Grassland degradation represents a major challenge in the maintenance of grassland productivity. This process has dramatic impacts on energy flows and soil nutrient dynamics, thus directly or indirectly influencing soil microbes. Here, we aim to (i) examine changes in soil microbial composition, diversity and functionality in response to different levels of grassland degradation (i.e. non-degraded, moderately and severely degraded) in a temperate grassland in Inner Mongolia, and (ii) elucidate biotic and abiotic factors that are responsible for these changes.

The composition structure of soil microbial community was determined by high-throughput sequencing. The functionality of bacterial communities was examined using the tool of FAPROTAX, and functional guilds of fungal communities were quantified using the FUNGuild pipeline.

Grassland degradation significantly decreased soil bacterial diversity but it did not affect fungal diversity. Belowground biomass, soil organic carbon and total nitrogen were positively related to changes in diversity of bacterial community. Grassland degradation significantly increased the relative abundance of Chloroflexi (from 2.48% to 8.40%) and decreased Firmicutes (from 3.62% to 1.08%) of bacterial community. Degradation also significantly increased the relative abundance of Glomeromycota (from 0.17% to 1.53%) and decreased Basidiomycota (from 19.30% to 4.83%) of fungal community. The relative abundance of pathogenic fungi (Didymella and Fusarium) was decreased significantly by degradation. In addition, degradation had a significant impact on putative functionality of soil bacteria related to soil carbon and nitrogen cycling. Our results suggest that soil bacterial community is more sensitive than fungal community in response to degradation in the temperate grassland.

Biomass allocation to different organs is a fundamental plant ecophysiological process to better respond to changing environments; yet, it remains poorly understood how patterns of biomass allocation respond to nitrogen (N) additions across terrestrial ecosystems worldwide.

We conducted a meta-analysis using 5474 pairwise observations from 333 articles to assess how N addition affected plant biomass and biomass allocation among different organs. We also tested the ‘ratio-based optimal partitioning’ vs. the ‘isometric allocation’ hypotheses to explain potential N addition effects on biomass allocation.

We found that (i) N addition significantly increased whole plant biomass and the biomass of different organs, but decreased root:shoot ratio (RS) and root mass fraction (RMF) while no effects of N addition on leaf mass fraction and stem mass fraction at the global scale; (ii) the effects of N addition on ratio-based biomass allocation were mediated by individual or interactive effects of moderator variables such as experimental conditions, plant functional types, latitudes and rates of N addition and (iii) N addition did not affect allometric relationships among different organs, suggesting that decreases in RS and RMF may result from isometric allocation patterns following increases in whole plant biomass. Despite alteration of ratio-based biomass allocation between root and shoot by N addition, the unaffected allometric scaling relationships among different organs (including root vs. shoot) suggest that plant biomass allocation patterns are more appropriately explained by the isometric allocation hypothesis rather than the optimal partitioning hypothesis. Our findings contribute to better understand N-induced effects on allometric relationships of terrestrial plants, and suggest that these ecophysiological responses should be incorporated into models that aim to predict how terrestrial ecosystems may respond to enhanced N deposition under future global change scenarios.

Generalized linear mixed models (GLMMs) have been widely used in contemporary ecology studies. However, determination of the relative importance of collinear predictors (i.e. fixed effects) to response variables is one of the challenges in GLMMs. Here, we developed a novel R package, glmm.hp, to decompose marginal R² explained by fixed effects in GLMMs. The algorithm of glmm.hp is based on the recently proposed approach ‘average shared variance’ i.e. used for multivariate analysis. We explained the principle and demonstrated the use of this package by simulated dataset. The output of glmm.hp shows individual marginal R²s that can be used to evaluate the relative importance of predictors, which sums up to the overall marginal R². Overall, we believe the glmm.hp package will be helpful in the interpretation of GLMM outcomes.

The limitations of classical Lotka–Volterra models for analyzing and interpreting competitive interactions among plant species have become increasingly clear in recent years. Three of the problems that have been identified are (i) the absence of frequency-dependence, which is important for long-term coexistence of species, (ii) the need to take unmeasured (often unmeasurable) variables influencing individual performance into account (e.g. spatial variation in soil nutrients or pathogens) and (iii) the need to separate measurement error from biological variation.

We modified the classical Lotka–Volterra competition models to address these limitations. We fitted eight alternative models to pin-point cover data on Festuca ovina and Agrostis capillaris over 3 years in an herbaceous plant community in Denmark. A Bayesian modeling framework was used to ascertain whether the model amendments improve the performance of the models and increase their ability to predict community dynamics and to test hypotheses.

Inclusion of frequency-dependence and measurement error, but not unmeasured variables, improved model performance greatly. Our results emphasize the importance of comparing alternative models in quantitative studies of plant community dynamics. Only by considering possible alternative models can we identify the forces driving community assembly and change, and improve our ability to predict the behavior of plant communities.

Dispersal through space or time via dormancy is one of the primary processes whereby organisms can influence the environment they experience. In plants, strong evolutionary correlations are expected between the two kinds of dispersal because both are performed by the seeds and play comparable adaptive roles. In this paper, we investigated these evolutionary correlations using amphicarpic plants, which simultaneously produce aerial seeds with high spatial dispersal propensity and subterranean seeds that do not disperse.

We investigated the variation in dormancy and germination in aerial and subterranean seeds of two amphicarpic legumes (Vicia amphicarpa L. and Lathyrus amphicarpos L.) and two closely related homocarpic taxa (Vicia sativa L. and Lathyrus cicera L.) by estimating germination percentages following different combinations of dormancy breaking treatments (i.e. dry after-ripening, cold stratification and physical scarification).

Our results showed complex interactions between spatial and temporal dispersal. Right after dispersal, aerial seeds were more dormant than their subterranean counterparts, but this trend reversed with after-ripening, as seeds developed physical dormancy. Seeds of homocarpic plants germinated at higher percentages than those of their amphicarpic congeners and lost dormancy homogeneously with after-ripening. Conversely, amphicarpic seeds exhibited varied dormancy strategies modulated by both physiological and physical dormancy. These are expected to increase variation in emergence timing, providing multiple levels of diversifying bet-hedging. This strategy might be adaptive under highly unpredictable conditions by enabling plants to rely on historically favorable sites in good seasons without preventing spatial and temporal migration.

Unmanned aerial vehicles (UAVs), i.e. drones, have recently emerged as cost-effective and flexible tools for acquiring remote sensing data with fine spatial and temporal resolution. It provides a new method and opportunity for plant ecologists to study issues from individual to regional scales. However, as a new method, UAVs remote sensing applications in plant ecology are still challenged. The needs of plant ecology research and the application development of UAVs remote sensing should be better integrated.

