by stochastic processes and higher niche diversity. Our null model approach highlights that analyzing the functional diversity of different life‐history dimensions provides a powerful framework to unravel community assembly processes on islands. These complex, non‐random assembly processes are masked by measures of functional diversity that do not account for differences in species richness between islands

RNase E biomolecular condensates stimulate PNPase activity

AbstractBacterial Ribonucleoprotein bodies (BR-bodies) play an essential role in organizing RNA degradation via liquid-liquid phase separation in the cytoplasm of bacteria. BR-bodies mediate multi-step mRNA decay through the concerted activity of the endoribonuclease RNase E coupled with the 3’-5’ exonuclease Polynucleotide Phosphorylase (PNPase). Our past in vivo studies indicated that the loss of PNPase recruitment into BR-bodies led to a significant build-up of RNA decay intermediates in Caulobacter crescentus. We reconstituted RNase E’s C-terminal domain together with PNPase to understand how RNase E biomolecular condensates can tailor the functions of PNPase. We found that PNPase catalytic activity is accelerated when colocalized with the RNase E biomolecular condensates. In contrast, disruption of the RNase E-PNPase protein-protein interaction led to a loss of PNPase recruitment into the BR-bodies and a loss of ribonuclease rate enhancement. We also found that BR-bodies could enhance the decay of select RNA substrates, as we observed a 3.4-fold enhancement of polyadenylic acid (poly(A)) degradation and no impact upon poly(U) degradation. Our investigation into the origins of the 3.4-fold rate enhancement for poly(A) decay indicates a combination of scaffolding and mass action effects impact due to the concentrated biomolecular condensate environment accelerating RNA decay. Consistent with our past in vivo work, these studies suggest BR-bodies are sites of accelerated RNA decay that can shape the available transcriptome.</jats:p