Biology subjects

van Kleunen, M.

Publications and source records attributed to van Kleunen, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Root hairs and mycorrhiza represent alternative phylogenetically conserved strategies for belowground absorptive surface maximization

O_LIPlants take up nutrients from the soil while investing in absorptive root surface or mycorrhizal partners. Root hairs - a major structure for nutrient uptake and cheap to build - increase the absorptive root surface. As such they are an important component of plant resource economics but largely neglected in root economic concepts so far. C_LIO_LIThis is mainly due to data scarcity, which we set out to overcome by measuring root-hair traits on 82 European grassland species in a greenhouse experiment. Using fluorescence and light microscopy, root-hair length and incidence was measured along with mycorrhizal colonization. C_LIO_LIWe found a phylogenetically conserved trade-off between plant investment into root hairs and mycorrhiza. A similar trade-off between root-hair incidence and mycorrhiza occurred at the intraspecific level, while patterns were heterogeneous among species. Plant species with high colonization rates showed the highest variability in root-hair incidence. C_LIO_LIWe conclude that plants vary along a gradient ranging from investment into root hairs as part of a "do-it-yourself" strategy to collaboration with mycorrhizal fungi while showing intraspecific variation in root-hair incidence. These findings demonstrate that root hairs play a fundamental role in fine-root trait variation and need to be considered when studying belowground plant economic strategies. C_LI

ecology↗

bioRxiv2026

Differential kin interactions between invasive and native plants: evidence from Alternanthera philoxeroides and its native congener

Reduced competition or facilitation between kin relative to nonkin can improve plant performance, particularly under resource-limited conditions. Understanding whether kin interactions differ between invasive and native species may provide insights into the mechanisms underlying the persistence and spread of invasive species, particularly for species that spread clonally. To explore this, we conducted a greenhouse experiment using the invasive Alternanthera philoxeroides and its native congener A. sessilis in China. For both species, we grew central plants without or with neighbors, and for the latter we had three intraspecific neighbor kinship treatments (kin only, nonkin only, and both kin and nonkin [mixed] neighbors). To test whether kinship effects are affected by resource limitation, we grew the plants under two watering conditions (well-watered and drought-stressed). Our findings revealed that at both the group (i.e., pot-level) and individual levels, invasive plants had a higher biomass production and experienced a less negative relative neighbor effect in kin groups than in nonkin groups, while these patterns were reversed in the native species. Although aboveground architecture of central plants did not differ significantly between kin and nonkin neighbors in either species, neighbor plants of the invasive species produced fewer nodes in kin groups than in nonkin groups, while the reverse was true for the native species. These patterns were not affected by the watering treatment. Together, these results indicate that while the native plants has stronger kin competition, the invasive species has reduced kin competition. Such reduced competition among kin in the invasive Alternanthera philoxeroides may enhance its population dominance and facilitate its spread.

ecology↗

bioRxiv2025

Global disruption of plant biogeography by non-native species

Biogeographical regions reflect differences in biotic composition resulting from long-term isolation and biogeographical processes, but how human-mediated introductions of non-native species have altered these biogeographical patterns remains unclear. Using global distribution data of 279,441 native and 10,067 non-native seed plant species, we analyzed the impact of species introductions on global organization of biogeographical regions. We show that species introductions have disrupted plant biogeography, causing the loss of distinct floristic realms and subrealms. Due to the impact of non-native species, geographic proximity and dispersal barriers are less important-- particularly as trade-facilitated species exchange drives floristic homogenization--while environmental factors remain critical in structuring floristic regions. Our findings reveal that plant introductions erode biogeographical distinctness and highlight the urgent need for coordinated action to protect native biotas.

ecology↗

bioRxiv2024

The dominance of non-native plants over native plants increases with the number of global change factors

Global environmental change and plant invasion are both recognized as key indicators of the Anthropocene, with the former potentially accelerating the latter. Still, whether multiple co-acting global change factors (GCFs) influence plant invasions even stronger remains untested despite the fact that in nature GCFs usually act together rather than alone. Here, four non-native and four native species were cultivated jointly as communities in mesocosm pots, and we tested their responses to increasing GCF numbers (0, 1, 2, 3, 4, 5). We found that GCF number had no influence on community productivity but increased the biomass proportion of non-native plants. GCF number increased biomass but had no influence on height for non-native plants, whereas both biomass and height of native plants decreased with increasing GCF number. Consequently, our findings indicate that dominance may increases when habitats experience multiple global change factors, and thus that invasion risk of non-native plants could potentially be underestimated from studies on single GCFs. Open Research statementThe data supporting the results will be made available upon acceptance.

