Vegetative Functions Research Articles

Soil calcium content as the driving factor for vegetative structure and soil microbial function diverging across a fire chronosequence of the boreal forests in northeast China

AbstractThe role of biophysical variables in constructing community structure changes with the time since fire. The major objective of this study is to verify the transition stage and its underlying variables for the postfire forest and soil microbial function in the boreal forested area of China. A 50-year fire chronosequence was presented, and biomass of forbs, shrubs and woody plants was separately weighted to assess their contribution to the whole community with the year since fire (YSF). Simultaneously, soil biophysical properties were measured for stands in different time periods after fire. Soil microbial functions, i.e. growth efficiency (GE) and carbon use efficiency (CUE), were calculated based on ecoenzymatic and soil nutrient stoichiometry. In terms of vegetative structure, forbs’ proportion decreased from 75% to 1.5%, but the proportion of woody plants increased from 0.04% to 70% across this fire chronosequence. GE and CUE of soil microorganisms averaged 0.242 and 0.236 and were significantly higher in 9, 15 and 31 YSF than in 2 and 3 YSF. Soil metal content was significantly increased at the late stage of this fire chronosequence, and soil calcium content showed a positive correlation with woody plant biomass and a negative correlation with soil microbial function. Overall, the present work highlights that the time period of 15 and 31 YSF is a hallmark stage for aboveground vegetative structure and soil microbial function to change in different trends and that the calcium content may partly account for these two divergent trajectories.

Exploring how groundwater buffers the influence of heatwaves on vegetation function during multi-year droughts

Abstract. The co-occurrence of droughts and heatwaves can have significant impacts on many socioeconomic and environmental systems. Groundwater has the potential to moderate the impact of droughts and heatwaves by moistening the soil and enabling vegetation to maintain higher evaporation, thereby cooling the canopy. We use the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model, coupled to a groundwater scheme, to examine how groundwater influences ecosystems under conditions of co-occurring droughts and heatwaves. We focus specifically on south-east Australia for the period 2000–2019, when two significant droughts and multiple extreme heatwave events occurred. We found groundwater plays an important role in helping vegetation maintain transpiration, particularly in the first 1–2 years of a multi-year drought. Groundwater impedes gravity-driven drainage and moistens the root zone via capillary rise. These mechanisms reduced forest canopy temperatures by up to 5 ∘C during individual heatwaves, particularly where the water table depth is shallow. The role of groundwater diminishes as the drought lengthens beyond 2 years and soil water reserves are depleted. Further, the lack of deep roots or stomatal closure caused by high vapour pressure deficit or high temperatures can reduce the additional transpiration induced by groundwater. The capacity of groundwater to moderate both water and heat stress on ecosystems during simultaneous droughts and heatwaves is not represented in most global climate models, suggesting that model projections may overestimate the risk of these events in the future.

Расстройство моторной функции верхнего отдела пищеварительного тракта у детей с вегетативной дисфункцией

Нами проведено комплексное клиническое, лабораторное и инструментальное обследование 109 детей в возрасте 6–16 лет с вегетативной дисфункцией и жалобами со стороны органов пищеварения. Изучена симптоматика заболеваний с учетом жалоб и анамнестических данных, результатов объективного обследования, общеклинического исследования крови и мочи, биохимического исследования крови, исследования кала на яйца гельминтов, данных электрокардиографии, консультаций врачей-специалистов, ультразвукового исследования органов брюшной полости. Состояние слизистой оболочки желудка и двенадцатиперстной кишки и наличие моторно-эвакуаторных нарушений в виде рефлюкса оценивалось по данным фиброэзофагогастродуоденоскопии. Исследование эвакуаторной функции желудка проводилось с помощью ультразвукового обследования методом наполнения. Всем детям проведено изучение вегетативной регуляции сердечного ритма методом кардиоритмографии. Также проведена диагностика уровней ситуативной (реактивной) и личностной тревожности с использованием теста Спилбергера. Выявлена группа детей с синдромом вегетативной дисфункции и моторными нарушениями верхнего отдела пищеварительного тракта (ВОПТ). Изучены клинические проявления, факторы риска возникновения, типы нарушений моторной функции ВОПТ при синдроме вегетативной дисфункции у детей, определена связь этих нарушений с H.pylori. Все обследованные дети были распределены на 2 группы. Основная группа — 87 детей с синдромом вегетативной дисфункции и нарушениями моторной функции ВОПТ и группа сравнения — 22 ребенка с синдромом вегетативной дисфункции без нарушений моторной функции ВОПТ. С целью проведения лечения дети основной группы были распределены на группы в зависимости от типа нарушений моторной функции ВОПТ: I группа пациентов — с ускорением моторной функции ВОПТ и II группа пациентов — с замедлением этой функции. Курс лечения пациентов обеих групп длился 30 дней. Была доказана эффективность лечения синдрома вегетативных дисфункций с учетом типа моторных расстройств ВОПТ.

