This research aims at finding the potential plant successions in riparian vegetation along gravel-bed streams of Lombardy (Northern Italy), investigating the influence of exotic species and proposing a more sustainable and efficient management planning for habitats conservation. To characterise the riparian vegetation, 65 phytosociological releves were carried out along four rivers in Lombardy (Pioverna, Staffora, Ogliolo and Grigna). We evaluated a series of ecological indexes to assess the ecology of plant communities. A clustering analysis detected five different plant communities characterised by specific ecological traits. On the basis of such results, we discuss about a model of plant succession describing: (i) the typical native species succession representing the riverine forests of the study areas; (ii) a succession with moderate presence of exotic species; and (iii) a succession dominated by alien species with an unclear development. To preserve the natural heritage and landscape with a small rate of alien species, it is important to plan vegetation management actions, which limit the presence of new empty space. For containing the exotic species, mechanical and chemical measures could lead to good results, but they can be expensive and cause adverse effects. Otherwise, biological control, combined with other actions, has the potential to bring results with low environmental and economic impact. Ecological restoration measures using fast-growing and spreading native species could restrict alien plant colonisation. In this regard, a better comprehension of the invasive alien plants behaviour is necessary, especially in terms of their competition mechanisms. Nevertheless, the application of long-term vegetation management of river ecosystems is crucial for a continuous monitoring and for addressing the goals of the 2030 global agenda concerning biodiversity conservation.

Robinia pseudoacacia L. has been widely planted worldwide for a variety of purposes, but it is an aggressive invader in many regions. To control invasion by the species, we examined the effectiveness of girdling young trees to ground level to kill trees and preclude sprout development through comparison among girdling, clearcut and control treatments on the Tama river terrace, Tokyo. More than 99% of R. pseudoacacia trees were killed by girdling. The number of sprouts that developed from roots and stumps after girdling was distinctly reduced compared with that observed after clearcutting. We also conducted girdling of young trees of Ailanthus altissima (Mill.) Swingle, which shows similar developmental and ecological characteristics to R. pseudoacacia, and the two species are often sympatric. More than 98% of A. altissima trees were killed, but a higher number of sprouts developed from A. altissima stumps compared with that from R. pseudoacacia stumps. These results indicate that girdling young trees to ground level is an effective method of controlling R. pseudoacacia by killing the stem and precluding sprout development. The girdling method is simple to apply and imposes a low burden on the surrounding environment.

To understand the mechanism of how Phragmites australis makes valuable floating mat biotopes under oligotrophic conditions, we investigated the environmental (water chemistry) and vegetational characteristics (growth, plant species richness, and floristic composition) of a floating mat consisting of three main mat-forming species with a zonal distribution (P. australis on the land side of the floating mat, Zizania latifolia on the middle area, and Typha angustifolia on the water side). Although they showed relatively low growth in the floating mat, compared to those in land-based wetlands, P. australis grew better than other mat-forming species in terms of shoot height and biomass production. Specifically, P. australis made more below-ground parts (593 ± 38 g/m2) than other mat-forming species (Z. latifolia, 100 ± 10 g/m2; T. angustifolia, 167 ± 8 g/m2) and more companion species were found in P. australis-dominated plots (8.5 ± 1.0 species/m2) than other plots (Z. latifolia-dominated plots, 2.7 ± 0.6 species/m2; T. angustifolia-dominated plots, 1.0 ± 0.0 species/m2). The larger amount of below-ground P. australis parts could contribute to thicker and denser mat structures, possibly providing more favorable habitats for neighboring plant species, thus facilitating more companion species within the P. australis-dominated area of the mat.

Perceived crowding is one of the important evaluative factors for environment quality. As a result, understanding the levels of perceived crowding is highly valued in recreation. According to previous studies, the earliest way to measure perceived crowding is to use the 9-point Likert scale. The smaller the figure, the less the users feel crowded on the spot. However, there are also different methods used in those studies to discuss the relationships between user's perceived crowding and other variables; including on-site survey, mail survey, picture simulation or virtual reality (VR). Among those different methods, as the new technology, VR may be considered the an appropriate research tool for the front-country crowing studies. In order to eliminating the limitations imposed by previous studies on measuring perceived crowding and understanding the potential of using IVR technology to measure perceived crowding. We used three studies to discuss the difference between photos and IVR, the difference between on-site experience and IVR, and the difference between on-site photo and VE in IVR method. This study progressively proves that: 1) IVR was more sensitive than photo evaluation method, and 2) IVR was not different from the on-site experience. 3) When IVR is used for research, there was no difference between on-site photo and VE. The results suggested that IVR might be more close to real on-site perceived crowding than traditional photo method; and it is possible to use 3D simulations in IVR.

