Search Results (68)

Islands subjected to anthropogenic disturbance are highly susceptible to alien plant invasions. However, the alien floral diversity of China’s islands has been insufficiently studied, hindering its control. Weizhou Island (northern South China Sea) has experienced long-term human exploitation. We inventorized its alien, naturalized, and invasive vascular plants (based on herbarium specimen data for 2018–2024 and surveys of 112 plots); analyzed species composition, origins, life forms, and habitats; and conducted an invasive species risk assessment. This identified 203 aliens, including infraspecific and hybrid taxa, 129 (63.5%) naturalized and 71 (55.0% of the naturalized species) invasive. The aliens were dominated by the Fabaceae, Asteraceae, and Euphorbiaceae, particularly genera such as Euphorbia, Senna, and Portulaca, originating primarily in North America, Oceania, and Africa. Perennial herbs were the most common lifeform, followed by annual herbs and shrubs. Invasion hotspots were primarily abandoned farmland, roadsides, and agricultural lands. Using the Analytic Hierarchy Process, we classified the 71 invasive species as representing high-risk, moderate-risk, and low-risk (20, 16, and 35 species, respectively). Bidens pilosa, Ageratum conyzoides, Opuntia dillenii, and Leucaena leucocephala pose severe threats to the island ecosystem. This first complete inventory of the alien flora on Weizhou Island offers critical insight into the management of invasive alien plants in island ecosystems. Full article

Disturbed ecosystems are particularly susceptible to biological invasions. Increasing freshwater salinization, caused by anthropogenic factors, can alter the phytoplankton community and favour newly arrived halotolerant species. This study investigates the halotolerance of four Nostocalean cyanobacterial species—the native to Europe, Aphanizomenon gracile, and alien Chrysosporum bergii, Cuspidothrix issatschenkoi, and Sphaerospermopsis aphanizomenoides—using monoculture experiments under varying NaCl concentrations. Additionally, we performed two microcosm experiments to explore shifts in biodiversity in freshwater phytoplankton communities sourced from artificial reservoirs and assess their susceptibility to cyanobacterial invasion under salinity stress. Results showed that all Nostocalean cyanobacteria were halotolerant under mild salinities (up to 1 g/L NaCl), with Chrysosporum bergii and Sphaerospermopsis aphanizomenoides demonstrating the most salt tolerance. In the microcosm experiment, changes in community composition were driven by the halotolerance of dominant groups. Water body 1, dominated by Bacillariophytina, reduced its biomass of phytoplankton at high salinity (5 g/L NaCl), while water body 2, dominated by Chlorophytina, remained stable regardless of disturbance. Both cyanobacteria successfully invaded both halotolerant and halosensitive communities, increasing their dominance as salinity rose. Our findings suggest that anthropogenic stressors such as freshwater salinization can alter the phytoplankton community and increase a competitive advantage to certain taxa, including widespread alien cyanobacteria, potentially promoting invasions and bloom formation. Full article

Invasive alien plant species, while ecologically and economically problematic, represent an underutilized source of bioactive phytochemicals with promising phytopharmaceutical applications. This study investigates the LC-DAD-MS phenolic profiles of 70% ethanol and 80% methanol leaf and flower extracts of Ailanthus altissima (Mill.) Swingle and Helianthus tuberosus L., collected in the Istria region of Croatia, alongside their antioxidant capacities using ABTS, DPPH, and FRAP assays. Both species exhibited high levels of flavonoids and phenolic acids, with consistently higher concentrations in leaf versus flower tissues and in ethanolic versus methanolic extracts. Strong correlations (r > 0.9) between total phenolics and antioxidant activity confirmed the functional significance of these compounds. With a targeted metabolomics approach, in A. altissima, 51 phenolics were identified in leaves and 47 in flowers, with ellagitannins predominating; vescalagin isomers reached 94 mg/g DW in leaves and 82 mg/g DW in flowers. H. tuberosus extracts contained 34 phenolics in leaves and 33 in flowers, with hydroxycinnamic acids and flavonols dominating; 5-caffeoylquinic acid was the principal compound (25 mg/g DW in leaves, 2 mg/g DW in flowers). The identified phytochemicals are known for their potent antioxidant, anti-inflammatory, anticancer, antimicrobial, and metabolic-regulating properties. Additionally, four leaf-specific compounds were identified in each species, indicating potential for targeted extraction. These findings advance the phytochemical characterization of invasive taxa and highlight their potential as sources of natural antioxidants for functional food and pharmaceutical development. Full article

