Article

Roads and Their Major Ecological Effects

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Abstract

Abstract A huge road network with vehicles ramifies across the land, representing a surprising frontier of ecology. Species-rich roadsides are conduits for few species. Roadkills are a premier mortality source, yet except for local spots, rates rarely limit population size. Road avoidance, especially due to traffic noise, has a greater ecological impact. The still-more-important barrier effect subdivides populations, with demographic and probably genetic consequences. Road networks crossing landscapes cause local hydrologic and erosion effects, whereas stream networks and distant valleys receive major peak-flow and sediment impacts. Chemical effects mainly occur near roads. Road networks interrupt horizontal ecological flows, alter landscape spatial pattern, and therefore inhibit important interior species. Thus, road density and network structure are informative landscape ecology assays. Australia has huge road-reserve networks of native vegetation, whereas the Dutch have tunnels and overpasses perforating road barriers to enhance ecological flows. Based on road-effect zones, an estimated 15–20% of the United States is ecologically impacted by roads.

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... Roads and trails are intended to connect settlements but also to facilitate access and human use of ecosystems. As they expand, sites that act as natural refuges for biodiversity are reduced (Forman and Alexander, 1998;Musiani and Paquet, 2004;Roedenbeck et al., 2007;Spellerberg, 1998;Trombulak and Frissell, 2000). Generally, the size of the road network is associated with the notion of economic development of a region, as it corresponds to the ability to transport goods and deliver services. ...
... In addition to emissions into the atmosphere and soil, the light and noise generated by the traffic circulating on the road disturb wildlife behavior and eventually demography. The propagation of all these pollutants throughout the roads' adjacent terrain, cause changes in the use that fauna makes of the habitat (Forman, 1998;Forman and Alexander, 1998;Trombulak and Frissell, 2000;van der Ree et al., 2011;Madadi et al., 2017). ...
... We suggest that those factors determine the distance that the effects of the roads can reach (Forman et al., 1997;Forman and Deblinger, 2000). The distance over which the effects of the road spreads, functionally defines the road's influence zone (Forman and Alexander, 1998). ...
Article
Roads cause disturbances to wildlife from the beginning of their construction and once the road is in operation, people usually make use of the habitats, reducing their quality. To this are added the effects caused by light and noise from vehicles. These propagate through the land adjacent to the road causing changes in the fauna's use of the habitat. This led us to ask ourselves what attributes inherent to the road and terrain influence the vertebrate fauna and what factors associated with human activities can be considered as confounding variables for the results interpretation? The study was conducted in proximity of the 40D highway in Mexico. Three paired areas were selected where signs of wildlife presence were recorded during spring and fall from 2018 to 2020 and these data were used as response variable (2108 records of 49 species). We used as explanatory variables the inherent characteristics of the natural terrain and road (e.g., height difference between road and habitat, distance from road), as well as those related to human presence in the habitat (e.g., distance to nearest town). GLM's were adjusted to determine the influence of these on our response variable. We found that the inherent variables of the road and terrain have a significant influence on the number of faunal of hunting interest traces found (p = 0.018, r² = 23.09). The method used allowed us to identify and distinguish the influence that human activities exert on the fauna within the road's influence zone. The differential way in which organisms respond to human presence and activity makes it difficult to isolate this effect from the one we wish to evaluate, such as that of the road. Therefore, it is suggested that the variables used in this study be used as a control measure of this effect in the work carried out in proximity of roads.
... Roadkills represent an important mortality factor that threatens mammal species sensitive to anthropic disturbances (Forman and Alexander 1998;Havlick 2003;Benítez-López et al. 2010), since some animals may be attracted to roads when searching for food such as carrion, which may lead to wildlifevehicle collisions and death (Forman and Alexander 1998;Spellerberg 1998;Arroyave et al. 2006;Monge-Nájera 2018). Therefore, it is essential to build safe wildlife passage structures to avoid animal-vehicle collisions (van der Grift et al. 2013). ...
... Roadkills represent an important mortality factor that threatens mammal species sensitive to anthropic disturbances (Forman and Alexander 1998;Havlick 2003;Benítez-López et al. 2010), since some animals may be attracted to roads when searching for food such as carrion, which may lead to wildlifevehicle collisions and death (Forman and Alexander 1998;Spellerberg 1998;Arroyave et al. 2006;Monge-Nájera 2018). Therefore, it is essential to build safe wildlife passage structures to avoid animal-vehicle collisions (van der Grift et al. 2013). ...
... For instance, mammal migration and dispersal movements increase the probability of encountering roads that limit-ing their free movement across the road or lead to a roadkill event (Arroyave et al. 2006;Zhang et al. 2018). Changes in traffic volume and speed, as well as the time of the day, also influence the collision rate; for example, the visual acuity of drivers can be reduced at night (Forman and Alexander 1998;Arroyave et al. 2006;Driessen 2021). ...
Article
Los puntos críticos del atropellamiento son aquellos sitios agregados espacialmente que no corresponden al azar. Para el caso de mamíferos, los puntos críticos han sido considerados como una de las aproximaciones para la ubicación de las obras de mitigación del atropellamiento, aunque estos sitios pueden ser variables a escalas temporales. El objetivo de este estudio fue identificar los cambios de los puntos críticos del atropellamiento de mamíferos entre dos temporadas en una carretera en la Sierra Madre Occidental en el noreste de México. Para el monitoreo de las especies atropelladas se realizaron 2 recorridos en vehículo por temporada con 15 días de separación entre recorridos. Estos se realizaron en la primavera de 2019 y 2020 y otoño de 2018 y 2019 en la carretera 40D (Durango-Mazatlán). Utilizando herramientas de sistemas de información geográfica, se estimaron los puntos críticos de atropellamiento de mamíferos para la primavera, el otoño y ambas estaciones. Se obtuvieron 217 registros de mamíferos silvestres atropellados en 8 recorridos sobre la carretera. Los puntos críticos de atropellamiento de fauna no coinciden espacialmente entre las estaciones, ni al compararlos con todos los registros. La acumulación espacial del atropellamiento de mamíferos no fue coincidente en el tiempo, lo cual podría relacionarse con los cambios en el movimiento de la fauna y otros factores. Se debe considerar la variación estacional de estos puntos críticos para las obras de mitigación, así como realizar monitoreos sistemáticos de la fauna atropellada.
... In the other side of the spectrum, road-effect zones (REZs) are the areas directly affected by a road (Forman and Alexander 1998;Forman and Deblinger 2000). The maximum distance at which changes in water, soil, and biota can be observed defines the width of this zone, which is influenced by road's type, width, and traffic volume, as well as by the vegetation of the area it crosses. ...
... Roads impact natural ecosystems in many ways, causing deforestation and physical and chemical interferences in soil and water bodies (Laurance et al. 2009;Trombulak and Frissell 2000;Southworth et al. 2011), and provoking deleterious effects on the fauna (Forman and Deblinger 2000;Nelson et al. 2017;Reijnen et al. 1995;Rheindt 2003). The distance in which these direct impacts can be observed ranges from a few meters to many kilometers (Forman and Alexander 1998;Forman and Deblinger 2000). Ibisch et al. (2016) made an extensive literature review, defining and mapping RLAs at a global scale, as areas that are ≥ 1 km from roads. ...