Local scour by inundating tsunami currents on the land side of coastal forests can greatly decrease the tsunami mitigation advantage of the forest by producing driftwood. The purpose of this study was to analyze the scour profiles inside and behind a forest model (FM) due to the flow passing through it, and to compare the scour phenomenon around fixed and moveable bed cases within the FM. Two series of flume experiments were conducted by changing initial water depths (water depth without FM in the flume, ho = 3 cm to 7 cm), densities of FM (dense G/d = 0.25, intermediate G/d = 1.09, and sparse G/d = 2.13, where G = clear spacing between each cylinder in a cross-stream direction, d = diameter of a cylinder) and vegetation thicknesses (dn) of 180, 380, and 580 No.cm. In series 1 and 2, experiments were performed with a fixed bed inside FM for the three vegetation densities and for moveable bed case only for the intermediate density, respectively. Downstream scour profiles behind FM, backwater rise, and water surface gradient inside FM were investigated. For the fixed bed case, minimum scour was measured in the intermediate FM case for the three densities of 180, 380, and 580 No.cm. In the fixed bed inside FM, the location of maximum scouring moved away from the downstream end of FM while in cases of a moveable bed inside FM, the location of maximum scour moved towards the downstream end inside FM. Scour inside coastal forest damages the trees; therefore, it is recommended to stabilize the bed inside the forest by planting grasses, etc., if there is no constraint on the light environment inside the forest and the space behind the forest where local scour occurs.

Urban functional zone (UFZ) comprises the basic unit of urban planning, with various production activities. Understanding the landscape heterogeneity in UFZs may be a way to mitigate urban heat island (UHI). The region within fifth ring road in Beijing is selected as the study area. Six common UFZ types were selected to understand the effects of three types of factors (surface biophysical parameters, building form, and landscape metrics) on land surface temperature (LST). A one-way analysis of variance and geographical detector were used to express spatial heterogeneity and key influencing factors of LST in UFZ, respectively. The results indicate the following: (1) the UFZ types, in order from highest to lowest LST, are industrial, commercial, public service, government, high-density residential, and recreational zones. The LST of industrial and recreational zones are significantly different from other zones, but other four types of UFZ exhibited similar thermal conditions. (2) The key influencing factors of LST in UFZs differ. Surface biophysical parameters have a significant effect on all UFZs. Building form in areas of high building height and density, such as commercial and high-density residential zones, should be the focus of UHI mitigation, whereas optimizing land cover composition and spatial configuration in other UFZs is more likely to alleviate LST. In addition, the LST is determined not only by the UFZ type and internal structure, but also by the complexity and diversity. Identifying UHI mitigation sensitivity metrics within UFZ will help improve the thermal environment of urban areas and provide strategies for resisting UHI.

Satoyama is one of the semi-natural ecosystems in Japan. Traditional agricultural practices in satoyama provide preferable habitats for many species, thus, enhancing biodiversity. However, many satoyama ecosystems have been altered by agricultural intensification and rapid urbanization. Meanwhile, ageing and shrinking population has led to the abandonment of remaining satoyama ecosystems, resulting in their potential degradation. We argue that counteracting the abandonment of satoyama is particularly essential in urbanized landscapes because conserving its biodiversity would have a payoff for urban communities. We focused on nature-oriented park use of satoyama ecosystems, utilizing their original scenery, topography, water features, and vegetation. To evaluate the potential of nature-oriented park use for biodiversity conservation, we examined the differences in diversity and species composition of vascular plants and butterflies among three land-use types (agricultural-use, park-use, and abandoned sites) of satoyama ecosystems. Diversity of native plants and butterflies did not significantly differ between agricultural-use and park-use sites and that of native plants was significantly lower at abandoned sites than at agricultural-use sites. Although species composition of native plants at agricultural-use sites and park-use sites significantly differ, that of native butterflies did not. The efficacy of park use for biodiversity conservation, thus, depended on the taxa. Nonetheless, for striking a balance between the difficulty in maintaining agricultural use and accelerating satoyama abandonment, our study highlights the utility of park use as an alternative usage, contributing to biodiversity conservation. Balancing the wise use of satoyama in urbanized landscapes is a fundamental step toward the conservation of its biodiversity and human–nature interactions.