Sewage Pollution Promotes the Invasion-Related Traits of Impatiens glandulifera in an Oligotrophic Habitat of the Sharr Mountain (Western Balkans)

An annual plant, Himalayan balsam (Impatiens glandulifera Royle) is globally widespread and one of Europe’s top invaders. We focused on two questions: does this species indeed not invade the southern areas and does the environment affect some of its key invisibility traits. In an isolated model mountainous valley, we jointly analyzed the soil (21 parameters), the life history traits of the invader (height, stem diameter, aboveground dw), and the resident vegetation (species composition and abundances, Ellenberg indicator values), and supplemented it with local knowledge (semi-structured interviews). Uncontrolled discharge of fecal wastewaters directly into the local dense hydrological network fostered mass infestation of an atypical habitat. The phenotypic plasticity of the measured invasion-related traits was very high in the surveyed early invasion (30–50% invader cover) stages. Different microhabitat conditions consistently correlated with its growth performance. The largest individuals were restricted to the deforested riparian habitats, with extreme soil nutrient enrichment (primarily by P and K) and low-competitive, species-poor resident vegetation. We showed that ecological context can modify invasion-related traits and what could affect a further invasion process. Finally, this species is likely underreported in the wider region; public attitude and loss of traditional ecological knowledge are further management risks.

Impacts of the Invasive Impatiens glandulifera: Lessons Learned from One of Europe’s Top Invasive Species

Biological invasions are renowned for their negative ecological and economic implications, however from studying invasions invaluable insights can be gained in the fields of ecology and evolution- potentially contributing towards conservation plans to deal, not only with biological invasion, but with other concerning issues, such as climate change. Impatiens glandulifera, or Himalayan balsam, is widely considered to be a highly problematic invasive, having spread across more than thirty countries during the past century. This paper will examine the findings which have arose from studying I. glandulifera and its impacts on the invaded ecosystem.

Impatiens glandulifera (Himalayan balsam).

I. glandulifera is a highly invasive annual species which has spread rapidly in many parts of Europe and North America after its introduction as an ornamental. The spread is likely to continue to more northerly or high montane areas as a result of global climatic change. Due to its ability to form dense stands and its conspicuous appearance it has been blamed for negative biodiversity effects. Even though these effects are less severe than often thought, further spread is undesirable and should not be facilitated by further use, in particular in natural areas. Control is advisable in certain situations, e.g. nature reserves and conservation sensitive areas, but eradication from larger parts of its invasive range is not feasible due to the need to control the plant on a catchment scale, which is often impossible due to the sheer scale of occurrence and division of land ownership.

Differing impacts of two major plant invaders on urban plant-dwelling spiders (Araneae) during flowering season

Plant invasions can have major impacts on ecosystems and influence global species diversity. In Central Europe, Himalayan balsam (Impatiens glandulifera) and American goldenrods (Solidago canadensis and S. gigantea) are important invaders often establishing dense and homogeneous stands, especially in urban and other disturbed habitats. We investigated their impacts on plant-dwelling spiders (abundance, family structure, guild structure) and potential spider prey items during flowering season within an urbanized landscape using a paired design comparing invaded and native reference vegetation plots. In general, flowering American goldenrods and Himalayan balsam had no significant impacts on the spider family composition. Invasion of American goldenrods further had no effect on total spider abundance and potential prey item abundance. In contrast, goldenrods showed a significantly increased crab spider (Thomisidae) abundance while being less inhabited by web builders. Himalayan balsam negatively influenced free hunters and running crab spider (Philodromidae) abundance, while we found no effects on other groups and total spider abundance. For Himalayan balsam, potential prey item abundance was higher than in native vegetation stands. Notwithstanding that our results only represent a snapshot of the system, they suggest that large-scale removal of urban goldenrod stands during flowering season might negatively influence local spider abundance, especially of crab spiders. Management efforts should therefore be accompanied by compensation measures to avoid disruptive effects on local plant-dwelling spider communities.

Impatiens glandulifera (Himalayan balsam) chloroplast genome sequence as a promising target for populations studies

Background Himalayan balsam Impatiens glandulifera Royle (Balsaminaceae) is a highly invasive annual species native of the Himalayas. Biocontrol of the plant using the rust fungus Puccinia komarovii var. glanduliferae is currently being implemented, but issues have arisen with matching UK weed genotypes with compatible strains of the pathogen. To support successful biocontrol, a better understanding of the host weed population, including potential sources of introductions, of Himalayan balsam is required. Methods In this molecular study, two new complete chloroplast (cp) genomes of I. glandulifera were obtained with low coverage whole genome sequencing (genome skimming). A 125-year-old herbarium specimen (HB92) collected from the native range was sequenced and assembled and compared with a 2-year-old specimen from UK field plants (HB10). Results The complete cp genomes were double-stranded molecules of 152,260 bp (HB92) and 152,203 bp (HB10) in length and showed 97 variable sites: 27 intragenic and 70 intergenic. The two genomes were aligned and mapped with two closely related genomes used as references. Genome skimming generates complete organellar genomes with limited technical and financial efforts and produces large datasets compared to multi-locus sequence typing. This study demonstrates the suitability of genome skimming for generating complete cp genomes of historic herbarium material. It also shows that complete cp genomes are solid genetic markers for population studies that could be linked to plant evolution and aid with targeting native range and natural enemy surveys for biocontrol of invasive species.

New microsatellite marker tools for genotype identification and analyses of genetic relationships in two ornamentals, the popular common lilac (Syringa vulgaris) and the invasive garden escapee Himalayan balsam (Impatiens glandulifera)

ABSTRACTNowadays, high-throughput sequencing technologies are widely available. Yet, it is practical to have an access to simpler and cheaper, yet effective low-throughput analyses as well. For that purpose, species-specific microsatellites, also called simple sequence repeats (SSR), are valuable, multi-purpose types of markers. In the present study, we introduce new sets of SSR markers for two ornamental plant species, the popular common lilac (Syringa vulgaris L.) (16 markers) and the invasive garden escapee Himalayan balsam (Impatiens glandulifera Royle) (259 markers). The markers were developed as a by-product of a genotyping-by-sequencing project producing a large amount of DNA sequence data. Both the frequency of SSRs and the success rate for marker development were considerably greater in I. glandulifera when compared to S. vulgaris. The new markers will contribute to the characterization of germplasm and to other types of genetic analyses on these two species.