Road Verges Research Articles

Factors determining the invasion pattern of Ageratina adenophora Spreng. in Kumaun Himalaya India

Factors such as topography, soil composition, and nutrient availability significantly influence the density patterns of Ageratina adenophora. Understanding these dynamics addresses a gap in our knowledge of the species' adaptive mechanisms in mountainous regions. Furthermore, the impact of habitat features along road corridors on the population dynamics of invasive plants remains underexplored, particularly regarding the effects of disturbance levels, light availability, and soil properties on their establishment. A species-specific rapid ecological assessment was conducted using stratified random sampling, with parallel transects of 50 × 2m established in triplicates at 20m intervals. This resulted in 43 main transects across the identified plots and 67 parallel transects in adjacent habitats. The number of individuals of A. adenophora and its clumps were recorded from each quadrat. Chemical and physical parameters of soil were measured for soil collected from 0-15cm depth. Linear Mixed Model analysis revealed a significant negative effect of elevation (p<0.05) on the density of clumped individuals (Estimate: -0.31, t-value: -3.05), total individuals (Estimate: -0.27, t-value: -2.61), and clump number (Estimate: -0.30, t-value: -4.78). Western aspect also showed a significant decrease in clumped individuals (Estimate: -1.83, t-value: -2.80), total individuals (Estimate: -2.24, t-value: -3.47), and clump number (Estimate: -0.81, t-value: -1.97). Total A. adenophora density was highest near settlements (133 ind. m², Estimate: 1.19) and grasslands (103 ind. m², Estimate: 1.16), but lowest in broadleaf forests (26 ind. m²). Density decreased significantly with increasing distance from road verges (Estimate: -0.24, t-value: -2.34). Soil moisture content positively influenced total individuals (Estimate: 0.19, t-value: 2.75), clumped individuals (Estimate: 0.23, t-value: 3.20), clump numbers (Estimate: 0.05, t-value: 1.09), and individuals per clump (Estimate: 0.37, t-value: 3.28). Available nitrogen positively influenced non-clumped individuals (Estimate: 0.17, t-value: 2.04) but negatively affected individuals per clump (Estimate: -0.25, t-value: -2.21), indicating that lower nitrogen levels correlate with higher individual density per clump. Hence, effective restoration efforts are needed including soil improvement, invasive species removal and control, and the planting of native species.

A Life Cycle Cost Comparison of Flexible Versus Rigidpavements in Nigeria: Case Study of Papalanto - Sagamu Road

The condition of roads in Nigeria, most of which are made from asphalt, is generally considered unsatisfactory. This has led to calls for a blanket switch from asphalt pavements to concrete pavements for new road construction. This study examines the characteristics and relative advantages of the two pavement types; and carried out the design and life cycle cost comparison of a case study road with heavy traffic and poor subgrade conditions. The results indicate that, the initial cost of construction is actually less for the concrete pavement by 12% when compared with the asphalt alternative, while the life cycle cost analysis further yielded an advantage of 36% for the concrete pavement. The paper therefore recommends that major roads, particularly those on the national and international transit corridor, being of heavy traffic, should be reconstructed as the need arises, as concrete pavements. The paper however further recommends that, axle load control should be enforced through the introduction of weigh bridges and that routine maintenance should mandatorily be carried out, as even the best constructed concrete pavements have failed due to lack of routine maintenance like clearing the road verges of weed and road sand and desilting of drainage structures

Limited function of road verges as habitat for species connecting plant-bee networks in remnant semi-natural grasslands.

