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The article discusses how building roads with wastes can deliver a heap of performance as well as environmental benefits. Topics discussed are the views of Fred Parrett on the use of waste material in the roads; chemical laws in European Union that made all chemical substances to be registered and assigned a CAS number before their use and road repairs; and challenges in designing an appropriate asphalt mixture for a chosen application in roads.

Roads have a pervasive multi-faceted influence on ecosystems, including pronounced impacts on wildlife movements. In recognition of the scale-transcending impacts of transportation infrastructure, ecologists have been encouraged to extend the study of barrier impacts from individual roads and animals to networks and populations. In this study, we adopt an analytical representation of road networks as mosaics of landscape tiles, separated by roads. We then adapt spatial capture-recapture analysis to estimate the propensity of wildlife to stay within the boundaries of the road network tiles (RNTs) that hold their activity centres. We fit the model to national non-invasive genetic monitoring data for brown bears Ursus arctos in Sweden and show that bears had up to 73% lower odds of using areas outside the network tile of their home range centre, even after accounting for the effect of natural barriers (major rivers) and the decrease in utilization with increasing distance from a bear's activity centre. Our study highlights the pronounced landscape-level barrier effect on wildlife mobility and, in doing so, introduces a novel and flexible approach for quantifying contemporary fragmentation from the scale of RNTs and individual animals to transportation networks and populations. [ABSTRACT FROM AUTHOR]

Roads are known to act as corridors for dispersal of plant species. With their variable microclimate, role as corridors for species movement and reoccurring disturbance events, they show several characteristics that might influence range dynamics of both native and non-native species. Previous research on plant species ranges in mountains however seldom included the effects of roads. To study how ranges of native and non-native species differ between roads and adjacent vegetation, we used a global dataset of plant species composition along mountain roads. We compared average elevation and range width of species, and used generalized linear mixed models (GLMMs) to compile their range optimum and amplitude. We then explored differences between roadside and adjacent plots based on a species' origin (native vs non-native) and nitrogen and temperature affinity. Most non-native species had on average higher elevational ranges and broader amplitudes in roadsides. Higher optima for non-native species were associated with high nitrogen and temperature affinity. While lowland native species showed patterns comparable to those in non-native species, highland native species had significantly lower elevational ranges in roadsides compared to the adjacent vegetation. We conclude that roadsides indeed change the elevational ranges of a variety of species. These changes are not limited to the expansion of non-native species along mountain roads, but also include both upward and downward changes in ranges of native species. Roadsides may thus facilitate upward range shifts, for instance related to climate change, and they could serve as corridors to facilitate migration of alpine species between adjacent high-elevation areas. We recommend including the effects of mountain roads in species distribution models to fine-tune the predictions of range changes in a warming climate. [ABSTRACT FROM AUTHOR]

Road crossings can act as barriers to the movement of stream fishes, resulting in habitat fragmentation, reduced population resilience to environmental disturbance and higher risks of extinction. Strategic barrier removal has the potential to improve connectivity in stream networks, but managers lack a consistent framework for determining which projects will most benefit target species. The objective of this study is to develop a method for identifying and prioritizing action on road crossings in order to restore stream network connectivity. We demonstrate the method using a case study from the Pine-Popple watershed in Wisconsin. First, we propose a new metric for quantifying stream connectivity status for stream-resident fish. The metric quantifies the individual and cumulative effects of barriers on reach and watershed level connectivity, while accounting for natural barriers, distance-based dispersal limitations and variation in habitat type and quality. We conducted a comprehensive field survey of road crossings in the watershed to identify barriers and estimate replacement costs. Of the 190 surveyed road crossings, 74% were determined to be barriers to the movement of at least one species or life stage of fish, primarily due to high water velocity, low water depth or outlet drops. The results of the barrier removal prioritization show that initial projects targeted for mitigation create much greater improvements in connectivity per unit cost than later projects. Benefit–cost curves from this type of analysis can be used to evaluate potential projects within and among watersheds and minimize overall expenditures for specified restoration targets. [ABSTRACT FROM AUTHOR]

Anthropogenic structures such as those associated with energy development are a major threat to wildlife as a result of direct and indirect effects on populations. Species already imperilled as a result of habitat loss and alteration also may be the most threatened by rapidly increasing energy development, and these added pressures could lead to species extinctions and further declines in biodiversity., Of particular concern are tetraonids (grouse spp.) which have life cycles that require large, intact habitats to persist. We searched the peer-reviewed literature to assess impacts of six anthropogenic structures (i.e. oil and gas, fences, wind turbines, buildings, roads and power lines) on grouse survival and displacement behaviour across four different time periods in a grouse life cycle (i.e. year around, lekking, nesting and brooding)., We used 5 studies that examined a total of 23 study-structure combinations to assess displacement behaviour in grouse and found an average effect of −1·40 (95% CI: −1·50, −1·31), indicating that anthropogenic structures displace grouse. Similarly, we used 9 studies examining a total of 17 study-structure combinations to assess survival and found an average effect of −1·11 (95% CI: −1·33, −0·88), indicating a negative effect of structures on grouse survival., Oil and gas structures had the greatest negative effect on displacement behaviour ( [ABSTRACT FROM AUTHOR]