Article
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Roadless areas (RLAs) are places with little to no influence of roads, usually sustaining well-preserved habitats, whereas road-effects zones (REZs) are areas affected by roads. Here, we map and characterize RLAs and REZs in Brazil, using national and international road network, land use and land cover, and protected areas databases. Following a global scale study, RLAs were defined as areas within ≥ 1 km from roads. Considering only paved roads, 8.2 M km2 (95%) of Brazil’s territory is RLAs, a figure that reduces to 6.8 M km2 (81%) when all built roads are included. In Brazil, the furthest location from roads is in the Amazon, 321 km away from the nearest road. Although RLAs differs among the Brazilian ecosystems, some common patterns emerge: (i) There is a lower percentage of natural vegetation cover on REZs than in RLAs, except for the Pampa; (ii) RLAs are mostly composed by natural vegetation, except in the Atlantic Forest, where farming lands dominate; (iii) protected RLAs are mostly covered by natural vegetation. Only 36.9% of Brazil’s RLAs are inside protected areas or indigenous lands. Even so, given the ongoing expansion of the road network and agriculture frontier in Brazil, it is unequivocal the role of those protected areas in stopping those drivers, making it paramount to explicitly include RLAs when planning new protected areas. Lastly, we found a positive relationship between a RLA patch size and its native vegetation cover as well as a positive relationship between the percentage of a protected area covered by RLA and its native vegetation cover.
... The effects of roads on forest fragmentation and species loss in natural ecosystems are well documented at different scales, particularly in temperate biomes. The negative impacts of road networks on wildlife communities have been reported, on average, five times as much as positive effects (Forman and Alexander, 1998;Trombulak and Frissell, 2000;Coffin, 2007;Fahrig and Rytwinski, 2009;Laurance et al., 2009). Road expansion increases the mortality rate of animals by introducing vehicles and collisions, reducing connectivity among populations, and allowing hunters and poachers better access to the forest. ...
... Corridors support the resilience and movement of animals alongside roads and across fragmented landscapes (Ng et al., 2004;Gregory et al., 2017;Shi et al., 2018), although their efficiency to reduce forest defaunation still needs to be evaluated. To our knowledge, few authors have addressed the consequences of changes in wildlife diversity for the ecology of native plants located in the vicinity of roads (Forman and Alexander, 1998;Wright and Duber, 2001;Coffin, 2007;Laurance et al., 2009). ...
Article
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Ecological interactions are being affected at unprecedented rates by human activities in tropical forests. Yet, the continuity of ecological functions provided by animals, such as seed dispersal, is crucial for forest regeneration and species resilience to anthropogenic pressures. The construction of new roads in tropical forests is one of the main boosters of habitat destruction as it facilitates human access to previously isolated areas and increases defaunation and loss of ecological functions. It, therefore, becomes increasingly urgent to rapidly assess how recently opened roads and associated anthropogenic activities affect ecological processes in natural habitats, so that appropriate management measures to conserve diversity can be taken. In this study, we aimed to evaluate the effects of anthropogenic pressures on the health status of a mature rainforest crossed by a newly opened road in French Guiana. For this, we combined different methods to conduct a rapid assessment of the forest’s health status. Firstly, we evaluated the activity of frugivores using camera traps deployed in four forest patches located near (<1 km) ecological corridors preserved as canopy bridges over the road during the fruiting periods of four animal-dispersed tree species. Secondly, we analyzed the fate of seeds enclosed in animal-dispersed tropical fruits by calculating the proportions of fruits consumed and seeds removed (either dispersed or predated) by frugivores. Results show that the proportion of fruits opened and consumed was lower in the forest areas located near the road than in the control forest, and this difference was more significant for plant species strictly dependent on large-bodied primates for seed dispersal than for species relying on both primates and birds. Camera traps showed the presence of small primates and kinkajous feeding on Virola fruits in the forest impacted by the road, where large primates were absent. It is thus likely that smaller frugivores exert a compensatory effect that maintains ecological functions near the road. Despite efforts made to preserve forest continuity through ecological corridors, anthropogenic pressures associated with road proximity are affecting wildlife and disrupting associated ecological functions crucial for plant regeneration, contributing to further forest degradation.
... With over 4 million miles of roads, it is estimated that nearly 15-20% of the United States is ecologically impacted by roads (Forman and Alexander, 1998;Forman, 2000). While the direct effects of roads (i.e., mortalities) on wildlife have been well documented, the indirect effects roads have on natural populations are less understood (Acevedo-Whitehouse and Duffus, 2009). ...
... We located four eastern newt populations and collected 10 terrestrial juvenile (eft) and 10 aquatic adult eastern newts from each population on 24-25 July 2019. Evidence suggests that edge effects from roads can extend up to 240 m into natural habitats (Franklin and Forman, 1987;Chen et al., 1995;Forman and Alexander, 1998) After Illumina sequencing 16S rRNA V4 amplicons produced using swab DNA, we processed 1,547,723 DNA sequence reads using QIIME2 to produce 11,771 ASV's following contaminant and non-bacteria taxonomy removal. We also generated a Bd-inhibitory ASV table with only ASV's whose representative sequence matched the 16S rRNA sequences of Bd-inhibiting bacteria at a 97% identity match or higher. ...
Article
Host‐associated microbiomes play an essential role in the health of organisms, including immune system activation, metabolism, and energy uptake. It is well established that microbial communities differ depending on the life stage and natural history of the organism. However, the effects of life stage and natural history on microbial communities may also be influenced by human activities. We investigated the effects of amphibian life stage (terrestrial eft vs. aquatic adult) and proximity to roadways on newt skin bacterial communities. We found that the eft and adult life stages differed in bacterial community composition; however, the effects of roads on community composition was more evident in the terrestrial eft stage compared to the aquatic adult stage. Terrestrial efts sampled close to roads possessed richer communities than those living further away from the influence of roads. When accounting for ASVs with predicted antifungal capabilities, in the adult life stage, we observed a decrease in anti‐fungal bacteria with distance to roads. In contrast, in the eft stage, we found an increase in anti‐fungal bacteria with distance to roads. Our results highlight the need to consider the effects of human activities when evaluating how host‐associated microbiomes differ across life stages of wildlife. This article is protected by copyright. All rights reserved.
... The human-induced fragmentation of natural habitats is one of the main determinants of the global biodiversity collapse (Fahrig, 2003). The most ubiquitous form of habitat fragmentation is due to large-scale transportation infrastructures (LTIs; Forman & Alexander, 1998). LTIs are linear infrastructures allowing the transportation of goods, vehicles or energy, such as roads, motorways, railways, power lines, pipelines and canals. ...
... The most obvious detrimental effects of LTIs on dispersal success are direct collisions with vehicles and physical crossing impediment when infrastructures are, for instance, fenced (Forman & Alexander, 1998;Trombulak & Frissell, 2000). Most animals are affected, from small invertebrates to large mammals (Balkenhol & Waits, 2009;Fahrig & Rytwinski, 2009). ...