Species-rich natural and semi-natural ecosystems are under threat owing to land use change. To conserve the biodiversity associated with these ecosystems, we must identify and target conservation efforts towards functionally important species and supporting habitats that create connections between remnant patches in the landscape. Here, we use a multi-layer network approach to identify species that connect a metanetwork of plant-bee interactions in remnant semi-natural grasslands which are biodiversity hotspots in European landscapes. We investigate how these landscape connecting species, and their interactions, persist in their proposed supporting habitat, road verges, across a landscape with high human impact. We identify 11 plant taxa and nine bee species that connect semi-natural grassland patches. We find the beta diversity of these connector species to be low across road verges, indicating a poor contribution of these habitats to the landscape-scale diversity in semi-natural grasslands. We also find a significant influence of the surrounding landscape on the beta diversity of connector species and their interactions with implications for landscape-scale management. Conservation actions targeted toward species with key functional roles as connectors of fragmented ecosystems can provide cost-effective management of the diversity and functioning of threatened ecosystems.This article is part of the theme issue 'Connected interactions: enriching food web research by spatial and social interactions'.

Traffic intensity and vegetation management affect flower‐visiting insects and their response to resources in road verges

Abstract Road verges can support high densities of flowers and could therefore provide new opportunities for the conservation of flower‐visiting insects. One way of optimizing road verges for vascular plant diversity is to adjust mowing regimes, but to date it is unclear how this affects flower‐visiting insects. Furthermore, for mobile organisms like wild bees and butterflies, there is a risk that the benefit of increased habitat quality in road verges is limited by the proximity to traffic, but this is poorly studied. In a crossed study design, we separated mowing time and frequency (early summer and autumn, or only late summer) from road verge habitat classification (valuable for biodiversity according to transport authority, or regular). We did so along a gradient of traffic intensity, to investigate if a mowing regime designed to enhance plant diversity can also benefit wild bees and butterflies, and if traffic limits the conservation potential of road verges. Road verges that were mown only in late summer had higher flower densities, and there was a positive relationship between flower density and wild bee abundance and species richness. Butterfly abundance and species richness only benefitted from a late summer mowing in valuable but not in regular road verges. Traffic intensity had a substantial negative impact on abundance and species richness of wild bees and butterflies. Higher traffic intensities limited the positive relationship between plant and butterfly species richness that we observed at lower traffic intensities. Increasing width of the road verges buffered negative effects of the traffic on wild bee as well as butterfly abundances, and on wild bee species richness. Synthesis and applications. Road verges can play a valuable role for the conservation of wild bees and butterflies, but there is a need to consider both traffic intensity and resource availability when implementing management strategies. To support wild bee and butterfly diversity, we recommend actions to enhance plant species richness and flower resource availability, and to focus these conservation efforts on roads with low traffic intensity, or on wide road verges.

The distribution and abundance of woody invasive alien plants in small towns in Eastern Cape Province, South Africa

Invasive alien plants (IAPs) are rapidly increasing around the world, mainly due to land transformation, climate change, and urbanisation. Whilst urban areas are highly susceptible to invasion by IAPs, crucial information on the distribution and abundance of woody invaders in small towns is limited. Here, we determined the distribution and abundance of woody IAPs across different suburbs and land use types in 12 small towns in the Eastern Cape province of South Africa. We enumerated 38 427 individual woody IAPs, and their abundance and distribution varied across surveyed towns. Although species such as Melia azedarach, Pinus elliotti, Jacaranda mimosifolia, Eucalyptus camaldulensis, and Ligustrum lucidum were the most distributed, species density varied across towns. More than half of the woody IAPs were identified in affluent (56%) suburbs compared to the townships (23%), Central business district (CBD) (16%), and low-income housing neighbourhoods (5%). There were significant differences in woody IAPs distribution across different land use types, with more than half (54%) found in the residential areas compared to road verges (32%) and public urban green spaces (14%). Some socio-economic and environmental predictors such as town population, mean temperature, unemployment rate, and Gross domestic product (GDP) showed significant and positive correlations with woody IAPs species richness and density. Our findings suggest an uneven spatial distribution and diversity of woody IAPs across the different small towns, suburbs, and land use types in the region. It is recommended that small towns in South Africa need financial and human resources support to effectively manage IAPs.

The effects of dry heat and steam on germination of dry and imbibed seeds of the invasive garden lupine (Lupinus polyphyllus Lindl.)

