Knotweed (Fallopia spp.) is an herbaceous perennial from East Asia that was brought to Europe and North America and, despite control efforts, subsequently spread aggressively on both continents. Data ...are available on knotweed’s modes of sexual and asexual spread, historical spread, preferred habitat, and ploidy levels. Incomplete information is available on knotweed’s current global geographic distribution and genetic diversity. The chemical composition of knotweed leaves and rhizomes has been partially discovered as related to its ability to inhibit growth and germination of neighboring plant communities via phytochemicals. There is still critical information missing. There are currently no studies detailing knotweed male and female fertility. Specifically, information on pollen viability would be important for further understanding sexual reproduction as a vector of spread in knotweed. This information would help managers determine the potential magnitude of knotweed sexual reproduction and the continued spread of diverse hybrid swarms. The potential range of knotweed and its ability to spread into diverse habitats makes studies on knotweed seed and rhizome cold tolerance of utmost importance, yet to date no such studies have been conducted. There is also a lack of genetic information available on knotweed in the upper Midwest. Detailed genetic information, such as ploidy levels and levels of genetic diversity, would answer many questions about knotweed in Minnesota, including understanding its means of spread, what species are present in what densities, and current levels of hybridization. This literature review summarizes current literature on knotweed to better understand its invasiveness and to highlight necessary future research that would benefit and inform knotweed management in the upper Midwest.
Intraspecific hybridization between distinct populations could increase the fitness and adaptive potential of biological control agents that often have low genetic diversity and can be inbred due to ...long‐term laboratory rearing often at small population sizes. Hybridization can also alter host preference and performance when the parental insect populations are adapted to different host plants. We investigated the effects of hybridization between two populations (Northern and Southern) of the psyllid, Aphalara itadori, that have different fitness on three invasive knotweed species (Japanese, giant, and Bohemian). Fecundity, host choice, and developmental success of second‐generation reciprocal hybrids and the parental psyllid populations were compared on the three knotweed species in multiple‐choice tests. Hybridization did not increase fecundity. All three knotweed species were accepted for oviposition without preference by the Southern and the two hybrid psyllid populations. The northern psyllid population laid the most eggs on Bohemian knotweeds but those were maladaptive choices since almost all eggs failed to develop. The developmental success of the parental psyllid populations was highest on the knotweed species they were originally collected from, on Japanese knotweed of the Southern psyllids and giant knotweed of the Northern psyllids. Hybrids had intermediate or higher survival on given knotweed hosts compared to their parents. These results can inform release tactics of A. itadori in different regions especially where there appear to be climatic and/or host mismatches such as in Michigan. In southern Michigan, based on climate the Northern psyllid population should be released. However, the most common knotweed species in the region are Bohemian and Japanese knotweeds that do not support the development of the Northern psyllids. In this case, hybrids that may carry cold adaptations of the Northern psyllids but have better developmental success on the prevailing knotweed species may be considered for release to increase establishment success.
Intraspecific hybrids between two host races of a biological control agent did not show hybrid vigor in terms of fecundity. One of the parental populations made maladaptive oviposition choices that did not support offspring development. The hybrids had intermediate developmental success on three knotweed species that could make them suitable for field release in different regions.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
La especie introducida Fallopia japonica (Houtt.) Ronse Decr. es registrada por primera vez en las ciudades de Puerto Natales y Punta Arenas en la Patagonia chilena. En este trabajo se entregan ...evaluaciones de los envolventes climáticas en Patagonia y explora a las implicancias de la gestión ambiental en el control de esta especie invasora.
Limiting the negative effects of an invasive species, such as Reynoutria japonica, has become a challenge for scientists and a necessity for managers. Ecologically relevant, technically feasible, and ...sustainable control methods must be created to reduce the development or spread of R. japonica in ecosystems. The objective of our study was to investigate how monthly mowing in association with plant competition affects the development of R. japonica over a three-year field experiment. Among the plant traits measured, the height growth of R. japonica was the most affected; it was strongly reduced in the presence of competing plants. Combined mowing and competition with restoration plants negatively affected the growth diameter of R. japonica. Most competitive sown species were well established and complementary in limiting the development of R. japonica. The plant communities showed interannual dynamics in which R. japonica declined progressively. The restoration methodology adopted in this study allows managers to make appropriate decisions to reduce the impact of R. japonica on ecosystems.
•We provide an efficient ecological strategy for limiting R. japonica development with the following findings:•Mowing and competition can decrease the height and diameter growth of R. japonica.•Installing restoration plants can help limit the recolonization of R. japonica.•This strategy is low cost and can be used according to the environmental context.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The rapid spread of invasive plants makes their management increasingly difficult. Remote sensing offers a means of fast and efficient monitoring, but still the optimal methodologies remain to be ...defined. The seasonal dynamics and spectral characteristics of the target invasive species are important factors, since, at certain time of the vegetation season (e.g., at flowering or senescing), plants are often more distinct (or more visible beneath the canopy). Our aim was to establish fast, repeatable and a cost-efficient, computer-assisted method applicable over larger areas, to reduce the costs of extensive field campaigns. To achieve this goal, we examined how the timing of monitoring affects the detection of noxious plant invaders in Central Europe, using two model herbaceous species with markedly different phenological, structural, and spectral characteristics. They are giant hogweed (
), a species with very distinct flowering phase, and the less distinct knotweeds (
, and their hybrid
. ×
). The variety of data generated, such as imagery from purposely-designed, unmanned aircraft vehicle (UAV), and VHR satellite, and aerial color orthophotos enabled us to assess the effects of spectral, spatial, and temporal resolution (i.e., the target species' phenological state) for successful recognition. The demands for both spatial and spectral resolution depended largely on the target plant species. In the case that a species was sampled at the most distinct phenological phase, high accuracy was achieved even with lower spectral resolution of our low-cost UAV. This demonstrates that proper timing can to some extent compensate for the lower spectral resolution. The results of our study could serve as a basis for identifying priorities for management, targeted at localities with the greatest risk of invasive species' spread and, once eradicated, to monitor over time any return. The best mapping strategy should reflect morphological and structural features of the target plant and choose appropriate spatial, spectral, and temporal resolution. The UAV enables flexible data acquisition for required time periods at low cost and is, therefore, well-suited for targeted monitoring; while satellite imagery provides the best solution for larger areas. Nonetheless, users must be aware of their limits.