ecology↗

bioRxiv2022

Phylogenetic endemism of the world's seed plants

Assessing phylogenetic endemism, i.e., the distribution of geographically restricted and evolutionarily unique species, is key to understanding biogeographic patterns and processes and critical for global conservation planning. Here, we quantified the geographic distribution and drivers of phylogenetic endemism for ~320,000 seed plants worldwide and identified centers and drivers of evolutionarily young (neoendemism) and evolutionarily old endemism (paleoendemism). Tropical and subtropical islands of the Southern Hemisphere as well as tropical mountainous regions displayed the worlds highest phylogenetic endemism. Tropical moist forests (e.g. Amazonia) and continental islands in south-east Asia emerged as centers of paleoendemism, while both high neo- and paleoendemism were found on ancient continental fragment islands (e.g. Madagascar) and in Mediterranean-climate regions. Global variation in phylogenetic endemism was best explained by a combination of past and present environmental factors (80.3% - 88.1% of variance explained). Geographic isolation and environmental heterogeneity emerged as primary drivers promoting high phylogenetic endemism. Also, warm and wet climates with long-term climatic stability showed a significant positive effect. However, environmental effects on phylogenetic endemism varied with geographic isolation, reflecting the unique evolutionary and biogeographic dynamics on oceanic islands. Long-term climatic stability promoted the persistence of paleoendemics, while isolation promoted higher neoendemism leading to oceanic islands and tropical mountainous regions being centers of both neo- and paleoendemism. Our study provides new insights into the evolutionary underpinnings of biogeographic patterns in seed plants, and by identifying areas of high evolutionary and biogeographic uniqueness, it may serve as a key resource for setting global conservation priorities.

ecology↗

bioRxiv2022

Drivers of the negative diversity-invasibility relationship: nutrient availablity, allelopathy, soil biota and soil legacy effects

Eltons diversity-invasibility hypothesis predicts that high-diversity native communities should be less easily invaded than low-diversity communities. Although various mechanisms have been proposed to explain it, it remains unclear which of those mechanisms is more important and whether they operate simultaneously. Using one pool of native plant species and one pool of invasive alien plant species that naturally co-occur in China, we here tested in four separate experiments whether nutrient availability, allelopathy, soil microbiota and soil-legacy effects can all mediate the diversity-invasibility relationship. While soil-nutrient availability, allelopathy, soil biota and soil-legacy effects separately influenced biomass production of alien plant species and native plant communities, our results suggest that only soil biota and allelopathy influenced diversity-invasibility relationship in our study system. Importantly, by excluding the potential effects of allelopathy and soil biota in the nutrient-competition experiment, nutrient competition alone is not necessarily related to the negative diversity-invasibility relationship.

ecology↗

bioRxiv2022

The more synthetic polymer types pollute the soil, the stronger the growth suppression of invasive alien and native plants

Although most studies on the ecological effects of microplastic pollution focus on a single type of synthetic polymer and a single species, most organisms will be exposed to multiple polymer types simultaneously and the effects may vary among species. To test the effects of polymer diversity on plants, we grew single plants of eight invasive and eight native species in pots with substrate polluted by 0, 1, 3 and 6 types of micro-sized synthetic polymers. We found that the growth suppression by microplastic pollution became stronger with the number of polymer types the plants were exposed to. This tended to be particularly the case for invasive species, whose biomass advantage over natives diminished with the number of polymer types. Our study thus shows that the negative effects of microplastic pollution on plant growth increase with the number of polymer types, and that these effects differ between invasive and native species.

ecology↗

bioRxiv2022

Flower visitation of alien plants is non-linearly related to phylogenetic and floral similarity to native plants