Abstract Regularly mown road verges are an important habitat for conservation of grassland vegetation. Disturbance and movement of seed-contaminated soil during road construction and maintenance makes road verges susceptible to the establishment of invasive alien plants such as garden lupine (Lupinus polyphyllus Lindl.). To combat spread of L. polyphyllus via seeds, we tested methods for seed destruction using heat. This study aimed at developing heat eradication methods for dry and imbibed L. polyphyllus seeds applying dry heat (88, 93, 98, 103 C at 1, 3, 5, 10 min) in a laboratory, steam (85, 90, 95 C at 3, 5, 10 min) in a test-box steaming device and (97 C at 10-17 min; dry seeds only) in a stationary soil-steaming machine (S30). In order to speed up water absorption and post-treatment germination, the imbibed seeds were manually scarified before the heat treatment and the dry seeds afterwards. Additionally, germination of two different age seed batches was tested applying dry heat (88, 98 C at 3, 5 min). The results showed that steam treatments inhibited seed germination more than dry heat in both dry and imbibed seeds. Germination dropped to &lt; 5% when steamed at ≥ 90 C or dry-heated at &gt; 100 C. Seed germination decreased with higher temperatures and longer exposure times. Imbibed seeds exhibited lower germination compared to dry seeds for dry and steam heat. Approximately 0.5% of dry seeds germinated when steamed using S30. 2022-collected seeds were less sensitive to dry heat than seeds from 2020. In conclusion, hot steam is more effective in reducing L. polyphyllus seed germination than dry heat. Thus, to successfully eradicate L. polyphyllus seeds in soil masses, we recommend steaming them at 97 C for at least 10 minutes.

Effects of microclimate on disease prevalence across an urbanization gradient.

Increased temperatures associated with urbanization (the "urban heat island" effect) have been shown to impact a wide range of traits across diverse taxa. At the same time, climatic conditions vary at fine spatial scales within habitats due to factors including shade from shrubs, trees, and built structures. Patches of shade may function as microclimate refugia that allow species to occur in habitats where high temperatures and/or exposure to ultraviolet radiation would otherwise be prohibitive. However, the importance of shaded microhabitats for interactions between species across urbanized landscapes remains poorly understood. Weedy plants and their foliar pathogens are a tractable system for studying how multiple scales of climatic variation influence infection prevalence. Powdery mildew pathogens are particularly well suited to this work, as these fungi can be visibly diagnosed on leaf surfaces. We studied the effects of shaded microclimates on rates of powdery mildew infection on Plantago host species in (1) "pandemic pivot" surveys in which undergraduate students recorded shade and infection status of thousands of plants along road verges in urban and suburban residential neighborhoods, (2) monthly surveys of plant populations in 22 parks along an urbanization gradient, and (3) a manipulative field experiment directly testing the effects of shade on the growth and transmission of powdery mildew. Together, our field survey results show strong positive effects of shade on mildew infection in wild Plantago populations across urban, suburban, and rural habitats. Our experiment suggests that this relationship is causal, where microclimate conditions associated with shade promote pathogen growth. Overall, infection prevalence increased with urbanization despite a negative association between urbanization and tree cover at the landscape scale. These findings highlight the importance of taking microclimate heterogeneity into account when establishing links between macroclimate or land use context and prevalence of disease.

