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In this long-term study, we examined the invasion by the exotic shrub glossy buckthorn (Rhamnus frangula L.) and the response of co-occurring plants in a large, undisturbed wetland. We first sampled the vegetation in 1991 and repeated the sample 15 years later using the same, permanently located sample units (n = 165). Despite dramatic increases in the abundance of buckthorn, the invasion elicited little apparent response by the resident plant community. Species richness and cover in the herbaceous plant stratum had no apparent relationship with change in buckthorn cover. The number of shrub species other than buckthorn showed no relationship with change in buckthorn cover, but the cover of other shrubs decreased as buckthorn cover increased. Species composition changed independently of changes in buckthorn cover. These results show that dramatic increases in the abundance of an invasive species do not necessarily cause large changes in the native plant community and suggest disturbance history influences community response to invasion.

The Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the safety of plant preparations from the root or rhizome of Rheum palmatum L., Rheum officinale Baill. and their hybrids, from the bark of Rhamnus frangula L. and Rhamnus purshiana DC. and from the leaf or fruit of Cassia senna L., which have been placed under Union scrutiny in Part C of Annex III in accordance with Article 8(4) of Regulation (EC) No 1925/2006. The NDA Panel reviewed the additional scientific data submitted during the period of scrutiny and the public consultation by interested parties. The pertinent scientific data were in vitro and in vivo genotoxicity studies on the plant preparations under consideration. All the results of the genotoxicity studies on plant preparations were negative. However, the plant preparations that were tested in the submitted studies were not sufficiently characterised with respect to the content of total and individual hydroxyanthracene derivatives (HADs) and components other than HADs. The studies confirmed the presence of ■■■■■, known to be genotoxic in vivo, and ■■■■■, shown to be genotoxic in vitro. In line with the EFSA Scientific Committee statement on genotoxicity assessment of chemical mixtures, considering the presence of an in vivo genotoxic compound, the plant preparations used in these studies have to be considered of concern for genotoxicity. Thus, the safety of preparations containing HADs from the root or rhizome of Rheum palmatum L., Rheum officinale Baill. and their hybrids, from the leaf or fruit of Cassia senna L. and from the bark of Rhamnus frangula L. and Rhamnus purshiana DC. cannot be established based on the submitted studies.

Glossy buckthorn (Frangula alnus Mill.) is an alien species in Canada that is invading many forested areas. Glossy buckthorn has impacts on the biodiversity and productivity of invaded forests. Currently, we do not know much about the species’ ecology and no thorough study of its distribution in temperate forests has been performed yet. As is often the case with invasive plant species, the phenology of glossy buckthorn differs from that of other indigenous plant species found in invaded communities. In the forests of eastern Canada, the main phenological difference is a delay in the shedding of glossy buckthorn leaves, which occurs later in the fall than for other indigenous tree species found in that region. Therefore, our objective was to use that phenological characteristic to map the spatial distribution of glossy buckthorn over a portion of southern Québec, Canada, using remote sensing-based approaches. We achieved this by applying a linear temporal unmixing model to a time series of the normalized difference vegetation index (NDVI) derived from Landsat 8 Operational Land Imager (OLI) images to create a map of the probability of the occurrence of glossy buckthorn for the study area. The map resulting from the temporal unmixing model shows an agreement of 69% with field estimates of glossy buckthorn occurrence measured in 121 plots distributed over the study area. Glossy buckthorn mapping accuracy was limited by evergreen species and by the spectral and spatial resolution of the Landsat 8 OLI.