Invasive plants can significantly alter the composition and functioning of soil ecosystems, which in turn affects soil fauna such as microorganisms; mesofauna including mites, springtails, nematodes, and insects; and other invertebrates. We used clusters of three different tree species to investigate how they affect the composition of belowground soil nematode communities. The clusters included Acer negundo (L.) (an invasive, non-native species), Fraxinus excelsior (L.), and Alnus glutinosa (Gaertn.) (both as native representatives) in floodplain forest habitats of the Morava River. We investigated the families, genera, trophic groups, and functional guilds of soil nematodes in each tree cluster to assess the usefulness of nematodes as indicators of the impact of alien tree species on native communities. The study was complemented by measuring basic soil physico-chemical properties. The data show that nematode communities were not sensitive to A. negundo invasion, as clusters of invasive trees had similar nematode abundance, genus richness, diversity, family and genus composition, and trophic structure compared to species-specific clusters of two native tree species. A cumulative total of 96 nematode genera, belonging to 52 families, were recorded in the investigated floodplain forest sites. The most abundant families across all clusters were Alaimidae, Cephalobidae, Hoplolaimidae, and Rhabditidae for all tree clusters. Among the genera, Helicotylenchus, Pratylenchus, Paratylenchus (as obligate plant parasites), Filenchus, and Malenchus (as facultative plant parasites), as well as Acrobeloides, Eucephalobus, Plectus, and Rhabditis (as bacterivores), were the most dominant taxa. The measured soil properties did not differ significantly among tree species (p < 0.05). Nevertheless, redundancy analysis identified a significant correlation between soil moisture content and abundance of several nematode genera, nematode trophic groups, and functional guilds. The results indicate that the presence of invasive ash-leaved maple trees in the studied floodplain forests had no adverse effect on the diversity and functional structure of soil nematode communities. This study offers initial insights into nematode communities in Acer negundo invaded habitats, but further studies are needed to verify these findings. Full article

Species belonging to the crustacean infraorder Astacoidea represent taxa of particular interest from a conservation point of view, such as the threatened European crayfish (i.e., Austropotamobius pallipes), and at the same time include invasive taxa having highly negative impacts where they are introduced. Among the latter, some freshwater-dwelling species seem to show some abilities to tolerate high salinity levels, such as Procambarus clarkii Girard, 1852. By using metadata and field observation, this review will investigate whether the alien P. clarkii can threaten coastal waters. Specifically, we will shed light on P. clarkii’s (1) invasiveness, (2) its dispersal pattern, (3) its tolerance to salinity, and (4) its ecological plasticity as an invasive species in relation to estuaries. This new habitat colonization is also possible as P. clarkii has been observed to survive up to 20 ppt of water salinity and a maximum of 30–35 ppt with its lifetime drastically reduced. As a result, P. clarkii colonizes different ecosystems globally, reaching estuarine and coastal ecosystems due to active and passive transport by human and animal vectors. Due to recent discoveries of alien crayfish in estuarine and coastal waters, monitoring activities have become mandatory to preserve coastal habitats and all the aquatic resources (e.g., limicolous birds, endemic fish, fishery and aquaculture activities) inhabiting therein. Full article

