The order of arrival of plant species during assembly can affect the structure and functioning of grassland communities. These so‐called priority effects have been extensively studied aboveground, but we still do not know how they affect the vertical distribution of roots in the soil and the rooting depth of plant communities. To test this hypothesis, we manipulated the order of arrival of three plant functional groups (forbs, grasses and legumes) in a rhizobox experiment. Priority effects were created by sowing one functional group 10 days before the other two. Rhizoboxes in which all functional groups were sown simultaneously were used as controls. During the experiment, the total visible root length and the mean and maximum rooting depth of plant communities were monitored using image analysis and a new methodological approach using deep learning (RootPainter) for root segmentation. At harvest, we measured aboveground (community and species level) and belowground (community level) biomass, and assessed the vertical distribution of the root biomass in different soil layers. At the community level, all scenarios where one functional group was sown before the other two had similar shoot and root productivity. At the species level, two forbs (Achillea millefolium and Centaurea jacea) benefited from arriving early, and one legume (Trifolium pratense) had a disadvantage when it was sown after the grasses. Priority effect treatments also affected the vertical distribution of roots. When grasses were sown first, plant communities rooted more shallowly (lower mean and maximum rooting depth) than when forbs or legumes were sown first. In addition, roots moved down the soil profile more slowly in grasses‐first communities. Our results highlight that plant functional group order of arrival in grassland communities can affect the vertical distribution of roots in the soil and this may have implications for species coexistence.
The order of arrival of plant species during assembly can affect the structure and functioning of grassland communities. These so-called priority effects have been extensively studied aboveground, but we still do not know how they affect the vertical distribution of roots in the soil and the rooting depth of plant communities. To test this hypothesis, we manipulated the order of arrival of three plant functional groups (forbs, grasses and legumes) in a rhizobox experiment. Priority effects were created by sowing one functional group 10 days before the other two. Rhizoboxes in which all functional groups were sown simultaneously were used as controls. During the experiment, the mean rooting depth of plant communities was monitored using image analysis and a new methodological approach using deep learning (RootPainter) for root segmentation. At harvest, we measured aboveground (community and species level) and belowground (community level) biomass, and assessed the vertical distribution of the root biomass in different soil layers. At the community level, all scenarios where one functional group was sown before the other two had similar shoot and root productivity. At the species level, two forbs (Achillea millefolium and Centaurea jacea) benefited from arriving early, and one legume (Trifolium pratense) had a disadvantage when it was sown after the grasses. Priority effect treatments also affected the vertical distribution of roots. When grasses were sown first, plant communities rooted more shallowly than when forbs or legumes were sown first,. In addition, roots moved down the soil profile 24% more slowly in grasses-first communities. Our results highlight that plant functional group order of arrival in grassland communities can affect the vertical distribution of roots in the soil and this may have implications for species coexistence.
The establishment of oak trees is often a slow and difficult process. Hence, it is necessary to determine the characteristics that can lead to improving their regeneration. In this genus, seed size is highly variable both at the interspecific and intraspecific levels, and the effects of intrapopulation variability are not well understood, being even less so for Quercus faginea. In this study, the effects of the age of the mother tree, seed weight and the interaction between these two factors on seed germination, emergence and growth (biomass) were analysed. For this purpose, 16 trees-8 young and 8 old-were selected with the intent to cover the entire range of acorn weights produced in this population. Among the main results, it should be noted that: (1) in older trees, it is easier to find larger acorns; (2) the percentage and the speed of germination of the acorns of young trees is greater than that of old trees; (3) the percentage and the speed of seedling emergence of young trees is greater than that of old trees; and (4) cotyledon weight is the variable that most influences biomass, quite often in a positive way. Therefore, maintaining intrapopulation variability seems to be an approach that most favours the persistence of these populations.
The interactions between different species in an ecosystem, such as predation and herbivory, are crucial for maintaining the ecosystem’s functioning, including pest control and nutrient cycling. Unfortunately, human activities are increasingly affecting these trophic relationships, contributing to the current decline in biodiversity, particularly due to urbanization and climate change. The intensity of trophic interactions is also affected by latitudinal gradients, which may be further impacted by urbanization, such as the urban island heat effect. This study aimed to investigate the hypothesis that the impact of human pressure on trophic interactions varies across different latitudes. To test this hypothesis, we selected 18 study sites at two latitudes (i.e., ~53°N and ~50°N) with varying human population density. We used artificial caterpillars placed on European beech branches to assess bird predation and took standardized pictures of the leaves to estimate insect herbivory. Remote sensing techniques were used to estimate human pressure. We found that the intensity of both bird predation and insect herbivory varied in response to human pressure, with opposite trends observed depending on the latitude. At the upper latitude, bird predation increased with human impact, while the opposite was observed at the lower latitude. All types of herbivory in both latitudes increased with urbanization. Moreover, at lower latitudes, species may face a disadvantage due to the urban heat island effect, as they tend to be relatively sensitive to temperature changes. Conversely, at higher latitudes, some species may benefit from a softer winter. Overall, this study highlights the complex and dynamic nature of trophic relationships in the face of human-driven changes to ecosystems. It also emphasizes the importance of considering both human pressure and latitudinal gradients when assessing the ecological consequences of future climate change scenarios, particularly in urban environments.
Domestication and intensive management practices have significantly shaped characteristics of modern crops. However, our understanding of domestication’s impact had mainly focused on aboveground plant traits, neglecting root and rhizospheric traits, as well as trait-trait interactions and root-microbial interactions. To address this knowledge gap, we grew modern ( Hordeum vulgare L. var. Barke) and wild barley ( H. spontaneum K. Koch var. spontaneum) in large rhizoboxes. We manipulated soil microbiome by comparing disturbed (sterilized soil inoculum, DSM) versus non-disturbed (non-sterilized inoculum, NSM) microbiome Results showed that modern barley grew faster and increased organic-carbon exudation (OC ) compared to wild barley. Interestingly, both barley species exhibited accelerated root growth and enhanced OC under DSM, indicating their ability to partially compensate and exploit the soil resources independently of microbes if need be. Plant trait network analysis revealed that modern barley had a denser, larger, and less modular network than wild barley indicating domestication’s impact on trait coordination. Further, soil microbiome influenced specific network parameters. While the relative abundance of bacteria didn’t vary between wild and modern barley rhizospheres, species-specific core bacteria were identified, with stronger effects under DSM. Overall, our findings highlight domestication-driven shifts in root traits, trait coordination, and their modulation by the soil microbiome.
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