Article
Large-scale Transportation Infrastructures (LTIs) are among the main determinants of landscape fragmentation, with strong impacts on animal dispersal movements and metapopulation functioning. Although the detection of LTIs impacts is now facilitated by landscape genetic tools, studies are often conducted on a single species, although different species might react differently to the same obstacle. We surveyed four species (a snake, an amphibian, a butterfly and a ground-beetle) in a landscape fragmented by six LTIs: a motorway, a railway, a country road, a gas pipeline, a power line and a secondary road network. We hypothesized that LTIs carrying vehicles would mostly impact ground-dwelling species, possibly in a cumulative way. We showed that half of the overall explained genetic variability across all species was due to LTIs. While the butterfly was seemingly not impacted by any LTI, the genetic structure of the three other species was mostly influenced by roads and motorway. The power line did not affect any species and the gas pipeline only impacted gene flow in the ground-beetle through forest fragmentation, but roads systematically affected at least two species. Interestingly, we also showed that some LTIs could somehow promote gene flow, embankments probably providing favourable habitats for vertebrate species. Considering the high variability in species response to LTIs, we argue that drawing general conclusions on landscape connectivity from the study of a single species may lead to counterproductive miti-gation measures and that multi-species approaches should be more systematically considered in conservation planning.
... This is especially the case for large mammals that humans perceive as threats, such as coyotes (Nagy et al., 2017). Finally, although not as well-studied, vehicles have a major impact on mammalian diversity, in some years even greater than that of hunting (Forman and Alexander, 1998). Due to the abundance of roads located near forested areas, vehicular killings have contributed to overall mammal diversity loss in recent decades (Bashore et al., 1985;Forman and Alexander, 1998;Seiler, 2001;Shilling et al., 2021). ...
... Finally, although not as well-studied, vehicles have a major impact on mammalian diversity, in some years even greater than that of hunting (Forman and Alexander, 1998). Due to the abundance of roads located near forested areas, vehicular killings have contributed to overall mammal diversity loss in recent decades (Bashore et al., 1985;Forman and Alexander, 1998;Seiler, 2001;Shilling et al., 2021). While an inverse relationship between biodiversity and human population density has been documented in many circumstances, on a local scale, species richness and abundance of certain taxa, such as freeranging cats (Felis catus), raccoons (P. ...
Article
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Urbanization can have profound consequences for mammalian biodiversity and is thought to contribute to patterns of species richness and community composition. Large cities can be particularly challenging environments for mammals because these habitats are often impacted by anthropogenic perturbations, including high human population density, fragmented habitats, and extensive human development. In this study, we investigated mammalian species richness, Shannon-Wiener diversity, and evenness in the most densely populated region in the United States: the New York metropolitan area. Specifically, we deployed camera traps from 2015-2019 to investigate six drivers of mammalian diversity across 31 greenspaces: (1) human population density, (2) patch size, (3) habitat type, (4) surrounding land cover, (5) geographical barriers to dispersal, and (6) habitat heterogeneity. We found that mammal community composition is largely influenced by a multitude of anthropogenic factors. Specifically, mammal species richness was higher in greenspaces with larger patch sizes and lower in greenspaces surrounded by more development. Moreover, Shannon-Weiner diversity and evenness were higher in urban natural landscapes than human-altered landscapes. In a subset of data that only included carnivores, we found that carnivore Shannon-Wiener diversity was higher in urban natural habitats and in sites with lower human population densities. Finally, we found that geographical barriers to dispersal contributed to both patterns of mammalian diversity and patterns of carnivore diversity: mammal taxa richness, Shannon-Weiner diversity, and evenness were all significantly higher on the continent (Bronx/Westchester) than on Long Island. These results suggest that preserving urban greenspaces is important for maintaining both mammalian and carnivore biodiversity and that management of mammals in cities should concentrate on maintaining large, connected, natural greenspaces.
... In addition, there is a plan to duplicate the BR-101 highway in the coming years. According to Forman and Alexander (1998), medium and large mammals are especially susceptible to being roadkill on double-lane and high-speed roads. Thus, an increased number of animals, including P. maximus, are expected to be roadkill in Sooretama. ...
Article
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Priodontes maximus is the largest living armadillo and is at risk of extinction. The species ranges throughout South America and one of its last refuges in the entire Atlantic Forest is a reserve complex called Sooretama. We investigated the conservation status of the species and its role as an ecosystem engineer in Sooretama. We employed camera-traps, active searches and checked the data from previous studies in the area. In the past 14 years, there were 70 records of the species in 31 sites, including 43 camera-trap images, 25 excavations and two carcasses. However, our recent field work (2018e2019) recorded images of only three adult individuals (a female, a male and one of unidentified sex) and one excavation with evidence that poachers had killed its occupant. We observed through camera-traps that at least 37 vertebrate species used monitored excavations. The species-richness detected in sites with excavations was greater than in sites without excavations. The number of species using excavations of P. maximus in Sooretama was one of the greatest recorded among studies carried out in different biomes. The interior of excavations tended to be used mainly by ground foraging stratum species and by invertebrate and omnivore diets species. This study demonstrated the important role of P. maximus as an ecosystem engineer in the Atlantic Forest. However, unless the course of its imminent extinction can be reversed, P. maximus soon will not be able to play its important ecological role in the Sooretama region.
... Such infrastructure development drives the loss and fragmentation of wildlife habitat, causes increased wildlife mortality during crossing attempts, and creates barriers to wildlife movement and dispersal (Jackson, 2000;Forman et al., 2003;Smith, 2003). Of all the primary effects of transport infrastructure, the barrier effect is the most concerning for highly mobile wildlife species (Forman and Alexander, 1998;Seiler and Folkeson, 2006). ...
Article
Wildlife crossing structures are effective interventions for mitigating fragmentation of habitats by linear infrastructure. The 2017 construction of a new railway cutting through the Tsavo Conservation Area (TCA), home to the largest elephant population in Kenya, affected wildlife movement and habitat connectivity. Although numerous studies have investigated the use of wildlife crossing structures by a wide range of species, few have focused on their use by megaherbivores. In this study, we examined use of 41 wildlife crossing structures by African savanna elephants (Loxodonta africana) along a 133 km section of new railway in Tsavo, Kenya. We used a generalized linear mixed modeling approach to assess the relationship between elephant crossing rate over 28 months between July 2017 to April 2021 and explanatory factors including crossing structure attributes, livestock presence and proximity to highways, water points and human settlement. We found that structural attributes of crossing structures were most strongly associated with the elephant crossing rate, particularly height and its interaction with type of crossing structure (bridges, wildlife underpasses and culverts). Higher crossing structures were associated with higher crossing rate, with the largest influence of height at culverts and wildlife underpasses. Although bridges comprised only 19.5 % of the 41 available crossing structures, they accounted for a disproportionately high number of elephants crossing events (56 %). The results demonstrated the importance of bridges over designated crossing structures for elephants, with predicted seasonal counts of elephant crossings being 0.31 for average sized culverts, 2.88 for wildlife underpasses and 5.86 for bridges. The environmental and anthropogenic variables were not strongly associated with elephant crossing rate. Our findings have direct application for future siting and design of crossing structures across elephant ranges.
... Moreover, as Forman and Alexander (1998) claim for roads, fauna tends to avoid linear openings, which act as a barrier and separate populations. Openings also affect the hydrological runoff of a forest, leaching out soil and generating high sedimentation downhill (Forman and Alexander 1998). Spellerberg (1998) and Pickering and Hill (2007) also cited a derivative impact of roads and trails on the transfer of spores along the openings, which increases the risk of pathogenic dispersal and could affect the most threatened species. ...
