Assessing the response of marine fish communities to climate change and fishing.

Globally, marine fish communities are being altered by climate change and human disturbances. We examined data on global marine fish communities to assess changes in community-weighted mean temperature affinity (i.e., mean temperatures within geographic ranges), maximum length, and trophic levels, which, respectively, represent the physiological, morphological, and trophic characteristics of marine fish communities. Then, we explored the influence of climate change and fishing on these characteristics because of their long-term role in shaping fish communities, especially their interactive effects. We employed spatial linear mixed models to investigate their impacts on community-weighted mean trait values and on abundance of different fish lengths and trophic groups. Globally, we observed an initial increasing trend in the temperature affinity of marine fish communities, whereas the weighted mean length and trophic levels of fish communities showed a declining trend. However, these shift trends were not significant, likely due to the large variation in midlatitude communities. Fishing pressure increased fish communities' temperature affinity in regions experiencing climate warming. Furthermore, climate warming was associated with an increase in weighted mean length and trophic levels of fish communities. Low climate baseline temperature appeared to mitigate the effect of climate warming on temperature affinity and trophic levels. The effect of climate warming on the relative abundance of different trophic classes and size classes both exhibited a nonlinear pattern. The small and relatively large fish species may benefit from climate warming, whereas the medium and largest size groups may be disadvantaged. Our results highlight the urgency of establishing stepping-stone marine protected areas to facilitate the migration of fishes to habitats in a warming ocean. Moreover, reducing human disturbance is crucial to mitigate rapid tropicalization, particularly in vulnerable temperate regions.

Análisis de la respuesta de las comunidades de peces marinos ante el cambio climático y la pesca Resumen Las comunidades de peces marinos sufren alteraciones en todo el mundo causadas por el cambio climático y las perturbaciones humanas. Analizamos los datos sobre las comunidades de peces marinos de todo el mundo para valorar los cambios en la afinidad térmica media (es decir, la temperatura media dentro de las distribuciones geográficas), la longitud máxima y los niveles tróficos, todos con ponderación comunitaria, los cuales representan respectivamente las características fisiológicas, morfológicas y tróficas de las comunidades de peces marinos. Después exploramos la influencia del cambio climático y la pesca sobre estos rasgos, ya que desempeñan un papel a largo plazo en la formación de las comunidades de peces, especialmente sus efectos interactivos. Empleamos modelos espaciales lineales mixtos para investigar el impacto del cambio climático y la pesca sobre los valores promedio de los rasgos con ponderación comunitaria y sobre la abundancia de las diferentes longitudes de peces y grupos tróficos. Observamos una tendencia inicial en incremento en la afinidad térmica de las comunidades de peces marinos en todo el mundo, mientras que el promedio con ponderación comunitaria de la longitud y el nivel trófico mostró una tendencia en declinación. Sin embargo, estos cambios en las tendencias no fueron significativas, probablemente debido a la gran variación de las comunidades de latitud media. La presión de pesca incrementó la afinidad térmica de las comunidades de peces en las regiones que experimentan el calentamiento climático. Además, este calentamiento estuvo asociado con un incremento en el promedio con ponderación comunitaria de la longitud y el nivel trófico de las comunidades. La temperatura de referencia climática baja pareció mitigar el efecto del calentamiento climático sobre la afinidad térmica y los niveles tróficos. El efecto del calentamiento sobre la abundancia relativa de las diferentes clases tróficas y el tamaño de las clases exhibió un patrón no lineal. Las especies de peces pequeños y relativamente grandes podrían beneficiarse con el calentamiento climático, mientras que los grupos de mayor tamaño y tamaño mediano estarían en desventaja. Nuestros resultados resaltan la urgencia por establecer áreas marinas protegidas que faciliten la migración de peces hacia hábitats en un océano cada vez más caliente. Además, es crucial reducir la perturbación humana para mitigar la rápida tropicalización, particularmente en las regiones templadas vulnerables.

Conservation priorities for global marine biodiversity across multiple dimensions.

Marine biodiversity plays important roles in ocean ecosystem services and has substantial economic value. Species diversity, genetic diversity and phylogenetic diversity, which reflect the number, evolutionary potential and evolutionary history of species in ecosystem functioning, are three important dimensions of biodiversity. Marine-protected areas have been demonstrated as an effective area-based tool for protecting marine biodiversity, but only 2.8% of the ocean has been fully protected. It is urgent to identify global conservation priority areas and percentage of the ocean across multiple dimensions of biodiversity based on Post-2020 Global Biodiversity Framework. Here, we investigate the spatial distribution of marine genetic and phylogenetic diversity using 80 075 mitochondrial DNA barcode sequences from 4316 species and a newly constructed phylogenetic tree of 8166 species. We identify that the Central Indo-Pacific Ocean, Central Pacific Ocean and Western Indian Ocean harbor high levels of biodiversity across three dimensions of biodiversity, which could be designated as conservation priority areas. We also find that strategically protecting ∼22% of the ocean would allow us to reach the target of conserving ∼95% of currently known taxonomic, genetic and phylogenetic diversity. Our study provides insights into the spatial distribution pattern of multiple marine diversities and the findings would help to design comprehensive conservation schemes for global marine biodiversity.

