The introduction of invasive alien plant species (IAPS) can modify plant-soil feedback, resulting in an alteration of the abiotic and biotic characteristics of ecosystems. Prunus serotina, Quercus rubra and Robinia pseudoacacia are IAPS of European temperate forests, where they can become dominant and suppress the native biodiversity. Assuming that the establishment of these invasive species may alter native forest ecosystems, this study comparatively assessed their impact on ecosystems. This study further investigated plant communities in 12 forest stands, dominated by the three IAPS and native trees, Quercus robur and Carpinus betulus (three plots per forest type), in Northern Italy, and collected soil samples. The relationships between the invasion of the three IAPS and modifications of humus forms, soil chemical properties, soil biological quality, bacterial activity and plant community structure and diversity (α-, β-, and γ-diversity) were assessed using one-way ANOVA and redundancy analyses (RDA). Our comparative study demonstrated that invaded forests often had unique plant and/or soil properties, relative to native forests, and the degree of dissimilarity depended on the invasive species. Particularly, Q. rubra is related to major negative impacts on soil organic horizons and low/modified levels of microarthropod and plant biodiversity. R. pseudoacacia is associated with an altered base content of soil and, in turn, with positive feedback to the soil biological quality (QBS-ar) and plant diversity, but with a high cover compared with other alien plant species. P. serotina is associated with intermediate impacts and exhibits a plant species assemblage that is more similar to those of native forest stands. Our work suggests impact-based management decisions for the three investigated IAPS, since their effects on the diversity and composition of resident ecosystems are very different.

Experimental evidence on the bio-ecological effects of microplastics on terrestrial plants is still lacking. In this study, we hypothesized that soil polluted with polyvinyl chloride (PVC) microparticles can negatively influence plant traits, photosynthetic efficiency and phenology of two weeds but with different strength in relation to the species’ life traits. Therefore, we conducted an experiment in a common garden growing the wild species Senecio inaequidens and Centaurea cyanus for about 60 days. The possible toxic effects of soil microplastics (1% of PVC in 100 g of soil medium) were investigated, coupling an analyses on plant traits with an evaluation of the microplastic-induced changes in terms of phenology and photosynthetic efficiency. Overall, results showed that plants in control pots were higher and larger than those in treated ones (C. cyanus plant width: p < 0.05; S. inaequidens—plant height: p < 0.05; plant width: p < 0.05). Moreover, for C. cyanus, photosynthetic efficiency (index Fv/Fm) was significantly lower in the treatment than that in control (p < 0.05). About phenology, the second leaf of S. inaequidens emerged earlier in control than that in treatments (day 12.2 ± 0.25 and 14.3 ± 0.3, respectively; p < 0.001). The obtained results highlight that PVC microparticles may have had negative effects on soil–plant system reducing the performance of plants. Since, up to now, research on the interaction between soil microplastics and terrestrial plants has mainly focused on agricultural plants, this work fills a gap of knowledge regarding wild species (weeds), highlighting the possible future impact of microplastics on biodiversity.

The intensive rice cultivation area in northwestern Italy hosts the largest surface of rice paddies in Europe, and it is valued as a substantial habitat for aquatic biodiversity, with the paddies acting as a surrogate for the lost natural wetlands. The extent of submerged paddies strictly depends on crop management practices: in this framework, the recent diffusion of rice seeding in dry conditions has led to a reduction of flooded surfaces during spring and could have contributed to the observed decline of the populations of some waterbird species that exploit rice fields as foraging habitat. In order to test the existence and magnitude of a decreasing trend in the extent of submerged rice paddies during the rice-sowing period, MODIS remotely-sensed data were used to estimate the extent of the average flooded surface and the proportion of flooded rice fields in the years 2000–2016 during the nesting period of waterbirds. A general reduction of flooded rice fields during the rice-sowing season was observed, averaging $-0.86\pm 0.20$ % per year (p-value < 0.01). Overall, the loss in submerged surface area during the sowing season reached $44\%$ of the original extent in 2016, with a peak of $78\%$ in the sub-districts to the east of the Ticino River. Results highlight the usefulness of remote sensing data and techniques to map and monitor water dynamics within rice cropping systems. These techniques could be of key importance to analyze the effects at the regional scale of the recent increase of dry-seeded rice cultivations on watershed recharge and water runoff and to interpret the decline of breeding waterbirds via a loss of foraging habitat.

Ambrosia artemisiifolia (common ragweed) is an invasive species native to North America and was accidentally introduced to Europe in the 19th century. Widespread in disturbed habitats, it is a major weed in spring-sown crops and it causes serious allergic rhinitis and asthma due to its allergenic pollen. The aim of this research was to analyse the effects of both competitive vegetation and herbivory by Ophraella communa to control A. artemisiifolia in an agricultural area of north-western Italy. Hayseed mixtures, both over-seeded over the resident plant community or after ploughing, when seeded before the winter season, were able to suppress the establishment of A. artemisiifolia as well as to reduce its growth in terms of plant height and inflorescence size. Defoliation of A. artemisiifolia by O. communa at the end of the growing season was conspicuous but most of the plants still produced flowers and seeds. However, significant O. communa attack was recorded for reproductive structures. As for non-target species, O. communa was mainly recorded on Asteraceae, with low density and low degree of damage. Reduction of inflorescence size due to competitive vegetation and damage to male flowers by O. communa may diminish the amount of available pollen. The results of this study may be useful for the implementation of management measures to control A. artemisiifolia in agricultural areas using mixtures of native species.