Article
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Generally considered a sustainable economic activity, tourism can generate environmental deterioration due to a lack of planning. In this case, the edge effect is utilized to assess the degree of human interference in the environment. Although the Atlantic Forest is known as a hotspot because of its high species richness and endemism, it is also a threatened biome. In this context of anthropogenic pressure, our work assesses the edge-interior gradient in the regenerating forest based on the physical characteristics of vegetation and floristic composition, in addition to providing overall guidelines to effectively assist in its management. For this study, 30 plots of 25 m² (10 m x 2.5 m) equally distributed among the edges of trails and locations 20 and 40 m away from them were established, with the greatest length measured parallel to the edge of the tracks. Overall, 443 individuals of 122 species were investigated. More than 60 of them were endemic to Brazil, 13.3% were threatened and 9.1% were widely distributed species. Some species were present at all distances from the trails, others co-occurred, but the majority were exclusive to a single plot category. Differences in species diversity were also observed with an increasing trend in dominance at the edges of trails along with a decreased richness at the same distance.
... Therefore, understanding how species assemble, function, and interact with environmental and soil factors is necessary for the development of ecosystem restoration projects [4,5]. In addition, areas degraded by road infrastructure have become a matter of scientific concern [6,7], due to the advancement of road networks and the negative ecological impacts caused to the landscape, such as habitat fragmentation, soil erosion, edge effects, and alien species invasion [7][8][9][10][11][12]. Consequently, roadsides represent an ideal scenario for studying the influence of environmental filters on the composition of plant communities [13], and, at the same time, they represent a great challenge for ecological restoration and selection of the most appropriate species in road revegetation processes [14]. ...
Article
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Roadsides are common ecosystems worldwide, with specific environmental characteristics and multiple effects on plant diversity. As such, they represent examples of highly dynamic anthropogenic ecosystems. Our objective was to assess patterns of vascular species diversity in response to elevation and soil characteristics on a roadside in the Andean mountains of Ecuador. The study area was located in the southern Ecuadorian Andes, at five elevations ± 400 m a.s.l. (2600, 2200, 1800, 1400 and 1000 m a.s.l.), where we recorded species richness and abundance in transects perpendicular to the road. The effects of elevation and soil characteristics on species abundance and richness were analyzed using generalized linear mixed models (GLMMs), while species composition was assessed with a non-metric multidimensional scaling analysis (NMDS) and its relationship to environmental variables. We used indicator species analyses (ISA) to identify which species significantly characterized specific elevation and soil factors from primary succession for restoration processes at the roadside. Although elevation and soil characteristics do not condition vascular species richness, the composition is more similar at elevations E1 and E2 (2600 m and 2200 m a.s.l.), differing from low elevations E4 and E5 (1400 m and 1000 m a.s.l.), which in turn are more similar to each other, while intermediate elevation E3 is similar to the highest and lowest elevations. Soil variables that limited plant communities were pH, bulk density (gr/cm3), silt (%), and sand (%) contents. The indicator species showed a preference for specific environmental and soil condition requirements associated with the different microhabitats and, thus, can be suggested for potential use in roadside revegetation processes in tropical areas. These results can help decision-makers in the implementation of biodiversity conservation and roadside environmental restoration projects in areas of Andean mountain ecosystems which have been affected by the construction of road infrastructure.
... For some small mammals and herpetofauna, roads can be a barrier to movement [67][68][69] and have the potential to create isolated subpopulations. Traffic on roads associated with gas well sites is also a direct source of mortality through vehicle collisions, especially during breeding and wintering seasons [70]. Additionally, roads can become corridors, facilitating the spread of invasive plant and animal species, which can cause losses of native habitat [71]. ...
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High-volume hydraulic fracturing (“fracking”) for natural gas in the Marcellus Shale has become a politically charged issue, primarily because of concerns about drinking water safety and human health. This paper examines fracking in the Marcellus region, and the tradeoffs between the energy and economic potential of natural gas extraction and the environmental impacts on wildlife. Therefore, we introduce a new E3 analysis that combines the costs and benefits as regards energy, economics, and the environment. The Marcellus Shale has the most proven reserves of natural gas of any basin in the United States, at 129 trillion cubic feet. Income from natural gas development comes primarily from direct and indirect jobs, and induced jobs (those created when direct workers spend their earnings in a community), taxes and fees, and royalty and lease payments to rights holders. Fracking, however, has detrimental effects on wildlife and wildlife habitats. Terrestrial habitat effects are primarily due to landscape fragmentation from the clearing of land for pipeline and well pad development, which often removes mature forest and creates open corridors and edge habitats. An increase in forest edge and open corridors is associated with shifts in the bird community, as generalist species that do well around people increase in abundance, while forest specialists decline. Invasive plants associated with disturbance further degrade forest habitats. Aquatic habitats are also affected, both directly and indirectly. Hydraulic fracturing requires up to 20 mil L of water per well fracture, most of which comes from surface water sources in the Marcellus region. The removal of water, especially in smaller headwaters, can increase sedimentation, alter water temperature and change its chemistry, resulting in reductions in aquatic biodiversity. Given the reality that hydraulic fracturing will continue, there is a need to develop practices that best minimize negative impacts on terrestrial and aquatic habitats, as well as policies and the resolve to enforce these practices. To achieve a more sustainable balance between economic, energy, and environmental costs and benefits, we recommend that industry, scientists, non-governmental organizations, mineral rights holders, landowners, and regulators work together to develop a set of best management practices that represent the best knowledge available.
... After the harvesting of animals, roads are the largest source of anthropogenic mortality worldwide for vertebrates (Hill et al., 2019). In addition to mortality due to wildlife-vehicle collisions (hereafter roadkill), roads also result in reduced animal movement and dispersal (Forman, 1998;Forman and Alexander, 1998;Holderegger and Di Giulio, 2010), reduced population connectivity altering ecosystem dynamics (Benítez-López et al., 2010), habitat loss (Forman, 2005), and habitat fragmentation (Delgado et al., 2007). ...
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Roadkills are a major threat to the wildlife in human-modified landscapes. Due to their ecology, relatively small size, and slow movement, amphibians and reptiles are particularly prone to roadkill. While standardized roadkill surveys provide valuable data for regional roadkill trends, such surveys are often resource-intensive and have limited geographic coverage. Herein, we analyzed a roadkill dataset of the Korean herpetofauna derived from the citizen science database iNaturalist, and compared the overall roadkill trends detected in the iNaturalist data with standardized survey-based literature data. Our results show that the citizen science data overall provide a good picture of roadkill trends for the Korean herpetofauna in terms of recorded species. We detected both similarities and notable differences between the iNaturalist and literature data. The most notable differences between the two datasets were found in the number of recorded species, distribution across habitat types, and distribution across elevational ranges. Even with spatially biased sampling, the iNaturalist data had a considerably broader geographic coverage compared to standardized surveys. In addition, we related the presence of amphibian and reptiles roadkills to the presence of agricultural lands, forests and grassland. While the unstandardized nature of the citizen science data can be criticized, we argue that this feature also acts an advantage for this type of data, as citizen science can better detect roadkills of rare species, or seasonal events such as mass migration of amphibians, and inform population trends and threats. Thus, our results highlight the importance of spatially biased and unstandardized citizen science data for roadkill detection. This study builds on previous studies demonstrating citizen science as a viable method of roadkill surveys.