This report provides a comprehensive review of UAV-based remote sensing applications in plant ecology to synthesize prospects of applying drones to advance plant ecology research.

Of the 400 references, 59% were published in remote sensing journals rather than in plant ecology journals, reflecting a substantial gap between the interests of remote sensing experts and plant ecologists. Most of the studies focused on UAV remote sensing’s technical aspects, such as data processing and remote sensing inversion, with little attention on answering ecological questions. There were 61% of studies involved community-scale research. RGB and multispectral cameras were the most used sensors (75%). More ecologically meaningful parameters can be extracted from UAV data to better understand the canopy surface irregularity and community heterogeneity, identify geometrical characteristics of canopy gaps and construct canopy chemical assemblies from living vegetation volumes. More cooperation between plant ecologists and remote sensing experts is needed to promote UAV remote sensing in advancing plant ecology research.

The factors affecting species abundance are a subject of ongoing debates in community ecology. Empirical studies have demonstrated that tree abundance is affected by plant functional traits and negative density dependence (NDD). However, few studies have focused on the combined effects of NDD and plant functional traits on species abundance.

In this study, we used tree functional traits and two census data from a 50-ha forest dynamic plot in the Heishiding (HSD) Nature Reserve to explore the combined effects of functional traits and NDD on species abundance. Using hierarchical Bayesian models, we analyzed how neighbor densities affected the survival of saplings from 130 species and extracted posterior means of the coefficients to represent NDD. The structural equation modeling (SEM) analysis was then applied to investigate the causal relationships among species functional traits, NDD and species abundance.

SEM showed that tree functional traits, including specific leaf area (SLA), leaf area (LA), leaf dry matter content (LDMC), leaf N content (LNC), maximum electron transport rate (ETR_max) and conspecific adult negative density dependence (CNDD_adult), together explained 20% of the total variation in tree abundance. Specifically, SLA affected tree abundance both directly and indirectly via CNDD_adult, with a totally negative influence on abundance. LDMC and LNC had only indirect effects mediated by CNDD_adult on tree abundance. ETR_max and LA had directly negative effects on abundance, but their direct connections with CNDD_adult were not observed. In addition, CNDD_adult was negatively correlated with species abundance, indicating that abundant species are under stronger NDD. Among these investigated traits, SLA contributed the most to the variation in CNDD_adult and abundance. We argued that our findings of trait–CNDD_adult–abundance relationships can improve our understanding of the determinants of species commonness and rarity in forests.

Functional group composition of a plant community is mainly driven by environmental factors and is one of the main determinants of grassland biodiversity and productivity. Therefore, it is important to understand the role of plant functional groups (PFGs) in mediating the impact of environmental conditions on ecosystem functions and biodiversity.

We measured plant biomass and species richness (SR) of grasslands in 65 sites on the Mongolian Plateau and classified 157 perennial herbaceous plants into two main PFGs (namely grasses and forbs). Using the random forest model and ordinary least squares regression, we identified that environmental factors (i.e. aridity index, soil total nitrogen [STN] and pH) were significantly related to the SR and aboveground biomass (AGB) of PFGs. We then used structural equation modeling to explore the relationship between the identified environmental factors and community SR and biomass, and the role of PFGs in driving this relationship.

We found that aridity index had unimodal relationships with both AGB and SR of the PFGs and the whole community. All SR and biomass metrics were significantly related to STN and pH. The relationship between aridity index and community biomass was mediated by an increase in the AGB of grasses. The influence of STN and pH on community SR was mainly due to their regulation in the SR of forbs. Our results indicate that community composition and the identity of the PFGs play a key role in linking environmental factors to ecosystem functioning.

Biodiversity patterns along elevational gradients have been well documented. Yet, the variations of biodiversity patterns along elevations and their underlying mechanisms are still unclear. Integrating multiple facets of biodiversity provides novel insights into the mechanisms for driving community assembly. In this study, species abundance information was incorporated into taxonomic and phylogenetic diversity to reveal the ecological and evolutionary forces of plant community assembly along an elevational gradient in subtropical forests.

We selected 17 woody plant plots along an elevational gradient from 270 to 1470 m in eastern China’s subtropical forests. Both presence-based and abundance-based measures of angiosperm species were used to quantify taxonomic alpha diversity, phylogenetic alpha diversity, phylogenetic relatedness, as well as taxonomic and phylogenetic dissimilarity among these plots. And the relations between these measures and climatic and topographic variables were analyzed.

For both abundance-weighted and unweighted measures, we observed an overall increasing pattern for taxonomic alpha diversity along elevation, and distance-decay trends of taxonomic and phylogenetic similarity with increased elevational distances. However, there were disparity patterns of phylogenetic alpha diversity between abundance-weighted and unweighted measures. For phylogenetic structure, there was no significant trend along elevation. Both topographical and microclimatic variables were main drivers of diversity patterns and phylogenetic structure. Compared with unweighted measures, abundance-weighted measures were strongly related with the slope and stand basal area. Overall, our results prove that deterministic processes mediated by local species abundance imprint on plant community composition along the elevational gradient.

Dioecious plants exhibit sexual dimorphism in both sexual features (reproductive organs) and secondary sex characteristics (vegetative traits). Sexual differences in secondary traits, including morphological, physiological and ecological characters, have been commonly associated with trade-offs between the cost of reproduction and other plant functions. Such trade-offs may be modified by environmental stressors, although there is evidence that sexually dimorphic responses to stress do not always exist in all plant species. When sexual dimorphism exists, sexually different responses appear to depend on the species and stress types. Yet, further studies on dioecious plant species are needed to allow the generalization of stress effects on males and females. Additionally, sexual dimorphism may influence the frequency and distribution of the sexes along environmental gradients, likely causing niche differentiation and spatial segregation of sexes. At the present, the causes and mechanisms governing sex ratio biases are poorly understood. This review aims to discuss sex-specific responses and sex ratio biases occurring under adverse conditions, which will advance our knowledge of sexually dimorphic responses to environmental stressors.

Both extreme drought and insect herbivores can suppress plant growth in grassland communities. However, most studies have examined extreme drought and insects in isolation, and there is reason to believe that insects might alter the ability of grasslands to withstand drought. Unfortunately, few studies have tested the interactive effects of extreme drought and insect herbivores in grassland communities.

Here, we tested the drought–herbivore interactions using a manipulative experiment that factorially crossed extreme drought with the exclusion of insect herbivores in a temperate semiarid grassland in Inner Mongolia.

