Search

Chemical elements support various plant functions, and their reutilization is important for plant ecological adaptation. However, there is a lack of studies comparing the elemental concentration and their reutilization in floral petals and leaves of the same plant. To address this research gap, we conducted a comparative study across 38 plant species with diverse life forms in a common garden. Our investigation focused on the nutrient concentration of 10 elements in both petals and leaves and functional traits, including flower lifespan, dry mass per unit area, water concentration, and vein density. We have found that the elements of nitrogen (N), calcium (Ca), magnesium (Mg), iron (Fe), and manganese (Mn) were more abundant in leaves. In contrast, petals contained higher concentrations of phosphorus (P) and potassium (K). N, P, K, Ca, Mg, and sodium (Na) concentrations of petals were positively related to leaves. In herbaceous plants, their petals showed significant resorption of P and K, while N, P, and K were detected with significant resorption in leaves from all life forms. A positive correlation was found between the resorption of P in leaves and petals. From the perspective of the carbon economic spectrum, N and P showed a negative correlation with dry mass per unit area in leaves. Meanwhile, petal dry mass per area and floral longevity were significantly negatively correlated with P. Our findings elucidate the nutritional basis for the functional differentiation between petals and leaves., (© 2024 Scandinavian Plant Physiology Society.)

Following the invasion by the pine wood nematode (PWN) into north‐east China, a notable disparity in susceptibility was observed among Pinaceae species. Larix olgensis exhibited marked resilience and suffered minimal fatalities, while Pinus koraiensis experienced significant mortality due to PWN infection. Our research demonstrated that the PWNs in L. olgensis showed a 13.43% reduction in lipid content compared to P. koraiensis (p < 0.05), which was attributable to the accumulation of caffeic acid in L. olgensis. This reduction in lipid content was correlated with a decreased overwintering survival of PWNs. The diminished lipid reserves were associated with substantial stunting in PWNs, including reduced body length and maximum body width. The result suggests that lower lipid content is a major factor contributing to the lower overwintering survival rate of PWNs in L. olgensis induced by caffeic acid. Through verification tests, we concluded that the minimal fatalities observed in L. olgensis could be attributed to the reduced overwintering survival of PWNs, a consequence of caffeic acid‐induced stunting. This study provides valuable insights into PWN–host interactions and suggests that targeting caffeic acid biosynthesis pathways could be a potential strategy for managing PWN in forest ecosystems. [ABSTRACT FROM AUTHOR]

Soil stoichiometry is essential for determining the ecological functioning of terrestrial ecosystems. Understanding the stoichiometric relationships in mixed forests could enhance our knowledge of nutrient cycling. In a mixed forest zone of Larix principis-rupprechtii (LP) and Betula Platyphylla (BP) in Hebei China, we conducted a study at six different sites with varying levels of tree species mixing. The proportion of L. principis-rupprechtii ranged from 0% to 100%, with intermediate values of 8.58%, 10.44%, 18.62%, and 38.32%. We compared soil stoichiometry, including carbon (C), nitrogen (N), and phosphorus (P), as well as chemical and physical properties across these sites. Piecewise structural equation modeling (piecewiseSEM) was used to assess the direct and indirect links between key ecosystem factors and their effects on soil stoichiometry. In mixed forests, the soil exhibited higher contents of soil organic matter (SOM), total nitrogen (TN), and total phosphorus (TP) compared to those in pure LP forests. Additionally, the soil C: N ratio in the 8.58% and 18.62% mixed forests as well as pure BP forests was significantly higher than that in LP forests. Structural equation modeling (SEM) revealed that the contents and ratios of soil C, N, and P exhibited different responses to mixed species proportions. The effect of mixed species proportions on soil nutrients was predominantly indirect, mediated primarily by variations in soil-available nutrients and, to a lesser extent, by physical properties and pH. Specifically, an increase in the proportion of LP in mixed forests had a direct negative effect on soil-available nutrients, which in turn had a positive effect on the content of SOM, TN, and TP and their respective ratios. Based on these findings, we can predict that soil nutrient limitation becomes more pronounced with increasing proportions of Larix principis-rupprechtii in the mixed forest. Our results emphasized the significance of changes in mixed species proportions on soil stoichiometry, providing valuable references for the sustainable development of forests. [ABSTRACT FROM AUTHOR]

In the strategic orientation of promoting high-quality development of metropolitan areas, ecological space is not only the core carrier for maintaining regional ecological balance and harmony but also a key element in shaping the scientific layout of metropolitan areas and promoting harmonious coexistence between cities and nature. This paper takes the Chang-Zhu-Tan metropolitan area as the research object and identifies and classifies ecological space based on the "Production-Life-Ecology" concept, extracts core ecological source areas through the minimum resistance model, and generates ecological resistance surfaces. Then, three types of ecological space corridors are constructed by using the MCR gravity model. This study finds that the ecological space in the Chang-Zhu-Tan metropolitan area is seriously fragmented, the number of corridors is insufficient, and the spatial configuration of the "Production-Life-Ecology" is imbalanced in the region and proposes optimization models and strategies in combination with the spatial network approach to identify and classify ecological space patterns for the metropolitan area. Accordingly, the study proposes optimization models and strategies based on the spatial network approach to provide theoretical support and practical guidance for the ecological spatial pattern and sustainable development of the metropolitan area. [ABSTRACT FROM AUTHOR]

