Effects of surrounding landscape on the performance of Solidago canadensis L. and plant functional diversity on heavily invaded post-agricultural wastelands

High invasiveness and well-documented negative impact on biodiversity and ecosystem functioning make Solidago canadensis L. a species of global concern. Despite a good understanding of the driving factors of its invasions, it remains unclear how the surrounding landscape may shape invasion success of this species in human-transformed ecosystems. In our study, we investigated the impacts of different landscape features in the proximity of early successional wastelands on S. canadensis biomass allocation patterns. Further, we examined the relationships between the surrounding landscape, S. canadensis cover, and plant functional diversity, used as a supportive approach for the explanation of mechanisms underlying successful S. canadensis invasion. We found that increasing river net length had positive impacts on S. canadensis rhizome, stem, and total above ground biomass, but negative effects on leaf biomass, indicating that vegetative spread may perform the dominant role in shaping the competitiveness of this invader in riverine landscapes. A higher proportion of arable lands positively influenced S. canadensis above ground and flower biomass; thus promoting S. canadensis invasion in agricultural landscapes with the prominent role of habitat filtering in shaping vegetation structure. Concerning an increasing proportion of settlements, flower biomass was higher and leaf biomass was lower, thereby influencing S. canadensis reproductive potential, maximizing the odds for survival, and indicating high adaptability to exist in an urban landscape. We demonstrated high context-dependency of relationships between functional diversity components and surrounding landscape, strongly influenced by S. canadensis cover, while the effects of surrounding landscape composition per se were of lower importance. Investigating the relationships between the surrounding landscape, invasive species performance, and plant functional diversity, may constitute a powerful tool for the monitoring, controlling, and predicting of invasion progress, as well as the assessment of ecosystem invasibility.

Impacts of soil properties and functional diversity on the performance of invasive plant species Solidago canadensis L. on post-agricultural wastelands

Amongst the numerous consequences of the rapid development of agriculture and urbanization, biological invasions are highlighted as having the biggest impact on the functioning of ecosystems. One of the alien plant species, considered in Europe and Asia to be highly invasive, is Solidago canadensis L.; and its impact on the functioning of ecosystems has been studied in numerous respects. However, knowledge about how the physico-chemical parameters of soils and biotic interactions between species shape the performance of S. canadensis in a transformed landscape is still insufficient. The aim of this study was to assess how complex soil abiotic conditions and the functional diversity of co-occurring vegetation shape the performance of S. canadensis on the wastelands abandoned by agriculture. Apart from detailed investigations of soil properties and S. canadensis biomass, to achieve our study aims, we used parameters of functional diversity, which allowed us to identify the main ecological processes determining the community assembly processes. Under higher contents of loamy fractions in soil, but lower functional richness in surroundings, S. canadensis achieved larger cover. Alongside increasing functional richness and dispersion in co-occurring vegetation, this species has demonstrated sturdy attributes when competing for water and nutrients, expressed by a higher production of rhizomes and roots. Under elevated zinc and lead levels, as well as higher functional evenness in the surroundings, the flower biomass decreased, while the biomass of stems increased. Thus, S. canadensis exhibits a highly adaptive capacity to grow in soils contaminated by heavy metals, due to the buffer properties and life strategies allowing the use of resources absorbed in loamy soils. Environmental factors seem to be more responsible for the shaping of the performance and for the colonization success of S. canadensis than biotic interactions with plants occurring in the surroundings.

The accumulation of Mn and Cu in the morphological parts of Solidago canadensis under different soil conditions

Solidago canadensis L. is a drought-tolerant, invasive plant, characterized by a large biomass of underground and aboveground parts. The aim of this study was to assess the accumulation of manganese (Mn) and copper (Cu) in the roots and rhizomes and the stems, leaves, and inflorescence parts in S. canadensis from two locations that differed in soil pH, organic carbon, and Mn and Cu concentrations. The concentration of the metals in the samples was determined by the AAS method; the pH was determined by the potentiometric method; and the content of organic carbon was determined using Tiurin's method. The concentration of Mn and Cu in the roots of S. candensis correlated with the concentrations of the metals in the soil without regard to the soil condition or its organic carbon content. With a low soil pH and organic carbon content, Mn accumulation per 1 ramet in the aboveground parts of S. canadensis consisted over 50% of the total Mn content in the plant. In neutral or alkaline soils, the amount of Mn per 1 ramet accumulated in underground parts was over 60%. Regardless of the soil conditions, about 35% of Mn accumulated in rhizomes. Approximately 60% of copper accumulated in the underground parts of S. candensis (45% in rhizomes) without regard to the soil reaction or organic carbon content. The ability of the plant to accumulate large amounts of metals disposes Solidago canadensis as a candidate for the phytoremediation of soils contaminated with heavy metals.