Research on alien invasive plants in Jingzhou County, Hunan Province, China

Harm from alien invasive plants is increasing in Jingzhou County, Hunan Province. Based on a one-year field investigation and available literature, we investigated species composition, origin, flora, degree of harm and distribution pattern of invasive plants in the county. The results showed that there were 34 invasive plant species from 27 genera and 16 families in this County. The dominant invasive species belonged to Asteraceae (8 species) and Amaranthaceae (6 species), which accounted for 23.5% and 17.7%, respectively. The majority of invasive plants originated from South America (45.7%) and North America (30.4%). Tropical flora showed a significantly higher representation than temperate flora, signifying robust tropical characteristics amongst the invasive plant population. Based on hazard level classification, we recognized four types as malicious invasion (Level 1): Alternanthera philoxeroides, Erigeron annuus, E. canadensis, and Xanthium chinense. In addition, five types were classified as severe invasion (Level 2), eight types as local invasion (Level 3), fifteen types as general invasion (Level 4), while two types were still under observation (Level 5). The pattern of distribution demonstrated that invasive plants in Jingzhou County mostly spread along the verges of transportation roads, in human settlements, and in a few areas of water flow. The higher levels of invasion damage were principally concentrated in the central part of Jingzhou County.

Possibilities of Utilising Biomass Collected from Road Verges to Produce Biogas and Biodiesel

Grass collected as part of roadside maintenance is conventionally subjected to composting, which has the disadvantage of generating significant CO2 emissions. Thus, it is crucial to find an alternative method for the utilisation of grass waste. The aim of this study was to determine the specific biogas yield (SBY) from the anaerobic mono-digestion of grass from road verges and to assess the content of Fatty Acid Methyl Esters (FAMEs) in grass in relation to the time of cutting and the preservation method of the studied material. The biochemical biogas potential (BBP) test and the FAMEs content were performed on fresh and ensiled grass collected in spring, summer, and autumn. The highest biogas production was obtained from fresh grass cut in spring (715.05 ± 26.43 NL kgVS−1), while the minimum SBY was observed for fresh grass cut in summer (540.19 ± 24.32 NL kgVS−1). The methane (CH4) content in the biogas ranged between 55.0 ± 2.0% and 60.0 ± 1.0%. The contents of ammonia (NH3) and hydrogen sulphide (H2S) in biogas remained below the threshold values for these inhibitors. The highest level of total FAMEs was determined in fresh grass cut in autumn (98.08 ± 19.25 mg gDM−1), while the lowest level was detected in fresh grass cut in spring (56.37 ± 7.03 mg gDM−1). C16:0 and C18:0, which are ideal for biofuel production, were present in the largest amount (66.87 ± 15.56 mg gDM−1) in fresh grass cut in autumn. The ensiling process significantly impacted the content of total FAMEs in spring grass, leading to a reduction in total saturated fatty acids (SFAs) and an increase in total unsaturated fatty acids (USFAs). We conclude that grass biomass collected during the maintenance of road verges is a valuable feedstock for the production of both liquid and gaseous biofuels; however, generating energy from biogas appears to be more efficient than producing biodiesel.

Rapid responses of bees and butterflies but not birds to targeted urban road verge habitat enhancements

Abstract Cities provide opportunities for biodiversity conservation through the design of urban greenspaces as wildlife habitat. A significant proportion of urban public land is narrow linear road verges, though their small size and harsh environmental conditions (e.g. high soil temperatures) may limit their ability to support plants and animals. We worked with a municipal government in a highly urbanised area to test whether conversion of standard road verges (e.g. lawn) to predominantly native understorey plants (forbs, grasses and shrubs) selected for their abilities to tolerate harsh growing conditions and provide habitat increased the abundance and richness of bees, butterflies and birds. We used a before‐after‐control‐impact experiment and characterised temporal dynamics of biodiversity responses 1 year prior to planting and 4 years post‐planting. We also tested whether traits known to influence species responses to urbanisation (body size and feeding specialisation) mediated responses to road verge plantings. Bee species richness and abundance increased at experimental plantings in the first post‐planting year and remained stable thereafter despite fluctuations at control sites. Butterfly abundance but not richness increased, and there was no evidence of bird responses to plantings. Larger bee species, which are known to be most negatively impacted by urbanisation, benefited more from the road verge plantings, while there was no effect of feeding specialisation. Bird and butterfly traits did not mediate responses to plantings. Synthesis and applications. Road verges comprise a significant proportion of urban green spaces, and our results suggest that despite their small sizes and harsh environmental conditions they can provide habitat for bees and to a lesser extent butterflies. We demonstrated that habitat value can be rapidly enhanced by converting standard road verges to native understorey plants and that these benefits may be greatest for the bee species most negatively impacted by urbanisation. Modifications such as additional plant species or wider verges may be required for urban road verges to provide habitat for a greater range of taxa including birds and butterflies.