Botanical gardens have historically introduced alien species for agronomic, medicinal, and ornamental purposes, but they also contribute to plant invasions. The Hortus Botanicus Karalitanus (HBK) is a historic botanical garden established in 1866, as an acclimatisation arboretum for tropical plants, by the University of Cagliari. This study inventoried alien vascular plants in the HBK that showed some degree of spontaneity, analysing their status, origin, life form, introduction pathways, reproductive strategies, and presence in Sardinian habitats. A focus on invasive species and their historical introduction based on their first records on the island and in the HBK was made. Field surveys from 2015 to 2024 allowed us to identify 146 alien taxa, primarily neophytes (83%), 45% of which were naturalised and 12% were invasive. Ornamental plants contributed to 70% of introductions, while accidental taxa (weeds and hitchhikers, 61%) were the most invasive. Seed reproduction was the most common way of propagation (41%). About the diffusion in Sardinia, 25% of taxa had no records in nature outside the HBK, 39% were found only in anthropogenic habitats, and 36% in natural habitats. Among them, 8% were invasive in both the HBK and Sardinia, with wetlands being the most affected (5%). However, only 3% of common invasive species were first recorded in the HBK. The results highlight the role of the HBK in alien species spread and early detection, aiding in invasion management and biodiversity conservation in Sardinia. Full article

The Ligurian Sea, located in the northwestern Mediterranean, is undergoing a dramatic shift in fish biodiversity due to climate change and species immigration. This study adopted a citizen science approach to provide new data on the current distribution of rare, thermophilic, and alien fish species in the Ligurian Sea. Observations were collected through social networks and personal acquaintances, involving fishermen, divers, and fishmongers. We obtained a total of 47 records, encompassing 18 species belonging to 18 different fish families. Considering existing literature, some species appear to prefer this part of the Mediterranean Sea, likely due to the Ligurian Sea’s unique hydrodynamic and oceanographic conditions that support nutrient-rich environments. Others appear to be less common in the region, probably due to the lower temperatures of the Ligurian Sea compared to other Mediterranean sectors. Our findings emphasize the dual and controversial role of the Ligurian Sea as a refuge for cold-adapted species and a hotspot for thermophilic invaders. Moreover, this research highlights the role of citizen science in complementing traditional survey approaches, providing an efficient tool to monitor many taxa across several diverse ecological niches. Full article

Based on literature data and new field investigations, a checklist of the ornamental vascular flora of Sicily is presented. Trees, shrubs, herbaceous, and succulent plants growing in street trees, parks, private gardens, and historic villas of Sicily are included in the checklist. For each taxon, information on growth forms, geographical and biome origin, resident time, and status (native/alien) in Italy is provided. A total of 928 taxa (including 823 species s. str., 33 cultivars, 31 hybrids, 24 varieties, 9 subspecies, and 8 forms), belonging to 486 genera included in 138 families, were recorded. Fabaceae, Rosaceae, Asteraceae, Cactaceae, Asparagaceae, Arecaceae, and Malvaceae are the richest families in taxa. Phanerophytes are the prevalent growth form, and the main part of such flora consists of Asiatic and American taxa. Taxa from subtropical and tropical biomes showed a prevalent presence; this is a peculiarity which characterizes the Sicilian ornamental flora. Delonix regia emerges as a peculiar case, representing the only documented cases of open-air cultivation in both Sicily and the entire country. A significant percentage of taxa (41%) is included in the list of alien vascular flora of Italy, showing a strong predominance of casual and naturalized neophytes alien species. Full article

The Costa Brava, a Mediterranean coastal strip spanning ca. 250 km (in NE Spain), is a hotspot of plant invasions. To address this issue, the LIFE medCLIFFS project was launched to improve the management of invasive species along sea cliffs in the region. The initial phase of the project involved designing more than 100 transects distributed across the coastline, each 1 km in length, which were to be monitored by volunteers. During the fieldwork for transect design, we identified a total of 126 alien species. This is a substantial number, considering that the observations were confined to the transect areas. Notably, among the 126 observed taxa, 24 represented floristic novelties: 7 were new to the Costa Brava, 7 to the province of Girona, 4 to Catalonia, 1 to Spain, 1 to the Iberian Peninsula, and 4 to Europe. Additionally, we provide information on other alien taxa that, although not novel for the study area, could be significant for control and management efforts. These observations provide a foundation for compiling a comprehensive catalog of the alien flora of the Costa Brava. Full article