... Habitat fragmentation due to linear infrastructure has detrimental impacts on wildlife (Benítez-López et al., 2010;Jenkins et al., 2010;Al-Razi et al., 2019;Dean et al., 2019). Mortality due to road accidents and electrocution from power lines is among the direct and increasing anthropogenic causes of mortality of terrestrial animals worldwide that are linked with linear infrastructure (Drews, 1995;Fedigan and Zohar, 1997;Forman and Alexander, 1998;Printes, 1999;Chhangani, 2004;Lokschin et al., 2007;Parker et al., 2008;Cáceres et al., 2010;Pragatheesh, 2011;Umapathy et al., 2011;Dittus, 2020;Cunneyworth and Slade, 2021;Riley et al., 2021;Chaves et al., 2022). Road accidents and electrocution are common occurrences near fragmented forest patches in Bangladesh (Al-Razi et al., 2019). ...
Article
Forest fragmentation has resulted in a breakdown in connectivity for arboreal species. Effects of fragmentation are particularly acute in forest patches in densely populated countries, resulting in high mortality in many species attempting to cross roads to travel between forest patches. We evaluated the use of three, single-line artificial canopy bridges made of polypropylene ropes in a forest patch in northeastern Bangladesh. Camera traps were used to determine the extent of bridge use by different species. A total of 1060 events of bridge use by mammals were observed using our artificial canopy bridges over the 157 camera trap days. Eight mammal species, including five primate species, two squirrel species and one palm civet species were recorded using the bridges at varying levels of frequency. The location of the bridge and season influenced bridge use. We did not observe mortality of mammals from road accidents or electrocution during the study period. We suggest that artificial canopy bridges increased connectivity between forest patches and reduced mortality from road accidents and electrocution. We strongly recommend the use of this and other, simple canopy bridges to prevent mortality of arboreal mammals.
... 1946-1977Holmes et al. 2008) when Cape Town's population grew nearly tenfold from ca. 171,000 to 1,114,000 (1901-1970Bickford-Smith et al. 1998;Baffi et al. 2018;World Population Review 2020). Urbanisation also included building of road networks, which in addition to contributing to mortalities due to increased road traffic, bisect the habitat and reduce genetic diversity through population isolation and increased inbreeding (Forman and Alexander 1998;Gibbs 1998;Hanski 1998;de Maynadier and Hunter 2000;Andersen et al. 2004;Johansson et al. 2007). Since most of the habitat loss in the study area occurred before 1990, this probably contributed substantially to the increased inbreeding and turnover in genetic structure that were detected over the 10-year period (2008-2018). ...
Article
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Genetic diversity provides the capacity for species to evolve in response to environmental change, and its importance in assessing the status of species is well established. However, there is a paucity of genetic monitoring studies. The Endangered western leopard toad (Sclerophrys pantherina), endemic to South Africa, is a good candidate for genetic monitoring, due to its restricted distribution consisting of two disjunct populations (within the City of Cape Town (CoCT) and the Overstrand), with the CoCT population having experienced more drastic habitat alteration due to urbanisation, and presumably a large population decline. To establish a baseline for genetic monitoring, we examined the change in genetic diversity and structure within the CoCT population across two time periods (2008 and 2018) using 12 microsatellite markers. Despite monitoring occurring over only four generations, there is evidence of increased inbreeding and a shift in the genetic structure. These changes are likely due to previous, severe impacts on the population, with 91% of natural habitat lost in the study area. There is also evidence of at least three historical bottlenecks that are likely the initial cause of inbreeding, with extreme habitat loss in the twentieth century leading to the genetic changes detected within the last decade. Although declines in allelic richness were not detected, the inbreeding and change in genetic structure can be considered early warning signs of genetic erosion, even over a short monitoring interval. This provides a baseline for future monitoring, with the ultimate goal of tracking long-term trends to guide conservation actions.
... Πάρα ταύτα, αναμένεται η επέκταση των υποδομών οδικού στο άμεσο μέλλον στις τελευταίες εκτεταμένες άγριες φυσικές περιοχές του πλανήτη όπως ο Αμαζόνιος, το Κονγκό ή η Ν. Γουιάνα [12]. Η σοβαρότητα των αρνητικών επιπτώσεων της επέκτασης του οδικού δικτύου στη βιοποικιλότητα και στις οικοσυστημικές λειτουργίες είναι τεκμηριωμένη και περιλαμβάνει επιπτώσεις όπως: η αύξηση του κατακερματισμού των οικοσυστημάτων, η επιτάχυνση της αποψίλωσης των δασών, η διάβρωση του εδάφους, η χημική ρύπανση των εσωτερικών υδάτων, η ηχητική ρύπανση, η αλλαγή του μικροκλίματος, η θνησιμότητα ειδών της άγριας πανίδας λόγω προσκρούσεων με διερχόμενα οχήματα, η αλλαγή συμπεριφοράς τους και η εμφάνιση προτύπων αποφυγής των δρόμων, η γενετική απομόνωση ειδών, η ταχύτερη εξάπλωση ασθενειών, παρασίτων, και χωροκατακτητικών ξενικών ειδών [13][14][15][16][17]. Η αξία των εναπομεινάντων αδιατάρακτων φυσικών περιοχών (ΑΦΠ), ως οι τελευταίες περιοχές του πλανήτη που δεν διατρέχονται από δρόμους (roadless areas) αλλά είναι υψηλής φυσικότητας και χαμηλής ανθρωπογενούς παρεμβατικότητας (wilderness) είναι αναγνωρισμένη διεθνώς, καθώς οι ΑΦΠ είναι ένας από τους αποτελεσματικότερους άμεσους και γρήγορους τρόπους προστασίας της βιοποικιλότητας και των οικοσυστημικών της υπηρεσιών (ecosystem services) παγκοσμίως, οι οποίες περιλαμβάνουν την προστασία από φυσικές καταστροφές, τη διατήρηση του υδρολογικού ισοζυγίου, τη δέσμευση του ατμοσφαιρικού διοξειδίου του άνθρακα από τα φυσικά οικοσυστήματα, τη διατήρηση καλής κατάστασης του εδάφους, την επικονίαση κ.α. ...