Protease inhibitors from plants are well known to be potent inhibitors of the growth of bacteria, fungi, and even certain viruses which make them excellent candidates for use as the lead compounds for the development of novel antimicrobial agents for applications in medicine. In this study, Rhamnus frangula was selected as a protease inhibitor source. The maximum recovery of the protease inhibitor against trypsin was recorded in the crude extract made in 0.1 M phosphate buffer (pH 7.0) and isolated from the mature leaves. Then, the protease inhibitor designated as RfIP1 was purified to homogeneity by Sephadex G50 with an apparent molecular mass of 22.5 kDa and its N-terminal sequence exhibited a high degree of homology with known serine protease inhibitor sequences. The RfIP1 displayed maximal activity at pH 7 and 37 °C. It maintained almost 80% of its maximal activity through a large pH range. The thermo-stability of RfIP1 was markedly enhanced by BSA, CaCl 2, and sorbitol, whereas the addition of Mg 2+ , Zn 2+ , NaTDC, SDS, DTT, and β-ME significantly promoted inhibitory activity. The protease inhibitor displayed high inhibitory activity toward some known proteases (cathepsin B, chymotrypsin, collagenase, thrombin, and trypsin) that have more importance in pharmaceutical industry and it acted as potent inhibitor of some commercially proteases from Aspergillus oryzae , Bacillus sp, and Bacillus licheniformis . The protease inhibitor also possessed an appreciable antibacterial effect against both Gram-positive and Gram-negative bacteria.

Invasive species are a major threat to global biodiversity and an important cause of biotic homogenization of ecosystems. Exotic plants have been identified as a particular concern because of the widely held belief that they competitively exclude native plant species. We examined the correlation between native and invasive species richness in 58 Ontario inland wetlands. The relationship between exotic and native species richness was positive even when we controlled for important covarying factors. In addition, we examined the relationship between the abundance of four native species (Typha latifolia, T. angustifolia, Salix petiolaris, Nuphar variegatum) and four invasive species (Lythrum salicaria, Hydrocharis morsus-ranae, Phalaris arundinacea, Rhamnus frangula) that often dominate temperate wetlands and native and rare native species richness. Exotic species were no more likely to dominate a wetland than native species, and the proportion of dominant exotic species that had a significant negative effect on the native plant community was the same as the proportion of native species with a significant negative effect. We conclude that the key to conservation of inland wetland biodiversity is to discourage the spread of community dominants, regardless of geographical origin.

This paper investigated the potential for the exotic shrub Rhamnus frangula L. (glossy buckthorn) to alter native plant community composition in southeastern New Hampshire. Stratified random sampling was performed with 2 m x 2 m plots randomly located in 5 m intervals along three 50 m transects in four even-aged Pinus-mixed hardwood forests, three of which were managed stands. The associations between R. frangula and the measured species abundances and environmental variables were investigated using linear, least-squares multiple regression and Non-metric Multidimensional Scaling Ordination. Plot basal area of R. frangula was inversely related to woody seedling density (p < 0.001), herb cover (p < 0.05), and species richness (p < 0.01). The relative contribution of R. frangula to explaining variance in seedling density was greater than canopy openness, soil pH, soil clay, or soil sand. Abundance of R. frangula was a statistically significant predictor (p < 0.05) of individual herb species abundances for all study sites. This evidence supports the hypothesis that R. frangula causes a decline in seedling density and alters native ground level plant species abundances. Furthermore, the patterns agree with the suppression of ground level plant species abundances by R. frangula found in removal experiments.

Effects of the non-indigenous shrub Rhamnus frangula L. (glossy buckthorn) on tree recruitment, herb cover, forest floor plant species richness, and R. frangula recruitment were tested in two southeastern New Hampshire Pinus forests using a randomized complete-block field experiment. The treatment, applied in January of 2000, was the presence of well-established R. frangula populations with three levels: R. frangula absent prior to experiment ('uninvaded'), > 90% R. frangula cover ('Rhamnus present'), and removal of > 90% R. frangula cover ('Rhamnus removed'). After 2 years of measurements, Rhamnus present had significantly lower first-year native tree seedling density than Rhamnus removed and uninvaded plots (0.11, 0.40, and 0.40 seedlings/m2 respectively). First-year native tree seedling density in the Rhamnus removed and uninvaded treatments were similar. Neither percent herb cover nor plant species richness were significantly affected by the removal of R. frangula in the two years following treatment. We believe these results indicate that the presence of dense R. frangula inhibits the establishment of tree seedlings. Rhamnus removed plots sampled one year after removal had five-fold greater first-year R. frangula seedling density than the other treatments. However, after two years first-year R. frangula seedling density was similarly low in all treatments (< 0.5 R. frangula seedlings/m2). Control efforts for R. frangula may need to focus on conspecific seedling emergence for at least two years following initial control.