New continuous-time models and statistical methods have been developed to estimate some sets related to animal movement, such as the home-range and the core-area among others, when the information of the trajectory is provided by a GPS. Because data transfer costs and GPS battery life are practical constraints, the experimental designer must make critical sampling decisions to maximise information. We introduce the on–off sampling scheme, where the GPS is alternately on and off. This scheme is already used in practice but with insufficient statistical theoretical support. We prove the consistency of home-range estimators with an underlying reflected diffusion model under this sampling method. The same rate of convergence is achieved as in the case where the GPS is always on for the whole experiment. This is illustrated by a simulation study and real data. We also provide estimators of the stationary distribution, its level sets and the drift function. [ABSTRACT FROM AUTHOR]

Assessing the functional traits and ecological stoichiometric characteristics of dominant species across different life forms within plant communities in karst environments and investigating the inherent connection between them can provide insights into how species adjust their functional attributes in response to habitat heterogeneity. This approach offers a more comprehensive understanding of ecosystem processes and functions in contrast to examination of the taxonomic diversity of species. This study examines the relationship between the functional characteristics of dominant species in plant communities of various life forms in karst environments, focusing on deciduous leaf–soil ecological stoichiometry. The investigation relies on community science surveys, as well as the determination and calculation of plant functional traits and ecological stoichiometries, in plant communities of various life forms in Guizhou (a province of China). The findings of our study revealed considerable variability in the functional trait characteristics of dominant species across different plant-community life forms. Specifically, strong positive correlations were observed among plant height (PLH), leaf area (LA), leaf dry matter content (LDMC), and specific leaf area (SLA) in the dominant species. Additionally, our results indicated no significant differences in leaf ecological stoichiometry among different life forms. However, we did observe significant differences and strong positive correlations between soil N:P, withered material C:N, and apomictic C:P. Furthermore, our study found that plant height (PLH), leaf area (LA), and specific leaf area (SLA) were particularly sensitive to the ecological stoichiometry of soil and apomixis. The results of our study suggest that the functional traits of diverse plant-community life forms in karst regions are capable of adapting to environmental changes through various expressions and survival strategies. The development of various plant-community life forms in karst areas is particularly vulnerable to phosphorus limitation, and the potential for litter decomposition and soil nutrient mineralization is comparatively weaker. The functional traits of various plant-community life forms in karst regions exhibit greater sensitivity to both the soil's C:N ratio and the C:N ratio of apomictic material. Habitat variations may influence the ecological stoichiometric characteristics of the plant leaf–apomictic soil continuum. [ABSTRACT FROM AUTHOR]

The interspecific relationship between functional traits and tree seedling performance can be inconsistent, potentially due to site-to-site or microsite variation in environmental conditions. Studies of seedling traits and performance often focus on above-ground traits, despite the importance of below-ground resource acquisition and biomass allocation to above versus below-ground functions. Here we investigate how varying environmental conditions across sites induce intraspecific variation in organ-level (above-ground, below-ground) and biomass allocation traits, affecting interspecific relationships between these traits and seedling performance. We analyzed trait expression for 12 organ-level and three allocation traits and their relationships with height growth (1716 seedlings) and mortality (15,862 seedlings) for 26 tree species across three sites along a forest successional gradient in Costa Rica. We found significant intraspecific differences across sites in all allocation traits, but only in three of seven above-ground and three of five below-ground organ-level traits. Allocation traits were better predictors of seedling performance than organ-level traits. Relationships between allocation traits and both growth and mortality varied among all sites, but for organ-level traits, only relationships with growth varied among sites. These results underscore that biomass allocation plays a key role in the earliest life stages of trees and that site-specific conditions can influence how functional traits mediate seedling establishment during succession. [ABSTRACT FROM AUTHOR]

Drylands cover more than 40% of global land surface and will continue to expand by 10% at the end of this century. Understanding the resistance mechanisms of native species is of particular importance for vegetation restoration and management in drylands. In the present study, metabolome of a dominant shrub Campylotropis polyantha in a dry-hot valley were investigated. Compared to plants grown at the wetter site, C. polyantha tended to slow down carbon (C) assimilation to prevent water loss concurrent with low foliar reactive oxygen species and sugar concentrations at the drier and hotter site. Nitrogen (N) assimilation and turn over were stimulated under stressful conditions and higher leaf N content was kept at the expense of root N pools. At the drier site, roots contained more water but less N compounds derived from the citric acid cycle. The site had little effect on metabolites partitioning between leaves and roots. Generally, roots contained more C but less N. Aromatic compounds were differently impacted by site conditions. The present study, for the first time, uncovers the apparent metabolic adaptations of C. polyantha to hostile dryland conditions. However, due to the limited number of samples, we are cautious about drawing general conclusions regarding the resistance mechanisms. Further studies with a broader spatial range and larger time scale are therefore recommended to provide more robust information for vegetation restoration and management in dryland areas under a changing climate. [ABSTRACT FROM AUTHOR]