Non coronary applications of cardiac computed tomography: A review

Acquired heart diseases including valvular pathologies and conduction abnormalities, along with coronary artery disease make cardiovascular disease one of the major causes of mortality and morbidity worldwide. Advances in cardiac computed tomography (CCT) have led to markedly improved image quality for assessment of several coronary and noncoronary cardiac abnormalities. With the latest versions of CT scanners, image acquisition can be completed within a few seconds, in a single breath hold and with much less radiation exposure, thus making CT an even more attractive diagnostic tool with its high temporal and excellent spatial resolution. Additional advantages are its noninvasive nature, wide availability, fast image acquisition and ability to provide additional data about the cardiac structure, function, valvular motion, and presence or absence of valvular vegetation, mass or intracardiac thrombus. These factors can result in change in management in many valvular pathologies pre- and post-intervention, and in electrophysiological procedures. The goal of this article is to review applications of cardiac CT in non-coronary indications including valvular assessment, pulmonary vein isolation procedure, and left atrial appendage evaluation for its transcatheter occlusion.

Performance of Singular Spectrum Analysis in Separating Seasonal and Fast Physiological Dynamics of Solar‐Induced Chlorophyll Fluorescence and PRI Optical Signals

AbstractHigh temporal resolution measurements of solar‐induced chlorophyll fluorescence (F) and the Photochemical Reflectance Index (PRI) encode vegetation functioning. However, these signals are modulated by time‐dependent processes. We tested the applicability of the Singular Spectrum Analysis (SSA) for disentangling fast components (physiology‐driven) and slow components (controlled by structural and biochemical properties) from PRI, far‐red F (F760), and far‐red apparent fluorescence yield (Fy∗760). The proof of concept was developed on spectral and flux time series simulated with the Soil Canopy Observation of Photochemistry and Energy fluxes (SCOPE) model. This allowed the evaluation of SSA decomposition against variables that are independent of physiology or are modified by it. Slow SSA‐decomposed components of PRI and Fy∗760 showed high correlations with the reference variables (R2 = 0.97 and 0.96, respectively). Fast SSA‐decomposed components of PRI and Fy∗760 were better related to the physiological reference variables than the original signals during periods when leaf area index (LAI) was above 1 m2 m−2. The method was also successfully applied to predict light‐use efficiency (LUE) from the fast SSA‐decomposed components of PRI (R2 = 0.70) and Fy∗760 (R2 = 0.68) when discarding data modeled with LAI < 1 m2 m−2 and short‐wave radiation Rin < 250 W m−2. The method was then tested on data acquired in a Mediterranean grassland. In this case, the fast SSA‐decomposed component of apparent LUE∗ showed a stronger correlation with the fast SSA‐decomposed component of Fy∗760 (R2 = 0.42) than with original Fy∗760 (R2 = 0.01). SSA‐based approach is a promising tool for decoupling physiological information from measurements acquired with automated proximal sensing systems.

Единство спорта и морали в теоретическом и практическом обучении боксу

The article shows that although sports and morality are perceived as separate concepts, there is a common point that unites the two areas, and there is a system of rules that constitute human and interpersonal relationships. Both concepts emerged as a result of the interaction of human relationships. Exercises and physical education classes in certain sports help students to form interests and play a major role in their social development. The main topic of the article is the physiological features of the moral boxer’s activity. Boxing is a non-cyclical form of sport, i. e. in boxing, the movement of the upper extremities is carried out with a certain intensity. Boxing is a sport of speed-speed-stroke. Therefore, the boxer must be able to use all the functional capabilities of the body, both during training and competition. In the process of training, both motor qualities (strength, endurance, speed) increase and improve, as well as physiological developmental processes take place in its vegetative functions: blood circulation, respiration, digestion and other systems. In boxing, the strength of long muscles, endurance and activity are of particular importance. In this regard, both the boxer and his coach must have a thorough knowledge of the general physiological and biochemical processes of the body.