Our results demonstrated that both extreme drought and insect herbivores separately decreased total plant cover. When combined, insect herbivores reduced the impact of drought on total cover by increasing the relative abundance of drought-resistant dominant species. Our results highlight that the negative effect of extreme drought on total plant cover could be alleviated by maintaining robust insect herbivore communities.

Precipitation (PPT) changes affect both aboveground vegetation dynamics and belowground carbon cycling processes, particularly in arid and semiarid regions. However, it remains unclear how extreme PPT variation can affect soil carbon sequestration potential. A 3-year PPT manipulation experiment with five levels (±40%, ±20% and ambient PPT) was conducted in a desert grassland of western Loess Plateau. Aboveground net primary productivity (ANPP) and soil respiration (Rs) were measured to examine whether the responses of ANPP and Rs to PPT changes displayed a double asymmetry model. The ANPP was more sensitive to extreme drought than extreme wet treatments in wet and dry years, which displayed a negative asymmetric model. The change in ANPP was mainly due to the direct effect of PPT change, and plant density variation also exerted some influence in the dry year. In contrast, Rs displayed a positive asymmetry response to PPT change in dry year. This may be ascribed to enhanced autotrophic respiration due to the enhanced positive responses of plant growth and ANPP to wet treatments as well as stronger birch effect of rainfall events on heterotrophic respiration. The saturating response of Rs to extreme drought (−40% PPT treatment) was also found in the dry year. Nevertheless, the response of Rs to PPT change displayed a negative asymmetry model in wet years. The contrasting models for ANPP and Rs in response to altered PPT regime suggest that extreme wet or dry treatments may increase soil C pools effluxes toward debt in this desert grassland.

Atmospheric nitrogen (N) deposition influences tree hydraulic architecture and thus the growth and survival; but the responses of leaf hydraulic traits remain uncertain, and may vary with species or plant functional types.

We used the 16-year N addition experiment (10 g N m⁻² year⁻¹) on Fraxinus mandshurica (ash, broadleaf angiosperm) and Larix gmelinii (larch, conifer gymnosperm) plantations in northeastern China and examined the effect of N addition on their leaf hydraulics. We measured the leaf pressure–volume traits by the bench drying method and quantified the maximum leaf hydraulic conductance (K_{leaf_max}) and resistance to embolism (P_50leaf) by the timed rehydration method.

Larch had higher K_{leaf_max} and stronger drought tolerance (i.e., lower relative water content at turgor loss point (RWC_tlp) and modulus of elasticity (ε), and more negative P_50leaf) than ash. N addition increased the leaf osmotic potential at turgor loss (π_tlp) and full turgor (π₀), and leaf capacitance (C_{leaf_mass}) for ash but not for larch, indicating that ash is more sensitive to N addition. N addition consistently increased K_{leaf_max} and P_50leaf values for both species. π_tlp and π₀ were positively while C_{leaf_mass} was negatively correlated with leaf density (LD) for ash. K_{leaf_max} was positively but P_50leaf was negatively related with LD for larch. There were negative relationships between K_{leaf_max} and P_50leaf for both species. Overall, our findings suggest that long-term N addition decreases the leaf drought tolerance for these two important tree species, which improve the understanding of the tree hydraulic performance under N deposition.

Alien plant invasion has become a major global environmental issue, causing severe economic and ecological damages. Severe invasions have been reported in some regions of China. However, most studies have been conducted at local and provincial levels, and the overall degree of invasion in natural forests across China remains unclear. Here, we explored the biogeographic patterns and their environmental and socioeconomic controls of the invaded alien woody plants in natural forests across the country.

We compiled the data of 3573 natural forest plots across the mainland China and mapped spatial distribution of alien woody plant invasion. We also used logistic regression models to identify the key socioeconomic and environmental factors that were associated with the observed invasion patterns.

We found that only 271 plots among 3573 natural forest plots were invaded by alien woody plants, accounting for 7.58% of all plots. Among all 2825 woody plant species across all plots surveyed, only 5 alien species (0.177%) were found. Both human activities and climate factors were related to the observed invasion patterns. Since China’s natural forests are mostly located in remote mountainous areas with limited human disturbance, alien woody plant invasions are less than those reported in North America and Europe. However, with the development of transportation and increased economic activities in mountainous areas, more invasions by alien plants may be expected in the future. Therefore, proactive management and policy making are desired to prevent or slow down the invasion processes.

Competition among plants in a community usually depends on their nitrogen (N)-use efficiency (NUE) and water-use efficiency (WUE) in arid and semi-arid regions. Artemisia frigida is an indicator species in heavily degraded grassland, however, how its NUE and WUE respond to N addition in different successional stages is still unclear, especially with mowing, a common management practice in semi-arid grasslands.

Based on a long-term controlled experiment with N addition and mowing in an abandoned cropland from 2006 to 2013, we investigated the NUE and WUE of A. frigida in two patches (i.e. grass and herb patches) in 2013 which represented two potential successional stages from herb to grass communities. The coverage of A. frigida was higher (about 50%) in the herb patch than in the grass patch (about 10%). Stable isotopic C (δ 13C) and N (δ 15N) as well as C and N pools were measured in plants and soils. NUE was calculated as leaf C/N, and leaf δ 13C values were used as a proxy for WUE.

N addition did not affect WUE of A. frigida, but significantly decreased NUE by 42.9% and 26.6% in grass and herb patches, respectively. The response of NUE to N addition was related to altering utilization of different N sources (NH₄+vs. NO₃−) by A. frigida according to the changed relationship between leaf δ 15N/soil δ 15N and NUE. Mowing had no effect on NUE regardless of N addition, but significantly increased WUE by 2.3% for A. frigida without N addition in the grass patch. The addition of N reduced the positive effect of mowing on its WUE in grass patch. Our results suggested that decreased NUE and/or WUE of A. frigida under mowing and N addition could reduce its competition, and further accelerate restoration succession from the abandoned cropland to natural grassland in the semi-arid region.

Interactions between plants and their soil biota, arbuscular mycorrhizal fungi (AMF) in particular, may play a vital role in the establishment and the range expansion of exotic plants in new environments. However, whether there are post-introduction shifts in dependence on AMF and how dependency interacts with competition remains poorly understood.

We conducted a common garden greenhouse experiment to examine how native (USA) and invasive (China) populations of the plant species Plantago virginica, respond to soil biota, and whether these responses change in the presence of a competitor.