Roads have a significant impact on wildlife world-wide. Two of the ways to mitigate the impact of roads are to improve connectivity and reduce mortality through fences and wildlife crossings. However, these are expensive actions that will have different effects in different places. Thus, deciding where and how to act in order to achieve the greatest return on investment is crucial. Currently, there are no quantitative approaches to prioritize different road mitigation options., Here, we use a decision science framework to determine the most cost-effective combination of actions to mitigate the effects of roads on wildlife under budget constraints. We illustrate our approach using a case study of a threatened koala Phascolarctos cinereus population in south-east Queensland. We applied a spatially explicit population model to explore the benefits of three kinds of mitigation actions: no action at all and fences with or without crossings, on different road segments., We explored the trade-off between expected koala population size, relative to the best outcome, and budget. There is a strong demand for mitigation as the already declining population was reduced even further when no mitigation was employed, while applying the most cost-effective combination of mitigation actions minimized that decline. Additionally, uncertainty in species attributes (speed of crossing a road and population growth rate) affected population viability but not the decision about which suite of actions (mitigation measures) to take - so our advice on the best action is robust to uncertainty even if the outcome is not. Most importantly, the trade-off curves between investment and population size are almost linear in this case study. Hence, there is no cheap solution and any reduction in the budget will result in a substantial reduction in expected population size., Synthesis and applications. This is the first time that the problem of mitigating the effects of roads on wildlife was formulated mathematically and systematically using decision science. Our approach is adaptable to a diversity of species and systems affected by road mortality allowing flexibility for a range of mitigation actions and biological outcomes. Our method will allow managers and decision-makers to increase the efficiency of mitigation actions. [ABSTRACT FROM AUTHOR]

Road mortality is a major component of human impacts on wildlife populations, and the pervasiveness of roads on the landscape presents a substantial challenge for managing those impacts. The feasibility of methods to reduce road mortality depends on the degree to which this threat is spatially or temporally concentrated, which can be based on habitat, human activities or species' ecology. Diamondback terrapins Malaclemys terrapin are a species of conservation concern across their range, and road mortality is a major threat contributing to local population declines., We used intensive road surveys of the 8·7-km Downing- Musgrove Causeway to Jekyll Island, Georgia, USA, over 2 years to determine whether road activity and mortality was diffused or concentrated spatially (hot spots) or temporally (hot moments) in order to guide efficient management., In 2009 and 2010, we documented 636 terrapin crossings that were temporally and spatially condensed. Temporally, there was a 70-80% chance of a terrapin occurring on the road within a 3-h period around the diurnal high tide and within the first 30 days of the ˜75 day nesting season. Over the two nesting seasons, 52% of terrapin occurrences on the road occurred within the 3-h period around high tide. Spatially, 30% of terrapins were observed crossing in three hot spots that composed less than 10% of the length of the entire causeway, and the percentage of unvegetated high marsh was negatively associated with the number of terrapins that occurred on a section of road., Synthesis and applications. Our results demonstrate that hot spots and hot moments can be identified for species at finer scales than those found by other studies and are related, strongly or weakly, to specific temporal processes or habitat features. We found patterns of road mortality, like most threats, can be diffused or concentrated; therefore, complementary management tools that focus on hot spots or moments and also address the more diffused component of road mortality will be required to reduce this threat for at-risk wildlife. [ABSTRACT FROM AUTHOR]

Roads are pervasive fixtures on most landscapes but are typically among many factors contributing to wildlife population declines. Addressing road mortality as part of larger conservation efforts is challenging because it can be difficult to measure per capita mortality from roads and other concurrent threats., We used 4 years of mark-recapture-recovery data for diamondback terrapins Malaclemys terrapin on a causeway in Georgia, USA, to directly estimate threats of adult road mortality and nest predation, contrast the consequences to population growth using stage-based matrix models and make management recommendations to stabilize the population., Mean estimated annual adult road mortality was 11·1% (range = 4·4-16·4%). Estimated annual nest predation was 61·9%. We estimated that the population was declining (λ < 0·98) in all scenarios where both threats were included. Variation in adult survival was the most influential (highest elasticity) contributor to population growth relative to other demographic rates; however, λ would remain below 1 with any nest predation rate exceeding our estimate even if actions to mitigate road mortality were 100% effective., Synthesis and applications. Our study provides some of the first direct estimates of vehicle mortality rates and shows that mortality can remain sufficiently high among years to cause population declines. We also demonstrate that management actions focused on singular threats are inadequate for recovering populations. We conclude that integrated road and predator management is necessary to conserve turtle populations, and we suggest alternative strategies to compensate for some vehicle mortality and nest depredation. [ABSTRACT FROM AUTHOR]