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•Hybrid crosses established between two strains of the psyllid Aphalara itadori.•We developed two SNP arrays to identify pure and hybrid individuals.•A broader SNP array successfully ...identified all individuals.•A reduced array failed to accurately identify most hybrid individuals.
Three species of invasive knotweeds (Fallopia japonica, Fallopia sachalinensis, and Fallopia×bohemica) cause extensive damage to riparian and roadside habitats in North America. Currently, two strains of the psyllid Aphalara itadori are being evaluated for introduction into the United States and Canada for the biological control of these knotweeds following the introduction of A. itadori into the United Kingdom. If approved and released, hybridization between individuals from these two strains is likely and understanding whether barriers to hybridization exist could have an important impact on the sustainability of this biological control program. Here we developed two single nucleotide polymorphism (SNP) arrays and examined their utility for identifying individuals of known pure strains (Hokkaido and Kyushu) and hybrid origins. Using an array of 141 SNPs we correctly identified all individuals to pure and hybrid classes, whereas using a smaller array of 29 SNPs we were able to correctly identify pure line individuals, but not hybrids.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Reynoutria japonica (Japanese knotweed) is one of the most potent global invasive plant species; however, there is still insufficient knowledge on the impact of its invasion on arbuscular mycorrhizal ...fungi (AMF, Glomeromycota). The aim of our study was to assess the condition of AMF communities under the influence of R. japonica and determine the temporal and site-dependent variability of this influence. We studied AMF spore number, species richness, and composition as well as biomass in pairs of adjacent plots encompassing R. japonica and resident plant species. We established these pairs of plots in different habitat conditions (light and heavier soil conditions), and we sampled them four times (two spring and two summer seasons) to check if the potential impact of the invader on AMF communities is soil- and/or season-dependent. We found that the invasion reduced AMF spore number, species richness, and biomass, but had no effect on AMF species composition. AMF parameters varied over time (spore number, species composition and biomass) and depended on soil condition (species richness), but were barely affected by interactions between the studied factors. The lower performance of AMF communities in R. japonica plots was probably due to the displacement of resident mycorrhizal plant species. This displacement was not complete as some mycorrhizal plants, especially spring ephemerals, managed to survive the invasion. These were probably responsible for the maintenance of AMF communities in the patches of R. japonica. In conclusion, AMF communities are negatively affected by the invasion, but R. japonica does not entirely eliminate AMF, which is optimistic from the viewpoint of restoring sites invaded by this non-mycorrhizal alien plant species.
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•The impact of Reynoutria japonica invasion on AMF communities was studied.•The invasion reduced AMF spore number, species richness, and biomass.•R. japonica had no impact on AMF species composition.•The invasion effects on AMF did not interact with season and soil type.•R. japonica reduced AMF abundance but did not completely eliminate AMF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The phenolic compositions of two different Polygonum cognatum samples collected from the Cumra and Manisa regions of Turkey were investigated for the first time. Both tested samples were rich in ...different phenolic compounds, mostly rutin, isorhamnetin, and catechin. The rutin content of Cumra’s sample was relatively higher than that of Manisa’s sample. P. cognatum has potential regarding rutin content as a functional dietary food or may be used as an ingredient to enrich functional foods. Our study will contribute to the previous works performed by different researchers on P. cognatum, commonly consumed in Turkey, to reveal its beneficial properties.
Sea buckthorn and Japanese knotweed are known in many traditional medicine systems to be a great source of bioactive substances. This research aims to compare the bioactivity and protective effects ...of the phenolic extracts of leaves from sea buckthorn and roots and leaves from the Japanese knotweed on erythrocytes. The polyphenol composition of the extract was analyzed using UPLC-PDA-ESI-MS/MS. The extracts’ toxicity and impact on the erythrocytes’ osmotic fragility were measured spectrophotometrically. The antioxidant activity was determined based on the inhibition of oxidation of erythrocytes and their membrane induced by 2,2′-Azobis(2-methylpropionamidine) dihydrochloride (AAPH),measured spectrophotometrically and using fluorimetry. To find the possible mechanism of the extracts’ action, extract-modified cells were observed under a microscope, and the potential localization of the extract’s phytochemical composition was checked using fluorescent probes. The results showed that the used extracts are not toxic to erythrocytes, increase their osmotic resistance, and successfully protect them against free radicals. Extract components localize on the outer part of the membrane, where they can scavenge the free radicals from the environment. Altogether, the presented extracts can greatly protect living organisms against free radicals and can be used to support the treatment of diseases caused by excess free radicals.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
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