We found that while native populations consistently had a higher AMF colonization rate and benefited from AMF in both biomass and seed production, invasive populations received less benefit from AMF, and even showed reduced biomass with AMF in the presence of a competitor. This low mycorrhizal dependency in invasive populations correlated with greater suppression by an indigenous competitor for the invader. The different responses of the invasive and native populations to AMF suggest that alteration of mycorrhizal dependency has occurred during the invasion of P. virginica into China. Our findings suggest that this reduced dependency incurs a cost during interspecific competition.

The evolution and expression of dispersal-related traits are intertwined with those of other life-history functions and are manifested within various physiological constraints. Such a relationship is predicted between inbreeding levels and dispersability, which may be anatomically and ontogenetically linked so that the selection pressures on one may affect the other. While both the effect of inbreeding on reproductive success and on dispersal strategies received much attention, only a few studies considered both simultaneously. Furthermore, such studies often rely on two dichotomic representations of breeding and dispersal: using selfing versus outcrossing as a representation of breeding level, and dispersal ratio as the sole representation of dispersal strategy.

Here, we used pollination experiments in the heterocarpic Crepis sancta (Asteraceae) to expand in two different manners on the common practice of using dichotomic representations of breeding and dispersal. First, we used pollination treatments that represent a continuum from selfing through pollination by kin to pollination by a distant neighbor. Second, we measured a whole set of continuous morphological and dispersal-related traits, in addition to measurements of reproductive success and dispersal ratio.

The proportion of developed capitula and the number of both dispersed and non-dispersed achenes were significantly lower in the self-pollination treatment in comparison to the outcrossed treatments. The effect of pollen sources on dispersal ratio was not statistically significant, though self-pollinated plants rarely produced non-dispersing seeds. Achene’s biomass increased with distance between parent plants, but pappus width did not, leading to a nonsignificant effect of pollination on falling velocity. Overall, pollen source affected mainly traits that were associated with reproductive output, but it had no clear effect on predominately dispersal-related traits. Such differences in the response of reproduction and dispersal traits to variation in pollen source suggest that dispersal-related selection is probably weak and/or masked by other forces.

Recent warmer and wetter climate in northern China remains a hot topic in recent years, yet its effect on vegetation growth has not been fully understood. This study investigated the temporal change of vegetation cover and its correlations with climatic variables from 1982 to 2018 for grasslands in northern China. Our aim is to clarify whether the warmer and wetter climate in recent years drives the greening of the vegetation in this region.

We investigated the temporal dynamic of vegetation normalized difference vegetation index (NDVI) and its driving forces based on long time-series data. Piecewise regression was used to examine whether there was a turning point of the trend of NDVI and climatic variables. Pearson correlation analyses were conducted to quantify the relationship between NDVI and climatic factors. Stepwise multivariable regression was used to quantify the contributions of climate variables to the temporal variations in NDVI.

We found a turning point of NDVI trend in 2008, with GIMMS NDVI indicating a slight increase of 0.00022 yr⁻¹ during 1982–2008 to an increase of 0.002 yr⁻¹ for GIMMS NDVI during 2008–2015 and 0.0018 yr⁻¹ for MODIS NDVI during 2008–2018. Precipitation was the predominant driver, and air temperature and vapor pressure deficit exerted a minor impact on the temporal dynamics of NDVI. Overall, our results suggest a turning point of NDVI trend, and that recent warmer and wetter climate has caused vegetation greening, which provides insights for better predicting the vegetation cover in this region under changing climate.

Litter is frequently buried in the soil in alpine grasslands due to grassland degradation, serious rodent infestation and frequent strong winds. However, the effects of various litter positions on litter decomposition rates and nutrient dynamics under nitrogen (N) enrichment in such areas remain unknown.

A field experiment was performed in the alpine grasslands of northwest China to investigate the influence of litter position (surface, buried in the soil and standing) and N enrichment on litter decomposition, using data from two dominant grass species (Festuca ovina and Leymus tianschanicus) in control and N-enriched plots.

Litter decomposition rates were much faster in buried litter and slower in standing litter than in surface litter. N enrichment significantly affected litter quality and then influenced decomposition. But no significant differences in litter mass remaining were observed between control and N-enriched soil burial. These results indicated that N enrichment significantly affected litter decomposition by changes in litter quality. In addition, all litter exhibited net carbon (C) and phosphorus (P) release regardless of treatments. Litter exhibited net N accumulation for litter from the control plots but showed N release for litter from N enrichment plots. These suggested that litter decomposition can be limited by N and N enrichment influenced N cycling of litter. Current study presented direct evidence that soil buried litter exhibited faster mass loss and C release, and that soil burial can be a candidate explanation why litter decomposes faster than expected in dryland.

Invasive plants may alter soil fungal communities in a way that improves their growth. Nitrogen (N) content of soil affects the symbiosis between plants and arbuscular mycorrhizal fungi (AMF), further determining plant growth. Yet, it is unclear whether altered AMF communities change the dependence of invasive and native species on N-form, and whether N forms alter the invasive plant–AMF interaction (PSI_M).

Two synthetic plant communities, including four Solidago canadensis individuals and four native plant species, were inoculated with AMF spores from S. canadensis-invaded soils and adjacent non-invaded soils, and were provided with nitrate, ammonia or glutamate. After their growth, the performance of the two plant communities in treatments of AMF origin and N forms, and the pathways of the N forms affecting S. canadensis growth and PSI_M were evaluated.

Solidago canadensis had no obvious N-form dependence in any of the AMF inoculations. Native plant species showed weak N-form dependence, but invasive AMF could remove their N-form dependence. In the absence of N, AMF did not affect growth of S. canadensis and the native plants. In contrast, with N addition, invasive AMF significantly increased belowground and total biomass of the invasive plants but not those of the native plants. Positive PSI_M of S. canadensis was also evidently greater than that of native plant species and was realized through directly or indirectly regulating phenotypic traits including plant height, leaf number and number of rhizomes. Our findings emphasize the importance of plant–AMF interactions and a unique N-acquisition strategy during plant invasions.

Human activities and global changes have led to alterations in global and regional precipitation regimes. Despite extensive studies on the effects of changes in precipitation regimes on plant community composition across different types of grassland worldwide, few studies have specifically focused on the effects of precipitation changes on high-altitude alpine steppe at community and plant species levels in the Tibetan Plateau.

We investigated the effects of growing-season precipitation changes (reduced precipitation by 50%, ambient precipitation, enhanced precipitation by 50%) for 6 years on plant community composition in an alpine steppe of the Tibetan Plateau by linking above- to belowground traits of dominant species.

