Can the implementation of household waste classification mitigate greenhouse gas emissions in Beijing? A comprehensive analysis of recent trends and future scenarios.

Household waste contributes significantly to global greenhouse gas (GHG) emissions, and waste classification is crucial for reducing emissions. This study focuses on Beijing and utilizes life cycle assessment (LCA) and material flow analysis (MFA) to calculate GHG emissions in waste management systems and quantify emission reduction potential of different measures. The results show that net emissions from the classification system in 2021 are 116.77 kg CO2-eq/t waste, reducing 61.82 % compared to the traditional mixed collection and transportation system. Waste volume, classification efficiency, and treatment strategies are the primary factors affecting emissions in classification systems. Recycling is identified as effective treatment methods. Three scenarios are designed to explore emission pathway of the system toward 2060. In the business-as-usual (BAU) Scenario, emissions will continue to grow to 108.57 × 104 t CO2-eq/yr in 2060. In the Classification Efficiency Scenario and the Comprehensive Scenario, emissions in 2060 will be cut to -177.26 × 104 t CO2-eq/yr and -702.00 × 104 t CO2-eq/yr, respectively. These results underscore the critical role of waste classification and recycling in mitigating the negative impacts of increasing waste volume. By 2060, combining waste classification with recycling can offset emissions by 803.51 × 104 t CO2-eq/yr, contributing 99 % to emission reduction potential. Improving classification efficiency and recycling ratio are key measures for achieving this reduction goal. Meanwhile, treatment methods and technologies should prioritize classification and recycling. Aiming at carbon neutrality, the study proposes several recommendations to improve classification systems, including enhancing classification efficiency, optimizing treatment facilities and strategies, and establishing recycling and utilization systems, etc.

Comparative genomics of widespread and narrow-range white-bellied rats in the Niviventer niviventer species complex sheds light on invasive rodent success.

Widespread species that inhabit diverse environments possess large population sizes and exhibit a high capacity for environmental adaptation, thus enabling range expansion. In contrast, narrow-range species are confined to restricted geographical areas and are ecologically adapted to narrow environmental conditions, thus limiting their ability to expand into novel environments. However, the genomic mechanisms underlying the differentiation between closely related species with varying distribution ranges remain poorly understood. The Niviventer niviventer species complex (NNSC), consisting of highly abundant wild rats in Southeast Asia and China, offers an excellent opportunity to investigate these questions due to the presence of both widespread and narrow-range species that are phylogenetically closely related. In the present study, we combined ecological niche modeling with phylogenetic analysis, which suggested that sister species cannot be both widespread and dominant within the same geographical region. Moreover, by assessing heterozygosity, linkage disequilibrium decay, and Tajima's D analysis, we found that widespread species exhibited higher genetic diversity than narrow-range species. In addition, by exploring the "genomic islands of speciation", we identified 13 genes in highly divergent regions that were shared by the two widespread species, distinguishing them from their narrow-range counterparts. Functional annotation analysis indicated that these genes are involved in nervous system development and regulation. The adaptive evolution of these genes likely played an important role in the speciation of these widespread species.

Tree communities and functional traits determine herbivore compositional turnover.

There are many factors known to drive species turnover, although the mechanisms by which these operate are less clear. Based on comprehensive datasets from the largest tree diversity experiment worldwide (BEF-China), we used shared herbivore species (zeta diversity) and multi-site generalized dissimilarity modelling to investigate the patterns and determinants of species turnover of Lepidoptera herbivores among study plots across a gradient in tree species richness. We found that zeta diversity declined sharply with an increasing number of study plots, with complete changes in caterpillar species composition observed even at the fine spatial scale of our study. Plant community characteristics rather than abiotic factors were found to play key roles in driving caterpillar compositional turnover, although these effects varied with an increasing number of study plots considered, due to the varying contributions of rare and common species to compositional turnover. Our study reveals details of the impact of phylogeny- and trait-mediated processes of trees on herbivore compositional turnover, which has implications for forest management and conservation and shows potential avenues for maintenance of heterogeneity in herbivore communities.

Whole-genome sequencing reveals adaptations of hairy-footed jerboas (Dipus, Dipodidae) to diverse desert environments.