The rapid increase of human activity in wild and developed areas presents novel challenges for wildlife. Some species may use human-dominated landscapes because of favourable resources (e.g. high prey availability along roadsides); however, use of these areas may increase exposure to anthropogenic stressors, such as human disturbance or noise, which can negatively affect reproduction or survival. In this case, human-dominated landscapes may act as an ecological trap., We evaluated whether American kestrel Falco sparverius reproductive failure was associated with human disturbance (traffic conditions and land development) or other common predictors of reproductive outcome, such as habitat and clutch initiation date. Also, we examined relationships among human disturbance, corticosterone ( CORT) concentrations and nest abandonment to explore potential mechanisms for stress-induced reproductive failure., Twenty-six (36%) of 73 kestrel nesting attempts failed and 88% of failures occurred during incubation. Kestrels nesting in higher disturbance areas were 9·9 times more likely to fail than kestrels nesting in lower disturbance areas. Habitat and clutch initiation date did not explain reproductive outcome., Females in higher disturbance areas had higher CORT and were more likely to abandon nests than females in lower disturbance areas. There was no relationship between male CORT and disturbance or abandonment. Females spent more time incubating than males and may have had more exposure to anthropogenic stressors. Specifically, traffic noise may affect a cavity-nesting bird's perception of the outside environment by masking auditory cues. In response, incubating birds may perceive a greater predation risk, increase vigilance behaviour, decrease parental care, or both., Synthesis and applications. Proximity to large, busy roads and developed areas negatively affected kestrel reproduction by causing increased stress hormones that promoted nest abandonment. These results demonstrate that species presence in a human-dominated landscape does not necessarily indicate a tolerance for anthropogenic stressors. Managers should carefully consider or discourage projects that juxtapose favourable habitat conditions with areas of high human activity to decrease risk of ecological traps. Noise mitigation, while locally effective, may not protect widespread populations from the pervasive threat of traffic noise. Innovative engineering that decreases anthropogenic noise at its source is necessary. [ABSTRACT FROM AUTHOR]

Understanding the consequences of environmental change on populations is an essential prerequisite for informed management of ecosystems and landscapes. In lieu of quantifying fitness effects directly, which is often difficult, behavioural functional responses provide insight into how animals balance trade-offs, and into thresholds in responses to environmental change., Here, we explore this principle using the response of moose Alces alces L. to roads and restricted-access tracks as a case study. Because roads are associated with the conversion of conifer to mixed deciduous-conifer forest that provides better foraging opportunities, moose in Ontario favour areas of moderate road density at a landscape scale. At a finer scale, however, moose avoid roads. These opposing effects indicate a cost-benefit trade-off. We quantified behavioural responses of moose to roads using road-crossing rate. An expected distribution of crossing rates was derived from correlated random walk null model simulations., Moose exhibited a seasonally variable, nonlinear functional response in road-crossing rate at the within seasonal range scale. A pronounced response to roads was observed when road density reached approximate thresholds of 0·2 and 0·4 km km [ABSTRACT FROM AUTHOR]

Road reclamation has emerged as an integral part of ecological restoration strategies, particularly on public lands. However, there are no consistent techniques for how road reclamation should be implemented to restore ecosystem structure and function. Resource managers are hindered by critical research gaps regarding the linkages between, as well as the effects of different restoration actions on, above- and belowground ecological and hydrological properties. In the western US, we examined how two road reclamation methods (recontouring and abandonment) affect ecosystem properties relative to "never-roaded" areas. Recontoured and abandoned sites displayed similar aboveground properties but exhibited notable differences in belowground properties, including soil hydraulic conductivity, organic matter, total carbon, and total nitrogen, among others. Our findings suggest that recontouring can dramatically accelerate recovery of above- and belowground properties so they resemble never-roaded reference conditions. In contrast, abandoning roads generates above- and belowground properties that follow a different path to recovery. [ABSTRACT FROM AUTHOR]

Roads are a widespread and growing form of habitat alteration, making their effects on wildlife a major conservation concern. We investigated effects of roads on occupancy patterns and stress physiology of the golden-cheeked warbler Setophaga chrysoparia, an endangered songbird that depends on large tracts of old-growth forest for breeding. We compared those effects in the white-eyed vireo Vireo griseus, a common songbird that prefers to breed in scrubby habitat that is common along forest roads. In warblers, older, socially dominant males were more likely to occupy territories, but had higher baseline plasma concentrations of corticosterone, in less-roaded habitats. In vireos, older males were equally likely to occupy territories, but, opposite to warblers, had lower baseline corticosterone concentrations, in less-roaded habitats. In both species, the corticosterone response to acute stress was unrelated to road density, and body condition and fat stores either increased or were sustained across road density groups during the breeding season, suggesting that breeding near roads did not cause chronic stress. Our results suggest that roads can cause increased male-male competition for territories in nearby roadless habitat, and may result in higher corticosterone concentrations in dominant individuals defending preferred sites near or far from edge, depending on species habitat preferences. Increased competition and chronically elevated corticosterone levels may be of concern if they alter parental care or immunity of individuals breeding in the best habitat. [ABSTRACT FROM AUTHOR]

Roads cause functional habitat loss, alter movement patterns and can become ecological traps for wildlife. Many of the negative effects of roads are likely to be a function of the human use of roads, not the road itself. However, few studies have examined the effect of temporally and spatially varying traffic patterns on large mammals, which could lead to misinterpretations about the impact of roads on wildlife. We developed models of traffic volume for an entire road network in south-western Alberta, Canada, and documented for the first time the response of grizzly bears Ursus arctos L to a wide range of traffic levels., Traffic patterns caused a clear behavioural shift in grizzly bears, with increased use of areas near roads and movement across roads during the night when traffic was low. Bears selected areas near roads travelled by fewer than 20 vehicles per day and were more likely to cross these roads. Bears avoided roads receiving moderate traffic (20-100 vehicles per day) and strongly avoided high-use roads (>100 vehicles per day) at all times., Synthesis and applications. Grizzly bear responses to traffic caused a departure from typical behavioural patterns, with bears in our study being largely nocturnal. In addition, bears selected private agricultural land, which had lower traffic levels, but higher road density, over multi-use public land. These results improve our understanding of bear responses to roads and can be used to refine management practices. Future management plans should employ a multi-pronged approach aimed at limiting both road density and traffic in core habitats. Access management will be critical in such plans and is an important tool for conserving threatened wildlife populations. [ABSTRACT FROM AUTHOR]

