Loss Of Plant Diversity Research Articles

Trade-offs and synergies of plant traits co-drive efficient nitrogen use in intercropping systems

ContextNitrogen (N) enrichment increases aboveground net primary productivity, but causes a loss of plant diversity and a decline in ecosystem stability. Diverse systems that enhance the N-use efficiency help achieve sustainable development goals. Functional traits have been used to predict ecosystem functions in diverse systems. However, few studies considered both the effect of functional traits and evaluated the relationship between traits and N acquisition in intercropping. ObjectiveThe aim of this study was to evaluate the relationships between functional traits resulting from interspecific interactions and determine relationships between functional traits and N acquisition of intercropping systems. MethodsBased on a four-year N-manipulation field experiment, we measured 10 functional traits related to light interception and nutrient-use efficiency in different systems (maize (Zea mays L.), peanut (Arachis hypogaea L.), soybean (Glycine max L. Merrill.) monocultures, and maize/peanut and maize/soybean intercrops) at the pre-tasseling stage of maize, calculated the crude protein yield and aboveground N content at harvest time. ResultsThe maize grain N concentration was increased by N application, and it increased by intercropping in legumes. Both maize/soybean and maize/peanut intercropping systems increased crude protein productivity. Synergies among plant functional traits of maize allowed maize to establish its dominance, which resulted in greater N acquisition and crude protein yield of intercrops. Trade-offs among plant functional traits (between root traits and shoot traits of legumes) show strategies of legumes in response to interspecific competition. The specific leaf area of the legume was a key trait and affected interspecific interactions. This N-use advantage of intercropping was directly influenced by the aboveground functional traits of the system (community-weighted mean values of functional traits), but indirectly affected by belowground functional traits of the system. Conclusions and significanceOur study highlights greater N uptake of the intercropping system and suggests that intercropping can be used to increase the quality of crop products via enhancing crude protein production. The synergy and trade-offs in plant functional traits together enhance efficient N use in the intercropping systems. These findings help to better understand the underlying mechanisms that determine efficient resource use in diverse cropping systems and have implications for the sustainable management of food-production systems.

Impacts of open‐pit coal mining and livestock grazing on plant diversity in a steppe: From the perspective of remote sensing

AbstractCoal mining and grazing cause land degradation. Plant diversity loss is one of the characteristics. Ground surveys cannot analyze the effects of mining and grazing on plant diversity in large areas, and remote sensing offers a novel solution. The aims of this study were as follows: (1) to analyze the impacts of mining and grazing on plant diversity composition by considering α‐, β‐, and γ‐ diversity comprehensively; (2) to determine the impacts of mining and grazing on the spatial distribution of α‐diversity; (3) to identify priority areas for ecological restoration. We applied a novel remote sensing method to obtain plant α‐, β‐, and γ‐ diversity maps and performed spatial analysis. The results were as follows: (1) mining reduced the proportion of α‐diversity in the total diversity (γ‐diversity) but increased that of β‐diversity. Grazing increased the proportion of α‐diversity but decreased that of β‐diversity. Mining increased the heterogeneity among plant communities, whereas grazing increased the homogeneity. (2) Both mining and grazing reduced α‐diversity. With increasing distance from the mine, α‐diversity increased logarithmically. (3) The severely affected range of mining on plant diversity is approximately 325 m. When there is grazing around the mine, the severely affected range is approximately 400 m. Severely affected areas are priority areas for ecological restoration. Improving the soil quality can be an effective measure. This study gains new insights into the effects of coal mining and grazing on plant diversity. These findings can provide some guidance for governments to formulate ecological restoration measures in mining areas.

Impact of Spartina alterniflora Invasion in Coastal Wetlands of China: Boon or Bane?