Simple Summary: We employed environmental DNA (eDNA) metabarcoding to assess fish biodiversity in three river basins in Beijing. Across all the 67 sampling sites, we identified a total of 60 fish taxa, with an average of 33.0 taxa per site. Of these, 20 taxa (33.3%) were non-native, distributed across 11 orders, 13 families, and 17 genera. We observed geographical homogenization among the native fish species, whereas non-native taxa exhibited varied geographical distributions—some taxa were widely distributed across river basins while others were restricted to specific sites or basins. Simple linear regression analyses revealed positive correlations between the number of taxa and species richness for both native and non-native taxa. Co-occurrence network analysis indicated positive relationships among both native and non-native taxa, with only two negative relationships involving one native and two non-native fish taxa. Rapid urbanization and its associated human activities have facilitated the colonization and spread of non-native species, rendering urban ecosystems, particularly in megacities such as Beijing, highly susceptible to biological invasions. This study employed environmental DNA (eDNA) metabarcoding to evaluate the biodiversity and geographical distribution of non-native fish, as well as their interactions with native fish species, across three river basins in Beijing pertaining to the Daqing River, the North Canal, and the Ji Canal. Across all the 67 sampling sites, we identified 60 fish taxa, representing 11 orders, 23 families, and 40 genera, with an average of 33.0 taxa per site. Of these, 40 taxa were native, accounting for only 47.1% of the historically recorded native fish species. Additionally, we detected 20 non-native fish taxa, spanning 11 orders, 13 families, and 17 genera. Native fish exhibited geographical homogenization across the basins, while non-native taxa displayed varied geographical distributions. Non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) revealed no significant variation in the non-native communities across the river basins. Although most of the non-native taxa were widespread, some were restricted to specific sites or basins. The North Canal exhibited significantly lower non-native biodiversity compared with the Ji Canal across all alpha diversity indices. Simple linear regression analyses indicated positive correlations between the number of taxa and species richness for both native and non-native taxa. Interestingly, species co-occurrence analyses revealed predominantly positive interactions among both native and non-native species pairs, with only two negative relationships involving one native and two non-native taxa. This study provides insights into the biodiversity and geographical distribution of non-native fish in Beijing and establishes a baseline for future biomonitoring and conservation efforts. The findings underscore the need for further investigation into the mechanisms and dynamics of biological invasions within urban environments in Beijing. [ABSTRACT FROM AUTHOR]

For many years, Pakistan's economic progress and development have primarily depended on agriculture. However, widespread rural poverty impairs agricultural productivity, which worsens the outlook for growth for both the agricultural sector and the nation as a whole. Raising farmers' incomes through rural development is a key component of agricultural reform, and the prime objective of this study is to identify how government policies and foreign aid affect Pakistan's degree of rural poverty. This research aims to check the mediating role of rural development for the relationship of foreign aid, agricultural production, and corporate social responsibility with poverty reduction. This research also examines the moderating role of government support in the relationship of rural development with poverty reduction. In this regard, the current study proposes four hypotheses of direct relationships, three mediating relationships, and one moderating relationship. The population comprised farmers. The sample size of 119 was determined using G*Power with medium effect size settings, ensuring a robust representation of the target group. To gather primary data, a close-ended structured questionnaire was administered, employing a 7-point Likert scale to gather respondents' opinions. This study investigates the Punjab province's agricultural landscape from a quantitative perspective, using convenient sampling to identify the characteristics that contribute to reducing poverty, and was conducted from January to December 2023. Analytical procedures utilizing Smart PLS 4.0.9.6 for SEM testing reveal that all proposed hypotheses, including direct, mediating, and moderating, are accepted. The main results show that rural development significantly mediates the relationship between foreign aid, agricultural production, and corporate social responsibility with poverty reduction. Furthermore, government support positively moderates the relationship between rural development and poverty reduction. The findings underscore the significance of rural development, coupled with government support, as a pivotal factor in effectively reducing poverty in Pakistan's economic landscape. [ABSTRACT FROM AUTHOR]

Ecosystems function in a series of feedback loops that can change or maintain vegetation structure. Vegetation structure influences the ecological niche space available to animals, shaping many aspects of behaviour and reproduction. In turn, animals perform ecological functions that shape vegetation structure. However, most studies concerning three-dimensional vegetation structure and animal ecology consider only a single direction of this relationship. Here, we review these separate lines of research and integrate them into a unified concept that describes a feedback mechanism. We also show how remote sensing and animal tracking technologies are now available at the global scale to describe feedback loops and their consequences for ecosystem functioning. An improved understanding of how animals interact with vegetation structure in feedback loops is needed to conserve ecosystems that face major disruptions in response to climate and land-use change., (© 2023 The Authors. Ecology Letters published by John Wiley & Sons Ltd.)

Land cover analysis is a key method used to understand past land use patterns and explore the driving forces and processes behind them. This study focuses on land cover in 18 counties and cities of Hainan Island, delving into the driving factors of land cover in specific areas of Hainan Island, including the southern, northern, eastern, western, inland, and coastal regions. The effects of socio-economic factors, landscape pattern, and urban functional units on land cover are considered, and three hypotheses are proposed to explain the observed trends. The results indicate that house prices are positively correlated with construction area, woodlands land, and urban green space, thereby supporting the luxury effect hypothesis on land cover. In addition, construction age was negatively correlated with the woodlands area, confirming the role of the inverse legacy effect hypothesis in land cover. Other relationships between urban functional units and land cover emphasized the importance of the land use hypothesis in land cover planning. These results will help decision-makers and managers to better understand the current drivers of land cover, allowing for a more scientific basis when planning and managing urban land cover. [ABSTRACT FROM AUTHOR]