We found that reduced precipitation shifted community composition from dominance by bunchgrass (primarily Stipa purpurea) to dominance by rhizomatous grass (primarily Leymus secalinus). Roots and leaf traits of L. secalinus and S. purpurea differed in their responses to reduced precipitation. Reduced precipitation enhanced root vertical length and carbon (C) allocation to deep soil layers, and decreased the leaf width in L. secalinus, but it did not change the traits in S. purpurea. Moreover, reduced precipitation significantly enhanced rhizome biomass, length, diameter and adventitious root at the rhizome nodes in L. secalinus. These changes in traits may render rhizomatous grass greater competitive during drought stress. Therefore, our findings highlight important roles of above- and belowground traits of dominant species in plant community composition of alpine steppe under precipitation change.

Foliar pH of terrestrial plants, a trait tightly associated with plant physiology and nutrient utilization, varies with plant functional types (PFTs) and environmental changes. However, it is yet unclear about the variation in foliar pH of aquatic plants, and the difference between aquatic and terrestrial plants.

Foliar pH, leaf carbon, nitrogen content of plants along the lakeshore zones and the environmental conditions (water or soil pH, water status) of the corresponding vegetation of three small plateau lakes were investigated, to determine the variation and potential influence factors of foliar pH at both PFT and community levels.

Foliar pH varied largely among aquatic plants, and across aquatic, helophytic and terrestrial plants. Floating-leaved macrophytes had more acidic foliage (pH = 4.21 ± 0.05) than emergent (5.71 ± 0.07) and submerged macrophytes (5.82 ± 0.06). Foliar pH of aquatic herbs (5.43 ± 0.10) was lower than that of helophytic (6.12 ± 0.07) and terrestrial herbs (5.74 ± 0.05). Terrestrial herbs had significantly higher foliar pH than woody plants. The variation in foliar pH across PFTs may be mainly ascribed to leaf structure, light utilization and nutrient characteristics. Consistent with the pattern on PFT level, aquatic communities had more acidic foliage than terrestrial communities, which was mainly shaped by species composition, water status and environmental pH. This study documented the first-time foliar pH of aquatic plants, and comparison of foliar pH among various plant types at a landscape scale. Our results provide bases for further exploration of the underlying mechanism and its ecological significance for wetland ecosystems.

To compare current methods of pretreatment/determination for plant foliar pH, we proposed a method for long-period sample preservation with little interference with the stability of foliar pH. Four hundred leaf samples from 20 species were collected and four methods of pH determination were used: refrigerated (stored at 4 °C for 4 days), frozen (stored at −16 °C for 4 days), oven-dried and fresh green-leaf pH (control). To explore the effects of different leaf:water mixing ratio on the pH determination results, we measured oven-dried green-leaf pH by leaf:water volume ratio of 1:8 and mass ratio of 1:10, and measured frozen senesced-leaf pH by mass ratio of 1:10 and 1:15. The standard major axis regression was used to analyze the relationship and the conversion equation between the measured pH with different methods. Foliar pH of refrigerated and frozen green leaves did not significantly differ from that of fresh green-leaf, but drying always overrated fresh green-leaf pH. During the field sampling, cryopreservation with a portable refrigerator was an advisable choice to get a precise pH. For long-duration field sampling, freezing was the optimal choice, and refrigeration is the best choice for the short-time preservation. The different leaf:water mixing ratio significantly influenced the measured foliar pH. High dilution reduced the proton concentration and increased the measured pH. Our findings provide the conversion relationships between the existing pretreatment and measurement methods, and establish a connection among pH determined by different methods. Our study can facilitate foliar pH measurement, thus contributing to understanding of this interesting plant functional trait.

Intraspecific variation in plant traits has important consequences for individual fitness and herbivore foraging. For plants, trait variability across spatial dimensions is well documented. However, temporal dimensions of trait variability are less well known, and may be influenced by seasonal differences in growing degree days (GDD), temperature and precipitation. Here, we aim to quantify intraspecific temporal variation in traits and the underlying drivers for four commonly occurring boreal plant species.

We sampled the elemental and stoichiometric traits (%C, %N, %P, C:N, C:P, N:P) of four common browse species’ foliage across 2 years. Using a two-step approach, we first fitted generalized linear models (GzLM, n = 24) to the species’ elemental and stoichiometric traits, and tested if they varied across years. When we observed evidence for temporal variability, we fitted a second set of GzLMs (n = 8) with temperature, productivity and moisture as explanatory variables.

We found no evidence of temporal variation for most of the elemental and stoichiometric traits of our four boreal plants, with two exceptions. Year was an important predictor for percent carbon across all four species (R2 = 0.47–0.67) and for multiple elemental and stoichiometric traits in balsam fir (5/8, R2 = 0.29–0.67). Thus, variation in percent carbon was related to interannual differences, more so than nitrogen and phosphorus, which are limiting nutrients in the boreal forest. These results also indicate that year may explain more variation in conifers’ stoichiometry than for deciduous plants due to life history differences. GDD was the most frequently occurring variable in the second round of models (8/8 times, R2 = 0.21–0.41), suggesting that temperature is an important driver of temporal variation in these traits.

Despite a large number of studies examining the effects of abiotic stress factors on plants, the mechanistic explanations of drought-induced tree mortality remain inconclusive and even less is known about how multiple stressors interact. The role of non-structural carbohydrates (NSCs) in preventing or postponing drought mortality is gaining attention. Here, we tested the role of NSCs in mitigating the effects of drought and salinity in New Zealand mangroves, Avicennia marina subsp. australasica. We experimentally manipulated plant NSC levels, prior to subjecting them to combinations of drought and salinity. Plant growth and survival rates were 2- and 3-fold higher in the high-NSC (H-NSC) group than in the low-NSC (L-NSC) group under high salinity and drought conditions, respectively. After 12 weeks under high salinity–high drought conditions, the H-NSC group showed higher stem hydraulic conductivity (281 ± 50 mmol cm⁻¹ s⁻¹ MPa⁻¹) compared with the L-NSC group (134 ± 40 mmol cm⁻¹ s⁻¹ MPa⁻¹). Although starch levels remained relatively constant, we found a 20% increase in soluble sugars in the stems of H-NSC group under high drought and high salinity in week 8 compared with week 12. Our results suggest (i) an important role of NSCs in mitigating the effects of low soil water potential caused by drought and salinity, and (ii) sink-limited growth under conditions of combined salinity and drought.

Leaf nutrient resorption is sensitive to changes in soil nutrients. However, the effects of N deposition on nutrient resorption efficiency (NuRE) in plant macro-nutrients remain unclear. Poplar (Populus deltoids) is one of the most extensively cultivated hardwood species worldwide. We explored general patterns and dominant drivers of NuRE and stoichiometry of poplar plantations in response to N addition.