Importance of the legacy effect for assessing spatiotemporal correspondence between interannual tree-ring width and remote sensing products in the Sierra Nevada

Carbon uptake and tree growth are important factors for assessing productivity and long-term carbon storage. Measurements of radial stem growth are mainly performed at the individual tree scale and can be used to infer ecosystem net primary productivity (NPP). However, these measurements are spatially limited, and remote sensing provides a promising tool to track vegetation function and productivity across spatial scales, making it a viable technique for assessing variation in interannual tree growth and carbon storage. In this study we examined the correspondence between in-situ annual tree-ring width across four dominant evergreen species in the Sierra Nevada and a wide range of remotely sensed products linked to carbon uptake including NPP, gross primary productivity (GPP), net photosynthesis (PSN), normalized difference vegetation index (NDVI), near infrared reflectance of vegetation index (NIRV), and chlorophyll/carotenoid index (CCI) from MODIS (Moderate resolution Imaging Spectroradiometer) as well as downscaled solar-induced fluorescence (SIF) products, using a 14 year dataset (2000–2014) across 62 forest sites. We show that variation of annual tree-ring width was best captured by the annual sum of MODIS GPP, with a legacy effect (5-month backwards shift). Across all forest sites, MODIS GPP with a 5-month legacy effect showed moderate correspondence with tree-ring width (r = 0.60). Within each individual site, however, the interannual correspondence between MODIS GPP with a legacy effect and tree growth was stronger (median r = 0.70 vs 0.14 without a legacy effect). The importance of legacy effects in explaining tree growth variation within sites indicates that tree growth each year is influenced by carbon uptake during the latter part of the previous growing season. Additional local environmental factors also explained annual variation in tree-ring width, including (in descending order of importance) local tree density, latitude, slope, DBH, elevation and aspect.

Impact of long‐term water level drawdown on functional plant trait composition of northern peatlands

Abstract Understanding how plant communities respond to increased evaporation and consequent water level drawdown (WLD) is critical for predicting the functioning of northern peatlands under climate change. Functional traits provide a quantitative link between vegetation and ecosystem functions and, therefore, constitute a useful concept for predicting responses to climate change. We studied the impact of long‐term experimental WLD on vascular plant and moss traits at a rich fen, poor fen and bog. Vegetation change was followed over a 15‐year period. In the final study year, the traits of the most common plant species were measured from control and WLD areas at each peatland type. We found equally high interspecific trait variation for Sphagnum mosses and vascular plants while the intraspecific variation was greater in the mosses. Community‐weighted mean (CWM) traits varied between sites; WLD had the strongest impact on those traits that the dominant plant group originally had high values for, and in most cases, WLD further increased these values. In the vascular‐plant‐dominated rich fen, WLD led to taller plants with a greater specific leaf area, features that under the prevailing water table were also greatest at that site. In the bog, characterized by dense Sphagnum moss stands with small individuals, WLD further enhanced these properties that increase the ability of a moss stand to remain moist under drier conditions. The poor fen was transitional between the two extremes, both in its vegetation composition and in its trait responses. Structural equation models (SEM) showed that WLD in the fens, indirectly via other traits, increased photosynthetic capacity while the impact in the bog site was the opposite. In the poor fen and bog, WLD directly increased vascular plant respiration while the increase in the rich fen was through other traits. WLD directly increased and decreased Sphagnum respiration in the poor fen and bog, respectively. Overall, the traits of the vascular plant and Sphagnum communities in the bog were more dependent on each other than they were in the fens. Based on these findings, it is evident that fens and bogs respond differently to WLD. This should be considered when predicting the effects of climate change on peatland carbon cycling. A free Plain Language Summary can be found within the Supporting Information of this article.

Lesion-induced changes of brevican expression in the perineuronal net of the superior vestibular nucleus.