Searching to improve connectivity in fragmented landscapes: Road verges as complementary habitats

AbstractAimsFunctional connectivity is crucial for conserving biodiversity and ecosystem services in fragmented landscapes. Linear landscape elements play an important role in providing refuge for plants and pollinators, as well as serving as biological corridors. The aim of this study was to assess the importance of road verges in maintaining the ecological connectivity of plant species assemblages in the Tandilia mountain system.LocationSouth America, Southern Pampa region of Argentina, Tandilia mountain system.MethodsUsing graph theory, landscape connectivity was quantified both at landscape scale and at the patch scale using the probability connectivity index (PCnum), taking into account the dispersal ability of observed species. The contribution of each landscape element to habitat availability and connectivity was evaluated using different fractions of the PCnum metric. Likewise, the influence of connectivity variables in explaining species assemblages grouped by functional categories was investigated using canonical ordination techniques.ResultsThe inclusion of road verges led to an 81% increase in overall connectivity at a threshold distance of 500 m. Connectivity significantly explained the assemblages of entomophilous plant species for all dispersal distances. Annual species assemblage variation was associated with intra‐patch connectivity. Variation in perennial and shrub species assemblages was explained by intra‐patch and inter‐patch connectivity.ConclusionsPreservation and restoration of these linear landscape elements play a pivotal role in transitioning toward more sustainable agroecosystems. This ecological and practical information may help prioritize plant species and the sites used to restore an essential but neglected ecosystem.

Neglected puzzle pieces of urban green infrastructure: richness, cover, and composition of insect-pollinated plants in traffic-related green spaces

ContextIn cities, insect-pollinated vascular plants enhance environmental quality, support pollinators, and provide essential ecosystem services for citizens. However, floral communities associated with traffic-related green spaces are rarely considered valuable elements of urban green infrastructure (UGI).ObjectivesThe main objective of this work was to assess if traffic-related green spaces in Finland possess species-rich floral communities and can assist urban ecological restoration—converting degraded areas into functionally diverse ecosystems. Thus, we evaluated richness, cover, and community composition of insect-pollinated plants (emphasizing flowering ones) on traffic islands, parking lots, and road verges.MethodsThe assessment was performed during the mean flowering phenophase of insect-pollinated plants in the European boreal zone (July and August) using a standard quadrat (1 m2) placement method. We studied plants in urban and suburban locations of three highly populated (> 170 000 inhabitants) Finnish cities—Helsinki, Tampere, and Turku. There were 90 sampling sites with 15 replicates per location type in each city and five measurement replicates per green space (habitat) type. The species richness, cover, and composition were assessed in relation to location, habitat type, city, the average daily traffic (ADT), and distance to the road.ResultsUrban locations had lower total plant species richness and fewer indicator species (characterized only by a single indicator species) compared to suburban locations (characterized by five indicator species). Species richness of plants flowering during the time of the survey did not differ among locations. Traffic islands were richer habitats for flowering plants than road verges but did not differ from parking lots. Total vegetation cover and cover of insect-pollinated flowering plants increased with an increasing distance from the road. Vegetation cover differed among habitats being higher on road verges than on traffic islands irrespective of ADT. In all habitat types, the two most common flowering species were yarrow Achillea millefolium and autumn hawkbit Leontodon autumnalis which occurred at 70.2% and 67.8% of the sampling sites, respectively. However, the mean cover of the ten most common flowering species (when present) was low and varied between 1.5 and 9.5% per m2.ConclusionsSimilar richness of flowering plants (but not total plant species) in urban and suburban locations might indicate equal importance of ecosystem services provided by flowering plants in cities irrespective of location. Because traffic islands and parking lots contain rich plant communities, they should be better integrated into UGI and valued by city planners. Management intensity in terms of grass cuts should be ecologically justified. An increase in the number of insect-pollinated plant species in urban traffic-related green spaces might help to improve environmental quality in cities in terms of increasing pollinator biodiversity and reducing pollution.