Simple Summary: The behaviours and needs of nocturnal animals can be overlooked by humans, potentially because of our poor night vision and diurnal waking hours. Despite certain challenges in studying many nocturnal animals, appropriate provisions for their welfare should be supported in both wild and managed environments. To investigate this issue and explore ways to offer technology-enhanced welfare, husbandry practices and enrichment opportunities for nocturnal species, we conducted a multidisciplinary workshop (Moon Jam). During the event, species experts provided animal welfare briefs that related to specific challenges for nocturnal animals in different contexts. Teams of participants addressed these challenges in collaborative design sessions, producing a collection of hand-crafted models to share their ideas. An important aspect of the workshop was to be inclusive of all the stakeholders involved, including zoo management teams, animal stewards and zoo visitors, as well as the individual species. In this paper, we present our reflections on managed nocturnal animal welfare, framing these within current practices and Moon Jam workshop outputs. We contribute a set of guidelines for those involved with caring for zoo-housed nocturnal species, emphasizing the provision of technology-enhanced husbandry and enrichment opportunities. This paper addresses the potential for technology to support husbandry and enrichment opportunities that enhance the welfare of zoo and sanctuary-housed nocturnal and crepuscular species. This topic was investigated through the medium of a multidisciplinary workshop (Moon Jam) that brought together species experts, zoo designers, Animal-Computer Interaction researchers and post-graduate students in collaborative discussions and design sessions. We explain the context through an examination of existing research and current practices, and report on specific challenges raised and addressed during the Moon Jam, highlighting and discussing key themes that emerged. Finally, we offer a set of guidelines to support the integration of technology into the design of animal husbandry and enrichment that support wellbeing, to advance the best practices in keeping and managing nocturnal and crepuscular animals. [ABSTRACT FROM AUTHOR]

Simple Summary: Individual quantity is the guarantee of the long-term survival of a population. Currently, approximately 70% of the 33 local populations of wild giant pandas (Aliuropoda melanoleuca) face the risk of extinction. We studied four typical populations, from Tangjiahe, Wanglang, Liziping, and Daxiangling, and attempted to translocate individuals from large populations to enhance the viability of small populations. Our results validated a classic conclusion that the introduction of individuals from Tangjiahe and Wanglang significantly improved the genetic diversity in Liziping and Daxiangling. To ensure the long-term survival of two small populations over the next 100 years, we have devised multiple specific strategies for individual introduction. Our research has certain value for the rejuvenation of small populations of giant pandas, and we hope to provide a reference for the protection of endangered animals such as giant pandas. Currently, nearly 70% of giant panda populations are facing survival challenges. The introduction of wild individuals can bring vitality to them. To explore this possibility, we hypothetically introduced giant pandas from Tangjiahe and Wanglang into Liziping and Daxiangling Nature Reserves. We collected feces from these areas and analyzed the genetic diversity and population viability before and after introduction using nine microsatellite loci. The results showed the genetic level and viability of the large populations were better than the small populations. We investigated the effects of time intervals (2a, 5a, and 10a; year: a) and gender combinations (female: F; male: M) on the rejuvenation of small populations. Finally, five introduction plans (1F/2a, 2F/5a, 1F1M/5a, 3F/10a, and 2F1M/10a) were obtained to make Liziping meet the long-term survival standard after 100 years, and six plans (1F/2a, 2F/5a, 1F1M/5a, 4F/10a, 3F1M/10a, and 2F2M/10a) were obtained in Daxiangling. The more females were introduced, the greater the impact on the large populations. After introducing individuals, the number of alleles and expected heterozygosity of the Liziping population are at least 6.667 and 0.688, and for the Daxiangling population, they are 7.111 and 0.734, respectively. Our study provides theoretical support for the translocation of giant pandas, a reference for the restoration of other endangered species worldwide. [ABSTRACT FROM AUTHOR]

Human interactions have led to the emergence of a higher complexity of urban metabolic networks; hence, traditional natural- or agriculture-oriented biogeochemical models might not be transferred well to urban environments. Increasingly serious environmental problems require the development of new concepts and models. Here, we propose a basic paradigm for urban–rural complex nitrogen (N) metabolic network reconstruction (NMNR) by introducing new concepts and methodologies from systems biology at the molecular scale, analyzing both local and global structural properties and exploring optimization and regulation methods. Using the Great Hangzhou Areas System (GHA) as a case study, we revealed that pathway fluxes follow a power law distribution, which indicates that human-dominated pathways constitute the principal part of the functions of the whole network. However, only 1.16% of the effective cycling pathways and an average hamming distance of only 5.23 between the main pathways indicate that the network lacks diverse pathways and feedback loops, which could lead to low robustness. Furthermore, more than half of the N fluxes did not pass through core metabolism, causing waste and pollution. We also provided strategies to design network structures and regulate system function: improving robustness and reducing pollution by referring to the characteristics of biochemical metabolic networks (e.g., the bow-tie structure). This method can be used to replace the trial-and-error method in system regulation and design. By decomposing the GHA N metabolic network into 4398 metabolic pathways and the corresponding fluxes with a power law distribution, NMNR helps us quantify the vulnerability in the current urban nitrogen cycle. The basic ideas and methodology in NMNR can be applied to coupled human and natural systems to advance global sustainable development studies, and they can also extend systems biology from the molecule to complex ecosystems and lead to the development of multi-scale unified theory in systems biology. [ABSTRACT FROM AUTHOR]