O_LIBiological invasions are key to understanding major ecological processes that determine the formation of novel interactions. Flower visitation to alien species may be facilitated by co-flowering natives if they share similar floral traits with the latter. However, if competition for pollinators is important, flower visitation to alien species may be higher if they have traits different from those of native species. We tested whether flower visitation to alien plants depended on phylogenetic relatedness and floral similarity to native plants. C_LIO_LIIn a field experiment, we simulated invaded communities by adding potted alien plants into co-flowering native communities. We recorded flower visitation to pairs of 34 alien and 20 native species totalling 151 species combinations for 3,068 hours. C_LIO_LIFlower visitation to alien species was highest when they had intermediate floral trait distances to native species, and either low or high phylogenetic distances. The alien plants received more similar flower-visitor groups to natives when they had low phylogenetic and either low or high floral trait distances to native plants. C_LIO_LIThe non-linear patterns between flower visitation and similarity of the alien and native species suggest that an interplay of facilitation and competition simultaneously drives the formation of novel plant-pollinator interactions. The shapes of the relationships of phylogenetic and floral trait distances with flower visitation to alien plants were contrasting, possibly due to different strengths of phylogenetic signal among traits. C_LIO_LIWe provide experimental evidence for the effects of relatedness and functional similarity to native plants on flower visitation of alien plants. We show that such effects might be non-linear, and that effects of trait dissimilarity and phylogenetic distance on pollinator-mediated interactions can reflect different mechanisms. C_LI

ecology↗

bioRxiv2021

Soil microbes mediate the effects of environmental variability on plant invasion

Many studies indicate that increases in resource variability promote plant invasion. However, it remains unknown to what extent these effects might indirectly be mediated by other organisms. To test this, we grew eight alien species in pot-mesocosms with five different native communities under eight combinations of two nutrient-availability, two nutrient-fluctuation and two soil-microbe treatments. We found that when plants grew in sterilized soil, nutrient fluctuation promoted the dominance of alien plants under low nutrient availability, whereas its effect was minimal under high nutrient availability. However, the opposite pattern was found when plants grew in living soil. Analysis of the soil microbial community suggests that this might reflect that nutrient fluctuation strongly increased the soil fungal pathogen diversity under high nutrient availability, but slightly decreased it under low nutrient availability. Our findings indicate that besides its direct influence, environmental variability could also indirectly affect plant invasion via changes in soil-microbial communities.

ecology↗

bioRxiv2021

Increases in multiple resources promote plant invasion

Invasion by alien plants is frequently attributed to increased resource availabilities. Still, our understanding is mainly based on effects of single resources despite the fact that plants rely on multiple resources. How multiple resources affect success of alien plants remains largely unexplored. Here, with two common garden experiments, one in China and one in Germany, we tested whether nutrient and light availabilities affected the competitive outcomes between alien and native plants. We found that under low resource availabilities or with addition of only one type of resource aliens were not more competitive than natives. However, with a joint increase of nutrients and light intensity, aliens outcompeted natives. Our finding indicates that addition of multiple resources could greatly reduce the number of limiting factors (i.e. niche dimensionality), and that this favors the dominance of alien species. It also indicates that habitats experiencing multiple global changes might be more vulnerable to plant invasion.

ecology↗

bioRxiv2021

Matthew effect: common species become more common and rare ones become more rare in response to artificial light at night

Artificial light at night (ALAN) has been and still is rapidly spreading, and has become an important component of global change. Although numerous studies have tested its potential biological and ecological impacts on animals, fewer have tested its impacts on plants, and very few studies have tested whether it affects alien and native plants differently. Furthermore, common plant species, and particularly common alien species, are often found to benefit more from additional resources than rare native and rare alien species. Whether this is also the case with regard to increasing light due to ALAN is still unknown. Here, we tested how ALAN affects the performance of common and rare alien and native plants directly and indirectly via flying insects. We grew five common alien, six rare alien, five common native and four rare native plant species under four combinations of two ALAN (no ALAN vs ALAN) and two insect-exclusion (no exclusion vs exclusion) treatments, and compared their biomass production. We found that common plant species, irrespective of whether they are alien or native, produced significantly more biomass than rare species, particularly under ALAN. Furthermore, alien species tended to show a slightly stronger positive response to ALAN than native species (marginally significant origin x ALAN interaction, p = 0.079). Our study shows that common plant species benefited more from ALAN than rare ones. This might lead to shifts in plant diversity and vegetation composition, further propelling global biodiversity decline, when ALAN becomes more widespread. In addition, the slightly more positive response of alien species indicates that ALAN might increase the risk of alien plant invasions.

ecology↗

bioRxiv2021

Widely naturalized species are not more promiscuous in the use of different nitrogen forms, but benefit more from inorganic nitrogen

