Understanding the mechanisms that maintain the coexistence of plant species is critical to addressing the global biodiversity crisis. Increasing attention has been paid to interactions between plants and soil microbes (plant-soil feedback, PSF), which can not only promote plant coexistence by increasing stabilizing effects but also hinder it by generating competitive fitness differences. However, the predictive power of the PSF has been questioned in recent studies because estimates of microbially mediated coexistence have correlated poorly with the outcomes of plant interactions observed in the field. This discrepancy may be due to the approaches typically used in PSF research, such as measuring PSF effects on a single vital rate or using soil conditioned for a short time period and without considering abiotic contexts. Here, I examined the effects of soil inoculum with different training histories and training environments (with and without added nutrients) on germination, seedling survival, and biomass of four grassland species. I then examined whether predictions of microbially mediated coexistence of four species pairs were sensitive to the vital rate identity, conditioning history, and soil training environment. I found that conspecific inoculum trained for longer had increasingly positive and negative effects on germination and biomass, respectively, although the effects of inoculum history varied across species and training environments. Estimates of microbially mediated outcomes were directly related to the vital rate used: when based on biomass and seedling survival, all four pairs were predicted to coexist, but only two pairs could do so when based on germination due to much reduced or even negative stabilization. Although coexistence predictions were not significantly related to conditioning history (including the effects of both variable conditioning durations and combinations of conditioning species) or nutrient treatments, both factors had a significant effect on stabilization. These results suggest that predictions of microbially mediated coexistence may be biased when based on a single vital rate, such as plant growth. To obtain more realistic and accurate outcome estimates, PSF effects should be integrated across different life stages, considering the temporal and abiotic contexts of these effects specific to a focal study system.

• Klíčová slova
• fitness differences, plant coexistence, plant–soil feedback, soil microbes, soil nutrients, stabilization, temperate grassland, temporal context,
• MeSH
• biomasa MeSH
• klíčení MeSH
• pastviny MeSH
• půda * chemie   MeSH
• půdní mikrobiologie * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda * MeSH

Exotic plant invaders pose a serious threat to native plants. However, despite showing inferior competitive ability and decreased performance, native species often subsist in invaded communities. The decline of native populations is hypothesized to be halted and eventually reversed if adaptive evolutionary changes can keep up with the environmental stress induced by invaders, that is, when population extinction is prevented by evolutionary rescue (ER). Nevertheless, evidence for the role of ER in postinvasion persistence of native flora remains scarce. Here, I explored the population density of a native forb, Veronica chamaedrys, and evaluated the changes in the shade-responsive traits of its populations distributed along the invasion chronosequence of an exotic transformer, Heracleum mantegazzianum, which was replicated in five areas. I found a U-shaped population trajectory that paralleled the evolution of plasticity to shade. Whereas V. chamaedrys genotypes from intact, more open sites exhibited a shade-tolerance strategy (pronounced leaf area/mass ratio), reduced light availability at the invaded sites selected for a shade-avoidance strategy (greater internode elongation). Field experiments subsequently confirmed that the shifts in shade-response strategies were adaptive and secured postinvasion population persistence, as indicated by further modeling. Alternative ecological mechanisms (habitat improvement or arrival of immigrants) were less likely explanations than ER for the observed population rebound, although the contribution of maternal effects cannot be dismissed. These results suggest that V. chamaedrys survived because of adaptive evolutionary changes operating on the same timescale as the invasion-induced stress, but the generality of ER for postinvasion persistence of native plants remains unknown.

• Klíčová slova
• biological invasions, evolutionary rescue, phenotypic plasticity, shade-response strategies,
• MeSH
• biologická evoluce * MeSH
• bolševník růst a vývoj   účinky záření   MeSH
• ekosystém MeSH
• extinkce biologická * MeSH
• fenotyp MeSH
• listy rostlin růst a vývoj   účinky záření   MeSH
• rostliny * účinky záření   MeSH
• sluneční záření MeSH
• Veronica * růst a vývoj   účinky záření   MeSH
• zavlečené druhy * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Plant-soil feedback (PSF) is a fundamental mechanism explaining plant community composition. Two-phase experiments, i.e., conditioning and feedback, represent a common methodology to study PSF. The duration of the conditioning phase varies among studies and the PSF observed is often explained by its biotic component. Little is known about the temporal variation of PSF and its abiotic component. As early life stages are crucial for plant establishment, we grew Rorippa austriaca in soil conditioned over 2, 4, 6 or 8 weeks by a conspecific or a co-occurring species, Agrostis capillaris. For each conditioning duration, we analysed the soil chemical properties and the direction and intensity of intra- or inter-specific feedbacks. With increasing duration, the negative intra- and inter-specific feedbacks became stronger and weaker, respectively. The inter-specific feedback was more negative than the intra-specific feedback at 2 weeks and this reversed thereafter. The Mg content decreased with conditioning duration whatever the conditioning species was. With increasing duration, conditioning by R. austriaca strongly decreased pH, while A. capillaris did not affect pH. The K and P contents were not affected by the conditioning duration and were higher in R. austriaca soil than in A. capillaris soil. Our results suggest that not only conditioning species but also duration of conditioning phase may affect the magnitude of PSF. The changes in soil chemical properties linked to the conditioning species or the conditioning phase duration may drive the feedbacks by affecting plant growth directly or via the interacting microbial communities.