The advent of the digital era has catalyzed transformative shifts in educational paradigms, seamlessly integrating sustainable education with innovative pedagogical approaches that cater to a broader spectrum of learners and educators. As the academic landscape evolves into an information-dense environment, traditional models of one-on-one feedback often fall short, resulting in delays and a lack of diverse intellectual engagement. This shift underscores the growing importance of peer feedback and asynchronous post-lesson feedback mechanisms, which have emerged as vital, process-oriented educational activities. Such mechanisms not only address the immediacy and diversity of feedback but also foster a sustainable, collaborative, and engaging learning environment that bolsters student autonomy and interaction. This study conducts a mapping review and synthesis of the literature on peer interaction, assessment, and participatory innovations in online and mobile learning within higher education, covering the period from 1993 to 2022. By employing topic modeling techniques to analyze a corpus of 485 articles, the literature was initially segmented into 19 distinct issues. These were subsequently consolidated into three major thematic models, thereby highlighting significant themes, research focal points, and prospective trends. This analytical process not only enriches the understanding of peer dynamics in digital learning settings but also integrates sustainable educational practices by promoting resource efficiency and inclusivity. The findings serve as a robust reference for future researchers aiming to explore the intersections of technology, peer interaction, and sustainability in educational settings. [ABSTRACT FROM AUTHOR]

Phosphorus (P) deficiency is one of the main reasons limiting plant production of Brassica napus L. Exploring the dynamics of leaf intracellular substances and the correlations with photosynthesis and growth helps to understand the response mechanisms of B. napus L. to P deficiency. This study conducted experiments on B. napus L. plants by measuring the leaf electrophysiological parameters, leaf structure, elastic modulus (Em), photosynthesis, and growth indices under different P treatment conditions. The dynamics of leaf intracellular water and nutrients of B. napus L. were calculated and analyzed by using the electrophysiological parameters, and the plant tolerance threshold to low-P stress was discovered. The results indicated that the status of the leaf intracellular water and nutrients remained stable when the P concentration was not lower than 0.250 mmol·L−1, but maximized the photosynthesis and growth at a P level of 0.250 mmol·L−1. The 0.125 mmol·L−1 P concentration significantly decreased the mesophyll cell volume, and the palisade–sponge ratio and tightness degree of leaf tissue structure were remarkably increased. This led to an increase in cell elastic modulus, and significantly improved the water retention capacity of leaf cells. At the same time, the intracellular water use efficiency and total nutrient transport capacity of leaves remained stable. As a result, the photosynthesis and growth of plants were maintained at the same level as that of the control group. However, photosynthesis and growth were clearly inhibited with a further decrease in P concentration. Therefore, 0.125 mmol·L−1 was the tolerance threshold of B. napus L. to low P. With the help of electrophysiological information, the effects of the dynamics of intracellular substances on photosynthesis and growth of B. napus L. under low-P stress can be investigated, and the plant's adaptive response can be revealed. However, the findings of the current hydroponic study are not directly applicable to field conditions with naturally P-deficient soils. [ABSTRACT FROM AUTHOR]

Ecological stoichiometry is essential for investigating biogeochemical cycling in an ecosystem. Thinning, a management practice that closely mimics natural processes, significantly influences stand structure and microclimate, thereby affecting nutrient cycling. Nonetheless, seasonal variations in ecological stoichiometry across the leaf-litter-soil continuum under different thinning regimes remain inadequately understood. In this study, we evaluated three thinning methods (strip filling (SF), ecological thinning (ET), and forest gap (FG)) to investigate the stoichiometric characteristics of Cupressus funebris Endl (C. funebris). within the leaf-litter-soil system in Southwest China. The samples were collected during four distinct seasonal periods: early dry season (January–March, EDS), late dry season (April–June, LDS), early wet season (July–September, EWS), and late wet season (October–December, LWS). The results indicated that the (1) carbon (C), nitrogen (N), and phosphorus (P) contents and C:N:P ratio in leaves, litter, and soils varied widely and were strongly influenced by thinning method and season. (2) In the EDS, the soil TP content significantly decreased by 36.9% (p < 0.05), 41.67% (p < 0.05), and 17.9% (p < 0.05) under ET, FG, and SF treatments compared to the pure C. funebris forest (PC). (3) Compared to the PC, the leaf organic C content under ET significantly increased by 6.6% (EDS, p < 0.05), 8.4% (EWS, p < 0.05), 24.8% (LDS, p < 0.05), and 11.5% (EWS, p < 0.05). (4) Under identical thinning methods, the contents of litter C, litter N, litter P, leaf N, and leaf P (excluding litter C in SF) were found to be highest in the LWS. Conversely, the ratios of litter C:N, litter C:P, litter N:P, leaf C:N, leaf C:P, leaf N:P, soil N:P, and soil C:P (except for the ratios of litter N:P in ET and FG) were observed to be lowest in the LWS. (5) Season and thinning method significantly affected the internal stability of P stoichiometric homeostasis, and litter P under ET (EWS) was categorized as "plastic" (p < 0.1, 0.75 < H). (6) The results of the structural equation model show that the thinning method has a direct positive impact on leaf C, N, and P contents and a direct negative impact on the chemical stoichiometry of leaves and soil. Season has a direct positive impact on soil C, N, and P contents, as well as on the chemical stoichiometry of litter and leaves; however, they have a direct negative impact on leaf C, N, and P contents. This study contributes to C. funebris plantation management and provides basic information for global stoichiometric analysis. [ABSTRACT FROM AUTHOR]