Invasive plants, like Spartina alterniflora (SA), have a competitive advantage over native flora due to their rapid utilization of vital soil nutrients. This results in the depletion of resources for native plant species, significantly impacting ecosystem diversity and stability. This comprehensive review addresses several key aspects related to SA's spread and spatial distribution in China's wetlands. The rapid expansion of Spartina alterniflora is attributed to its high reproductive ability, adaptability to environmental factors like elevated salinity, and ability to disperse its seeds via tides. Spartina alterniflora mainly were found in Zhejiang, Jiangsu, Fujian, and Shanghai provinces, accounting for more than 90% of China's total Spartina alterniflora area. Spartina alterniflora rapid growth results in displacement of native species and loss of vital microbial, plant, and animal diversity. Some studies reported that Spartina alterniflora increases carbon storage, while others argue that it weakens this function. The impact of Spartina alterniflora on organic and inorganic carbon requires further research for better understanding dynamics of carbon in coastal wetlands. The controlled growth of Spartina alterniflora can be beneficial in many aspects of the coastal wetlands' ecosystem. In China, various methods have been employed to control the invasion of SA. Physical control, such as removing the plants and converting them into fertilizer or bioenergy, has been commonly used but has limitations like air pollution and the potential for re-invasion. Chemical herbicides like Imazapyr and Haloxyfop-R-methyl have effectively controlled and prevented re-invasion in specific areas, but their potential adverse impacts are still uncertain. Wetland Park construction, aquaculture development, and substituting native or exotic species with mangroves or reed communities have also been successful. It becomes evident that a long-standing and Contextual approach is necessary to effectively manage the advantages and curtail the drawbacks associated with S. alterniflora across China.

Foliar fungal communities in agroecosystems depend on crop identity and neighboring vegetation

Agricultural intensification causes plant diversity loss and environmental homogenization, which may result in changes to plant-microbiome interactions mediating plant growth and stress tolerance. We hypothesized that foliar fungal microbiomes would depend on plant traits and environmental filters, constrained by neighboring vegetation expected to serve as a fungal source. Thus, we sampled foliar fungi from four crops (three annual and one perennial), four sites per crop, and three varieties per annual crop, across a 500-km expanse in North Carolina, USA and tested the role of host traits, environmental traits, and vegetative landcover on foliar fungal community structure. Crop species and site were major determinants of community structure, primarily due to differences in plant size and growing season. Site consistently explained 10× more variation in community structure than host variety across the annual crops. Finally, reduced natural vegetative cover surrounding farms was correlated with decreased fungal richness and more homogeneous microbiome assembly. Based on these results, we posit that foliar fungal assembly in crops results from host and environmental filters acting on inputs from the nearby vegetation. Future efforts at agricultural microbiome management must therefore consider landscape management and will require an improved understanding of how agricultural intensification alters microbial source pools.

Grazing alters the relationship between alpine meadow biodiversity and ecosystem multifunctionality

The relationship between biodiversity and ecosystem multifunctionality (EMF) depends on changes in environmental disturbance. Plant and soil biological diversity can mediate EMF, but how these change in response to grazing disturbance remains unknown. Here we present an 8-year experiment on sheep grazing control in alpine grasslands in Gannan Tibetan Autonomous Prefecture, Gansu Province, China. Plant species richness, FRic (functional richness), PD (Faith's phylogenetic diversity), soil biological diversity (bacterial, fungal, and ciliate diversity), and multiple ecosystem functions were measured and calculated. The results showed that increasing grazing intensity caused a decrease in biodiversity and EMF and that biodiversity and ecosystem function differed significantly (P < 0.05) between grazing intensities. EMF was positively correlated with species richness, functional diversity, and soil bacterial diversity (P < 0.05), with 23.6 %, 10.8 %, and 12.1 % of EMF explained by changes in grazing intensity, respectively. The interaction terms of grazing intensity, plant species richness, and soil biological diversity were negatively correlated with EMF (P < 0.05). This shift in the relationship between plant or soil biological diversity and EMF occurs at a grazing intensity index of around 0.7, i.e., the impact of plant species richness on EMF is more significant when the grazing intensity index is below 0.67. The effect of soil biological diversity on EMF is more substantial when the grazing intensity index is above 0.86. Conclusion: High grazing intensity directly affects soil bulk density and pH and indirectly affects EMF by regulating plant species richness and soil biological diversity changes. Loss of plant and soil biological diversity can have extreme consequences under low and high grazing intensity disturbance conditions. Therefore, we must develop biodiversity conservation strategies for external disturbances to mitigate the effects of land use practices such as grazing disturbances.