BACKGROUND: Environmental conditions vary among deserts across the world, spanning from hyper-arid to high-elevation deserts. However, prior genomic studies on desert adaptation have focused on desert and non-desert comparisons overlooking the complexity of conditions within deserts. Focusing on the adaptation mechanisms to diverse desert environments will advance our understanding of how species adapt to extreme desert environments. The hairy-footed jerboas are well adapted to diverse desert environments, inhabiting high-altitude arid regions, hyper-arid deserts, and semi-deserts, but the genetic basis of their adaptation to different deserts remains unknown. RESULTS: Here, we sequenced the whole genome of 83 hairy-footed jerboas from distinct desert zones in China to assess how they responded under contrasting conditions. Population genomics analyses reveal the existence of three species in hairy-footed jerboas distributed in China: Dipus deasyi, Dipus sagitta, and Dipus sowerbyi. Analyses of selection between high-altitude desert (elevation ≥ 3000m) and low-altitude desert (< 500m) populations identified two strongly selected genes, ATR and HIF1AN, associated with intense UV radiation and hypoxia in high-altitude environments. A number of candidate genes involved in energy and water homeostasis were detected in the comparative genomic analyses of hyper-arid desert (average annual precipitation < 70mm) and arid desert (< 200mm) populations versus semi-desert (> 360mm) populations. Hyper-arid desert animals also exhibited stronger adaptive selection in energy homeostasis, suggesting water and resource scarcity may be the main drivers of desert adaptation in hairy-footed jerboas. CONCLUSIONS: Our study challenges the view of deserts as homogeneous environments and shows that distinct genomic adaptations can be found among desert animals depending on their habitats.

Ecological predictors of interspecific variation in bird bill and leg lengths on a global scale.

Bills and legs are two vital appendages for birds, and they exhibit huge interspecific variation in form and function, yet no study has examined the global predictors of this variation. This study examined global gradients in the relative lengths of bird bills and tarsi (i.e. exposed leg parts) to body size across non-migratory birds, while accounting for phylogeny. We found that relative bill length and tarsus length were related to diet, habitat density, latitude, annual mean temperature, temperature variability and hand-wing index (HWI), a proxy for birds' flight efficiency. Among these factors, diet played a primary role in predicting bill length, with nectar-feeding pollinators, vertivores, invertivores and omnivores having longer bills; HWI emerged as the predominant predictor of tarsus length, wherein species with higher HWI had shorter tarsi. However, the effects of these factors differed between passerines and non-passerines, with some temperature-related effects exhibiting opposite trends between these two groups. Our findings highlight the compromise in adaptations for feeding, thermoregulation and flight performance between the two distinct appendages.

Similar adaptative mechanism but divergent demographic history of four sympatric desert rodents in Eurasian inland.

Phenotypes associated with metabolism and water retention are thought to be key to the adaptation of desert species. However, knowledge on the genetic changes and selective regimes on the similar and divergent ways to desert adaptation in sympatric and phylogenetically close desert organisms remains limited. Here, we generate a chromosome level genome assembly for Northern three-toed jerboa (Dipus sagitta) and three other high-quality genome assemblies for Siberian jerboa (Orientallactaga sibirica), Midday jird (Meriones meridianus), and Desert hamster (Phodopus roborovskii). Genomic analyses unveil that desert adaptation of the four species mainly result from similar metabolic pathways, such as arachidonic acid metabolism, thermogenesis, oxidative phosphorylation, insulin related pathway, DNA repair and protein synthesis and degradation. However, the specific evolved genes in the same adaptative molecular pathway often differ in the four species. We also reveal similar niche selection but different demographic histories and sensitivity to climate changes, which may be related to the diversified genomic adaptative features. In addition, our study suggests that nocturnal rodents have evolved some specific adaptative mechanism to desert environments compared to large desert animals. Our genomic resources will provide an important foundation for further research on desert genetic adaptations.

Genomic Consequences of and Demographic Response to Pervasive Hybridization Over Time in Climate-Sensitive Pikas.