The concentrations and ratios of plants C, N, and P serve as important indicators of ecological processes. However, how plant and soil C:N:P relationships and ratios change with forest stand types remain unclear. Here, we analyzed the ecological stoichiometric characteristics by measuring leaf and soil organic C, total N, and P contents in four stand types in Liaocheng, including Populus tomentosa Carrière pure forest, Populus tomentosa–Robinia pseudoacacia L. mixture forests, Platanus orientalis L. pure forest, and Salix matsudana Koidz. pure forests. We find that (1) The N and P leaf contents varied significantly across the four forest stands, with Populus tomentosa–Robinia pseudoacacia mixture forests having higher P levels. Platanus orientalis pure forests had lower C and N but higher P levels compared to others. (2) Uncoupled cycling of P in leaf–soil systems due to environmental influences, but C and N elements showed coupled cycles in some forest stands. (3) Populus tomentosa pure forests, Populus tomentosa–Robinia pseudoacacia mixture forests, Platanus orientalis pure forests are limited by N, and Salix matsudana pure forests are limited by both N and P elements. Overall, environmental factors, in addition to species variations, influence the C, N, P, and C:N:P ratios in leaves and soils of different forest stand types. Enhancing conservation and efficient use of N and P elements is crucial for sustainable plantation forest management to promote optimal growth in the region. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore the inherent links between elemental cycling in Rosa roxburghii Tratt litter and soil, as well as their coupled relationships, within barren soil environments typical of karst rocky desertification regions in Guizhou Province. Ecological stoichiometric methods were used to systematically analyze the nutrient concentrations of C, N, P, and K and their stoichiometry in the litter and soil of Rosa roxburghii, with a focus on the impacts of seasonal variations and rocky desertification regions. High C and K levels and low N and P levels are observed in the litter, whereas the soil has lower concentrations of C, N, P, and K, with nutrient replenishment priorities of N > P > K > C. Strong positive correlations are found among the C/N, C/P, and N/K stoichiometric ratios in both the litter and the soil. Furthermore, nutrient concentrations and stoichiometric ratios vary significantly by season. Seasonal variations influence nutrient concentrations, with notable increases in litter P and K levels and in soil N and P levels in September compared with March. Seasonal variations influence the stoichiometric ratios of C/N, C/P, and N/K in litter and soil, contributing to elemental balance and ecosystem stability. Moreover, significant variations in nutrient contents and stoichiometric ratios are observed across distinct rocky desertification grades. Nonrocky desertified areas present elevated P and K contents in litter, whereas light desertified areas present increased C and N concentrations. Moderately desertified areas presented increased soil P and K concentrations, whereas severely desertified areas presented the highest N levels. These discernible trends in nutrient profiles highlight the synergistic impacts of soil nutrient inadequacy and plant utilization strategies. These findings contribute to a better understanding of element cycling mechanisms in Rosa roxburghii woodland ecosystems, offering valuable information for sustainable forest management practices. [ABSTRACT FROM AUTHOR]

Headwater streams are reliant on riparian tree leaf litterfall to fuel brown food webs. Terrestrial agents like herbivores and contaminants can alter plant growth, litter production, litter quality, and the timing of litterfall into streams, influencing aspects of the brown food web. At Mount St. Helens (USA), early successional streams are developing willow (Salix sitchensis) riparian zones. The willows are attacked by stem-boring herbivores, altering litter quality and the timing of litterfall. Within a established experimental plots, willows (male and female plants) were protected from herbivores using insecticides and provided with experimental additions of nitrogen. This enabled us to test the interacting influences of herbivores, nitrogen deposition, and willow sex on leaf litter quality, aquatic litter decomposition, and microbial and invertebrate detritivores. We found weak litter quality effects (higher N and lower C:N) for the herbivore treatment, but no effect of nitrogen deposition. Although litter decomposition rates were not strongly affected by litter treatments, detritivore communities were altered by all treatments. Nitrogen deposition resulted in decreased bacterial richness and decreased fungal diversity in-stream. Aquatic macroinvertebrate communities were influenced by the interacting effects of herbivory and nitrogen addition, with abundances highest in herbivore litter with the greatest N addition. Shredders showed the highest abundance in male, herbivore-attacked litter. The establishment of riparian willows along early successional streams and their interacting effects with herbivores and nitrogen deposition may be influencing detritivore community assembly at Mount St. Helens. More broadly, global changes like increased wet and dry N deposition and expanded ranges of key herbivores might influence tree litter decomposition in many ecosystems. [ABSTRACT FROM AUTHOR]