We conducted a 4-year N-addition experiment to explore NuRE and stoichiometric responses to N addition in two poplar (P. deltoids) plantations (8- and 12-year-old stands) in a coastal region of eastern China. We measured soil and foliar (green and senesced leaves) concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) for a series of N addition treatments including N₀ (0 kg N ha−1 yr−1), N₁ (50 kg N ha−1 yr−1), N₂ (100 kg N ha−1 yr−1), N₃ (150 kg N ha−1 yr−1) and N₄ (300 kg N ha−1 yr−1).

Consistent for (both) 8- and 12-year-old stands, N addition did not affect the NuRE and stoichiometry (with the exception of CaRE and CaRE:MgRE ratio). N resorption efficiency–P resorption efficiency (NRE–PRE) scaling slopes were consistently less than 1.0 under N addition. These results suggest that NRE generally decouples from PRE within each N treatment. Moreover, these results point to robust control of green leaf nutritional status on nutrient resorption processes as indicated by the positive relationships between NuRE and green leaf nutrient concentrations. Our findings provided a direct evidence that growth in 12-year-old poplar plantations was N-limited in the coastal region of eastern China.

As one of the main food bamboo species of the giant panda (Ailuropoda melanoleuca), Fargesia denudata is widely distributed in the understory of spruce–fir forests in the mountainous area of southwestern China. However, the driving factors of its biomass and distribution in the forests are still unclear. We conducted a systematic investigation of the tree and shrub layers (including bamboos) of 209 subplots (20 m × 20 m) in a Forest Global Earth Observatory plot, the Wanglang Plot (25.2 ha), to explore the effects of abiotic (topographic and soil characteristics) and biotic (tree density, total basal area (TBA), shrub coverage, etc.) factors on the aboveground biomass of F. denudata (bamboo biomass hereafter). Bamboo biomass averaged 1.17 ton/ha, with a large variation from 0 to 4.88 ton/ha (95% confidence interval) among the 209 subplots. Bamboo biomass increased significantly with elevation, slope and mean diameter at breast height of trees, and decreased significantly with tree density, shrub coverage and soil pH. However, bamboo biomass was not significantly correlated with tree TBA, aspect, soil organic matter or total nitrogen content. The random forest model indicated that topographic factors and biotic factors had greater influences on the bamboo biomass than soil characteristics in general. Specifically, topographic factors mainly affected the bamboo biomass by changing tree density and soil characteristics. Our results can provide valuable guidance for the protection of giant pandas and the management of subalpine spruce–fir forests.

Understanding variation and coordination of leaf traits at multiscales along elevational gradients can help predict the likely responses of dominant species to climate change. We seek to determine the extent to which variation in leaf stomatal, anatomical and morphological traits is associated with environmental factors, and whether ecological strategies of Cyclobalanopsis species shift with elevations.

In a tropical forest landscape in Jianfengling, South China, we determined leaf traits related to stomata, anatomy and morphology of six evergreen oak species (Cyclobalanopsis bambusaefolia, C. hui, C. patelliformis, C. fleuryi, C. tiaoloshanica and C. phanera) along a long elevational gradient (400–1400 m above sea level).

We found that stomatal density and stomatal pore index increased, whereas spongy mesophyll thickness to leaf thickness ratios decreased, significantly with elevation. The leaf area and leaf dry matter content increased and decreased, respectively, with elevation. Variations in stomatal, anatomical and morphological traits were mainly correlated to the mean annual temperature, mean annual sum precipitation and soil pH. At low and high elevations, the oak species exhibited strong stress tolerance combined with competition strategy, while they shifted toward more clearly the competitive strategy at intermediate elevations. And the changes in soil phosphorus concentration and soil pH along the elevation may drive the shift of ecological strategy. The results showed that the dominant oak species in tropical forests respond to environmental change by modulating traits at multiple levels, from that of the individual cell, through tissue and up to the whole leaf scale.

To explore whether grazing-induced legacy effects on plants could benefit plants adaptation to drought.

A water-controlled experiment was conducted in the greenhouse, which with Agropyron cristatum and Carex korshinskyi collected from free-grazing and enclosed plots on a typical grassland in Inner Mongolia.

We found that A. cristatum and C. korshinskyi collected from the free-grazing plot were less affected by drought in terms of ramet biomass, ramet number and total biomass than those collected from the enclosed plot. The enhanced adaptation to drought for plants collected from the free-grazing plot should partly be ascribed to the larger root biomass allocation plasticity under drought treatment. Our findings suggest that grazing management can be used to improve the adaptation of grassland plants to climate change.

Drought can affect the growth and soil enzyme activities of invasive alien plants (IAPs). It is imperative to evaluate the competitive advantage of IAPs compared with that of the native species and the activities of soil enzymes under drought. This study aimed to evaluate the competitive advantage of the IAP Amaranthus spinosus that originated from tropical America compared with the native Chinese species A. tricolor and the activities of soil enzymes under drought. A competitive co-culture of A. spinosus and A. tricolor was established using a planting basin experiment. The two species were treated with different levels of drought, i.e. (i) the control; (ii) a light level of drought and (iii) a heavy level of drought. The functional traits, osmotic adjustment and the activities of antioxidant enzymes of the two species, as well as soil pH and electrical conductivity, contents of soil microbial biomass carbon and the activities of soil enzymes were determined. The relative competition intensity and relative dominance of A. spinosus were greater than those of A. tricolor under drought. Drought may provide an advantage to the competitive advantage of A. spinosus. Soil water-soluble salt content and sucrose hydrolytic power of A. spinosus were greater than those of A. tricolor under drought. The ability of A. spinosus to grow in soil with higher levels of water-soluble salt contents and sucrose hydrolytic power under drought may aid in its acquisition and utilization of nutrients.

In multiflowered species, the architecture of inflorescences is of primary importance in shaping plant attractiveness. The aim of this study was to disentangle the role of inflorescence traits in plant female reproductive success and pollination patterns along the inflorescence in the lax-flowered orchid Anacamptis laxiflora, a terrestrial species exploiting a deceptive pollination strategy. We also evaluated whether the relationship between inflorescence traits and female reproductive success was modified by the height of surrounding vegetation and/or by population density.

We delimited experimental plots in a natural population of A. laxiflora. We tallied the individuals within each plot and categorized low-density plots and high-density plots; then, in part of the plots we manually removed surrounding grass thus producing an equal number of plots with high grass and low grass. Within these plots, we recorded inflorescence traits and female reproductive success (i.e. the number of fruit and their position along the inflorescence). We analyzed these data using generalized linear mixed-effects models (GLMMs) and calculated selection gradients.