1. It is well known that roads can have a significant impact, usually negative, on species and ecosystems. However, despite their protected status in many countries, little research has been done into the effects of roads on bats. With a view to making more informed management recommendations, we address the simple question: are bat activity and diversity (as measured with ultrasonic detectors) correlated with distance from a major road? 2. Broadband acoustic surveys were conducted on 20 walked transects perpendicular to the M6, a major road in Cumbria (UK), with bat activity recorded at eight spot checks per transect at different distances from the road. Climatic and habitat variables were also recorded, and the relationships between bat activity and these variables were investigated using generalised estimated equations (GEE) and ordinal logistic regression. 3. Total bat activity, the number of species and the activity of Pipistrellus pipistrellus (the most abundant species) were all positively correlated with distance from the road. Total activity increased more than threefold between 0 and 1600 m from the road. These effects were found to be consistent over 2 years. 4. Synthesis and applications. This study is one of the first to show that roads have a major negative impact on bat foraging activity and diversity and is broadly applicable to insectivorous bat communities worldwide. Mitigation requires that roads are made more permeable to bats through the use of effective crossings, such as underpasses and overpasses, and that habitat is improved within 1 km of major roads. Because the effectiveness of current mitigation measures is unknown, well-designed monitoring of mitigation is essential. [ABSTRACT FROM AUTHOR]

Paired watershed studies have limited researchers wishing to disentangle road and harvesting effects on peak flows or to study management schemes other than the existing scenario. The outcomes of many paired watershed studies examining peak flows have also recently been challenged since only an approach that pairs peak flows by frequency can adequately evaluate the effects of harvesting on peak flows. This study takes advantage of a model that has been developed and extensively tested at a site containing a rich set of internal catchment process observations to examine the isolated and combined effects of roads and harvesting on the peak flow regime of a snow-dominated catchment for return periods of up to 100 years. Contrary to the prevailing perception in forest hydrology, the effects of harvesting are found to increase with return period, which is attributable to the uniqueness of peak flow runoff generation processes in snow-dominated catchments. Planned harvesting (50% harvest area) is found to have a significant effect (9%-25% over control) on peak flows with recurrence intervals ranging 10-100 years. Peak flow frequency increases after harvesting increase with return period, with the largest events (100 year) becoming 5-6.7 times more frequent, and medium-sized events (10 year) becoming 1.7-2 times more frequent. Such changes may have substantial ecological, hydrological, and geomorphological consequences within the watershed and farther downstream. Study findings suggest that peak flow regimes are fairly tolerant to the current level of harvesting in this particular watershed but that further harvesting may affect this element significantly. [ABSTRACT FROM AUTHOR]

Summary 1. Caribou and reindeer Rangifer tarandus are declining across North America and Scandinavia in part from wolf Canis lupus-mediated apparent competition with more abundant ungulate prey species. While caribou generally persist in areas with low wolf density, wolf packs that overlap caribou ranges could trigger caribou declines. Moreover, anthropogenic linear features such as roads, trails and seismic lines are hypothesized to increase predation risk for caribou, yet few studies have examined the mechanistic effects of linear features or spatial overlap on wolf-caribou encounter rates and predation risk. 2. We used (a) time-to-event models of wolf-caribou encounters estimated from concurrent global positioning system (GPS) radio-collar data from wolves and caribou and (b) wolf resource selection models of travel locations, to determine the potential influence of wolf-caribou spatial overlap, linear features, elevation and season on encounter rates. Analyses were based on data from 35 adult female caribou and 37 male and female wolves from 11 wolf packs from Banff and Jasper National Parks, Canada, from 2002 until 2010. 3. Wolf-caribou encounter rates increased with high wolf-caribou overlap, proximity to linear features and lower elevations. Wolves strongly selected low elevations, especially during winter and spring. Selection for linear features as travel routes increased with elevation. 4. Caribou risk of encounter was highest during the summer and autumn when wolves spent the most time at high elevations. Most wolf-caused mortalities ( n = 12) occurred during spring and summer. 5. Synthesis and applications. The presence of anthropogenic linear features and the amount of time wolves spend in caribou range could be equally as important as wolf density when prioritizing caribou recovery actions such as wolf or primary prey reductions or re-introductions. The use of GPS locations and time-to-event modelling offers a powerful tool for evaluating factors affecting predation risk of threatened and endangered species. [ABSTRACT FROM AUTHOR]