Nitrogen (N) is an essential mineral nutrient necessary for plant growth and has been considered a crucial factor influencing invasion success. Former studies mainly focused on responses of alien plants to different levels of N availability. However, in natural soils, N comes in different forms. Few experimental studies have explored responses of naturalized alien species to different N forms, and whether such responses are related to their naturalization success globally. We selected 22 common herbaceous species native to Germany that have all become naturalized and thus been introduced elsewhere in the world. We grew these species under six different N conditions that differed in the amount or form of N, and assessed their growth performance in a greenhouse experiment. We found that plants produced more biomass when grown under high N levels than under low N levels, and when N was provided in inorganic form than when provided in organic form. Neither biomass production nor promiscuity to different N forms was related to naturalization success of the species. However, the biomass response to inorganic N, relative to organic N, was stronger for the widely naturalized species than for the less widely naturalized ones. Our study shows that although the widely naturalized alien species were not more promiscuous than the less widely naturalized species, they took more advantage of the inorganic-N forms. This indicates that naturalization success might be partly driven by a species ability to take advantage of increased inorganic N levels.

ecology↗

bioRxiv2021

Soil fauna may buffer the negative effects of drought on alien plant invasion

Although many studies have tested the direct effects of drought on alien plant invasion, less is known about how drought affects alien plant invasion indirectly via other groups of organisms such as soil fauna. To test for such indirect effects, we grew single plant of nine naturalized alien target species in pot-mesocosms with a native community of five native grassland species under four combinations of two drought (well-watered vs drought) and two soil-fauna-inoculation (with vs without) treatments. We found that drought decreased the absolute and the relative biomass production of the alien plants, and thus reduced their competitive advantage in the native community. Drought decreased the abundance of soil fauna, particularly the soil mites, but did not affect abundance and richness of soil herbivores. Soil-fauna inoculation increased the biomass of the native plant community and thereby decreased the relative biomass production of the alien species. The increased invasion resistance due to soil fauna, however, tended (p = 0.09) to be stronger for plants growing under well-watered conditions than under drought. Our multispecies experiment thus shows that soil fauna might help native resident communities to resist alien plant invasions, but that this effect might be diminished by drought.

ecology↗

bioRxiv2021

Interactive effects of herbivory and the level and fluctuations of nutrient availability on dominance of alien plants in synthetic native communities

Numerous studies have highlighted the role of nutrient availability and fluctuations therein for invasion success of alien plants. Others also highlighted the role of herbivores in invasion success. However, how herbivory and the level and fluctuations in nutrient availability interact in driving alien plant invasion into resident communities remains largely unexplored. We grew eight invasive alien species as target species in pot{square}mesocosms with five different synthetic native communities in a three-factorial design with two levels of nutrient availability (low vs high), two levels of nutrient fluctuations (constant vs pulsed) and two levels of herbivory (with vs without). The relative biomass production of the alien target plants decreased in response to an increase in nutrient availability, and increased in response to the presence of herbivores. Furthermore, herbivory could interact with changes in nutrient availability and nutrient fluctuations to affect the dominance of the alien target species (a marginally significant interaction; 90% CIs: [0.125, 2.712]). Our multispecies experiment indicates that herbivory could mediate the interactive effect of nutrient enrichment and variability in nutrient supply on invasion of alien plants into native communities. Therefore, we recommend that studies testing the fluctuating resources hypothesis should also consider interactive effect of other trophic levels.

ecology↗

bioRxiv2021

Soil conditions drive belowground trait space in temperate agricultural grasslands

O_LIPlant belowground organs perform essential functions, including water and nutrient uptake, anchorage, vegetative reproduction and recruitment of mutualistic soil microbiota. Determining how belowground traits jointly determine dimensions of the trait space and how these dimensions are linked to environmental conditions would further advance our understanding of plant functioning and community assembly. C_LIO_LIHere, we investigated belowground plant-trait dimensionality and its variation along 10 soil and land-use parameters in 150 temperate grasslands plots. We used eight belowground traits collected in greenhouse and common garden experiments, as well as bud-bank size and specific leaf area from databases, for a total of 313 species, to calculate community weighted means (CWMs). C_LIO_LIUsing PCA, we found that about 55% of variance in CWMs was explained by two main dimensions, corresponding to a mycorrhizal collaboration and a resource conservation gradient. Frequently overlooked traits such as rooting depth, bud-bank size and root branching intensity were largely integrated in this bidimensional trait space. The two plant-strategy gradients were partially dependent on each other, with outsourcing communities along the collaboration gradient being more often slow. These outsourcing communities were also more often deep-rooting, and associated with soil parameters, such as low moisture and sand content, high topsoil pH, high C:N and low {delta}15N. Slow communities had large bud-banks and were associated with low land-use intensity, high topsoil pH, and low nitrate but high ammonium concentrations in the soil. We did not find a substantial role of phosphorus-availability as an indicator along the collaboration gradient. C_LIO_LIIn conclusion, the collaboration and conservation gradients previously identified at the species level scale up to community level in grasslands, encompass more traits than previously described, and vary with the environment. C_LI