Technical Report
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Η επιστημονική έκθεση παρουσιάζει τον εθνικό χάρτη των περιοχών χωρίς δρόμους της Ελλάδας. Πρόκειται για 389 πολύγωνα που ονομάζονται Αδιατάρακτες Φυσικές Περιοχές (ΑΦΠ), έχουν έκταση άνω των 2 τ.χλμ έκαστο και δεν διατρέχονται από δρόμους.Επιπλέον ο χάρτης περιλαμβάνει 3518 νησιά άνευ δρόμων, ή Νησιωτικές Αδιατάρακτες Φυσικές Περιοχές (ΝΑΦΠ) ανεξαρτήτως μεγέθους. Το 93% των νησιών που αξιολογήθηκαν είναι ΝΑΦΠ. Συνολικά ο εθνικός χάρτης των περιοχών χωρίς δρόμους (ΑΦΠ+ΝΑΦΠ) αποτελείται από 3.907 περιοχές, η συνολική έκταση των οποίων αντιστοιχεί στο 6,18% της έκτασης της Ελλάδας. Η έκθεση δίνει μια ανασκόπηση της αξίας των περιοχών χωρίς δρόμους με τη συναφή επιστημονική τεκμηρίωση σε παγκόσμιο, ευρωπαϊκό και εθνικό επίπεδο και μια σύντομη αναφορά για την άποψη της Ελληνικής κοινωνίας επί των ΑΦΠ. Παρουσιάζει τη σύνδεση της πολιτικής προστασίας των περιοχών χωρίς δρόμους με τους στόχους βιώσιμης ανάπτυξης, το παγκόσμιο πλαίσιο για τη βιοποικιλότητα, την Ευρωπαϊκή στρατηγική για τη βιοποικιλότητα, το στόχο μηδενικής καθαρής δέσμευσης γης μέχρι το 2050, την Ευρωπαϊκή Σύμβαση του Τοπίου, και την Εθνική Στρατηγική για τη Βιοποικιλότητα. Παράλληλα παρουσιάζει το παρόν θεσμικό πλαίσιο των μέχρι σήμερα 6 Υπουργικών Αποφάσεων προστασίας των Περιοχών Άνευ Δρόμων και τη σημασία προστασίας των ΑΦΠ ως προς τα εθνικά σχέδια δράσης για το αγριόγιδο και την καφέ αρκούδα. Εν τέλει δίνει μια σύντομη ανασκόπηση για τη διεθνή τάση προστασίας των περιοχών χωρίς δρόμους στον κόσμο με αναφορά στη θεσμική προστασία τους στις Η.Π.Α. Το κύριο μέρος της επιστημονικής έκθεσης είναι μια σειρά από 13 προτάσεις αξιοποίησης των αποτελεσμάτων της έρευνας στη χάραξη και εφαρμογή εθνικής περιβαλλοντικής πολιτικής, από τον ορισμό περιοχών αυστηρής προστασίας εντός του δικτύου Natura, έως τη θεσμική προτασία του τοπίου και τη βιώσιμη ανάπτυξη. Η έκθεση παρήχθηκε από το Εργαστήριο Διατήρησης της Βιοποικιλότητας (BCL) του Τμήματος Βιολογικών Εφαρμογών & Τεχνολογιών του Πανεπιστημίου Ιωαννίνων, υπό τη χρηματοδότηση του Πράσινου Ταμείου. Ο ιστοχώρος της προγράμματος για περισσότερες πληροφορίες είναι https://bc.lab.uoi.gr/el/research/projects/roadless/. Σχετικές ανακοινώσεις αναρτώνται στο https://www.facebook.com/BCL.Ioannina/
... Disturbance caused by roads facilitates the entry of alien species (Alston and Richardson 2006) and was likely to have been responsible for the arrival of S. bocconi and S. purpurea into the Park. Road networks are considered to disturb biodiversity, causing landscape fragmentation, barriers to organism movement, and reduction of overall landscape connectivity for many native species (Forman and Alexander 1998;Spellerberg 1998;Trombulak and Frissell 2000;Chen and Roberts 2008). In the meantime, roads also affect the abiotic components of landscapes, facilitating the entry of exotic species (Coffin 2007;Craig et al. 2010), and contributing to the dispersal of exotic species propagules by motorised vehicles (Hansen and Clevenger 2005;Birdsall et al. 2012). ...
... There are currently more than 64 million kilometres of paved and unpaved roads in the world (CIA, 2021). Although roads are essential infrastructure for the development of a country or region (Amador-Jimenez and Willis, 2012;Weiss et al, 2018), they also induce harmful effects on biodiversity, such as loss or reduction of habitat quality (eg, noise, artificial lighting, pollution, visual disturbances), barrier effect (eg, interruption of migration or dispersal) and direct mortality by motor vehicle collisions (MVCs) (Forman and Alexander, 1998;Forman et al, 2003;Fahrig and Rytwinski, 2009). ...
Article
Motor vehicle collisions (MVCs) are a severe threat to wildlife biodiversity worldwide and most vertebrate species are at risk. However, there is a considerable knowledge gap on the traumatic features and potential patterns of MVCs in wildlife. We investigated traumatic injuries (TIs) caused by MVCs (MVCs-TIs) in 430 neotropical wild mammals representing 44 species from Brazil. Injuries were classified topographically into four categories: abdomen/pelvis (AP), chest (TX), head/neck (HN) and extremities (EX). We also determined the prevalence of pathological changes in MVC fatalities. AP (n = 381; 89%) was the most affected body segment, followed by TX (n = 372; 87%), HN (n = 363; 84%) and EX (n = 288; 67%). The most prevalent gross pathological findings were single or multiple bone fractures (n = 397; 92%), visceral organ rupture (n = 371; 86%), haemothorax (n = 220; 51%) and pulmonary haemorrhage (n = 212; 49%). Microscopically, pulmonary oedema (n = 324; 82%) and haemorrhage (n = 272; 69%) were the most prevalent lesions. No distinct TI patterns were evident across the various taxonomic groups, although trends were found in some taxa, such as armadillos. These results may help clinicians performing emergency care on MVC wildlife patients and may be of value in pathological and forensic investigations where a MVC has been deemed a likely contributory factor to death.
... Therefore, distance to the main road has also become an important factor affecting the change in PLES patterns, which increases the land of production and living in the surrounding areas. On the other hand, roads, as a channel of human access nature, greatly increase the scope of human activities and profoundly change the pattern of ES [58]. ...
Article
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Production-living-ecological space (PLES) constitutes territorial space, and how to scientifically optimize PLES has become the core issue of territorial spatial planning in China. This paper constructs a spatial classification system for PLES based on merge classification. Taking Longli County, Guizhou Province, China, as an example, this paper studies the spatial patterns in 2015 and 2019, the driving factors of the changes in the spatial patterns, and the interrelationships of production space (PS), living space (LS) and ecological space (ES) and proposes a new scheme for dominant functional zoning. The results show that: (1) The high-scoring areas of PS and LS in Longli County are mainly located near the center of each town, with obvious consistency in the spatial distribution. The high-scoring areas of ES are located in the suburbs far from the towns, conflicting with PS and LS; (2) In the five-year period, PS and LS in Longli County continuously expanded. Specifically, LS expanded the most from the perspective of the rate of change, and ES shrunk continuously; (3) Socioeconomic factors are the dominant factor affecting the changes in PLES, among which the distance to town has the greatest influence; (4) Based on the correlation coefficient, PS and LS have a significant positive correlation, but they have a significant negative correlation with ES. In terms of spatial relationships, PS and LS mainly have synergistic relationships, but their relationships with ES mainly involve tradeoffs; (5) In the spatial functional areas of PLES in Longli County, the single dominant functional area is the main area, among which the ecological-dominant functional area is the largest. The results of this study provide a reference for territorial spatial planning and sustainable regional development.
... Native plants with deep roots can reduce erosion by increasing slope stability on steep slopes (Forman and Alexander 1998;Stokes et al. 2009;Rahardjo et al. 2014). In the Midwestern United States, the dense, fine root systems typical of tallgrass prairie grasses are more effective at binding soil compared to coarse root systems (Loades et al. 2010). ...