Rare and geographically restricted species may be vulnerable to genetic effects from inbreeding depression in small populations or from genetic swamping through hybridization with common species, but a third possibility is that selective gene flow can restore fitness (genetic rescue). Climate-sensitive pikas (Ochotona spp.) of the Qinghai-Tibetan Plateau (QHTP) and its vicinity have been reduced to residual populations through the movement of climatic zones during the Pleistocene and recent anthropogenic disturbance, whereas the plateau pika (O. curzoniae) remains common. Population-level whole-genome sequencing (n = 142) of six closely related species in the subgenus Ochotona revealed several phases of ancient introgression, lineage replacement, and bidirectional introgression. The strength of gene flow was the greatest from the dominant O. curzoniae to ecologically distinct species in areas peripheral to the QHTP. Genetic analyses were consistent with environmental reconstructions of past population movements. Recurrent periods of introgression throughout the Pleistocene revealed an increase in genetic variation at first but subsequent loss of genetic variation in later phases. Enhanced dispersion of introgressed genomic regions apparently contributed to demographic recovery in three peripheral species that underwent range shifts following climate oscillations on the QHTP, although it failed to drive recovery of northeastern O. dauurica and geographically isolated O. sikimaria. Our findings highlight differences in timescale and environmental background to determine the consequence of hybridization and the unique role of the QHTP in conserving key evolutionary processes of sky island species.

Transcriptome analysis of pika heart tissue reveals mechanisms underlying the adaptation of a keystone species on the roof of the world.

High-altitude environments impose intense stresses on living organisms and drive striking phenotypic and genetic adaptations, such as hypoxia resistance, cold tolerance, and increases in metabolic capacity and body mass. As one of the most successful and dominant mammals on the Qinghai-Tibetan Plateau (QHTP), the plateau pika (Ochotona curzoniae) has adapted to the extreme environments of the highest altitudes of this region and exhibits tolerance to cold and hypoxia, in contrast to closely related species that inhabit the peripheral alpine bush or forests. To explore the potential genetic mechanisms underlying the adaptation of O. curzoniae to a high-altitude environment, we sequenced the heart tissue transcriptomes of adult plateau pikas (comparing specimens from sites at two different altitudes) and Gansu pikas (O. cansus). Differential expression analysis and weighted gene co-expression network analysis (WGCNA) were used to identify differentially expressed genes (DEGs) and their primary functions. Key genes and pathways related to high-altitude adaptation were identified. In addition to the biological processes of signal transduction, energy metabolism and material transport, the identified plateau pika genes were mainly enriched in biological pathways such as the negative regulation of smooth muscle cell proliferation, the apoptosis signalling pathway, the cellular response to DNA damage stimulus, and ossification involved in bone maturation and heart development. Our results showed that the plateau pika has adapted to the extreme environments of the QHTP via protection against cardiomyopathy, tissue structure alterations and improvements in the blood circulation system and energy metabolism. These adaptations shed light on how pikas thrive on the roof of the world.

Mammalian diversification bursts and biotic turnovers are synchronous with Cenozoic geoclimatic events in Asia.

Asia's rich species diversity has been linked to its Cenozoic geodiversity, including active mountain building and dramatic climatic changes. However, prior studies on the diversification and assembly of Asian faunas have been derived mainly from analyses at taxonomic or geographic scales too limited to offer a comprehensive view of this complex region's biotic evolution. Here, using the class Mammalia, we built historical biogeographic models drawn on phylogenies of 1,543 species occurring across Asia to investigate how and when the mammal diversity in Asian regions and mountain hotspots was assembled. We explore the roles of in situ speciation, colonization, and vicariance and geoclimatic events to explain the buildup of Asia's regional mammal diversity through time. We found that southern Asia has served as the main cradle of Asia's mammal diversity. Present-day species richness in other regions is mainly derived from colonization, but by the Miocene, in situ speciation increased in importance. The high biodiversity present in the mountain hotspots (Himalayas and Hengduan) that flank the Qinghai-Tibetan plateau is a product of high colonization instead of in situ speciation, making them important centers of lineage accumulation. Overall, Neogene was marked by great diversification and migrations across Asia and surrounding continents but Paleogene environments already hosted rich mammal assemblages. Our study revealed that synchronous diversification bursts and biotic turnovers are temporally associated with tectonic events (mountain building, continental collisions) and drastic reorganization of climate (aridification of Asian interior, intensification of Asian monsoons, sea retreat) that took place throughout the Cenozoic in Asia.

Environmental drivers of sympatric mammalian species compositional turnover in giant panda nature reserves: Implications for conservation.