The morphological adjustments of euhalophytes are well-known to be influenced by the soil-soluble salt variation; however, whether and how these changes in morphological traits alter the biomass allocation pattern remains unclear, especially under different NaCl levels. Therefore, an allometric analysis was applied to investigate the biomass allocation pattern and morphological plasticity, and the carbon (C), nitrogen (N), and phosphorus (P) stoichiometric characteristics of the euhalophyte Suaeda Salsa (S. salsa) at the four soil-soluble salt levels of no salt (NS), light salt (LS), moderate salt (MS), and heavy salt (HS). The results showed that soil-soluble salts significantly change the biomass allocation to the stems and leaves (p < 0.05). With the growth of S. salsa, the NS treatment produced a downward leaf mass ratio (LMR) and upward stem mass ratio (SMR); this finding was completely different from that for the salt treatments. When S. salsa was harvested on the 100th day, the HS treatment had the highest LMR (61%) and the lowest SMR (31%), while the NS treatment was the opposite, with an LMR of 44% and an SMR of 50%. Meanwhile, the soil-soluble salt reshaped the morphological characteristics of S. salsa (e.g., root length, plant height, basal stem diameter, and leaf succulence). Combined with the stoichiometric characteristics, N uptake restriction under salt stress is a vital reason for inhibited stem growth. Although the NS treatment had the highest biomass (48.65 g root box−1), the LS treatment had the highest salt absorption (3.73 g root box−1). In conclusion, S. salsa can change its biomass allocation pattern through morphological adjustments to adapt to different saline–alkali habitats. Moreover, it has an optimal biological desalting effect in lightly saline soil dominated by NaCl. [ABSTRACT FROM AUTHOR]

Vegetation dynamics result from the interaction between human activities and climate change. Numerous studies have investigated the contributions of human activities and climate change to vegetation cover dynamics using statistical methods. However, these studies have not focused much on the spatially non-stationary effects of human activities on vegetation cover changes and future trends. Taking the Three Gorges Reservoir (TGR) area as the case study area, it was divided into 32 combinations by considering the spatially varying effects of five factors related to human activity and climate change, including gross domestic product (GDP), population, land use change, precipitation, and temperature. Regression in terms of pixels was then performed for each combination at the pixel scale. The result showed that from 2001 to 2020, the annual average normalized digital vegetation index (NDVI) in the TGR area exhibited an upward trend (slope = 0.0051, p < 0.01), with the mean NDVI increasing from 0.53 to 0.64. Compared with the regression with climate variables, the proposed model improved the R 2 value from 0.2567 to 0.6484, with the p-value in the t-test reduced from 0.2579 to 0.0056. It indicated that changes in vegetation were dominated by human activities and climate change in 48.77% and 3.19% of the TGR area, respectively, and 43.70% of the vegetation coverage was dominated by both human activities and climate change. This study also predicted the future NDVI according to the shared socioeconomic pathways (SSPs) and representative concentration pathway (RCP) scenarios provided by the Intergovernmental Panel on Climate Change. It suggests that, assuming future regional policies are the same as the historical policies in the TGR, the SSP5–8.5 scenario would have the highest and fastest growth in average NDVI, with the average NDVI increasing from 0.68 to 0.89, because of the large increase in the GDP, lower population in this scenario, and adequate hydrothermal conditions. [ABSTRACT FROM AUTHOR]

Understanding the ecological dynamics of forest ecosystems, particularly the influence of forest age structure on soil carbon (C), nitrogen (N), and phosphorus (P) content, is crucial for effective forest management and conservation. This study aimed to investigate the nutrient storage and ecological stoichiometry across different-aged stands of Chinese fir forests. Soil samples were collected from various depths (0–15 cm, 15–30 cm, and 30–45 cm) across four age groups of Chinese fir forests (8-year-old, 12-year-old, 20-year-old, and 25-year-old) in the Forest Farm, Pingjiang County, China. Soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) were measured, and their stoichiometries were calculated. The results showed that both individual tree biomass and stand biomass, along with SOC, TN, and TP content, increased with stand age, highlighting the significant importance of stand age on biomass production and nutrient accumulation in forests. Specifically, soil C and P contents significantly increased as the forest aged, while variation in N content was relatively minor. Soil C/N and C/P ratios exhibited variation corresponding to forest age, suggesting alterations in the ecological stoichiometry characteristics of the forests over time. These findings are crucial for understanding the dynamics of ecosystem functioning and nutrient cycling within Chinese fir forests and provide a solid scientific basis for the effective management and conservation of these vital forest ecosystems. [ABSTRACT FROM AUTHOR]

The Asian tapir Tapirus indicus is the only tapir species in Southeast Asia. It is declining across its range and is categorized as Endangered on the IUCN Red List. The forests of Sumatra are critical to Asian tapir conservation as they contain some of the last remaining populations of the species, yet conservation efforts are hindered by a lack of information on habitat suitability. We collated camera-trap data from nine landscapes across 69,500 km2 of Sumatran rainforest to help predict suitable habitat for Asian tapirs on the island. Predictions from Bayesian occupancy models demonstrated that tapir occupancy was greatest in forests below 600 m elevation and exclusively in forests with high aboveground biomass. Forests around the Barisan Mountains on the west of Sumatra provide the most suitable habitat for the species. Only 36% of the most critical habitat (i.e. 80th percentile of predicted occupancy values, or above) for tapirs is formally protected for conservation, with much of the remainder found in forests allocated to watershed protection (35%) or logging (23%). We highlight several key areas in Sumatra where tapir conservation could be bolstered, such as by leveraging existing conservation efforts for other charismatic flagships species on the island. [ABSTRACT FROM AUTHOR]