Magnitude and drivers of plant diversity loss differ between spatial scales in Scania, Sweden 1957–2021

AbstractQuestionsChanged land use, nitrogen deposition, climate change, and the spread of non‐native species have repeatedly been reported as the main drivers of recent floristic changes in northern Europe. However, the relevance of the geographical scale at which floristic changes are observed is less well understood and it has only rarely been possible to quantify biodiversity loss. Therefore, we assessed changes in species richness, species composition and mean ecological indicator values (EIVs) at three nested geographic scales during two different time periods, each ca 30 years, since the mid‐1900s.LocationTwo parishes in central Scania, southernmost Sweden.MethodsWe analyzed species presence/absence data from three inventories at ca 30‐year intervals over 1957–2021 and three geographic scales (157 m2, ca 7 km2 and ca 45 km2) to document temporal trends and differences between geographic scales in terms of species richness, species composition and mean EIVs.ResultsWe found shifts in species composition across all geographical scales. However, the magnitude of biodiversity loss and the main drivers of these changes were scale‐dependent. At the smallest spatial scale, we saw a dramatic loss of plant biodiversity with local species richness in 2021 being only 48% of that of 1960. In contrast, at the larger geographic scales no significant changes in species richness were observed because species losses were compensated for by gains of predominantly non‐native species, which made up at least 78% of the new species richness. At the smallest spatial scale, changed land use (ceased grazing/mowing and intensified forestry) appeared as the main driver, while an increasing proportion of non‐native species, as well as climatic changes and increasing nitrogen loads appeared relatively more important at larger geographic scales.ConclusionOur results highlight the precarious situation for biodiversity in the region and at the same time the fundamental importance of geographic scale in studies of biodiversity change. Both the magnitude and drivers of changes may differ depending on the geographic scale and must be considered also when previously published studies are interpreted.

Long-Term Anthropogenic Management and Associated Loss of Plant Diversity Deeply Impact Virome Richness and Composition of Poaceae Communities.

Modern agriculture has influenced plant virus emergence through ecosystem simplification, introduction of new host species, and reduction in crop genetic diversity. Therefore, it is crucial to better understand virus distributions across cultivated and uncultivated communities in agro-ecological interfaces, as well as virus exchange among them. Here, we advance fundamental understanding in this area by characterizing the virome of three co-occurring replicated Poaceae community types that represent a gradient of grass species richness and management intensity, from highly managed crop monocultures to little-managed, species-rich grasslands. We performed a large-scale study on 950 wild and cultivated Poaceae over 2 years, combining untargeted virome analysis down to the virus species level with targeted detection of three plant viruses. Deep sequencing revealed (i) a diversified and largely unknown Poaceae virome (at least 51 virus species or taxa), with an abundance of so-called persistent viruses; (ii) an increase of virome richness with grass species richness within the community; (iii) stability of virome richness over time but a large viral intraspecific variability; and (iv) contrasting patterns of virus prevalence, coinfections, and spatial distribution among plant communities and species. Our findings highlight the complex structure of plant virus communities in nature and suggest the influence of anthropogenic management on viral distribution and prevalence. IMPORTANCE Because viruses have been mostly studied in cultivated plants, little is known about virus diversity and ecology in less-managed vegetation or about the influence of human management and agriculture on virome composition. Poaceae (grass family)-dominated communities provide invaluable opportunities to examine these ecological issues, as they are distributed worldwide across agro-ecological gradients, are essential for food security and conservation, and can be infected by numerous viruses. Here, we used multiple levels of analysis that considered plant communities, individual plants, virus species, and haplotypes to broaden understanding of the Poaceae virome and to evaluate host-parasite richness relationships within agro-ecological landscapes in our study area. We emphasized the influence of grass diversity and land use on the composition of viral communities and their life history strategies, and we demonstrated the complexity of plant-virus interactions in less-managed grass communities, such as the higher virus prevalence and overrepresentation of mixed virus infection compared to theoretical predictions.