The charismatic giant panda (Ailuropoda melanoleuca) is an iconic species of wildlife conservation worldwide. As the most effective measure to protect giant pandas and their habitats, China has established 67 giant panda nature reserves (GPNR) during the last five decades, which also bring benefits to many sympatric medium- and large-bodied mammals (MLM). To better inform the planning of the GPNR network with the view of preserving regional MLM diversity, we investigated the zeta diversity (a novel index to measure species compositional turnover considering the contributions of both rare and common species) patterns (i.e. zeta decline and retention rate curve) of MLMs across 40 GPNRs. The effects of species' body mass and conservation status on the zeta diversity patterns were tested. Further, we applied the multi-site generalized dissimilarity modelling (MS-GDM) framework to explore the impacts of environmental and geographic distances on MLM turnover. The results indicated that there are a core set of 17 MLM species sympatric with the giant panda in the GPNRs. Species' body mass can affect the patterns of zeta decline and retention rate curves, and the number of large-bodied species shared by multiple GPNRs is higher than that of medium-bodied species across zeta orders. The MS-GDM revealed the important roles of difference in habitat heterogeneity and spatial distance between GPNRs in driving MLM turnover. Consequently, we advocate maintaining and increasing the diversity of (natural) habitats in GPNRs to protect giant panda's sympatric MLM diversity. The government should consider optimizing the GPNR network (e.g. incorporating multiple small GPNRs into one single large reserve) to capture the most turnover of MLMs, and the newly-established Giant Panda National Park is relevant to fulfilling this long-term goal.

Effects of microbial community and disease resistance against Vibrio splendidus of Yesso scallop (Patinopecten yessoensis) fed supplementary diets of tussah immunoreactive substances and antimicrobial peptides.

This study was conducted to investigate the effects of dietary supplementation of tussah immunoreactive substances (TIS) and antimicrobial peptides (AMPs) on microbial community and resistance against Vibrio splendidus of Yesso scallop Patinopecten yessoensis. Scallops were fed with the basal diets supplemented with TIS (T group), AMPs (A group), or both of the two (TA group). After the feeding trial, the microbial community changes were evaluated, and the challenge test with V. splendidus was conducted, as well as the immune parameters and digestive enzyme activities were determined. The results revealed that the TA group was more capable of modulating the bacterial community composition of scallops by increasing the potentially beneficial bacteria and suppressing the pathogenic microorganism during the feeding trial. After injection, the cumulative mortality rate in TA group was notably lower than others. In addition, the TA group showed better digestive and immune parameters involved in digestive capacity, phagocyte function, phosphatase-responsiveness, and oxidation resistance. These results collectively confirmed that dietary TIS and AMPs in diet could effectively modulate the microflora structure and improve disease resistance against V. splendidus of scallop, and the positive effects were more obvious when dietary supplementation of them in combination.

Ecological and evolutionary constraints on regional avifauna of passerines in China.

Strong correlations between species diversity and climate have been widely observed, but the mechanism underlying this relationship is unclear. Here, we explored the causes of the richness-climate relationships among passerine birds in China by integrating tropical conservatism and diversification rate hypotheses using path models. We found that assemblages with higher species richness southwest of the Salween-Mekong-Pearl River Divide are phylogenetically overdispersed and have shorter mean root distances (MRDs), while species-rich regions northeast of this divide (e.g., north Hengduan Mountains-south Qinling Mountains) are phylogenetically clustered and have longer MRDs. The results of the path analyses showed that the direct effect of climatic factors on species richness was stronger than their indirect effects on species richness via phylogenetic relatedness, indicating that neither tropical conservatism nor diversification rate hypotheses can well explain the richness-climate relationship among passerines in China. However, when path analyses were conducted within subregions separately, we found that the tropical conservatism hypothesis was well supported in the southwestern Salween-Mekong-Pearl River Divide, while the diversification rate hypothesis could explain the richness-climate relationship well in the northeastern divide. We conclude that the diversity patterns of passerines in different subregions of the Eastern Himalayas-Mountains of Southwest China may be shaped by different evolutionary processes related to geological and climatic histories, which explains why the tropical conservatism or diversification rate hypothesis alone cannot fully explain the richness-climate relationships.

Positive abundance-elevational range size relationship weakened from temperate to subtropical ecosystems.