Summary 1. The effects of roads on wildlife populations are widespread and well documented. Many studies have shown that bird abundance, occurrence and species richness are reduced near roads, with the largest reductions where traffic levels are high. Negative correlations have been reported between bird richness/abundance and traffic noise but the possible causes of road effects are inter-correlated. It is important to disentangle the different effects so that appropriate mitigation measures can be implemented. 2. We tested the hypothesis that traffic noise is a key negative effect by testing three predictions: (i) bird richness/abundance should reach a maximum at the same distance from roads that traffic noise reaches a minimum; (ii) the effect of traffic noise on bird richness/abundance should be stronger than the effect of distance from the road on bird richness/abundance; and (iii) sites with more traffic noise at a given distance from the road should show lower bird richness/abundance than sites with less traffic noise at the same distance. 3. We collected breeding bird occurrence and traffic noise data along twenty 600-m transects perpendicular to roads at 10 high-traffic road sites. 4. Traffic noise decreased and bird species richness increased with increasing distance from the roads. However, none of the predictions derived from the traffic noise hypothesis was supported. 5. Synthesis and applications. Our results suggest that traffic noise is not the main cause of the negative relationship between bird species richness/abundance and proximity to roads. Instead, traffic mortality may be the main mechanism causing this relationship. We suggest that mitigation of road impacts on birds should focus mainly on reducing mortality rather than reducing traffic noise. In particular, engineering road surfaces, tyres and vehicle engines to reduce noise would not mitigate road effects; instead, structures to keep birds away from roads or force them to fly above the traffic would be more effective. [ABSTRACT FROM AUTHOR]

1. Linear features associated with transportation and riparian corridors are known to inhibit the mobility of birds and other wildlife, yet the factors contributing to their barrier effects are poorly understood. The diversity of roads in urban landscapes provides an opportunity for elucidating the relative importance of factors such as noise, traffic volume, gap width and adjacent vegetation on animal movement. 2. Using an avian mobbing call as a lure, we tested the willingness of forest songbirds to cross four types of linear features in the urban landscape of Calgary, Alberta, Canada: (1) roads of varying widths and traffic volumes, (2) conventional railways and light transit lines, (3) transportation bridges across riparian corridors, and (4) rivers. 3. Using mixed effects logistic regression, we found that the size of the gap in vegetation was the most important determinant of movement ( P < 0·001). As the gap in vegetation exceeded 30 m, the likelihood of movement decreased dramatically and by 45 m, birds were only half as likely to move across gaps as they were to move an equivalent distance in continuous tree cover. Traffic volume also had a significant dampening effect on movement (odds ratio = 0·952 per 1000 vehicle per day increase; P < 0·001) and generally explained more variation in the data than noise levels. 4. Railroads proved to be the most permeable of the features we tested, probably owing to their relatively narrow width, which never exceeded 30 m. Surprisingly, rivers were less permeable than the anthropogenic linear features we tested, with a significant barrier effect evident even at widths <50 m. 5. The birds in our study showed a marked preference for flying over, rather than under, transportation bridges, particularly when adjacent vegetation was available. 6. Synthesis and applications. Our results suggest that linear features, both anthropogenic and natural, can significantly impede the movements of forest songbirds and that managing adjacent vegetation is a potentially effective way to mitigate these barrier effects in cities and other fragmented landscapes. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the combined effects of topography, tillage direction and unpaved roads on gully incision with the use of airphotographs, digital elevation models (DEMs) and field data. It notes that the research intends to design a geographic information system (GIS) database, map gully characteristics, and examine the impacts of the controlling factors. It features the findings on the topographic threshold coefficients noted in the Yehezkel catchment in Israel.

1. Roads are an important conduit for the spread of invasive species. Road age is a key factor that could influence the susceptibility of roads to invasion as older roads are typically subject to higher cumulative levels of human disturbance and propagule pressure than younger roads. We investigated the effects of road age on the spread of non-native earthworms, which act as ecosystem engineers. 2. We sampled earthworms and habitat variables at 98 roads in the boreal forest of Alberta, Canada, to determine the influence of road age on non-native earthworm occurrence at the landscape level. The extent and rate of local spread were also assessed at seven sites adjacent to old and young roads. Generalized estimating equations and zero-inflated negative binomial regression were used to analyze landscape- and local-level results, respectively. We used our models to create maps that predict the current and potential future extent of earthworms in north-eastern Alberta. 3. Probability of earthworm occurrence and extent of spread increased as road age increased. Areas closer to agriculture and towards the south and west of our study area were also significantly more likely to be invaded by earthworms. 4. Our spread model indicated that approximately 9% of the boreal forest of north-eastern Alberta is likely invaded by earthworms currently. This is projected to increase to 49% of suitable forest habitat over the next 50 years as human development intensifies in this region. 5. Synthesis and applications. Although the effects of roads and linear features are commonly investigated in relation to native species, our results emphasize the importance of considering the impacts of linear feature creation on the spread of invasive species. We demonstrate that road age in particular can be an important factor affecting the spread of invasive species. In the boreal forest, reducing the number of roads being constructed, restricting traffic, and reclaiming temporary roads will be critical to reduce the future extent of earthworm invasions. [ABSTRACT FROM AUTHOR]