ecology↗

bioRxiv2020

Population genomic and historical analysis reveals a global invasion by bridgehead processes in Mimulus guttatus

Humans are transforming species ranges worldwide. While artificial translocations trigger biological invasions with negative effects on biodiversity, invasions provide exceptional opportunities to generate ecological and evolutionary hypotheses. Unfortunately, imperfect historical records and exceedingly complex demographic histories present challenges for the reconstruction of invasion histories. Here we combine historical records, extensive worldwide and genome-wide sampling, and demographic analyses to investigate the global invasion of yellow monkeyflowers (Mimulus guttatus) from North America to Europe and the Southwest Pacific. By sampling 521 plants from 158 native and introduced populations genotyped at >44,000 loci, we determined that invasive North American M. guttatus was first likely introduced to the British Isles from the Aleutian Islands (Alaska), followed by rapid admixture from multiple parts of the native range. Populations in the British Isles then appear to have served as a bridgehead for vanguard invasions worldwide into the rest of Europe, New Zealand and eastern North America. Our results emphasise the highly admixed nature of introduced M. guttatus and demonstrate the potential of introduced populations to serve as sources of secondary admixture, producing novel hybrids. Unravelling the history of biological invasions provides a starting point to understand how invasive populations adapt to novel environments.

evolutionary biology↗

bioRxiv2020

Effect of allelopathy on plant performance

Allelopathy (i.e. chemical interactions between plants) is known to affect individual performance, community structure and plant invasions. Yet, a quantitative synthesis is lacking. We performed a meta-analysis of 385 studies that measured allelopathic effects of one species (allelopathy plant) on another species or itself (test plant). Overall, allelopathy reduced plant performance by 25%, but the variation in allelopathy was high. Type of method affected allelopathic effect. Compared to leachates, allelopathy was more negative when residues of allelopathy plants were applied, and less negative when soil conditioned by allelopathy plants was applied. The negative effects of allelopathy diminished with study duration, and increased with concentrations of leachates or residues. Although allelopathy was not significantly related to life span, life form and domestication of the interacting plants, it became more negative with increasing phylogenetic distance. Moreover, native plants suffered more negative effects from leachates of naturalized alien plants than of other native plants. Our synthesis reveals that allelopathy could contribute to success of alien plants. The negative relationship between phylogenetic distance and allelopathy indicates that allelopathy might drive coexistence of close-related species (i.e. convergence) or dominance of single species.

ecology↗

bioRxiv2020

Plant-soil feedback as a pathway of invasional meltdown

While most alien species fail to establish, some invade native communities and become widespread. Many of these communities have been invaded by multiple aliens, suggesting that aliens may cause invasional meltdowns. Here, we tested whether and how a third plant species affects the competitive outcome between alien and native plants through its soil legacy. We first conditioned soil with one of ten species (six natives and four aliens) or without plants. Then, we grew on these 11 soils, five aliens and five natives without competition, and with intra- or interspecific competition (all pairwise alien-native combinations). We found that aliens were not more competitive than natives when grown on soil conditioned by other natives or on non-conditioned soil. However, aliens were more competitive than natives on soil conditioned by other aliens. Although soil conditioning rarely affected the strength of competition between later plants, soil conditioned by aliens changed the competitive outcomes by affecting growth of aliens less negatively than that of natives. Microbiome analysis confirmed this finding by showing that the soil-legacy effects of one species on later species were less negative when their fungal endophyte communities were less similar; and that fungal endophyte communities were less similar between two aliens than between aliens and natives. Our study suggests that coexistence between aliens and natives is less likely with more alien species. Such invasional meltdown is likely mediated by spill-over of fungal endophytes, some of which are pathogenic.

ecology↗