Space resource utilization of dominant species integrates abundance‐ and functional‐based processes for better predictions of plant diversity dynamics

Sustainable ecosystem management relies on our ability to predict changes in plant diversity and to understand the underlying mechanisms. Empirical evidence demonstrates that abundance‐ and functional‐based processes simultaneously explain the loss of plant diversity in response to human activities. Recently, a novel indicator based on percent cover (CoverD) and maximum height (HeightD) of the dominant plant species – space resource utilization (SRUD) – has proven to give robust and better predictions of plant diversity dynamics than community biomass. Whether the superior predictive ability of SRUD is due to its capacity to simultaneously capture abundance‐ and functional‐based processes remains unknown. Here, we tested this hypothesis by quantifying mechanistic links between changes in SRUD and biodiversity in response to nutrients and herbivores. Furthermore, we assessed the relative contribution of dominant, intermediate and rare species to reduced density of individuals by combining null model analysis with field experiments. We found that SRUD successfully captured changes in ground‐level light availability and changes in the number of individuals to predict plant diversity dynamics, and each of CoverD and HeightD partly and independently contributed to both processes. Comparative results from null model analysis and field experiments confirmed that individual losses of dominant, intermediate and rare species followed non‐random processes. Specifically, compared with random loss process, rare species lost proportionally more individuals and thus disproportionately contributed to species loss, while dominant and intermediate species lost less. Our results demonstrate that SRUD captures both abundance‐ and functional‐based processes thus explaining why SRUD provides more accurate predictions of changes in species diversity. Given that rare species can play an important role in shaping community structure, resisting against invasion, impacting higher trophic levels and providing multiple ecosystem functions, reducing the SRU of dominant species could alleviate the risk of exclusion of rare species by mitigating abundance‐ and functional‐based competition processes.

Short-Term Effects and Vegetation Response after a Megafire in a Mediterranean Area

In Mediterranean-climate areas, wildfires have an important ecological role, selecting organisms, influencing species composition and structure of vegetation, and shaping landscapes. However, the increase in frequency and severity of fires can cause, among others, progressive vegetation degradation, biodiversity, and ecosystem services loss. Under the climate change scenario, the frequency and severity of wildfires are expected to increase, especially in the Mediterranean Basin, recognized as among the most affected by the intensification of droughts and heat waves in the future. Therefore, from the perspective of adaptation, it is important not only to assess the sudden effects after a fire but also to investigate the ecological changes and vegetation response over time. In this framework, this study investigates the effects and the short-term vegetation response in an area struck by a megafire. The vegetation response one year after a fire has been assessed in semi-natural grasslands, shrublands, and woodlands at the landscape scale through spectral indices, and at the field scale through floristic and vegetation surveys. Our results showed that after a severe wildfire, although some areas did not exhibit vegetation regrowth, the response of natural vegetation was notable after one year. In the study area, the most resilient vegetation type was semi-natural grasslands, suggesting that this type of vegetation can be crucial for landscape recovery. The other vegetation types showed different response patterns that also prefigure possible changes in species composition and loss of plant diversity over the medium term. This study highlights the value of combining remote sensing spectral analyses and detailed floristic and vegetation surveys for understanding the direction of the early stages of post-fire vegetation dynamics.

Light competition drives herbivore and nutrient effects on plant diversity

Enrichment of nutrients and loss of herbivores are assumed to cause a loss of plant diversity in grassland ecosystems because they increase plant cover, which leads to a decrease of light in the understory1–3. Empirical tests of the role of competition for light in natural systems are based on indirect evidence, and have been a topic of debate for the last 40 years. Here we show that experimentally restoring light to understory plants in a natural grassland mitigates the loss of plant diversity that is caused by either nutrient enrichment or the absence of mammalian herbivores. The initial effect of light addition on restoring diversity under fertilization was transitory and outweighed by the greater effect of herbivory on light levels, indicating that herbivory is a major factor that controls diversity, partly through light. Our results provide direct experimental evidence, in a natural system, that competition for light is a key mechanism that contributes to the loss of biodiversity after cessation of mammalian herbivory. Our findings also show that the effects of herbivores can outpace the effects of fertilization on competition for light. Management practices that target maintaining grazing by native or domestic herbivores could therefore have applications in protecting biodiversity in grassland ecosystems, because they alleviate competition for light in the understory.