Stoichiometric homeostasis is an important mechanism in maintaining ecosystem structure, function, and stability. Phyllostachys edulis (moso bamboo) is a typical clone plant, forming pure bamboo forests or bamboo–wood mixed forests by expanding rhizomes around. Studying the stoichiometric homeostasis characteristics of moso bamboo at different ages after expansion contributes to a deeper understanding of the stability of bamboo forest ecosystems, and is of great significance for expanding the research scope of ecological stoichiometry. Based on the stoichiometric internal stability theory, the nitrogen (N) and phosphorus (P) elements in the soil and plants of typical moso bamboo forests in Tianbaoyan National Nature Reserve of Fujian Province were determined, and the internal stability index (H) of bamboo leaves of different ages (I-du, II-du, III-du, and IV-du bamboos) was calculated. The results showed that the dependence of moso bamboo on soil nutrients and the ability of moso bamboo to regulate nutrient elements were both significantly affected by the plant's age. Under the condition of the same soil nutrients (N, P), the content of N and P in bamboo leaves decreased significantly with the increase in bamboo age. The limiting effect of phosphorus on the growth and development of moso bamboo was greater than that of nitrogen, and the limiting effect of phosphorus on aged bamboo was greater than that of young bamboo. The stoichiometric internal stability index of N and P in bamboo leaves is HN:P > HN > HP, which means that the internal stability of moso bamboo is closely related to the limiting elements. Therefore, the regulation ability of the internal stability of moso bamboo of different ages makes it grow well in the changeable environment, has stronger adaptability and competitiveness, and the leaf internal stability of I-du bamboo was higher than that of other ages, which may be one of the reasons for its successful expansion to form a stable bamboo stand structure. [ABSTRACT FROM AUTHOR]

Understanding the determinants of the availability and spatial fairness of street greenery is crucial for improving urban green spaces and addressing green justice concerns. While previous studies have mainly examined factors influencing street greenery from an aerial perspective, there has been limited investigation into determinants at eye level, which more closely aligns with people's actual encounters with green spaces. To address this, the Green View Index (GVI) and Gini coefficient were used to assess the availability and spatial fairness of street greenery from a pedestrian's perspective, using Baidu Street View (BSV) images across 49 subdistricts in Changchun City, China. A dataset of 33,786 BSV images from 1877 sites was compiled. Additionally, 21 explanatory factors were collected and divided into three groups: socioeconomic, biogeographic, and landscape patterns. The Boosted Regression Tree (BRT) method was employed to assess the relative influence and marginal effects of these factors on street greenery's availability and spatial fairness. The results showed that street greenery's availability and spatial fairness are predominantly influenced by landscape patterns. Specifically, the percentage of landscape and edge density emerged as the most significant factors, exhibiting a threshold effect on the availability and fairness of street greenery. Increasing the proportion and complexity of urban green spaces can efficiently enhance the availability and spatial fairness of street greenery. These findings lay a new foundation for urban green infrastructure management. [ABSTRACT FROM AUTHOR]

Caribou (Rangifer tarandus) undergo exceptionally large, annual synchronized migrations of thousands of kilometers, triggered by their shared environmental stimuli. The proximate triggers of those migrations remain mysterious, though snow characteristics play an important role due to their influence on the mechanics of locomotion. We investigate whether the snow melt–refreeze status relates to caribou movement, using previously collected Global Positioning System (GPS) caribou collar data. We analyzed 117 individual female caribou with >30,000 observations between 2007 and 2016 from the Bathurst herd in Northern Canada. We used a hierarchical model to estimate the beginning, duration, and end of spring migration and compared these statistics against snow pack melt characteristics derived from 37 GHz vertically polarized (37V GHz) Calibrated Enhanced-Resolution Brightness Temperatures (CETB) at 3.125 km resolution. The timing of migration for Bathurst caribou generally tracked the snowmelt onset. The start of migration was closely linked to the main melt onset in the wintering areas, occurring on average 2.6 days later (range −1.9 to 8.4, se 0.28, n = 10). The weighted linear regression was also highly significant (p-value = 0.002, R 2 = 0.717 ). The relationship between migration arrival times and the main melt onset on the calving grounds ( R 2 = 0.688, p-value = 0.003), however, had a considerably more variable lag (mean 13.3 d, se 0.67, range 3.1–20.4). No migrations ended before the main melt onset at the calving grounds. Thawing conditions may provide a trigger for migration or favorable conditions that increase animal mobility, and suggest that the snow properties are more important than snow presence. Further work is needed to understand how widespread this is and why there is such a relationship. [ABSTRACT FROM AUTHOR]

Comprehending the impacts of land-use type on soil nutrition and stoichiometry in watersheds is crucial for effective regional ecosystem management. However, a deeper understanding of the influence of land-use type on soil stoichiometry in karst agricultural watersheds is still lacking. Here, we analyzed the contents, stoichiometries, and drivers of topsoil C, N, and P in a karst agricultural watershed in China, focusing on six land-use types: paddy fields, dry farmland, tussock land, shrubland, shrubby tussock land, and woodland. We found that woodland exhibited significantly higher soil organic carbon (SOC) content than other land-use types except shrubland. Moreover, woodland exhibited the highest total nitrogen (TN) and total phosphorus (TP) contents compared with other land-use types. C/N and N/P ratios did not vary significantly with land-use type, whereas dry farmland (18.68) showed a significantly lower C/P ratio than woodland (39), shrubland (39.92), and paddy fields (34.87). In addition, our results revealed that soil pH, catalase and invertase activity, and bacterial and actinomycetes abundance significantly influenced C, N, and P content and stoichiometry. These findings reveal that interactions between multiple biotic and abiotic factors drive variability in soil stoichiometry, offering valuable insight for land improvement and ecological management in karst agricultural watersheds. [ABSTRACT FROM AUTHOR]