Damage to the vestibular sense organs evokes static and dynamic deficits in the eye movements, posture and vegetative functions. After a shorter or longer period of time, the vestibular function is partially or completely restored via a series of processes such as modification in the efficacy of synaptic inputs. As the plasticity of adult central nervous system is associated with the alteration of extracellular matrix, including its condensed form, the perineuronal net, we studied the changes of brevican expression in the perineuronal nets of the superior vestibular nucleus after unilateral labyrinth lesion. Our results demonstrated that the unilateral labyrinth lesion and subsequent compensation are accompanied by the changing of brevican staining pattern in the perineuronal nets of superior vestibular nucleus of the rat. The reduction of brevican in the perineuronal nets of superior vestibular nucleus may contribute to the vestibular plasticity by suspending the non-permissive role of brevican in the restoration of perineuronal net assembly. After a transitory decrease, the brevican expression restored to the control level parallel to the partial restoration of impaired vestibular function. The bilateral changing in the brevican expression supports the involvement of commissural vestibular fibers in the vestibular compensation. All experimental procedures were approved by the 'University of Debrecen - Committee of Animal Welfare' (approval No. 6/2017/DEMAB) and the 'Scientific Ethics Committee of Animal Experimentation' (approval No. HB/06/ÉLB/2270-10/2017; approved on June 6, 2017).

The effect of water stress on net primary productivity in northwest China.

Net primary productivity (NPP) has been widely used as the indicator of vegetation function and exhibits large spatial and temporal variations caused by numerous factors. Northwest China (NWC) is one of the driest regions in China, and water supply is the key determinant of NPP here. However, studies on the effects of water stress on NPP in NWC at the regional scale are still relatively lacking. Thus, in this study, based on a set of Moderate-Resolution Imaging Spectroradiometer (MODIS) NPP and evapotranspiration (ET) datasets, we quantified the response of NPP to water stress, which is indicated by crop water stress index (CWSI). Regional average of annual NPP in NWC showed an increasing trend during the study period, at a rate of 0.84 g C m-2 yr-1. At the province level, the NPP increase rates increased in the order of Ningxia (7.7%), Shaanxi (6.5%), Gansu (4.5%), Qinghai (3.8%), and Xinjiang (1.7%). NPP was negatively correlated with CWSI (p<0.05) in 73% of areas, indicating the key role of water stress in constraining NPP over this arid region. The effect of water stress on NPP changes with elevation. Water stress has the strongest negative impact on NPP in areas with elevations around 2000 m. In elevations above 5000 m, NPP is not limited by water stress, mostly positively correlated with CWSI. Our findings further clarify the importance of water stress in dryland ecosystems, while highlighting that elevation gradients can significantly affect the correlation between NPP and water stress.

Landscape-scale characterization of Arctic tundra vegetation composition, structure, and function with a multi-sensor unoccupied aerial system

The Arctic is experiencing some of the most rapid climate change on Earth, with strong impacts on tundra ecosystems that are characterized by high land-surface and vegetation heterogeneity. Previous studies have explored this complexity using satellite remote sensing, however these typically coarse spatial resolution data have generally missed sub-pixel heterogeneity, leaving critical gaps in our understanding of tundra vegetation dynamics from the community to landscape scales. To address these gaps, we collected very high-resolution (1–5 cm) optical, structural, and thermal data at three low-Arctic tundra sites on the Seward Peninsula, Alaska, using a multi-sensor unoccupied aerial system (UAS). We examined the application of these data to studying tundra vegetation dynamics, by quantifying (a) canopy height and thermoregulation (leaf–air temperature) of representative plant functional types (PFTs), (b) fine-scale patterns of vegetation composition across landscapes, and (c) impacts of fine-scale vegetation composition on landscape-scale variation of canopy height and thermoregulation. Our results show that deciduous tall shrubs (those that can potentially grow >2 m) had a strong cooling effect, with canopy temperatures significantly lower than local air temperatures and other PFTs. Increased cover of tall shrubs also had the potential to reduce the cover of low-stature PFTs across the landscape, potentially associated with their closed canopy (i.e. increased light competition) and strong thermoregulation. To understand the connections between fine-scale vegetation composition and large-scale ecosystem processes, we produced a random forest model which showed that fine-scale PFT composition accounted for 86.8% and 74.2% of the landscape-scale variation in canopy height and thermoregulation, respectively. These findings highlight the importance of spatially detailed characterization of tundra PFTs to improve our ecological understanding and model representation of tundra vegetation, also transcend our study to show the need for continued collection of similar datasets to better understand the impacts of surface heterogeneity on the mapping and modeling of tundra ecosystem dynamics, as well as assist with conservation management and biodiversity monitoring strategies.