Fishers’ Perspectives: the Drivers Behind the Decline in Fish Catch in Laguna Lake, Philippines

Aquatic ecosystems are strongly affected by global change. Fishers hold local ecological knowledge (LEK) that is especially relevant for improving our understanding of aquatic ecosystems that experience major environmental changes while also providing crucial ecosystem services. This research explores the perceptions of the ecological changes in Laguna Lake (Philippines) among local fisherfolks. In 2019, we conducted 30 semi-structured interviews with fisherfolks with up to 60 years’ experience. They reported catching 31 fish species and one shrimp genus as a staple food and income source, with more than one-third of the species being exotic or introduced. The fisherfolks noted repeated fish kill events and dramatic changes in their catch such as fewer and smaller fish. Also noticeable were the widespread catch of knifefish, a comparably newly introduced species, and the fact that all native fish species were reported to be less often caught now than in the past. This included the reduced catch of talilong (mullet), dalag (snakehead), and ayungin (silver perch). Locals emphasized various drivers behind these changes, which are linked to one another in complex interrelationships. Invasive species, the deterioration of fish habitats, and increased water turbidity were cited as the main drivers. Interviewees highlighted an additional link between declining catches and the loss of aquatic plant diversity, which has been understudied in Laguna Lake and has not been the focus of regional policy efforts. The empirical evidence provided by the fisherfolks enhances earlier existing scientific evidence of this aquatic ecosystem as well as highlights the importance of contributions coming from different knowledge systems.

The Impacts of Post-Fire Straw Mulching and Salvage Logging on Soil Properties and Plant Diversity in a Mediterranean Burned Pine Forest

In the Mediterranean forests, wildfires and post-fire management actions may degrade soil properties and negatively impact vegetation characteristics. These effects may reduce soil functionality and result in loss of plant diversity. Although straw mulching and salvage logging are commonly carried out in burned forests, their impacts on respiration of forest soils as well as on species richness and evenness of forest plants have been little explored. To fill these gaps, this study has evaluated the soil respiration, different soil physico-chemical properties, as well as plant diversity in a forest of Castilla La Mancha (Central Eastern Spain), burned by a wildfire and then subjected alternatively to salvage logging or straw mulching or to both techniques. Compared to the unburned soils, immediately after the fire mulching and salvage logging alone increased (+146%) and reduced the soil respiration (−9%), respectively, the latter especially in combination with mulching. However, these differences decreased over time, and the mulched and non-logged areas always showed the maximum soil respiration. The post-fire treatments also significantly influenced the main physico-chemical properties of the experimental soils. No evident changes were found for the pH of the logged and mulched soils compared to the control. Mulching coupled with logging did not modify the OM increase due to fire, while the lowest increase was measured in the logged but non-mulched areas. Mulched and non-logged soils maintained high OM and TN one year after fire, but also in areas that were treated with logging (with or without mulching) these parameters were significantly higher compared to the unburned areas. Mulching increased the species richness and evenness, especially when itis carried out without logging, in comparison to the unburned areas. Logging without mulching did not exert negative impacts on plant biodiversity, whose species richness increased and evenness was unvaried compared to the burned and unburned areas. The results of this study can provide land managers easy to measure tools such as soil respiration and plant diversity, which can serve to assess and evaluate the effectiveness of management measures that are taken post-forest fire in order to conserve the delicate ecosystems of the Mediterranean forests.

Review on Plant Biodiversity and Conservation in Bangladesh: Drawbacks and Prospects

Biodiversity has become the talk of topic for so many years of its rapid decrease worldwide. Due to the geographical position and soil fertility Bangladesh is exceptionally endowed with a huge variety of plant species. In Bangladesh, the destruction of plant species in the forests and protected areas is a continuous process due to increasing population pressure, rural poverty, joblessness, lack of knowledge, absence of public awareness and other natural calamities etc. which pose a serious threat to the plant biodiversity. The Government and researchers of Bangladesh have undertaken several surveys, scientific researches, and monitoring, which helps to document related databases, to protect and restore ecosystems and biodiversity. This paper is based on the literature survey of some renowned researchers’ studies and applications in biodiversity conservation in Bangladesh. Thus, this study attempts to review the present scenario of plant diversity, causes of loss or depletion of plant diversity, initiatives taken for the conservation by the government and last but not least the prospects of plant biodiversity in Bangladesh.