Despite concern over potential detrimental effects of non-native invasive species on human and natural systems, the factors controlling regional distributions of invasive species remain unresolved. Few studies have evaluated the influence of both environmental factors and disturbance history on invasive species distributions, or assessed synthetically the importance of landscape-level disturbances like historical land-use, forest harvesting, and contemporary forest fragmentation. We analyzed vegetation, soils, and recent and historical land-use and landscape context for forests across central and western Massachusetts to identify controls on invasive species distributions. Almost half (49.3%) of 148 randomly selected sites had at least one non-native invasive plant present, and invasive species occurred more frequently on former agricultural sites than in continuous woodlands. We used logistic regression to model the probability of finding the four most common species: Japanese barberry (Berberis thunbergii DC), glossy buckthorn (Rhamnus frangula L.), multiflora rose (Rosa multiflora Thunb. ex Murr.), and oriental bittersweet (Celastrus orbiculata Thunb.). Soil richness was the most important predictor of invasive presence, with rich soils (i.e., lower C: N) being more likely to have these species. The structure of the current forested landscape (i.e., the amount of forest within a 10 km buffer around a site) is also important, with sites that are surrounded by more forest being less likely to have invasives. After accounting for variation in C: N ratios and the structure of the current forested landscape, historical land-use was not a significant predictor of non-native species occurrence; however, C:N ratios may be influenced by historical land-use and by current vegetation, thus complicating interpretations of this edaphic variable. Recent forest harvesting increased the likelihood of invasive occurrence for some but not all species. Overall, our results suggest that regional patterns of invasive plant distributions result from a complex function of edaphic conditions, and present and historical land-uses.

The widely used name Frangula alnus (syn. Rhamnus frangula) has in recent years been threatened by F. dodonei, an allegedly older name said to be published in a rare work by Pietro Arduino. However, from the context of Arduino's paper it is clear that \"F. dodonei\" is not a binomial; it just happens to look like one, and has no nomenclatural status.

Glossy buckthorn (Rhamnus frangula L. or Frangula alnus Mill.) is a tall shrub to small tree, native to Eurasia and North Africa, which can invade both wetland and upland sites in northeastern and midwestern North America. Invasion by R. frangula is often patchy in riparian savannas of the Allegheny High Plateau of northwestern Pennsylvania: Some sites are heavily invaded, whereas others nearby are sparsely invaded or not invaded at all. Because microtopography in riparian savannas can be diverse, with slightly elevated dry hummocks and wet depressions providing habitats for a range of upland and wetland plant species, we tested the hypothesis that the patchy nature of R. frangula invasion of riparian savannas is determined in part by soil drainage, which may ultimately affect shrub establishment and growth. We used depth to mottling by iron oxides as a primary, indirect measure of soil drainage and inundation and also measured the depth of leaf litter, humus, and A and B horizons in belt transects that were either heavily or sparsely to noninvaded by R. frangula at three riparian savanna study sites in the Allegheny National Forest. Sites with relatively well-drained soils, indicated by greater mottling and B horizon depths, supported significantly greater densities of R. frangula seedlings and shrubs than did sites with apparently wetter soils having shallower mottling and B horizon depths. We suggest that physiological stress associated with wet soils may restrict establishment of R. frangula, explaining in part its patchy invasion patterns in Allegheny High Plateau riparian savannas.