• Klíčová slova
• Brassicaceae, Conditioning, Native species, Negative feedback, Plant-soil feedback indices,
• MeSH
• půda * MeSH
• půdní mikrobiologie MeSH
• rostliny * MeSH
• vývoj rostlin MeSH
• zpětná vazba MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• půda * MeSH

Predicting the impacts of non-native species remains a challenge. As populations of a species are genetically and phenotypically variable, the impact of non-native species on local taxa could crucially depend on population-specific traits and adaptations of both native and non-native species. Bitterling fishes are brood parasites of unionid mussels and unionid mussels produce larvae that parasitize fishes. We used common garden experiments to measure three key elements in the bitterling-mussel association among two populations of an invasive mussel (Anodonta woodiana) and four populations of European bitterling (Rhodeus amarus). The impact of the invasive mussel varied between geographically distinct R. amarus lineages and between local populations within lineages. The capacity of parasitic larvae of the invasive mussel to exploit R. amarus was higher in a Danubian than in a Baltic R. amarus lineage and in allopatric than in sympatric R. amarus populations. Maladaptive oviposition by R. amarus into A. woodiana varied among populations, with significant population-specific consequences for R. amarus recruitment. We suggest that variation in coevolutionary states may predispose different populations to divergent responses. Given that coevolutionary relationships are ubiquitous, population-specific attributes of invasive and native populations may play a critical role in the outcome of invasion. We argue for a shift from a species-centred to population-centred perspective of the impacts of invasions.

• Klíčová slova
• Anodonta woodiana, alien species, glochidia, host–parasite dynamics, intraspecific variation, symbiosis,
• MeSH
• Anodonta genetika   růst a vývoj   fyziologie   MeSH
• Cyprinidae parazitologie   fyziologie   MeSH
• interakce hostitele a parazita MeSH
• kladení vajíček * MeSH
• larva genetika   růst a vývoj   fyziologie   MeSH
• rozmnožování MeSH
• učení vyhýbat se * MeSH
• zavlečené druhy * MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH

Terrestrial invasive plants are a global problem and are becoming ubiquitous components of most ecosystems. They are implicated in altering disturbance regimes, reducing biodiversity, and changing ecosystem function, sometimes in profound and irreversible ways. However, the ecological impacts of most invasive plants have not been studied experimentally, and most research to date focuses on few types of impacts, which can vary greatly among studies. Thus, our knowledge of existing ecological impacts ascribed to invasive plants is surprisingly limited in both breadth and depth. Our aim was to propose a standard methodology for quantifying baseline ecological impact that, in theory, is scalable to any terrestrial plant invader (e.g., annual grasses to trees) and any invaded system (e.g., grassland to forest). The Global Invader Impact Network (GIIN) is a coordinated distributed experiment composed of an observational and manipulative methodology. The protocol consists of a series of plots located in (1) an invaded area; (2) an adjacent removal treatment within the invaded area; and (3) a spatially separate uninvaded area thought to be similar to pre-invasion conditions of the invaded area. A standardized and inexpensive suite of community, soil, and ecosystem metrics are collected allowing broad comparisons among measurements, populations, and species. The method allows for one-time comparisons and for long-term monitoring enabling one to derive information about change due to invasion over time. Invader removal plots will also allow for quantification of legacy effects and their return rates, which will be monitored for several years. GIIN uses a nested hierarchical scale approach encompassing multiple sites, regions, and continents. Currently, GIIN has network members in six countries, with new members encouraged. To date, study species include representatives of annual and perennial grasses; annual and perennial forbs; shrubs; and trees. The goal of the GIIN framework is to create a standard yet flexible platform for understanding the ecological impacts of invasive plants, allowing both individual and synthetic analyses across a range of taxa and ecosystems. If broadly adopted, this standard approach will offer unique insight into the ecological impacts of invasive plants at local, regional, and global scales.