Review on Plant Biodiversity and Conservation in Bangladesh: Drawbacks and Prospects

Biodiversity has become the talk of topic for so many years of its rapid decrease worldwide. Due to the geographical position and soil fertility Bangladesh is exceptionally endowed with a huge variety of plant species. In Bangladesh, the destruction of plant species in the forests and protected areas is a continuous process due to increasing population pressure, rural poverty, joblessness, lack of knowledge, absence of public awareness and other natural calamities etc. which pose a serious threat to the plant biodiversity. The Government and researchers of Bangladesh have undertaken several surveys, scientific researches, and monitoring, which helps to document related databases, to protect and restore ecosystems and biodiversity. This paper is based on the literature survey of some renowned researchers’ studies and applications in biodiversity conservation in Bangladesh. Thus, this study attempts to review the present scenario of plant diversity, causes of loss or depletion of plant diversity, initiatives taken for the conservation by the government and last but not least the prospects of plant biodiversity in Bangladesh.

Impact of Climate Change on Fruit Crops- A Review

Climate change is becoming an observed reality. Several researchers around the world have been working for decades to model predicted climatic changes that will occur in the 21st century and forecast the potential impact on the global eco-system. Climate plays a major role in deciding perennial fruit crop’s distribution, phenology, fruit quality, and disease and pest incidents. Physiological and yield attributes of fruits are sensitive to changing global climate as the climatic factors such as temperature rainfall etc. has direct co-relation with the regulatory physiological events of fruit trees. Despite increasing atmospheric CO2, which is needed for plant photosynthetic activity, the future of food production remains uncertain due to global warming and abnormal precipitation. Furthermore, there is a scarcity of information on the practical effects of pests and diseases in a climate change, which may have an effect on food availability in future. Studies suggested not only productivity but also quality of fruits will be impaired under the variable growing climates year to year. Plant diversity loss and area suitability issues would lead to more problems. In the face of such challenges to world fruit production, a plan-based strategic scientific evaluation of such effects, as well as adaptation and mitigation strategies, should be quantified. This review article briefly discusses effect of climate change on various fruit crops as well as approaches to mitigate with these future challenges.

A review of the vascular plant flora of the Cairngorms Connect project area, Scotland, and some possible implications of forest expansion to the natural tree line

Cairngorms Connect, a partnership of four adjoining land owners, is committed to a 200-year vision to enhance and restore habitats, species and ecological processes across a 592 km2 area within the Cairngorms National Park. This will be achieved by, inter alia, expanding woodland to its natural altitudinal limit, including high altitude sub-alpine scrub. All or parts of six native Caledonian pinewoods occur here, c.26% of the national total. Ancient, semi-natural woodland within the Cairngorms Connect area is 43% of the National Park total. Modelling of the extent of potential-natural woodland (sensu Peterken, 1981, 1996) indicates that below 600 m all terrestrial habitats are potentially capable of supporting some degree of tree and scrub cover. 899 vascular plant taxa have been recorded here, of which 693 are native to the area. 7.6% of native taxa are endemic to Great Britain (and Ireland) or to Scotland; these are mainly Hieracia (Hawkweeds). Of the native taxa, 23% are of national, and 11% of regional conservation concern. Few native taxa are widespread within the Cairngorms Connect area, most are local or rare. 40% of native taxa have been recorded in five or less monads (1 km squares), with 16% recorded from just a single monad. 12% of native taxa are associated with shaded locations or semi-shade (Ellenberg Light values 3-5). 51% of taxa are found in partial shade to well lit locations (values 6 and 7) and 37% of taxa in well lit to fully lit locations (values 8 and 9). Native taxa with Light values of 6-7 are the most frequent in 92% of monads with more than 10 recorded taxa. 65% of taxa of national conservation concern favour well lit to fully lit locations (Light values 8-9). Shading of plants, at altitudes below the potential tree line, is strongly influenced by the extent of woodland and scrub and its structure, and by herbivore grazing levels determining height and structure of the field layer. To achieve forest expansion to the natural tree line by natural regeneration will require sustained low levels of grazing and browsing, for decades, or longer. This is already leading to a taller field layer and an increased density of tree regeneration. 40% of native taxa may be negatively impacted, if existing and new woodland becomes dense with a high level of shading. Of these 'at risk' taxa, 50% have maximum height less than 50 cm and may be especially at risk from sustained periods of low grazing. Limited disturbance and lack of open sites and bare ground for seedling recruitment is another potential constraint on vascular plants. The issue of vegetation succession and shading, leading to possible loss of plant diversity is likely to be much less of an issue at altitudes around and above the tree line. Here there are likely to be benefits, with possible expansion of tall herb communities.

