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 EXU) compared to wild barley. Interestingly, both barley species exhibited accelerated root growth and enhanced OC EXU 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.