We found that all the investigated inflorescence traits influenced female reproductive success. In particular, our GLMMs showed that ‘average flower distance’ was the best predictor for shaping reproductive success patterns. We detected significant positive selection on the investigated inflorescence traits, but these selective trends were strictly linked to both the height of the surrounding vegetation and the population density, suggesting a significant influence of local environmental context in shaping selective patterns. Female reproductive success was not linked to the position of flowers along the inflorescence, suggesting that pollinators visit flowers randomly along the inflorescence without a detectable preference for a specific part. This study highlights the importance of inflorescence traits in shaping female reproductive success of multiflowered deceptive orchids, and confirms a primary role for the environmental context in modifying pollinator-mediated selection patterns.

Plants growing in nutrient-rich environment are predicted to be less defended than conspecifics under nutrient limitation. However, less is known about the effects of nutrient levels on tolerance and induced resistance, and whether the effects differ between native and introduced populations of invasive plants. We performed a greenhouse experiment with introduced (the USA) and native (Argentina) genotypes of Alternanthera philoxeroides in order to study the effects of soil nitrogen levels on plant growth, constitutive and herbivore (Agasicles hygrophila)-induced chemical defense, and herbivory tolerance. We measured total biomass, elongation rate (as proxy of growth rate), carbon and nitrogen, and the concentration of triterpenoid saponins (defensive chemicals) in leaves and roots. Constitutive resistance (+33% higher leaf triterpenoid saponins in control treatment at low nitrogen level) and tolerance [less decreased total biomass after herbivory treatment (−24% and −15% for high and low nitrogen levels)] were favored at lower nitrogen level, while induced resistance was favored at higher nitrogen level (+24% increased leaf triterpenoid saponins after herbivory treatment at high nitrogen level). Constitutive resistance and tolerance exhibited trade-offs with growth rate, while induced resistance positively correlated with growth rate. Additionally, the introduced genotypes had −6% lower content of leaf carbon in the presence of herbivores than the native genotypes at low nitrogen level, but such difference was absent at high nitrogen level. Our results indicate that soil nitrogen levels influence the preference of different defensive strategies of plant, and interweave with herbivory to determine the performance of introduced genotypes.

Species diversity–productivity relationships in natural ecosystems have been well documented in the literature. However, biotic and abiotic factors that determine their relationships are still poorly understood, especially under future climate change scenarios.

Randomized block factorial experiments were performed in three meadows along an elevational gradient on Yulong Mountain, China, where open-top chambers and urea fertilizer manipulations were used to simulate warming and nitrogen addition, respectively. Besides species diversity, we measured functional diversity based on five traits: plant height, specific leaf area and leaf carbon, nitrogen and phosphorus contents. Several abiotic factors relating to climate (air temperature and precipitation) and soil chemistry (pH, organic carbon concentration, total nitrogen concentration and phosphorus concentration) were also measured. Generalized linear mixed-effect models were used to investigate the responses of species diversity and productivity to elevation, warming, nitrogen addition and their interactions. The effects of biotic and abiotic factors on the direction and magnitude of their relationship were also assessed.

Species diversity decreased with increasing elevation and declined under warming at mid-elevation, while productivity decreased with increasing elevation. Functional richness, maximum air temperature, soil pH and their interactions showed strong but negative influences on the species diversity–productivity relationship; the relationship shifted from positive to neutral and then to slightly negative as these sources of variation increased. Our study highlights the negative effects of short-term warming on species diversity and emphasizes the importance of both biotic and abiotic drivers of species diversity–productivity relationships in mountain meadow communities.

The aims of this study were to assess how functional diversity (FD) and functional redundancy respond to subalpine meadow ecosystem degradation under anthropogenic disturbance and how species contribute to functional redundancy along the disturbance gradient.

The study was carried out in the subalpine meadow in Mount Jade Dragon, which is located at the southeastern edge of the Tibetan Plateau. Four disturbance intensities [no disturbance (ND), weak disturbance (WD), moderate disturbance (MD) and severe disturbance (SD)] were identified. Species richness, soil properties and five key plant functional traits were assessed along the disturbance gradient. Simpson’s diversity index, FD based on the Rao algorithm, functional redundancy, community-weighted mean of each functional trait and species-level functional redundancy were determined.

Unimodal change pattern of FD and functional redundancy along the disturbance gradient were found in the present study, with their maximum in MD and WD, respectively. Species diversity showed a decreasing trend with increasing disturbance intensity. As disturbance intensified, species with traits related to conservative growth strategies, such as low specific leaf area (SLA) and high leaf dry matter content (LDMC), decreased, whereas species with resource acquisitive strategies, such as small plant, high SLA and low LDMC, increased in the community. At the species level, species showed species-specific roles in functional redundancy. Notably, some species were important in the community in terms of their unique function. For instance, Ligularia dictyoneura in ND and Potentilla delavayi in MD and SD.

The Nihewan Basin of North China, considered the cradle of Eastern civilization, contains a set of late Cenozoic strata and artifacts used by Homo erectus in the early Pleistocene (~1.66 Ma to 780 ka) and the cranial bones and teeth of early H. sapiens from the late middle Pleistocene (~370 to 260 ka). Palynological studies provide an opportunity to explore the living environment of early humans.

Palynological samples from the Hutouliang Section (~603–587 ka) of the Xiaodukou Formation of the Nihewan Basin were treated by heavy liquid flotation. Based on the palynological assemblages from the section, vegetation and climate in the Nihewan Basin were reconstructed.

The dynamic vegetation changed from temperate needle- and broad-leaved mixed forest-steppe (mainly Picea, Abies, Betula, Juglans, Artemisia and Chenopodiaceae) to conifer forest (mainly Pinus, Picea and Abies), which saw the replacement of H. erectus by early H. sapiens. The comparison of the Nihewan Basin with other human sites around the world during the same period reveals that early humans preferred to live in caves, accompanied by relatively open steppe or forest-steppe environments, inhabited by numerous mammals. Therefore, it is inferred that the emergence of dense conifer forest and the disappearance of open steppe environments in the Nihewan Basin at approximately 603–587 ka provide new evidence that early humans followed most mammals to steppe or forest-steppe environments and thus left the Nihewan Basin. These new findings not only enrich our knowledge of early human behavior, such as their diet, migration and settlement, but also fill in gaps in paleovegetation and paleoenvironmental research in the Nihewan Basin during the middle Pleistocene (780–400 ka).