Spatial variation in the direct and indirect effects of plant diversity on soil respiration in an arid region

Soil respiration (Rs) is a key ecosystem function that controls the terrestrial energy balance and element cycling. Quantifying how plant diversity affects Rs is critical for predicting the impact of global plant diversity loss on ecosystem function. However, it is unclear how soil factors and plant diversity are spatially interrelated under natural environmental gradients, and how plant diversity affects the spatial variation of Rs on the basis of soil factors. Our objectives were to quantify the direction and magnitude of direct and indirect effects of plant diversity on Rs. We assessed spatial variability in the relationships between soil factors (soil chemistry and microclimate), multiple dimensions of plant diversity (taxonomic, functional, and phylogenetic diversity), and Rs using a new combination of geographically weighted regression and structural equation modeling based on survey data from three plots (river bank, transitional zone, and desert margin plots) along an environmental gradient in northwest China. Reduced plant diversity had a negative impact on Rs. However, when the effects of soil factors on Rs and spatial non-stationarity were considered simultaneously, the relationship between plant diversity and Rs changed in magnitude and direction. From the river bank to the desert margin, the positive effect of taxonomic and functional diversity on Rs gradually weakened, while the effect of phylogenetic diversity on Rs changed from a negative to a positive effect. Plant diversity and soil factors together explained 55%–75% of the spatial variation in Rs. Among them, the contribution of plant diversity to the spatial variation of Rs gradually decreased from the river bank to the desert margin, while the contribution of soil factors gradually increased. Functional diversity (17.39%–18.93%) and phylogenetic diversity (10.75%–19.53%) better explained the spatial variability of Rs compared with taxonomic diversity (2.67%–6.01%). The results provide strong evidence that plant diversity, especially functional and phylogenetic diversity, is a key driver of Rs, expanding our understanding of the relationship between plant diversity and Rs. These findings more accurately reveal the changing characteristics of carbon dynamics in desert ecosystems, and provide a methodological framework for studying the spatial variability of the relationship between plant diversity and ecosystem function.

Perceptions of the impacts of invasive alien plants in the riparian zone of the Ganga River: Insights from Varanasi, India

AbstractRiparian zones are among the most threatened habitats due to invasive species. Traditionally, studies on invasive alien plants (IAPs) of riparian zones have focused on their ecological implications. Studies assessing the impacts of IAPs on ecosystem services (ES) and ecosystem disservices (EDS) through people's perceptions are lacking in this habitat. This study was conducted in the riparian zone of the Ganga River in Varanasi, India. We used a questionnaire‐based survey to assess people's perceptions of IAPs and their potential to provide ES and EDS. Results indicated that residents were aware of IAPs and perceived these both positively (providing ES) and negatively (providing EDS). Soil stabilization and loss of native plant diversity were the most commonly perceived ES and EDS respectively. Socio‐demographic variables such as age and education shape people's perceptions of IAPs. Younger and educated respondents were more likely to perceive IAPs negatively. Respondents most commonly used fire as a practice to manage IAPs. They placedParthenium hysterophorusL. as the highest priority based on its impacts and management needs. This study highlights the need to incorporate public perceptions into the policy, planning, and management of IAPs, particularly in the riparian zone.

Plant Diversity and Fungal Richness Regulate the Changes in Soil Multifunctionality in a Semi-Arid Grassland.