Unpaved road verges are attractive habitats for dung beetles (Coleoptera: Scarabaeidae) in a plantation forestry-grassland mosaic

Roads have direct and indirect impacts on biodiversity, although the impacts on insects are not yet fully understood. In a plantation forestry-dominated landscape in South Africa, where natural grasslands make up ecological networks of conservation corridors among plantation compartments, we investigated the impact of maintained unpaved roads and unmanaged tracks on dung beetles. We show that these two types of roads have little impact on dung beetle species richness and assemblage structure, indicating that road verges are attractive habitats for dung beetles. Yet, nocturnal dung beetle abundance increased with distance away from roads, suggesting that areas farther away from roads are important to maintain their population sizes. Vegetation characteristics, especially total cover by grasses and overall vegetation height, were important drivers of dung beetles, yet substrate characteristics were unimportant. With vegetation characteristics being related to road maintenance, roads in the landscape have an indirect impact on dung beetle species richness, abundance, and assemblage composition, rather than a direct impact. Road construction in production landscapes is unavoidable, and their edges are attractive to dung beetles. This means that road users should avoid unnecessary road killings by strictly keeping to the road tracks. Habitat heterogeneity across the overall landscape should be encouraged to minimize current and future impacts of roads on dung beetles. The expansion of road networks, or the maintenance of existing road networks, should be done cautiously so as to promote habitat heterogeneity which is important for maintaining regional dung beetle diversity patterns.

Towards a functional understanding of rehabilitated urban road verge grasslands: Effects of planting year, site conditions, and landscape factors

Urbanization causes ecosystem degradation and losses of biodiversity. Still, urban landscapes favor organisms, depending on how well they fit the anthropogenic conditions. Creating urban green spaces of high ecological quality, such as pollinator-friendly road verges, promotes biodiversity in cities. We sowed a seed mixture consisting of 26 native plant species with diverse functional traits in 46 road verge patches along four urban roads in Munich (South Germany) in 2019/20 and monitored in 2020/21. Control were pre-existing turfgrass patches with conventional management. We assessed species richness, Shannon diversity, and Pielou's evenness, whereas functional composition was evaluated via functional richness, evenness, and divergence, based on 13 plant traits. To study urbanization effects on species and functional composition, we analyzed soil characteristics and tree shading at the local level, as well as distance to city center, imperviousness, and edge density at the landscape level. We used linear models and ordination analysis to assess treatment, local and landscape effects, and the influence of planting year on taxonomic and functional composition. Rehabilitation treatment explained most differences in species and functional composition. Species richness was lower in the city center and at sites with high soil organic matter; Pielou's evenness increased with soil pH. Trait composition differed between rehabilitated and control patches, and varied according to planting year. Soil bulk density negatively affected functional richness for all traits combined, and edge density reduced functional evenness of establishment traits. We conclude that urban filtering, in combination with planting year, shapes species and trait composition of rehabilitated road verges. Hence, local and landscape-level trait–environment interactions affect the assembly of road verge grasslands. Finally, our findings suggest that establishment traits have a pivotal role in the development of rehabilitated road verges, while the predictability of rehabilitation outcomes may be hindered even when seeding specifically designed seed mixtures.