Roadsides are preferential migration corridors for invasive plant species and can act as starting points for plant invasions into adjacent habitats. Rapid spread and interrupted distribution patterns of introduced plant species indicate long-distance dispersal along roads. The extent to which this process is due to species' migration along linear habitats or, alternatively, to seed transport by vehicles has not yet been tested systematically. We tested this by sampling seeds inside long motorway tunnels to exclude nontraffic dispersal. Vehicles transported large amounts of seeds. The annual seed rain caused by vehicles on the roadsides of five different tunnel lanes within three tunnels along a single urban motorway in Berlin, Germany, ranged from 635 to 1579 seeds/m2/year. Seeds of non-native species accounted for 50.0% of the 204 species and 54.4% of the total 11,818 seeds trapped inside the tunnels. Among the samples were 39 (19.1%) highly invasive species that exhibit detrimental effects on native biodiversity in some parts of the world. By comparing the flora in the tunnel with that adjacent to the tunnel entrances we confirmed long-distance dispersal events (>250 m) for 32.3% of the sampled species. Seed sources in a radius of 100 m around the entrances of the tunnels had no significant effect on species richness and species composition of seed samples from inside the tunnels, indicating a strong effect of long-distance dispersal by vehicles. Consistently, the species composition of the tunnel seeds was more similar to the regional roadside flora of Berlin than to the local flora around the tunnel entrances. Long-distance dispersal occurred significantly more frequently in seeds of non-native (mean share 38.5%) than native species (mean share 4.1%). Our results showed that long-distance dispersal by vehicles was a routine rather than an occasional mechanism. Dispersal of plants by vehicles will thus accelerate plant invasions and induce rapid changes in biodiversity patterns. [ABSTRACT FROM AUTHOR]

Unpaved roads are believed to be the primary source of terrigenous sediments being delivered to marine ecosystems around the island of St John in the eastern Caribbean. The objectives of this study were to: (1) measure runoff and suspended sediment yields from a road segment: (2) develop and test two event-based runoff and sedimera prediction models: and (3) compare the predicted sediment yields against measured values from an empirical mad erosion model and from a sediment trap. The runoff models use the Green-Ampt infiltration equation to predict excess precipitation and then use either an empirically derived unit hydrograph or a kinematic wave to generate runoff hydrographs. Precipitation. runoff, and suspended sediment data were collected from a 230 m long, mostly unpaved road segment over an 8-month period. Only 3-5 mm of rainfall was sufficient to initiate runoff from the road surface. Both models simulated similar hydrographs. Model performance was poor for storms with less than 1 cm of rainfall, but improved for larger events. The largest source of error was the inability to predict initial infiltration rates. The two runoff models were coupled with empirical sediment rating curves, and the predicted sediment yields were approximately 0-11 kg per square meter of road surface per centimetre of precipitation. The sediment trap data indicated a road erosion rate of 0.27 kg m-2 cm-1. The difference in sediment production between these two methods can be attributed to the fact that the suspended sediment samples were predominantly sand and silt, whereas the sediment trap yielded mostly sand and gravel. The combination of these data sets yields a mad surface erosion rate of 0.31 kg m-2 cm-1, or approximately 36 kg m-2year-1. This is four orders of magnitude higher than the measured erosion rate from undisturbed hillslopes. The results confirm the importance of unpaved roads in altering runoff and erosion rates in a tropical setting, provide insights into the controlling processes, and provide guidance for predicting runoff and sediment yields at the mad-segment scale. [ABSTRACT FROM AUTHOR]

Highway surface runoff discharges may contain pollutants that have accumulated on the carriageway, particularly following periods of dry weather. The Highways Agency, in association with the Environment Agency, commissioned a 5-year study in 1997 to collect data to improve the understanding of pollutants in highway runoff and the treatment efficiency of drainage systems. The study involved the monitoring of nonurban highway drainage at six sites, each for a minimum of 1 year. The results have been used to identify ranges of pollutant concentrations in highway runoff, relationships between runoff concentrations/loads and both highway and environmental factors, drainage system treatment efficiencies, and impacts on receiving waters. This paper describes the methods used for runoff monitoring, the results obtained to characterise pollutants in highway runoff, and the measured pollutant removal efficiency of a number of drainage system types. [ABSTRACT FROM AUTHOR]

Road expansion and associated increases in hunting pressure are a rapidly growing threat to African tropical wildlife. In the rainforests of southern Gabon, we compared abundances of larger (>1 kg) mammal species at varying distances from forest roads and between hunted and unhunted treatments (comparing a 130-km2 oil concession that was almost entirely protected from hunting with nearby areas outside the concession that had moderate hunting pressure). At each of 12 study sites that were evenly divided between hunted and unhunted areas, we established standardized 1-km transects at five distances (50, 300, 600, 900, and 1200 m) from an unpaved road, and then repeatedly surveyed mammals during the 2004 dry and wet seasons. Hunting had the greatest impact on duikers (Cephalophus spp. ), forest buffalo (Syncerus caffer nanus ), and red river hogs (Potamochoerus porcus ), which declined in abundance outside the oil concession, and lesser effects on lowland gorillas (Gorilla gorilla gorilla ) and carnivores. Roads depressed abundances of duikers, sitatungas (Tragelaphus spekei gratus ), and forest elephants (Loxondonta africana cyclotis ), with avoidance of roads being stronger outside than inside the concession. Five monkey species showed little response to roads or hunting, whereas some rodents and pangolins increased in abundance outside the concession, possibly in response to greater forest disturbance. Our findings suggest that even moderate hunting pressure can markedly alter the structure of mammal communities in central Africa. Roads had the greatest impacts on large and small ungulates, with the magnitude of road avoidance increasing with local hunting pressure. [ABSTRACT FROM AUTHOR]