Floristic and biodiversity knowledge play a crucial role in ecosystem conservation and sustainable land management, particularly in urban-rural contexts that can serve as biodiversity reservoirs, hosting species of high biogeographic value. Focusing on the new municipality of Misiliscemi, established in 2021 in Sicily and now facing the challenge of developing new management strategies, this study provides fundamental knowledge on the plant biodiversity of the area and explores how the integration of floristic and environmental data can guide territorial planning strategies aimed at preserving natural capital and ecosystem services. The research, based on field surveys conducted over many years, taxonomic identification of species, analysis of biological forms and chorological data, evaluation of ecological indicators, and GIS-based habitat mapping according to the EUNIS classification, has made it possible to obtain a comprehensive dataset. The results of this work led to the identification of 623 taxa, recording new findings for the Sicilian flora, including both native and alien species, which represent primary biodiversity data crucial for plant resource management. In addition, 42 habitat types were mapped, highlighting that approximately 80% of the territory is occupied by vegetated man-made habitats. Despite anthropogenic pressures and landscape modifications, Misiliscemi retains significant plant biodiversity, including habitats and species of conservation interest, that represent a vital resource for natural capital and ecosystem services. This knowledge base, in addition to constituting the scientific foundation upon which this young municipality can develop an urban planning strategy aimed at achieving sustainable local development, also represents a methodological approach that highlights how basic knowledge of urban biodiversity should be considered a crucial aspect of sustainable urban planning worldwide. Full article

We present the first vascular flora of the municipality of Pisa. The floristic inventory was built on previous literature and field observations deposited in the online database Wikiplantbase #Toscana, integrated by observations from iNaturalist. The established flora of Pisa includes a total of 1404 specific and subspecific taxa (594 genera, 123 families), out of which 112 are alien species. Silene subconica is excluded from the regional flora of Tuscany, while Solanum nitidibaccatum is reported as a new regional casual alien, and the regional alien status of Salpichroa origanifolia shifts from naturalized to invasive. Native taxa exceed species-area predictions by 33.3%, attesting for a high floristic richness, and there are taxa of high biogeographical and conservation interest. However, also alien taxa exceed predictions by 34.9%, and there are many invasive species, pointing out a high anthropogenic impact in the territory of Pisa, mostly due to urbanization. The biological and chorological spectra reflect the coexistence of typical Mediterranean and central European habitats in this territory, especially within the Migliarino–San Rossore–Massaciuccoli Regional Park. The vascular flora of the municipality is quite rich, although threatened by anthropic pressures, fostering the arrival and establishment of invasive alien species. Full article

Extreme weather events, considered to be the most destructive natural hazards connected with rapid climate changes in the temperate zone of Europe, necessitate swift adjustments to the selection of ornamental plants for cultivation in multi-stress urbanized areas, public greeneries, and gardens. Moreover, given the rising average air temperature and prolonged growing season, as well as the delay and shortening of the dormancy period, plant phenology is subject to significant alternations. Herbaceous plants fulfill most elements of ecosystem service, e.g., they may enhance biodiversity in climate-warming conditions and create a favorable environment for trees in cities. In this work, we consider the advantages and disadvantages of the dissemination or introduction of annuals and perennials. We draw attention to species rarely or never known to have been cultivated in Europe, which currently occupy hotspots with the highest biodiversity value, including (i) the Mediterranean Basin, (ii) the Caucasus, (iii) Irano-Anatolian, (iv), and the mountains of Central Asia. We emphasize the importance of protecting threatened taxa through safe ex situ cultivation. Ornamentals should be characterized not only by aesthetic values but also by their ability to adapt to environmental changes. However, bearing in mind that horticulture is an important source of invasive alien species, further research assessing the ecological threats and advantages should be conducted. Full article