Article
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Recently the value of roadside vegetation as habitat for pollinators has gained increased attention, particularly in areas dominated by agriculture where there is little native vegetation available. However, many factors, including safety, cost, public perception, erosion control, and weedy plants must be considered when managing roadside vegetation. Although their decisions influence thousands of hectares of public rights-of-way, how engineers and roadside managers maintain roadside vegetation has been the subject of little research. In this study, we surveyed county engineers and roadside managers who manage vegetation along secondary roads in Iowa, USA to assess how they maintain roadside vegetation. Some counties employ roadside managers, who often have an environmental sciences background, to implement the on-the-ground management of roadside vegetation, while some counties use other staff. Compared to engineers, roadside managers more strongly agreed that using the ecological principles of integrated roadside vegetation management (IRVM) provided environmental benefits. Engineers in counties with a roadside manager more strongly agreed that IRVM practices reduce the spread of invasive species and provide attractive roadsides. Both engineers and roadside managers mentioned challenges to managing roadside vegetation, including interference with some native plantings by adjacent landowners, and ranked safety and soil erosion concerns as the highest priorities when making decisions. Four in ten roadside managers said their counties had protected native plant community remnants on secondary roadsides. Our findings can inform conservation outreach efforts to those responsible for managing roadside vegetation, and emphasize the importance of addressing safety and soil erosion concerns in roadside research and communications.
... [ [41][42][43][44] Private garden Located in suburban areas and the most prevalent form of UF in cities [45] Easement garden Located within community properties but often regulated by the local government; established to improve water quality and for erosion control. [46,47] Roof-top Garden Any garden established on the roof of a building (for decorative or agricultural purposes) [48] Urban orchard Tree-based food production systems that can be owned or run privately/by the community. [49] Institutional garden Located at any government or non-governmental institution/buildings which are managed by an organisation; not necessarily for food production [50] Demonstration garden Small gardens located in private areas, housing areas, and commercial areas for demonstration purposes only; referred to as learning or teaching gardens. ...
Article
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Urbanisation and related insufficiency of food sources is due to the high urban population, in-sufficient urban food sources, and inability of some urban communities to afford food due to rising costs. Food supply can also be jeopardised by natural and man-made disasters, such as warfare, pandemics, or any other calamities which result in the destruction of crop fields and disruption of food distribution. The COVID-19 pandemic exposed the impact of such calamities on the fresh food supply chain in Malaysia, especially when the Movement Control Order (MCO) policy was first implemented. The resulting panic buying caused some food shortage, while more importantly, the fresh food supply chain was severely disrupted, especially in urban areas, in the early stages of implementation. In this regard, urban farming, while a simple con-cept, can have a significant impact in terms of securing food sources for urban households. It has been used in several countries such as Canada, the Netherlands, and Singapore to ensure a con-tinuous food supply. This paper thus attempted to review how the pandemic has affected Malay-sian participation in urban farming and, in relation to that, the acceptance of urban farming in Malaysia and the initiatives and approaches of local governmental and non-governmental or-ganisations in encouraging the urban community to participate in urban farming through peer-reviewed journal articles and other articles related to urban agriculture using the ROSES protocol. About 93 articles were selected after screening to ensure that the articles were related to the study. During the COVID-19 pandemic, the surge in Malaysians’ awareness of the im-portance of urban farming has offered great opportunities for the government to encourage more Malaysian urban communities to participate in urban farming activities. Limitations such as relevant knowledge, area, and space, however, are impediments to urban communities’ par-ticipation in these activities. Government initiatives, such as the Urban Community Garden Pol-icy (Dasar Kebun Komuniti Bandar (DKKB), are still inadequate as some issues are still not ad-dressed. Permanent Food Production Parks (TKPM) and technology-driven practices are seen as possible solutions to the primary problem of land and space. Additionally, relevant stakehold-ers play a crucial role in disseminating relevant and appropriate knowledge and methodology applicable for urban farming. Partnerships between government agencies, the education sector, and the private sector are necessary to develop modern urban agricultural technologies as well as knowledge, know-how, and supports to build and sustain urban community participation in urban farming activities.
... But in China fences have also increased on rangelands since the introduction of the "Rangeland Contract Responsibility System" in the mid-1980 s (basically introducing a system of grazing prohibition and grazing rest often implemented through fencing; Greenfield et al., 2021). These fences pose a serious threat to wildlife by splitting populations, impeding migrations, restricting access to resources, and killing animals attempting to cross (Forman and Alexander, 1998;You et al., 2013;Greenfield et al., 2021). ...
Article
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Understanding the changes in population size, distribution and threats, is essential for assessing the status of threatened species. Northern China is believed to be an important stronghold for the Near Threatened Asiatic wild ass or khulan (Equus hemionus), but a recent assessment of the species has been lacking. To document change and updated the current status of khulan in China, we conducted a literature review targeting peer-reviewed and grey literature, newspaper articles, and summarized the results own field surveys and interviews from part of the species range. For a better understanding of the threats to khulan in China, we summarized the results of studies on environmental habitat factors and human disturbances for khulan, most of which are only available in Chinese language. Our results suggest that khulan in China have experienced a dramatic decline and fragmentation of their distribution range caused by excessive anthropogenic interferences. The remaining khulan range in China covers probably less than 40,000 km² and is scattered over several nature reserves and the border areas in northern Xinjiang, northwestern Gansu, and western Inner Mongolia. We estimate the remaining population at about 4000 individuals, with ~80% found in Kalamaili Mountain Ungulate National Nature Reserve in Xinjiang. The occurrences along the border with Mongolia are small and dependent on cross-border movements, which are currently severely hindered by border fences. Over the past 15 years, Kalamaili Mountain Ungulate National Nature Reserve was exposed to various human pressures and experienced dramatic population fluctuation in the khulan population size. Key factors which negatively influenced khulan were habitat loss, fragmentation, and disturbance due to mining exploration and infrastructure development. No systematic monitoring of khulan is done in the rest of the khulan range, but whereas illegal hunting seems no longer a serious threat, infrastructure development and land use changes (including increasing livestock numbers) are happening throughout the remaining range of khulan in China. Hence there is an urgent need to develop a national khulan conservation strategy and initiate cross-border cooperation with Mongolia to safeguard the long-term survival of the species in the Gobi region.
... In the contiguous United States, 82% of the total land area is within 1 km of a road (including unpaved and private roads) (Riitters and Wickham 2003); in Europe, 50% of all land area is located within 1.54 km of the nearest paved road or railway line (Torres et al. 2016). Roads and vehicular traffic have complex impacts on wildlife and biodiversity, such as increased wildlife-vehicle collisions (WVCs), habitat fragmentation, and decreased habitat quality (Forman and Alexander 1998;van der Ree et al. 2015). When an animal confronts a road, it is either forced to move in a different direction, i.e., access to habitats on the other side is inhibited, or it must attempt to cross, thus being exposed to traffic. ...