The Øresund Link is a 4-lane motorway with a 2-line rail link between Copenhagen, Denmark, and Maim0, Sweden, built across the Øresund Sound between the 2 countries. The environmental concerns associated with construction of the Link were that that it might affect the water and salt flow through the Sound and into and out of the Baltic Sea, lead to destruction of the cod fishery, and affect other biological systems. An International Expert Panel was formed to design mitigation strategies to avoid negative environmental impacts. The Panel designed stringent environmental controls for the construction, of which the most significant was to limit sediment discharges to 5% of the dredged material. This was one-fifth of the discharge limit construction companies usually accept as normal for such a large-scale project. An environmental monitoring program was instituted to monitor compliance with the environmental control measures. As a result of the imposition of tough environmental requirements, the Link was built with little environmental impact and 3 y after it was completed, environmental conditions have returned to normal. [ABSTRACT FROM AUTHOR]

Abstract Post-mining coastal dune rehabilitation north of Richards Bay, KwaZulu-Natal started 20 years before field work for the present study commenced. This resulted in the development of a known age sere of coastal dune forest succession. These rehabilitating areas are fragmented by roads that may act as ecological edges. To establish whether roads affect regenerating bird, millipede, and rodent assemblages, multivariate techniques were applied to test for existence of edge and core assemblages within seral stages representative of the coastal dune forest successional sere. Edge and core assemblages were identified for both the bird and millipede communities but not for the rodent community. Low rodent numbers may have concealed edge effects, but the absence of edge and core assemblages could also be ascribed to the absence of a forest core. In the bird community species composition, richness, density, and total number of species contributed to the identification of edge and core assemblages. Within seral stages the species composition of millipedes differed between the edge and core assemblages. However, if the site was the same age the number of species in edge and core assemblages was similar. The generality of the edge concept should be approached with caution when dealing with taxa comprising species with such diverse natural histories as in the present study. It should also be kept in mind that some species require forest interiors for survival. [ABSTRACT FROM AUTHOR]

Roads are a widespread and increasing feature of most landscapes. We reviewed the scientific literature on the ecological effects of roads and found support for the general conclusion that they are associated with negative effects on biotic integrity in both terrestrial and aquatic ecosystems. Roads of all kinds have seven general effects: mortality from road construction, mortality from collision with vehicles, modification of animal behavior, alteration of the physical environment, alteration of the chemical environment, spread of exotics, and increased use of areas by humans. Road construction kills sessile and slow-moving organisms, injures organisms adjacent to a road, and alters physical conditions beneath a road. Vehicle collisions affect the demography of many species, both vertebrates and invertebrates; mitigation measures to reduce roadkill have been only partly successful. Roads alter animal behavior by causing changes in home ranges, movement, reproductive success, escape response, and physiological state. Roads change soil density, temperature, soil water content, light levels, dust, surface waters, patterns of runoff, and sedimentation, as well as adding heavy metals (especially lead), salts, organic molecules, ozone, and nutrients to roadside environments. Roads promote the dispersal of exotic species by altering habitats, stressing native species, and providing movement corridors. Roads also promote increased hunting, fishing, passive harassment of animals, and landscape modifications. Not all species and ecosystems are equally affected by roads, but overall the presence of roads is highly correlated with changes in species composition, population sizes, and hydrologic and geomorphic processes that shape aquatic and riparian systems. More experimental research is needed to complement post-hoc correlative studies. Our review underscores the importance to conservation of avoiding construction of new roads in roadless or sparsely roaded areas and of... [ABSTRACT FROM AUTHOR]

We outline a view of how road networks interact with stream networks at the landscape scale and, based on examples from recent and current research, illustrate how these interactions might affect biological and ecological processes in stream and riparian systems. At the landscape scale, certain definable geometric interactions involving peak flows ( floods) and debris flows (rapid movements of soil, sediment, and large wood down steep stream channels) are influenced by the arrangement of the road network relative to the stream network. Although disturbance patches are created by peak-flow and debris-flow disturbances in mountain landscapes without roads, roads can alter the landscape distributions of the starting and stopping points of debris flows, and they can alter the balance between the intensity of flood peaks and the stream network's resistance to change. We examined this conceptual model of interactions between road networks and stream networks based on observations from a number of studies in the H. J. Andrews Experimental Forest, Oregon (U.S.A.). Road networks appear to affect floods and debris flows and thus modify disturbance patch dynamics in stream and riparian networks in mountain landscapes. We speculate that these changes may influence the rates and patterns of survival and recovery of disturbed patches in stream networks, affecting ecosystem resilience, and we outline an approach for detecting such effects based on a patch dynamics perspective. A field sampling scheme for detecting the magnitude of various road effects on stream and riparian ecology could involve (1) landscape stratification of inherent stream network susceptibility to floods or debris flows, (2) overlay of road and stream networks and creation of areas with various densities of road-stream crossings, emphasizing midslope road-stream crossings, and (3) designations of expected high- and low-impact stream segments based on numbers of upstream road-stream crossings where sampling... [ABSTRACT FROM AUTHOR]