Describing the patterns and revealing the underlying mechanisms responsible for variations in community structure remain a central focus in ecology. However, important gaps remain, including our understanding of species abundance. Most studies on abundance-based relationships are from either temperate ecosystems or tropical ecosystems, and few have explicitly tested abundance-based relationships across a temperate to tropical ecotone. Here, we use a comprehensive dataset of breeding birds across elevation spanning a temperate to subtropical gradient in the Himalayas-Hengduan Mountains of China to examine the relationship between species abundance and (a) elevational range size, (b) body size, (c) elevational range centre and (d) endemicity. We tested a priori predictions for abundance-elevational range size relationship, abundance-body size relationship and abundance-elevational range centre relationship, and explored how these relationships change along this temperate to subtropical mountain ecosystem. We found that species abundance was significantly positively correlated with elevational range size across the study sites, demonstrating the key importance of elevational range size towards species abundance. Body size and elevational range centre are weakly correlated with abundance. A novel finding of our study is that the abundance-elevational range size relationship gradually weakened from temperate to subtropical ecosystems, adding to a growing body of evidence suggesting that abundance-elevational range size tracks a temperate to tropical ecotone. Our study demonstrates that abundance range-size relationship can transition across ecotones where faunas of different evolutionary origins converge. Furthermore, measuring abundance relationships across different environmental variables at the same spatial scale with comparable biogeography is a key strategy that can reveal the underlying mechanisms behind abundance patterns.

Ring distribution patterns-diversification or speciation? Comparative phylogeography of two small mammals in the mountains surrounding the Sichuan Basin.

Studying the genetic differentiation in a unique geographical area contributes to understanding the process of speciation. Here, we explore the spatial genetic structure and underlying formation mechanism of two congeneric small mammal species (Apodemus draco and A. chevrieri), which are mainly distributed in the mountains surrounding the lowland Sichuan Basin, southwest China. We applied a set of comparative phylogeographical analyses to determine their genetic diversification patterns, combining mitochondrial (Cytb and COI) and nuclear (microsatellite loci) markers, with dense sampling throughout the range (411 A. draco from 21 sites and 191 A. chevrieri from 22 sites). Moreover, we performed three complementary statistical methods to investigate the correlation between genotype and geographical and environmental components, and predicted the potential suitable distributional range under the present and historical climate conditions. Our results suggest that both species have experienced allopatric differentiation and admixture in historical periods, resulting in a ring-shape diversification, under the barrier effect of the Sichuan Basin. We infer that the tectonic events of the Qinghai-Tibetan Plateau and climatic oscillations during the Quaternary played an important role on the genetic divergence of the two species by providing environmental heterogeneity and geographical variation. Our study reveals a case of two sympatric small mammals following a ring-shaped diversification pattern and provides insight into the process of differentiation.

A multi-faceted comparative perspective on elevational beta-diversity: the patterns and their causes.

The observed patterns and underlying mechanisms of elevational beta-diversity have been explored intensively, but multi-dimensional comparative studies remain scarce. Herein, across distinct beta-diversity components, dimensions and species groups, we designed a multi-faceted comparative framework aiming to reveal the general rules in the observed patterns and underlying causes of elevational beta-diversity. We have found that: first, the turnover process dominated altitudinal patterns of species beta-diversity (ßsim > ßsne), whereas the nestedness process appeared relatively more important for elevational trait dissimilarity (ßfuncsim < ßfuncsne); second, the taxonomic turnover was relative higher than its phylogenetic and functional analogues (ßsim > ßphylosim/ßfuncsim), conversely, nestedness-resultant trait dissimilarity tended to be higher than the taxonomic and phylogenetic measures (ßfuncsne > ßsne/ßphylosne); and third, as elevational distance increased, the contradicting dynamics of environmental filtering and limiting similarity have jointly led the elevational patterns of beta-diversity, especially at taxonomic dimension. Based on these findings, we infer that the species turnover among phylogenetic relatives sharing similar functional attributes appears to be the main cause of shaping the altitudinal patterns of multi-dimensional beta-diversity. Owing to the methodological limitation in the randomization approach, currently, it remains extremely challenging to distinguish the influence of the neutral process from the offset between opposing niche-based processes. Despite the complexities and uncertainties during species assembling, with a multi-dimensional comparative perspective, this work offers us several important commonalities of elevational beta-diversity dynamics.