Metal Element Traces Sampled from Peri-Urban Road Verge Particulate Matter

The objective of this research is to analyze metal elements, such as Na (sodium), Mg (magnesium), Al (aluminum), Si (silicon), Pb (lead), K (potassium), Ca (calcium), and Fe (iron), found in dust particles within two distinct areas from which the samplings were taken. The first sampling was taken from the road verge of a highly trafficked road section, while the second sampling was taken from a residential garden area 90 m away from the road. Several metal elements were detected with a high difference in Si, which presented higher concentrations in the dust samples from the road verge area. Pb has only been detected in the samples taken from the road verge, which could be explained by residual remnants from old lead gasoline and wheel weights. Additionally, during the same investigation, airborne particulate matter (PM) concentrations were measured in comparison between the road verge and the garden area; this presented a substantial difference in the concentration levels, suggesting that dense vegetation is protecting and blocking a majority of airborne PM. A literature highlight of the health effects of different metal elements and PM concentrations is presented.

Using airborne LiDAR to map forest microclimate temperature buffering or amplification

Mapping the microclimate effect of forest canopies on understory temperature requires spatially explicit predictors at very fine spatial resolutions. Light Detection And Ranging (LiDAR) offers promising prospects in that regard, as it allows capturing the vertical dimension of vegetation structure at a very high resolution over large areas.To explore the potential of airborne LiDAR-derived metrics to predict understory temperature, we focused on the forest of Blois (France), a 2740-ha lowland managed forest dominated by oak (Quercus petraea). We installed HOBO sensors measuring microclimate air temperature at one-metre height in 53 stands of contrasting vegetation structure, from open to very dense and from young regeneration to mature stages. Using a nearby weather station as the macroclimate temperature reference, we calculated the slope (log scale) coefficient of the linear regression between microclimate and macroclimate, as a simple parameter describing the microclimatic buffering (log(slope) < 0) or amplification (log(slope) > 0) capacity of the habitat.An airborne LiDAR flight was conducted during summer 2021, matching the timing of our temperature measurements. From the resulting 3D point cloud, three complementary metrics of forest structure were derived: the maximum height, the Plant Area Index and the Vertical Complexity Index. They were calculated for circular buffers of different radii (1 m to 100 m) centred on each HOBO sensor.We found that the 5-m radius combining the three metrics into a single multivariate model explained the greatest proportion of variance in the microclimate effect of each stand (R2 = 0.91). We mapped the buffering or amplification effect of vegetation structure on understory temperatures over the entire forest of Blois at a 10-m resolution. 91.4% of the surface of the forest was significantly buffered relative to macroclimate temperature, while 2.7% was amplified, especially in road verges, clear-cut and regeneration areas. Based on our simple linear model, we were able to derive understory air temperature maps for any temporal resolution (i.e. hourly, daily, or seasonal). The results highlight the great capacity of airborne LiDAR to retrieve forest structure parameters and generate high-resolution maps of the thermal environment.Applications for mapping the buffering or amplification of microclimate temperature are plentiful, especially in the context of climate change. They include improving the understanding of physiological processes such as thermoregulation or phenology, modelling the thermal connectivity of the landscape, improving species redistribution models, spotting microrefugia for conservation, informing forest management for tree regeneration or wildfire control, or even prioritising cooling recreational areas for humans to escape heatwaves in urban forests.

Carbon Sequestration Potential of Biomass Production along Highways in China.

In response to climate change, China is making great efforts to increase the green area for carbon sequestration. Road verges, as marginal land with favorable conditions for plant growth and ease of transportation, can be used for biomass production, but the biomass production and carbon sequestration potential have not been assessed. Here, we mapped the biomass production potential of road verges in China by combining a biomass model and Geographic Information System and then evaluated the effect of road runoff and CO2 fertilization on the production according to the runoff coefficient and vehicle emission inventory. Nationwide, road verges can produce 15.86 Mt C yr-1 of biomass. Road runoff contributes to a biomass production of 1.26 Mt C yr-1 through increasing soil water availability, which mainly occurs in arid regions. The CO2 fertilization effect by vehicle emission is considerable in Eastern and Southern China, contributing to a production of 0.09 Mt C yr-1. Life cycle assessment shows that major road verges in China have a carbon sequestration potential of 6.87 Mt C yr-1 currently. Our results revealed that road verges can make a significant contribution to carbon neutrality under proper management.

