Alien plant species: A real fear for urban ecosystems in Europe?

Chemical and enzymatic deinking efficiency of agricultural and industrial waste fiber-based paper packaging

BACKGROUND

Deinking is an important part of paper recycling that involves the removal of ink particles from the paper fibres. This industrial process is important so that the fibres can be recirculated back into paper production, which enables better sustainability as fewer fresh fibres are needed. In this study, we examined five different alternative fibre materials from different agricultural residues and industrial processes for the pilot production of papers. Papers containing fibres from invasive plants (Japanese knotweed), dedicated crops (miscanthus, acacia), agricultural residues (tomato stems), and industrial waste (jute - fibres from coffee bags) were printed with water-based flexo inks and deinked with two separate processes (chemical and enzymes). Mechanical (break and tensile index, breaking length) and optical properties (ISO whiteness, brightness and CIE L*a*b* values) were measured and ink elimination IR700 and deinking efficiency was calculated for the two deinking processes.

RESULTS

Enzymatic treatment improved the mechanical properties of deinked pulp in comparison with the classic chemical treatment. Mechanical strength for almost all papers increased slightly (breaking length up to 20% in tomato and jute), and the optical result (brightness) increased similarly for both processes due to the bleaching action of the colour-shaded samples, whereas the deinking efficiency showed mixed results between chemical- and enzyme-type deinking (with chemical achieving better elimination measured at 700 nm) in the typical range of ink elimination values (15-35%) for flexographic inks. This indicates further optimization of the deinking with enzymes is needed due to different alternative fibre compositions and variations of residues in the delignification processes.

CONCLUSION

Using a combination of adjusted enzymatic treatment as a precursor for deinking of paper-based packaging materials sourced from alternative fibres showed promising results regarding mechanical properties, whereas the optical properties need to be improved with cellulase optimization or by using mixes of different enzymes. These kinds of paper materials printed with flexo inks were found to be successfully deinkable with the chemical ISO-based deinking protocol. © 2022 Society of Chemical Industry.

Bioclimatic Suitability of Actual and Potential Cultivation Areas for Jacaranda mimosifolia in Chinese Cities

Jacaranda mimosifolia is regarded as a prized ornamental tree in the urban landscape with attractive, abundant and long-lasting violet-colored flowers and graceful tree form. It has been widely cultivated in recent years in many Chinese cities. However, the lack of scientific and practical guidance to cultivate the exotic species has brought about planting failures in some areas, incurring substantial economic losses and landscape decline. A comprehensive understanding of the current spatial pattern and climatic conditions of J. mimosifolia in China can inform species choice, planting and management. We collected data on the geographical coordinates of 257 planting cities and acquired additional information from the literature and field surveys. The limiting factors for cultivation were investigated using principal component analysis (PCA) of 19 bioclimatic parameters of the sampled sites. The potentially suitable habitats were predicted by BIOCLIM modeling using eight selected ecological-important climatic parameters. We found that the present cultivated areas were focused in the low-altitude parts of the subtropical zone, mainly covering the provinces of Yunnan, Sichuan, Guangxi, Guangdong and Fujian. The PCA results indicated that temperature was the clinching determinant of the current cultivation patterns, especially annual mean temperature, the minimum temperature of the coldest month and the mean temperature of the warmest quarter. Moisture was a necessary but not critical secondary factor. The predicting model for potential habitats was graded as “excellent” by objective validation measures. The findings can provide science-based evidence to plan the expansion of the biogeographical range of cultivation into hitherto unplanted cities and rationalize urban tree introduction and management practices.

You Can’t See the Woods for the Trees: Invasive Acer negundo L. in Urban Riparian Forests Harms Biodiversity and Limits Recreation Activity

Public access to high quality green environments has become a key issue for city managers and a matter of environmental justice. Urban pressures on ecosystem remnants may act to favor the expansion of some invasive species in cities. Whilst the negative impacts of invasive species on ecosystem function is well documented, little is known about how invasive species influence the use of green space by people. Here, we examined one of the few remnants of urban riparian forests in Europe, the Vistula river valley in Warsaw, which has recently become an attractive recreation site. Despite their high ecological value, the poplar and willow forests have been increasingly taken over by the invasive tree species Acer negundo. We examined the status of the invasion process and the relationship between recreational ecosystem services and the characteristics of the tree stands—tree species, tree density, and age and NDVI values. We found the willow forest to be more susceptible to invasion by A. negundo than the poplar forest, which was revealed in significantly higher share of the maple individuals and their greater volume per unit area. Ash-leaved maples also prevailed in numbers in younger stands (<10 years) than in older ones. The presence of A. negundo affected biodiversity, resulting in decreased undergrowth density and biodiversity expressed in number of species. The use intensity by the public, assessed on the basis of soil compaction of existing informal tracks, as revealed by GLM analysis, was related to volume of invasive maple and distance from the main track. This study highlights the need to integrate invasive species management into green infrastructure planning and management.

Citizen Science as a Tool in Biological Recording—A Case Study of Ailanthus altissima (Mill.) Swingle

Non-native invasive species frequently appear in urban and non-urban ecosystems and may become a threat to biodiversity. Some of these newcomers are introduced accidentally, and others are introduced through a sequence of events caused by conscious human decisions. Involving the general public in biodiversity preservation activities could prevent the negative consequences of these actions. Accurate and reliable data collecting is the first step in invasive species management, and citizen science can be a useful tool to collect data and engage the public in science. We present a case study of biological recording of tree of heaven (Ailanthus altissima (Mill.) Swingle) using a participatory citizen model. The first goal in this case study was to develop a cheap, widely accessible, and effective inventory method, and to test it by mapping tree of heaven in Croatia. A total of 90.61 km of roads and trails was mapped; 20 single plants and 19 multi-plant clusters (mapped as polygons) were detected. The total infested area was 2610 m2. The second goal was to educate citizens and raise awareness of this invasive species. The developed tool and suggested approach aided in improving invasive risk management in accordance with citizen science principles and can be applied to other species or areas.