Enzymatic Hydrolysis of Defatted Antheraea pernyi (Lepidoptera: Saturniidae) Pupa Protein by Combined Neutral Protease Yield Peptides With Antioxidant Activity.

In this study, peptides were prepared from defatted Antheraea pernyi (Lepidoptera: Saturniidae) pupa protein via hydrolysis with combined neutral proteases. Single-factor tests and response surface methodology (RSM) were used to determine the optimal hydrolysis condition suitable for industrial application. Optimal hydrolysis of the defatted pupa protein was found to occur at an enzyme concentration of 4.85 g/liter, a substrate concentration of 41 g/liter, a hydrolysis temperature of 55°C, and a hydrolysis time of 10 h and 40 min. Under these conditions, the predicted and actual rates of hydrolysis were 45.82% and 45.75%, respectively. Peptides with a molecular weight of less than 2,000 Da accounted for 90.5% of the total peptides generated. Some of the peptides were antioxidant peptides as revealed by sequencing and functional analysis. The antioxidant activity of the mixed peptides was subsequently confirmed by an antioxidant activity assay. The results showed that peptides with high antioxidant activity could be obtained from the hydrolysis of A. pernyi pupa protein.

Demographic History and Genomic Response to Environmental Changes in a Rapid Radiation of Wild Rats.

For organisms to survive and prosper in a harsh environment, particularly under rapid climate change, poses tremendous challenges. Recent studies have highlighted the continued loss of megafauna in terrestrial ecosystems and the subsequent surge of small mammals, such as rodents, bats, lagomorphs, and insectivores. However, the ecological partitioning of these animals will likely lead to large variation in their responses to environmental change. In the present study, we investigated the evolutionary history and genetic adaptations of white-bellied rats (Niviventer Marshall, 1976), which are widespread in the natural terrestrial ecosystems in Asia but also known as important zoonotic pathogen vectors and transmitters. The southeastern Qinghai-Tibet Plateau was inferred as the origin center of this genus, with parallel diversification in temperate and tropical niches. Demographic history analyses from mitochondrial and nuclear sequences of Niviventer demonstrated population size increases and range expansion for species in Southeast Asia, and habitat generalists elsewhere. Unexpectedly, population increases were seen in N. eha, which inhabits the highest elevation among Niviventer species. Genome scans of nuclear exons revealed that among the congeneric species, N. eha has the largest number of positively selected genes. Protein functions of these genes are mainly related to olfaction, taste, and tumor suppression. Extensive genetic modification presents a major strategy in response to global changes in these alpine species.

Enhanced protein phosphorylation in Apostichopus japonicus intestine triggered by tussah immunoreactive substances might be involved in the regulation of immune-related signaling pathways.

The sea cucumber Apostichopus japonicus is an economically important species owing to its high nutritive and medicinal value. In order to avoid the pollution resulting from the overuse of antibiotics in A. japonicus aquaculture, various immunostimulants have been used as an alternative to improve the efficiency of A. japonicus farming. Our previous proteomic investigation has shown that several proteins participating in the immune-related physiology of A. japonicus were differentially expressed in the intestinal tissue in response to tussah immunoreactive substances (TIS). This study further explored the immunostimulation mechanism of TIS in A. japonicus. Phosphoproteomics technology was used to investigate the effect of TIS on protein phosphorylation in the intestine of A. japonicus following feeding with a TIS-supplemented diet. A total of 213 unique phosphoproteins were detected from 225 unique phosphopeptides. KEGG pathway analysis showed that majority of the phosphoproteins are involved in endocytosis, carbon metabolism and spliceosome functional group. Sixteen of the phosphoproteins exhibited differential phosphorylation in response to TIS and 12 of these were found to associate with biological functions. Of these 12 phosphoproteins, eight exhibited enhanced phosphorylation while four displayed reduced phosphorylation. These 12 proteins were further analyzed and all were found to play a role in regulating some aspects of the immune system and the growth of sea cucumbers, especially in phagocytosis, energy metabolism and disease resistance. The findings of this study could therefore shed new light on the immune pathways of sea cucumber that are affected by TIS. This could help us to better understand the underlying mechanism linked to the immunoenhancement of A. japonicus in response to TIS, one that is associated with the change in protein phosphorylation.