Rapid warming at high altitudes may lead to a higher sensitivity in tree growth to temperature. The key factors constraining tree radial growth and to what extent regional tree growth has suffered from climatic changes are unclear.

Tree-ring width data were collected from 73 sites across the Hindu Kush Himalaya (HKH), including three dominant genera (Abies, Juniperus and Picea) at high altitudes over 3000 m. Dynamic time warping was introduced to develop subregional chronologies by considering the synchrony of annual tree growth among different sites. We quantified the contribution of the climate variables, and analyzed the spatiotemporal variation of the growth–climate relationship.

The site chronologies were grouped into three clusters, corresponding to the three distinct bioclimatic zones, i.e. the western HKH, central-eastern HKH and southeastern Tibetan Plateau (TP). Tree growth was positively correlated to winter and spring precipitation in the drier western HKH, and to winter temperature and spring precipitation in the humid southeastern TP. Tree growth was markedly constrained by the minimum temperature, especially in winter, with its importance increasing from the west toward the east. As shown by moving correlation analysis, the signal of winter temperature in tree growth was weakened in the western and central-eastern HKH, while it was enhanced in the southeastern TP following rapid warming since the 1980s. Our results highlight that continuous warming may cause forest recession due to warming-induced moisture deficit in the western HKH, but forest expansion in the southeastern TP.

Invasive alien plants not only decrease riparian vegetation diversity but also alter wetland ecosystem carbon processes, especially when they displace the original vegetation. Invasive Canada goldenrod (Solidago canadensis L.) has colonized large areas of disturbed and undisturbed land in southeastern China, yet little is known regarding how it affects soil carbon cycling. To explore the response patterns of soil respiration following S. canadensis invasion and their driving mechanisms, an observational field study and a greenhouse experiment simulating invasion were performed. In the field study, soil respiration was measured weekly from 21th July 2018 to 15th December 2018. In the greenhouse experiment, soil, autotrophic and heterotrophic respiration were measured every 1st and 15th of the month from 15th July 2019 to 15th December 2019. Soil, autotrophic and heterotrophic respiration were measured using a closed-chamber system with the deep gauze collar root exclusion method. Solidago canadensis invasion appeared to decrease the total soil CO₂ emissions in both the field study and the greenhouse experiment. The suppressive effects on soil respiration may be attributed to S. canadensis invasion-induced alterations in the quality and quantity of available soil substrate, suggesting that S. canadensis invasion may impact soil carbon cycling via plant-released substrates and by competing for the soil available substrate with native plant and/or soil microbes. These results have substantial implications for estimations of the effects of invasive plants on belowground carbon dynamics and their contribution to the warming world.

Current plant diversity can influence exotic plant invasion, but it is unclear whether there is a legacy effect of plant diversity on exotic plant invasion. As plant diversity can affect soil microbial communities and physio-chemical properties, which may cascade to impact subsequent exotic plant growth, we hypothesize that the soil legacy effect of plant diversity can influence exotic plant invasion. We conducted a plant–soil feedback experiment. In the conditioning phase, we trained soils by monocultures of 12 plant species from three functional groups (4 grasses, 3 legumes and 5 forbs) and mixtures of 8 randomly selected species with all three functional groups from this 12-species pool. In the test phase, we grew the invasive plant Bidens pilosa with a co-occurring native grass (Arthraxon hispidus), with a co-occurring native forb (Pterocypsela indica) or with both in each type of the conditioned soils. The performance of B. pilosa relative to its native competitors varied depending on the functional type of both conditioning plant species in the conditioning phase and competing plant species in the test phase. Diversity of the conditioning plants did not influence the growth difference between B. pilosa and its native competitors. However, increasing diversity of the competing plant species reduced the performance of B. pilosa relative to its native competitors. Our results suggest that current plant diversity can reduce exotic plant invasion through increasing growth inequality between invasive and native plants, but the soil legacy effect of plant diversity may have little impact on exotic plant invasion.

Floral traits and the number of visitors are expected to change with different mating systems. We tested this hypothesis by comparing flowers of Prunella vulgaris (Lamiaceae) with inserted and exserted styles across a strongly exserted style biased, an exserted style biased, and a strongly inserted style biased subalpine population. We examined flowering phenology, floral morphology, flower visitation rate, capacity for autonomous self-pollination and visitor contribution to seed production for each style type and in each population. We also examined inbreeding depression (ID) by comparing the relative performance of progeny from self- and cross-pollination. Exserted style plants had larger and more open flowers, increased pollen production, higher amounts of nectar rewards and higher visitation and outcrossing rates than inserted style plants. Similarly on the population level, the visitation rates were higher in the exserted style-biased populations than in the inserted style-biased population. Inserted style plants provided a stronger reproductive assurance (RA) through autonomous selfing than exserted style plants. RA and outcrossing rates did not differ among populations, showing low visitation rates may be sufficient for adequate seed production in P. vulgaris. Although inserted style plants had a lower ID level than exserted style plants, the ID of both was less than 0.5, suggesting that an ID should not counteract the evolution of selfing in this species. Inserted style plants provide RA through autonomous selfing, and exserted style plants ensure outcrossing through pollinator services, supporting a stable mixed mating system in this subalpine plant.

We explored if and how seasonal fires interact with microhabitat type (i.e. under Pistacia shrub, under Cistus shrub or a canopy gap) to influence the composition of the germinable soil seed bank (GSSB) community in a typical eastern Mediterranean woodland. We conducted a field experiment, involving prescribed spring and autumn burns, and thereafter quantified the seed germination patterns using soil samples collected from both burned and adjacent unburned control plots. Soil temperature was significantly higher during autumn burns, while being more variable during spring burns. Fire caused overall reductions in GSSB density, richness and diversity. The reductions in GSSB richness and diversity were significantly stronger under Pistacia and Cistus shrubs located within plots subjected to autumn burns, and these patterns were mainly evident among annuals. GSSB density of dwarf shrubs was higher in samples collected from burned plots, and this pattern was more pronounced in samples collected under Pistacia and Cistus shrubs. Together with the appearance of unique species, seasonal fires led to significant changes in the composition of the GSSB community. Our results illustrate that seasonal fires interact with spatial heterogeneity to influence the composition of the GSSB community mostly via differential effects on the germination densities of annuals and dwarf shrubs. These findings imply that the increase in the frequency of seasonal fires, which has occurred in the eastern Mediterranean basin during the last few decades, may translate into a shift in eco-evolutionary selection pressures, operating on plants inhabiting this unique ecosystem.