Ecological restoration policy should pay more attention to the high productivity grasslands

To address severe grassland degradation problems, China has been implementing several national restoration programs, which have been reported to mitigate the deterioration of grassland ecosystem function. However, the regional differences in the effectiveness of the programs are not yet known. In this study, gross primary productivity (GPP) was selected as an indicator to analyze grassland degradation dynamics, and the residual trend method was used to assess the driving force of grassland degradation based on GPP. The results showed the GPP of Inner Mongolia grassland significantly increased by 3.94 g C m−2 yr−1 during 2000–2015, climate change was the dominant driving factors, while human activities slightly reduced grassland productivity (−0.17 g C m−2 yr−1). But there are obviously spatial heterogeneous on the impact of human activities. Specifically, grassland management significantly promoted the GPP increase in semidesert steppe, while grazing activity decreased the GPP in meadow and typical steppes. These findings suggest that ecological restoration programs could obviously improve vegetation functioning in ecologically fragile grassland which has relatively very low productivity. However, the grasslands with relative higher productivity or initially non-degraded are still facing with great degradation risk due to the continuous growing livestock scale. Therefore, policy-makers should pay more attention to the originally non-degraded or high productivity grasslands, especially at those years the negative impacts of intensive grazing could be concealed by the well-growth grass under abundant precipitation.

Effects of the interaction among climate, terrain and human activities on biodiversity on the Qinghai-Tibet Plateau

Disentangling the driving factors of biodiversity is critical for understanding biogeographical patterns of vegetation and ecosystem function. However, the biotic and abiotic attributes that shape biodiversity on the Qinghai-Tibet Plateau (QTP) are still not been quantified. Previous studies have not distinguished the direct and indirect effects of climate, terrain, and human disturbance on biodiversity. In this study, we applied a structural equation model (SEM) to assess the interactions among 4 attributes and biodiversity. A conceptual framework with 8 explanatory variables was built to identify the driving forces of biodiversity. A geographically weighted regression (GWR) model was applied to explore the response sensitivity of biodiversity to climate, terrain, and human attributes. We found that the SEM passed the tests of validity, reliability and fit, indicating that the hypothetical model was reasonable and credible. Among terrain conditions, elevation had the greatest, most-negative effect on biodiversity. Among the human factors, distance to town showed the strongest and most negative influence on biodiversity. Among the climate factors, precipitation had the greatest influence on biodiversity. Moreover, the direct effects of terrain and human activity were 0.348 and 0.135, respectively, and their indirect effects were 0.769 and 0.213, respectively, revealing that they had stronger indirect effects on biodiversity than direct effects. Climate exhibited only direct effects on biodiversity and had no indirect effects. The total effects of climate, terrain and human activity on biodiversity were 1.39, 0.35 and 0.13, respectively, indicating that climate was the main driving force of biodiversity on the QTP. The response sensitivity of biodiversity to climate, terrain and human factors showed obvious spatial variations. This study contributes to exploring the interactive effects and driving mechanisms of human-natural attributes on biodiversity and provides further effective guidance and support for biodiversity conservation and restoration.

Remote Sensing of Ecosystem Water Use Efficiency: A Review of Direct and Indirect Estimation Methods

Water use efficiency (WUE) is a key index for understanding the ecosystem of carbon–water coupling. The undistinguishable carbon–water coupling mechanism and uncertainties of indirect methods by remote sensing products and process models render challenges for WUE remote sensing. In this paper, current progress in direct and indirect methods of WUE estimation by remote sensing is reviewed. Indirect methods based on gross primary production (GPP)/evapotranspiration (ET) from ground observation, processed models and remote sensing are the main ways to estimate WUE in which carbon and water cycles are independent processes. Various empirical models based on meteorological variables and remote sensed vegetation indices to estimate WUE proved the ability of remotely sensed data for WUE estimating. The analytical model provides a mechanistic opportunity for WUE estimation on an ecosystem scale, while the hypothesis has yet to be validated and applied for the shorter time scales. An optimized response of canopy conductance to atmospheric vapor pressure deficit (VPD) in an analytical model inverted from the conductance model has been also challenged. Partitioning transpiration (T) and evaporation (E) is a more complex phenomenon than that stated in the analytic model and needs a more precise remote sensing retrieval algorithm as well as ground validation, which is an opportunity for remote sensing to extrapolate WUE estimation from sites to a regional scale. Although studies on controlling the mechanism of environmental factors have provided an opportunity to improve WUE remote sensing, the mismatch in the spatial and temporal resolution of meteorological products and remote sensing data, as well as the uncertainty of meteorological reanalysis data, add further challenges. Therefore, improving the remote sensing-based methods of GPP and ET, developing high-quality meteorological forcing datasets and building mechanistic remote sensing models directly acting on carbon–water cycle coupling are possible ways to improve WUE remote sensing. Improvement in direct WUE remote sensing methods or remote sensing-driven ecosystem analysis methods can promote a better understanding of the global ecosystem carbon–water coupling mechanisms and vegetation functions–climate feedbacks to serve for the future global carbon neutrality.