The Wadi El-Rayan lakes are important aquatic environments located at the border of the great North African Sahara. Quantifying the temporal changes in these lakes due to natural and/or anthropogenic stressors is critical when assessing potential impacts on aquatic ecosystem health and the sustainability of fisheries. To detect the changes in fish communities and their drivers, the landing composition of the Wadi El-Rayan lakes over the past 30 years was quantitatively analyzed. The areas of the lakes dramatically decreased from 110 km² in 1991 to 73 km² in 2019. The loss of the lake area was attributed to climate warming, where the evaporation rate exceeded the volume of recharge and the recharge decreased due to an increase in agriculture and aquaculture. The total landing significantly increased in the past three decades due to an increase in the fishing effort (number of licensed boats). Nile tilapia, mullet, and grass carp dominated the landings. The pelagic-to-demersal ratio indicated a shift in the fish community composition towards demersal species. This shift was attributed to an increase in the eutrophication level. The fish communities of the landing data were clustered into four distinct groups. These clusters were significantly differentiated (p < 0.001) in both a PERMANOVA test and a PCA plot. There was a gradual replacement of the dominant species among these clusters. The most recent cluster (2018–2019) was characterized by rare species dominating the community. This shift in species composition suggests that target taxa may have been overexploited. The total landing also decreased, which may have been a result of climate warming. Furthermore, the presence of alien and warm-water species significantly increased. The fish community structure and composition shift could be attributed to anthropogenic (mismanagement) and natural climatic changes (warming). Full article

Glossy buckthorn (Frangula alnus Miller) is an invasive alien plant species (IAPS) rapidly expanding in North America but is largely understudied compared to the common buckthorn (Rhamnus cathartica). Our study investigated the effects of a 27-year-old F. alnus invasion on native understory plant and saprophagous macroarthropod communities in a wet deciduous woodland in Southern Québec, Canada. We hypothesized a decreased taxonomic diversity and a change in community composition of both indicator taxa with increasing F. alnus density. The understory plant and saprophagous macroarthropod communities were characterized, respectively, through vegetation surveys and pitfall trapping across a density gradient of 43 plots invaded by F. alnus. Our results demonstrated that F. alnus did not exert a strong influence on species community composition, although the homogenization of understory plant communities was observed. Despite several decades of F. alnus invasion at our study site, the consequences on the selected indicator taxa were overall relatively small, suggesting that the magnitude of effects is variable. We suggest that further investigation at a larger scale should be performed to evaluate the effect of F. alnus on a broad diversity of indicators and understand any context dependency. Full article

In this study we focused on the need to fill a knowledge gap among Italian botanical studies namely that of ornamental species census. In particular, we addressed one of the regions in southern Italy with less knowledge in the field of such studies and with an obvious presence of non-native species. A widespread census of the Apulian territory was carried out between 2021 and 2024 in both urban and suburban areas including street trees, parks, and private and historic gardens. The inventory of ornamental trees, shrubs, and succulents of Apulia (southern Italy) was carried out in six provinces, i.e., Bari, Barletta-Andria-Trani, Brindisi, Foggia, Lecce, and Taranto. The checklist comprises 287 taxa (including 265 species, 6 varieties, 5 subspecies, and 11 forms) included in 179 genera belonging to 78 families. We evaluated the number of taxa per families and genera, the presence of each taxa in the provinces of Apulia, the number of taxa per occurrence status, growth forms, geographical origin, and the number of native and alien taxa and also the artificial hybrids. Remarks of the most significant taxa and evaluation of geographical distribution in Italy were also taken into consideration. A large number of surveyed taxa (51.74%) are comprised in the list reported in the recent study on allochthonous vascular flora in Italy with a marked prevalence of Neophyte Casual Alien and Neophyte Naturalized Alien species. Full article