• Klíčová slova
• Coordinated distributed experiment, impact assessment, invasive plants, meta-analysis, natural experiment, research network, research protocol,
• Publikační typ
• časopisecké články MeSH

BACKGROUND AND AIMS: Allelopathy may drive invasions of some exotic plants, although empirical evidence for this theory remains largely inconclusive. This could be related to the large intraspecific variability of chemically mediated plant-plant interactions, which is poorly studied. This study addressed intraspecific variability in allelopathy of Heracleum mantegazzianum (giant hogweed), an invasive species with a considerable negative impact on native communities and ecosystems. METHODS: Bioassays were carried out to test the alleopathic effects of H. mantegazzianum root exudates on germination of Arabidopsis thaliana and Plantago lanceolata. Populations of H. mantegazzianum from the Czech Republic were sampled and variation in the phytotoxic effects of the exudates was partitioned between areas, populations within areas, and maternal lines. The composition of the root exudates was determined by metabolic profiling using ultra-high-performance liquid chromatography with time-of-flight mass spectrometry, and the relationships between the metabolic profiles and the effects observed in the bioassays were tested using orthogonal partial least-squares analysis. KEY RESULTS: Variance partitioning indicated that the highest variance in phytotoxic effects was within populations. The inhibition of germination observed in the bioassay for the co-occurring native species P. lanceolata could be predicted by the metabolic profiles of the root exudates of particular maternal lines. Fifteen compounds associated with this inhibition were tentatively identified. CONCLUSIONS: The results present strong evidence that intraspecific variability needs to be considered in research on allelopathy, and suggest that metabolic profiling provides an efficient tool for studying chemically mediated plant-plant interactions whenever unknown metabolites are involved.

• Klíčová slova
• Allelopathy, Apiaceae, Heracleum mantegazzianum, OPLS analysis, Plantago lanceolata, UHPLC–TOF–MS, compound identification, germination bioassay, giant hogweed, invasion ecology, invasive species, metabolic profile, novel weapons hypothesis, plant metabolomics, root exudates,
• MeSH
• alelopatie * MeSH
• Arabidopsis účinky léků   MeSH
• bolševník chemie   genetika   metabolismus   MeSH
• druhová specificita MeSH
• ekosystém MeSH
• klíčení účinky léků   MeSH
• kořeny rostlin chemie   genetika   metabolismus   MeSH
• metabolom * MeSH
• Plantago účinky léků   MeSH
• rostlinné exsudáty chemie   izolace a purifikace   metabolismus   MeSH
• zavlečené druhy MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• rostlinné exsudáty MeSH

Species moved by human activities beyond the limits of their native geographic ranges into areas in which they do not naturally occur (termed aliens) can cause a broad range of significant changes to recipient ecosystems; however, their impacts vary greatly across species and the ecosystems into which they are introduced. There is therefore a critical need for a standardised method to evaluate, compare, and eventually predict the magnitudes of these different impacts. Here, we propose a straightforward system for classifying alien species according to the magnitude of their environmental impacts, based on the mechanisms of impact used to code species in the International Union for Conservation of Nature (IUCN) Global Invasive Species Database, which are presented here for the first time. The classification system uses five semi-quantitative scenarios describing impacts under each mechanism to assign species to different levels of impact-ranging from Minimal to Massive-with assignment corresponding to the highest level of deleterious impact associated with any of the mechanisms. The scheme also includes categories for species that are Not Evaluated, have No Alien Population, or are Data Deficient, and a method for assigning uncertainty to all the classifications. We show how this classification system is applicable at different levels of ecological complexity and different spatial and temporal scales, and embraces existing impact metrics. In fact, the scheme is analogous to the already widely adopted and accepted Red List approach to categorising extinction risk, and so could conceivably be readily integrated with existing practices and policies in many regions.

• MeSH
• biodiverzita MeSH
• býložravci fyziologie   MeSH
• distribuce rostlin fyziologie   MeSH
• druhová specificita MeSH
• extinkce biologická MeSH
• lidé MeSH
• lidské činnosti trendy   MeSH
• nejistota MeSH
• populační dynamika trendy   MeSH
• potravní řetězec MeSH
• predátorské chování fyziologie   MeSH
• půda chemie   MeSH
• rostliny mikrobiologie   parazitologie   virologie   MeSH
• rozšíření zvířat fyziologie   MeSH
• zavlečené druhy statistika a číselné údaje   MeSH
• životní prostředí * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• půda MeSH