Tree species dominance in neotropical savanna aboveground biomass and productivity

The relationship between biodiversity and ecosystem functioning is one of the most currently acclaimed ecological topics. One remarkable aspect of tree communities in tropical forests and savannas is the concentration of individuals into few species or simply the species stem dominance. In addition, species dominance in biomass and productivity are indicators of how much it can affect ecosystem processes. Here, we investigated if tree species dominance in abundance is followed by a dominance in biomass and productivity, and if there is consistence in the functional traits associated to dominance in biomass, productivity, and stem abundance in neotropical savannas of Central and Southeastern Brazil. Our findings showed slightly stronger functional (biomass and productivity) dominance compared to the abundance dominance, with 3.4 and 4.2% of the species accounting for 50% of the biomass and productivity, respectively, and 4.3% of the species accounting for 50% of the individuals. There were overlaps, but mostly mismatches, between dominant species lists for biomass, productivity, and abundance, especially in the top three species. We found that the same traits which make a species capable to deal with savanna environmental odds (i.e., adaptations) and achieve high abundance, also make it possible for this species to reach larger diameters and consequently dominance in biomass. Species relative contributions to productivity responded to bark thickness, wood density and maximum potential size. The fact that just a few species concentrate most savanna trees, biomass, and productivity show a high level of adaptation of this species to the environmental conditions found in this biome. Regardless, the conservation of the entire pool of species is crucial because climate change, land use and species invasion might cause shifts in the vegetation structure and function.

Учение о последствиях черепно-мозговой травмы Часть I. Дефиниции, классификация, клиническая и количественно-томографическая синдромология

The paper presents the experience of assessment and treatment of 5000 cases of various traumatic brain injury (TBI) effects using brain imaging methods, minimally invasive and reconstructive neurosurgery. Definitions of TBI “effects” and “complications” have been proposed for the first time. Clinical and morphological classification of those has been developed, which identifies tissue effects, effects on cerebrospinal fluid system dynamics, and vascular effects of TBI. The major clinical symptoms of TBI effects have been described: neurologic deficit, mental dysfunctions, disturbances of vegetative function, epilepsy. Focal and diffuse alterations in brain tissue, intrathecal space and ventricular system resulting from TBI, identified by x-ray computed tomography, have been systematized. This has become the basis for investigation of pathogenesis and sanogenesis of brain disorders resulting from TBI, as well as for developing theory about the TBI effects.

Temporal patterns of vegetation recovery after wildfire in two obligate seeder ash forests

In recent years, novel, high-severity wildfire regimes have driven major changes in the structure and function of forests globally. Indeed, many forests are vulnerable to recruitment failures and collapse in the event of decreased intervals between fires, including forests dominated by the Australian obligate seeders, Alpine Ash (Eucalyptus delegatensis) and Mountain Ash (Eucalyptus regnans). Disturbance responses in these forests are often described collectively, with limited understanding of their potential differences. Despite this, management recommendations and ecological implications are often applied broadly across both forest types. Here, using an empirical dataset collected over an eleven-year period (2009–2020), we compare plant communities in south-eastern Australian Alpine Ash and Mountain Ash forests in mature stands (last burned in 1926/1939), and young stands (burned by high-severity wildfire in 2009). To do this, we used measures of forest structure (basal area of dominant plant life-forms) collected over eight years, and the abundance (projective foliage cover) of vascular plant species. We provide evidence of similar, positive-linear trends in the recovery of forest structure in both Alpine Ash and Mountain Ash forests in the first eight years post-wildfire in 2009. Mature Alpine Ash and Mountain Ash forests were compositionally different but had a similar structure and abundance of plant life-forms. Moreover, controlling for the influence of forest type, young stands were compositionally different from mature stands, and were associated with an increase in the abundance of Acacia, herb, ground-fern and graminoid species, and a decline in tree-fern and tree species. Further investigation in young stands revealed marked differences in plant community composition between forest types, with young Mountain Ash forests characterized by a lower abundance of shrub, Acacia and graminoid species, relative to Alpine Ash forests of the same age. Overall, our findings indicate that Alpine Ash and Mountain Ash forest plant communities may have similar structural and functional responses to predicted increases in wildfire. This suggests that when the broad structure and function of forest vegetation is a consideration, ecological implications and management recommendations may be broadly applicable to both Alpine Ash and Mountain Ash forests. However, further consideration is required in early successional stands where differences in species composition between forest types may have implications for management (e.g. increases in flammability). In a period of uncertainty in the future of ash-type forests, our study provides a timely insight into the comparative successional trajectories of their respective plant communities and provides a baseline for future studies.