Ecological flows and biological diversity trace broad patterns across the landscape, whereas transportation planning for human mobility traditionally focuses on a narrow strip close to a road or highway. To help close this gap we examined the “road-effect zone” over which significant ecological effects extend outward from a road. Nine ecological factors—involving wetlands, streams, road salt, exotic plants, moose, deer, amphibians, forest birds, and grassland birds—were measured or estimated near 25 km of a busy four-lane highway west of Boston, Massachusetts. The effects of all factors extended >100 m from the road, and moose corridors, road avoidance by grassland birds, and perhaps road salt in a shallow reservoir extended outwards >1 km. Most factors had effects at 2–5 specific locations, whereas traffic noise apparently exerted effects along most of the road length. Creating a map of these effects indicates that the road-effect zone averages approximately 600 m in width and is asymmetric, with convoluted boundaries and a few long fingers. We conclude that busy roads and nature reserves should be well separated, and that future transportation systems across landscapes can provide for ecological flows and biological diversity in addition to safe and efficient human mobility. [ABSTRACT FROM AUTHOR]

In view of an extensive road system, abundant and rapidly growing vehicular traffic, and a scattered literature indicating that some ecological effects of roads extend outward for >100 m, it seems likely that the cumulative ecological effect of the road system in the United States is considerable. Two recent studies in The Netherlands and Massachusetts ( U.S.A.) evaluated several ecological effects of roads, including traffic noise effects, and provide quantitative evidence for a definable “road-effect zone.” Based on the approximate width of this asymmetric convoluted zone, I estimate that about one-fifth of the U.S. land area is directly affected ecologically by the system of public roads. I identify a series of assumptions and variables suggesting that over time this preliminary estimate is more likely to rise than drop. Several transportation planning and policy recommendations, ranging from perforating the road barrier for wildlife crossings to closing certain roads, offer promise for reducing this enormous ecological effect. [ABSTRACT FROM AUTHOR]

A correction is provided for the article "Influence of Hunting on Movements of Moose Near Roads" by W. Neumann and G. Ericsson which appears in a 2018 issue of the journal.

Predicting the occurrence, level, and duration of high air pollution concentrations exceeding a given critical level enables researchers to study the health impact of road traffic on local air quality and to inform public policy action. Precise estimates of the probabilities of occurrence and level of extreme concentrations are formidable due to the combination of complex physical and chemical processes involved. This underpins the need for developing sophisticated extreme value models, in particular allowing for nonstationarity of environmental time series. In this paper, extremes of nitrogen oxide (NO), nitrogen dioxide (NO2), and ozone (O3) concentrations are investigated using two models. Model I is based on an extended peaks-over-threshold (POT) approach developed by A. C. Davison and R. L. Smith, whereby the parameters of the underlying generalized Pareto distribution (GPD) are treated as functions of covariates (i.e., traffic and meteorological factors). The new Model II resolves the lack of threshold stability in the Davison-Smith model by constructing a special functional form for the GPD parameters. For each of the models, the effects of traffic and meteorological factors on the frequency and size of extreme values are estimated using Markov chain Monte Carlo methods. Finally, appropriate goodness-of-fit tests and model selection criteria confirm that Model II significantly outperforms Model I in estimation and forecasting of extremes. [ABSTRACT FROM AUTHOR]

The article presents a commentary on the cohort study regarding the association of the air pollution exposure to adiposity measures in the health condition of participants living in Framingham, Massachussetts. Topics mentioned include the focus of the study on acute cardiovascular events and short-term health outcomes, the comparative analysis of the methods in estimating particulate matter (PM) exposure and co-pollutants, and the quantifying of the socioeconomic or residential position.

Discusses a research on the effects of roads on the structure of freshwater turtle populations in the U.S., by David Steen and James Gibbs, that was published in the August 2004 issue of the periodical "Conservation Biology." Total number of turtle species in the country; Comparison of the sex ratios between painted and snapping turtle populations; Ways to protect turtles from traffic near wetlands.

Introduces a series of articles discussing the ecological effects of roads. Impact of roads on soil invertebrate abundance and diversity along a transect from road to forest interior; Hydrology and geomorphology for biologists interested in the interactions between roads and aquatic ecology; Species of plants that benefit from roads.

Research into mitigation of the ecological impacts of rainforest roads in North Queensland has a long history, commencing during the formative years of Australian road ecology. In Queensland's Wet Tropics and throughout Australia, installation of engineered structures to ameliorate ecological road impacts is now common during larger construction projects, but unusual in smaller road projects. Retro-fitting of engineering solutions to roads that are causing obvious impacts is also uncommon. Currently, Australian mitigation measures concentrate on two important impacts: road mortality and terrestrial habitat fragmentation. Unfortunately, other important ecological impacts of roads are seldom addressed. These include edge effects, traffic disturbance, exotic invasions and fragmentation of stream habitats. In North Queensland, faunal underpasses and canopy bridges across rainforest roads have been monitored over long periods. These structures are used frequently by multiple individuals of various species, implying effectiveness for movements and dispersal of many generalist and specialised rainforest animals. However, without addressing population and genetic implications, assessment of effectiveness of these connectivity structures is not holistic. These aspects need sufficient long-term funding to allow similar systematic monitoring before and after construction. Throughout Australia, more holistic approaches to mitigation of road impacts would routinely examine population and genetic connectivity, consider mitigation against more ecological impacts where appropriate and include landscape-scale replication. [ABSTRACT FROM AUTHOR]