Isolation and characterization of phosphate-solubilizing bacteria from rhizosphere of poplar on road verge and their antagonistic potential against various phytopathogens

BackgroundPhosphate-solubilizing bacteria (PSB) can solubilize insoluble phosphate compounds and improve phosphate availability in soil. Road verges are important in urban landscaping, but the population structure of PSB and their ecological functions in the road verge soil is still unclear.ResultsTwenty-one mineral PSB strains and 14 organic PSB strains were isolated from the rhizosphere of poplar on urban road verge. All the mineral PSB strains showed better solubilization to Ca3(PO4)2 than FePO4 or AlPO4. Among them, 7 strains showed high phosphate-solubilizing (PS) activities to Ca3(PO4)2 (150–453 mg/L). All the organic PSB strains displayed weak solubilization to lecithin. 16S rRNA gene-based phylogenetic analysis showed good species diversity of the PSB strains, which belongs to 12 genera: Bacillus, Cedecea, Cellulosimicrobium, Delftia, Ensifer, Paenibacillus, Pantoea, Phyllobacterium, Pseudomonas, Rhizobium, Sinorhizobium and Staphylococcus. Moreover, 8 PSB strains showed various degrees of growth inhibition against 4 plant pathogenic fungi, Fusarium oxysporum S1, F. oxysporum S2, Pythium deliense Meurs Z4, Phomopsis sp. AC1 and a plant pathogenic bacterium, Pectobacterium carotovorum TP1.ConclusionsThe results indicated that these PSB strains could perform multiple ecological functions on road verge. The development and application of bio-agents based on the strains would provide a new strategy for maintaining and improving the ecosystem stability of road verges.

Use of road infrastructure for movement by common terrestrial vertebrates

AbstractWildlife‐vehicle collisions are increasing with road expansion. This problem could be minimised if the use of existing infrastructure to cross roads could be enhanced. We aimed to determine whether common terrestrial vertebrates used drainage culverts to cross roads, relative to rates of surface crossings. Camera traps were deployed on road verges at 30 locations in southeast Queensland, Australia for 2 weeks each over a 3‐month period. Of 1671 independent animal observations, 397 were direct observations of road crossings, either over‐road (365) or under‐road via culverts (32). Native species and small species were found more commonly at roadsides than culverts and where vegetation density was lower. Our data showed that animals used culverts only about 6% of the time. Management such as funnel fencing or vegetation manipulation could encourage wildlife to use culverts, but this would require a substantial investment given the propensity for animals to cross via the road surface.

Is the protection of habitat directive Eleocharis carniolica in its northern limits really needed? – A life strategy based investigation

Eleocharis carniolica is included in the EU Habitat Directive and legally protected in many European countries. It is also considered as one of the most threatened plants in Poland. It typically occurs in muddy habitats, wet meadows, lake or pond shores or temporary puddles, but in Poland this species usually occurs at disturbed anthropogenic sites such as road verges or drainage ditches. Despite being the focus of a number of ecological and conservation studies, E. carniolica still does not have a fully recognized ecology and life-strategy, particularly with regard to breaking seed dormancy and germination. To find out the population performance and species propagation potential in Poland, we have conducted experiments aimed at assessing the seed germination conditions and efficiency. The main goal was to discover the crucial factors that stimulate germination. The results of the experiments suggest that light is a pivotal factor for triggering germination of E. carniolica seeds. Moreover, E. carniolica’s seed bank consisted of about 80 % dormant seeds. The only effective method for dormancy breaking was warm stratification (placing the seeds at high temperature on a moist substrate) with application of gibberellic acid (GA3), and even a few days of warm stratification resulted in effectively overcoming dormancy. Eleocharis carniolica's germination features are typical for plants adapted to frequent disturbances with a short life expectancy and large reproductive effort. Our results strongly suggest that E. carniolica has a ruderal life strategy at its northern distribution limits and probably can be considered as an alien species in Poland.