Assembly processes lead to divergent soil fungal communities within and among 12 forest ecosystems along a latitudinal gradient.

Latitudinal gradients provide opportunities to better understand soil fungal community assembly and its relationship with vegetation, climate, soil and ecosystem function. Understanding the mechanisms underlying community assembly is essential for predicting compositional responses to changing environments. We quantified the relative importance of stochastic and deterministic processes in structuring soil fungal communities using patterns of community dissimilarity observed within and between 12 natural forests and related these to environmental variation within and among sites. The results revealed that whole fungal communities and communities of arbuscular and ectomycorrhizal fungi consistently exhibited divergent patterns but with less divergence for ectomycorrhizal fungi at most sites. Within those forests, no clear relationships were observed between the degree of divergence within fungal and plant communities. When comparing communities at larger spatial scales, among the 12 forests, we observed distinct separation in all three fungal groups among tropical, subtropical and temperate climatic zones. Soil fungal β-diversity patterns between forests were also greater when comparing forests exhibiting high environmental heterogeneity. Taken together, although large-scale community turnover could be attributed to specific environmental drivers, the differences among fungal communities in soils within forests was high even at local scales.

Community Trait Responses of Three Dominant Macrophytes to Variations in Flooding During 2011-2019 in a Yangtze River-Connected Floodplain Wetland (Dongting Lake, China).

In lacustrine wetlands connected to rivers, the changes in flood regimes caused by hydrological projects lead to changes in the community traits of dominant macrophytes and, consequently, influence the structure and function of wetland vegetation. However, community trait responses of macrophytes to the timing and duration of flood disturbance have been rarely quantified. In 2011–2019, we investigated plant species diversity, density, and biomass in three dominant macrophyte communities (Carex brevicuspis C.B. Clarke, Miscanthus sacchariflorus (Maxim.) Hackel, and Polygonum hydropiper L.) through monthly field surveys in Dongting Lake wetlands. Partial least squares regressions were used to analyze how the variations in hydrological regimes affected plant community traits. Apparent inter-annual fluctuations in plant community traits were detected during 2011–2019. The species richness and Shannon index of diversity of Miscanthus and Polygonum communities increased, whereas the Shannon index of diversity of Carex community decreased. Variation in flooding had a greater effect on Polygonum and Carex community traits than on Miscanthus community traits. Flooding disturbed all plant communities, especially when the duration and timing varied. Shorter inundation periods caused the biomass of Miscanthus community to decline, and that of Carex and Polygonum communities to increase. Earlier flood recession caused the species richness and Shannon index of diversity of Polygonum and Miscanthus community to increase, and those of Carex community to decrease. These findings imply that shorter inundation durations and earlier flood recession generated by the operation of the Three Gorges Dam have changed the macrophyte growth pattern.

Reduced resilience of terrestrial ecosystems locally is not reflected on a global scale

Global climate change likely alters the structure and function of vegetation and the stability of terrestrial ecosystems. It is therefore important to assess the factors controlling ecosystem resilience from local to global scales. Here we assess terrestrial vegetation resilience over the past 35 years using early warning indicators calculated from normalized difference vegetation index data. On a local scale we find that climate change reduced the resilience of ecosystems in 64.5% of the global terrestrial vegetated area. Temperature had a greater influence on vegetation resilience than precipitation, while climate mean state had a greater influence than climate variability. However, there is no evidence for decreased ecological resilience on larger scales. Instead, climate warming increased spatial asynchrony of vegetation which buffered the global-scale impacts on resilience. We suggest that the response of terrestrial ecosystem resilience to global climate change is scale-dependent and influenced by spatial asynchrony on the global scale.