Solidago canadensis as a bioaccumulator and phytoremediator of Pb and Zn

Canadian goldenrod (Solidago canadensis L.) is a plant that grows in a variety of environmental conditions. It shows high capability to spread in various habitats, including fallow lands and brownfield land. The research aimed at analyzing the content of Pb and Zn in the underground (roots, rhizomes) and aboveground parts (stems, leaves, inflorences) of Solidago canadensis (SC) originating from two locations that are clearly different in terms of metal content in soil. Statistically significant differences were determined in the content of Pb and Zn in soil and particular morphological parts of the plant, depending on the sampling location. It has been shown that in the conditions of increased (compared with natural) Pb and Zn content in the soil, SC may serve as a bioaccumulator of these metals. It was determined that SC can be used as a phytostabilizer of Pb and Zn in soils heavily contaminated with these elements. The content of Zn in the aboveground parts of SC indicates that this plant can also be used for phytoextraction of soils contaminated with this metal.

Environmental Factors Determining the Accumulation of Metals: Cu, Zn, Mn and Fe in Tissues of Taraxacum sp. sect. Taraxacum

The genus Taraxacum is used in the assessment of soil contamination with heavy metals. There are relatively few studies using sections or species representing this genus. The presented research was conducted in Poland on two habitats, varied in terms of nutrients and metals content. The content of selected metals in leaves and roots of Taraxacum sect. Taraxacum was determined. It was found that in the conditions of increased content of metals in the soil, the analysed species representing sect. Taraxacum accumulate higher amounts of metals in their leaves and roots. Factors of translocation of selected metals from roots to leaves of Taraxacum species, representing the Taraxacum section, are affected by i.a. soil reaction and the content of Corg, Ntot. in the soil. No influence of soil properties on metal biological concentration factor was observed.

Activity of cesium 137Cs and potassium content in new potatoes imported to Poland

BACKGROUND

Potatoes are an important component of the human diet. In addition to components which determine the nutrition and dietary values, potato tubers also contain anti-nutritional substances, inter alia radioactive elements. Natural and artifical radionuclides are released to the environment as a result of antropogenic activity, in a controlled or uncontrolled manner, and they are transferred to the human body through the food chain.

OBJECTIVE

The aim of the study was to determine the activity of radioactive cesium 137Cs isotope and potassium content, including the activity of 40K isotope, in new potatoes imported to Poland during the winter period from Mediterranean countries.

MATERIAL AND METHODS

The study material included new potatoes imported from Cyprus, Egypt and Israel, purchased in the city of Siedlce from the beginning of February to the end of March 2015. The activity of 137Cs and 40K isotopes in potato tubers was determined. Analyses were performed by γ-spectrometric method. Laboratory tests were performed on a total of 18 samples. Based on the activity of 40K isotope, the total potassium content of potato tubers was calculated, with the assumption that 31.00 Bq 40K is equivalent to 1 g potassium.

RESULTS

The activity of 137Cs in most tested potato samples was below 0.2 Bq kg-1 (limit of quantification), and in other samles it was from 0.3 Bq kg-1 to 5.4 Bq kg-1. Potatoes of the same variety, originating from the same country, differed in terms of the activity of 137Cs. The highest activity of 137C, determined in potatoes imported from Cyprus, was seven times higher than the lowest value. The activity of 40K changed from 93.3 Bq kg-1 to 259.1 Bq kg-1. The average activity of 40K in potatoes imported from Cyprus, Egypt and Israel was at a similar level. The ratio of the activity of 137Cs determined in the tested potatoes to the activity of 40K changed from 0.00242 to 0.04163. The calculated potassium content in imported new potatoes was on average 4.376 g K kg-1 of the fresh weight of tubers and ranged from 3.010 g K kg-1 to 8.358 g K kg-1.

CONCLUSIONS

The activity of the 137Cs cesium isotope in imported new potatoes in most tested samples was at a very low level (below the limit of quantification) and in other samples it did not exceed 5.5 Bq kg-1 and posed no threat to human lives. Potatoes originating from the same country differed in terms of the activity of 137Cs. The average activity of 40K in potatoes imported from Cyprus, Egypt and Israel was at a similar level and did not differ from the activity of 40K in domestically produced potatoes. The potassium content in imported new potatoes was determined by the variety.