Simple SummaryUnderstanding relationships between biodiversity and ecosystem functions is important in the context of global plant diversity loss. We evaluated the relationships between soil bacterial and fungal diversity, rare microbial taxa, and soil multifunctionality in a semi-arid grassland with varied plant diversity levels. The fungal richness rather than bacterial richness was positively related to soil multifunctionality. The relative abundance of saprotrophs was positively correlated with soil multifunctionality, and the relative abundance of pathogens was negatively correlated with soil multifunctionality. Furthermore, the rare fungal taxa played a disproportionate role in regulating soil multifunctionality. The shift of plant biomass allocation patterns increased plant below-ground biomass in the high diversity plant assemblages, which can alleviate soil microbial carbon limitations and enhance the fungal richness, thus promoting soil multifunctionality. This study provides a new perspective for evaluating the relative roles of fungal and bacterial diversity in maintaining multiple soil functions under global plant diversity loss scenarios.Loss in plant diversity is expected to impact biodiversity and ecosystem functioning (BEF) in terrestrial ecosystems. Soil microbes play essential roles in regulating ecosystem functions. However, the important roles and differences in bacterial and fungal diversity and rare microbial taxa in driving soil multifunctionality based on plant diversity remain poorly understood in grassland ecosystems. Here, we carried out an experiment in six study sites with varied plant diversity levels to evaluate the relationships between soil bacterial and fungal diversity, rare taxa, and soil multifunctionality in a semi-arid grassland. We used Illumina HiSeq sequencing to determine soil bacterial and fungal diversity and evaluated soil functions associated with the nutrient cycle. We found that high diversity plant assemblages had a higher ratio of below-ground biomass to above-ground biomass, soil multifunctionality, and lower microbial carbon limitation than those with low diversity. Moreover, the fungal richness was negatively and significantly associated with microbial carbon limitations. The fungal richness was positively related to soil multifunctionality, but the bacterial richness was not. We also found that the relative abundance of saprotrophs was positively correlated with soil multifunctionality, and the relative abundance of pathogens was negatively correlated with soil multifunctionality. In addition, the rare fungal taxa played a disproportionate role in regulating soil multifunctionality. Structural equation modeling showed that the shift of plant biomass allocation patterns increased plant below-ground biomass in the highly diverse plant plots, which can alleviate soil microbial carbon limitations and enhance the fungal richness, thus promoting soil multifunctionality. Overall, these findings expand our comprehensive understanding of the critical role of soil fungal diversity and rare taxa in regulating soil multifunctionality under global plant diversity loss scenarios.

Plants Play Stronger Effects on Soil Fungal than Bacterial Communities and Co-Occurrence Network Structures in a Subtropical Tree Diversity Experiment.

ABSTRACTIncreasing biodiversity loss profoundly affects community structure and ecosystem functioning. However, the differences in community assembly and potential drivers of the co-occurrence network structure of soil fungi and bacteria in association with tree species richness gradients are poorly documented. Here, we examined soil fungal and bacterial communities in a Chinese subtropical tree species richness experiment (from 1 to 16 species) using amplicon sequencing targeting the internal transcribed spacer 2 and V4 hypervariable region of the rRNA genes, respectively. Tree species richness had no significant effect on the diversity of either fungi or bacteria. In addition to soil and spatial distance, tree species richness and composition had a significant effect on fungal community composition but not on bacterial community composition. In fungal rather than bacterial co-occurrence networks, the average degree, degree centralization, and clustering coefficient significantly decreased, but the modularity significantly increased with increasing tree species richness. Fungal co-occurrence network structure was influenced by tree species richness and community composition as well as the soil carbon: nitrogen ratio, but the bacterial co-occurrence network structure was affected by soil pH and spatial distance. This study demonstrates that the community assembly and potential drivers of the co-occurrence network structure of soil fungi and bacteria differ in the subtropical forest.IMPORTANCE Increasing biodiversity loss profoundly affects community structure and ecosystem functioning. Therefore, revealing the mechanisms associated with community assembly and co-occurrence network structure of microbes along plant species diversity gradients is very important for understanding biodiversity maintenance and community stability in response to plant diversity loss. Here, we compared the differences in community assembly and potential drivers of the co-occurrence network structure of soil fungi and bacteria in a subtropical tree diversity experiment. In addition to soil and spatial distance, plants are more strongly predictive of the community and co-occurrence network structure of fungi than those of bacteria. The study highlighted that plants play more important roles in shaping community assembly and interactions of fungi than of bacteria in the subtropical tree diversity experiment.