Influence of Last Glacial Maximum legacies on functional diversity and community assembly of extant Chinese terrestrial vertebrates.

Contemporary biodiversity patterns are shaped by not only modern climate but also factors such as past climate fluctuations. Investigating the relative degree of paleoclimate legacy could help us understand the formation of current biodiversity patterns. However, an assessment of this issue in China is lacking. Here, we investigated the phylogenetic structure and functional diversity patterns of Chinese terrestrial vertebrates. We found that Southern China harbored higher functional richness, while Northern and Western China were more phylogenetically clustered with higher functional divergence and evenness, indicating environmental filtering effects. Moreover, we found that drastic Last Glacial Maximum climate changes were positively related to phylogenetic clustering, lower functional richness, and higher functional divergence and evenness, although this effect varied among different taxonomic groups. We further found that mammal communities experiencing more drastic Last Glacial Maximum temperature changes were characterized by "faster" life-history trait values. Our findings provide new evidence of the paleoclimate change legacies influencing contemporary biodiversity patterns that will help guide national-level conservation plans.

Global patterns of phylogenetic diversity and transmission of bat coronavirus.

Bats are reservoirs for multiple coronaviruses (CoVs). However, the phylogenetic diversity and transmission of global bat-borne CoVs remain poorly understood. Here, we performed a Bayesian phylogeographic analysis based on 3,594 bat CoV RdRp gene sequences to study the phylogenetic diversity and transmission of bat-borne CoVs and the underlying driving factors. We found that host-switching events occurred more frequently for α-CoVs than for ß-CoVs, and the latter was highly constrained by bat phylogeny. Bat species in the families Molossidae, Rhinolophidae, Miniopteridae, and Vespertilionidae had larger contributions to the cross-species transmission of bat CoVs. Regions of eastern and southern Africa, southern South America, Western Europe, and Southeast Asia were more frequently involved in cross-region transmission events of bat CoVs than other regions. Phylogenetic and geographic distances were the most important factors limiting CoV transmission. Bat taxa and global geographic hotspots associated with bat CoV phylogenetic diversity were identified, and bat species richness, mean annual temperature, global agricultural cropland, and human population density were strongly correlated with the phylogenetic diversity of bat CoVs. These findings provide insight into bat CoV evolution and ecological transmission among bat taxa. The identified hotspots of bat CoV evolution and transmission will guide early warnings of bat-borne CoV zoonotic diseases.

Global landscape of gut microbiome diversity and antibiotic resistomes across vertebrates.

Multiple factors influence gut microbiome diversity in vertebrate hosts. Most previous studies have only investigated specific factors and certain host species or taxa. However, a comprehensive assessment of the relative contributions of individual factors towards gut microbial diversity within a broader evolutionary context remains lacking. Here, 2202 16S rRNA gene sequencing samples of gut bacterial communities collected from 452 host species across seven classes were analyzed together to understand the factors broadly affecting vertebrate gut microbiomes across hosts with different diets, threatened status, captivity status, and habitat environmental factors. Among wild vertebrates, diet was most significantly associated with gut microbiome alpha diversity, while host phylogeny and diet were significantly associated with beta diversity, consistent with a previous study. Host threatened status and habitat environmental factors (e.g., geography and climate) were also associated with gut bacterial community beta diversity. Subsequent ecological modeling revealed a strong association between stochastic assembly processes and patterns of gut bacterial diversity among free-ranging vertebrates. In addition, metagenomic analysis of gut microbiomes from 62 captive vertebrates and sympatric humans revealed similar diversity and resistome profiles despite differences in host phylogeny, diet, and threatened status. These results thus suggest that captivity diminishes the effects of host phylogeny, diet, and threatened status on the diversity of vertebrate gut bacterial communities. The most overrepresented antibiotic resistant genes (ARGs) observed in these samples are involved in resistance to ß-lactams, aminoglycosides, and tetracycline. These results also revealed potential horizontal transfers of ARGs between captive animals and humans, thereby jointly threatening public health and vertebrate conservation. Together, this study provides a comprehensive overview of the diversity and resistomes of vertebrate gut microbiomes. These combined analyses will help guide future vertebrate conservation via the rational manipulation of microbial diversity and reducing antibiotic usage.

Integrated index-based assessment reveals long-term conservation progress in implementation of Convention on Biological Diversity.

The Convention on Biological Diversity (CBD) has launched two long-term, target-based conservation Strategic Plans in the past two decades. We compiled an index-based assessment framework to evaluate target achievements of the CBD using long-term indicators. The CBD Index is steadily increasing, with the Goal Indices for biodiversity mainstreaming, protection, and supporting mechanisms all improving over time. While the State and Pressure Indices continue to deteriorate coupled with human population and economic development, their changing rates have slowed down, most likely because of the constantly growing conservation efforts as revealed by the Response Index. The first quantitative assessment of the CBD's long-term performance may provide critical science-based evidence for continuing commitments to developing and implementing a new Post-2020 Global Biodiversity Framework. We also call for enhanced efforts to address the emerging challenges in achieving the 2050 Vision for Biodiversity and the adoption of a rapid assessment framework to track future progress.