Article
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This study assesses existing human-purpose underpasses below an unfenced high-traffic 4-lane highway in the Appalachian region of Quebec, Canada, as potential crossing structures for native mammal species. Eight underpasses of three types (five water culverts with minimum height and width of 1.8 m, one low-use gravel road byway, and two railroad underpasses) were continuously monitored by motion-detection infrared camera traps for time periods spanning up to 778 days (September 2016 to November 2018). We asked how the ratios of successful crossings through the structures (termed full crossings) and aversions to the structures (termed aversions) differed between species and we explored the influence of human activity levels on the use of these structures by wildlife. All monitored crossing structures had low human observations (with averages of less than 35 human activities per day). Our results provide evidence that 21 species of mammals in the study area successfully crossed through at least one of the eight observed underpasses on a minimum of one occasion. Some species were observed crossing through some of the underpasses on a regular basis, namely raccoon, red fox, and white-tailed deer. We propose a classification of mammal species into five human co-use classes (no or low co-use to very high co-use) to explore the relationship between mammal use of the structures and human presence. We found that humans and mammals were observed sharing passages for the four mammal species identified as tolerant of human co-use (high and very high co-use classes), but co-use was observed to be limited or not occurring for most other species. The strengths of this study include the length of time during which monitoring took place, as well as the placement of four cameras at each structure (two facing inward and two facing outward) to determine whether individuals successfully crossed through the structures or displayed avoidance behaviour. The results suggest select species of mammals show some co-use with humans at existing underpasses. The activity patterns of mammals documented over the two-year study can assist with future estimates of highway permeability. Further, measurements of human and mammal co-use have species-specific implications for retrofitting existing structures and constructing wildlife fences and purpose-built wildlife passages.
... The development of linear transport infrastructures (LTI) and networks are one of the main reasons for habitat fragmentation (Geneletti 2003(Geneletti , 2004Trocmé et al. 2003;Rhodes et al. 2014), particularly in mountain areas and it negatively affects large carnivores (Forman and Alexander 1998;Fahrig and Rytwinski 2009;Morales-González et al. 2020) not only at local, but also at landscape level (Proctor et al. 2012;Bischof et al. 2017;Finďo et al. 2018). Large LTI are usually overlapping, altering or sometimes even interrupting wildlife/ecological corridors, especially if the infrastructures are not permeable, in the absence of properly designed and placed underpasses, overpasses and other crossing structures (Van der Ree et al. 2009). ...
Article
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The development of sustainable transport is a key challenge in societies where there is an accelerated need for socio-economic development. This is the case for seven countries from central and south-eastern Europe that share the Carpathian Mountains. The challenge of developing sustainable transport requires transdisciplinary, or at least cross-sectoral cooperation, between the transport development and nature conservation sectors. Such cooperation is not in the culture of the Carpathian countries, which together host some of the most remarkable biodiversity values in Europe, including the largest populations of brown bear, grey wolf and Eurasian lynx. The overall length of motorways in these countries more than quintupled in the last 30 years and the rapid expansion of Linear Transport Infrastructure (LTI) continues at exacerbating rates. The rich biodiversity habitats are being fragmented and the concept of ecological connectivity is poorly understood and implemented by the national authorities. Ecological networks for large carnivores are not defined nor officially recognised in the Carpathian countries, with little exceptions. The legislation is not consistent across the strands of ecological connectivity and is not harmonised between the countries to effectively support transnational conservation efforts. Thus, the critical intersections between planned or even existing LTI and ecological corridors for large carnivores cannot be identified, in most cases leading to increasing habitat fragmentation and isolation of wildlife populations in the region. We summarised all this key context-related information for the Carpathians in relation to LTI development and ecological connectivity. To counteract this trend in the Carpathian ecoregion, we propose a set of recommendations to: improve and harmonise the legislation; develop and endorse methodologies for designating ecological corridors; address the cumulative impact on ecological connectivity; define other threats on landscape permeability; improve stakeholder engagement, cooperation and communication; develop comprehensive and transparent biodiversity and transport databases; monitor wildlife and transport for implementing most appropriate mitigation measures and strategies; build capacity to address the issue of sustainable transportation; and foster transnational cooperation and dialogue. Bringing these elements together will support the design of ecological networks in a way that considers the needs and location of both current and future habitats and contribute to efforts to address the climate crisis. These specific recommendations are relevant also for other areas of the world facing similar problems as the Carpathians.
... Salinization effects on plant communities cascade to biogeochemical implications. Effects on plants include osmotic stress, ion toxicity, and nutrient deficiencies linked to the displacement and leaching of cations by Na + (Forman and Alexander 1998;Findlay and Kelly 2011;Tiwari and Rachlin 2018). At very high concentrations, as are often found within a few meters of roads, plants suffer direct injury (Lumis et al. 1976), sometimes creating "salt-burned" areas devoid of vegetation (Scott and Davison 1982). ...
Article
Salinization and eutrophication are nearly ubiquitous in watersheds with human activity. Despite the known impacts of the freshwater salinization syndrome (FSS) to organisms, we demonstrate a pronounced knowledge gap on how FSS alters wetland biogeochemistry. Most experiments assessing FSS and biogeochemistry pertain to coastal saltwater intrusion. The few inland wetland studies mostly add salt as sodium chloride. Sodium chloride alone does not reflect the ionic composition of inland salinization, which derives from heterogeneous sources, producing spatially and temporally variable ionic mixtures. We develop mechanistic hypotheses for how elevated ionic strength and changing ionic composition alter urban wetland sediment biogeochemistry, with the prediction that FSS diminishes nutrient removal capacity via a suite of related direct and indirect processes. We propose that future efforts specifically investigate inland urban wetlands, a category of wetland heavily relied on for its biogeochemical processing ability that is likely to be among the most impacted by salinization.
Article
For several species, roadkill is not spatially aggregated on hotspots, having instead a more diffuse pattern along the roads. For such species, management measures such as road passages may be insufficient for effective mitigation, since a large part of the road crossings is likely to occur outside the influence of those structures. One complementary approach could be to implement temporary mitigation actions, such as traffic calming. This requires understanding when roadkill peaks may occur. We tested the feasibility of predicting seasonal peaks of roadkill using data from a 3-year systematic monitoring (78 surveys over ca. 960 km of roads) from eight non-flying vertebrate species from Mato Grosso do Sul, Brazil, with different body size and life history traits (ca. 6400 records from focal species). We modelled the time-series of the roadkill of these species at large scale (state level) using generalized additive mixed models (GAMMs). We used the data of the first 2 years as training datasets, and the information from the third year of surveys as testing datasets to evaluate the prediction performance of models. Overall, the models of species feed with a higher number of records were able to follow reasonably well the variations of roadkill over time, although they were not able to correctly predict the number of collisions. For species with fewer observations, the models presented a poorer goodness-of-fit and prediction ability. Our results suggest that, at least for those species with higher roadkill rates, it can be possible to forecast periods of higher probability of occurring hot-moments of mortality. Such models can provide valuable information to implement seasonal management actions.
Chapter
Juvenile Schleiereulen wandern von ihrem Geburtsort ab und suchen eine neue Heimat, wo es genügend Nahrung gibt, um erfolgreich eine Familie aufzuziehen. Diese Reise – von wenigen hundert Metern bis zu mehr als 3000 Kilometern – findet bald nach dem Flüggewerden statt. Die Männchen müssen lange vor dem ersten Fortpflanzungsversuch bereits ein Territorium in Besitz nehmen und gegen Rivalen verteidigen; dies könnte erklären, warum die Dispersal-Distanz bei ihnen geringer ist als bei den Weibchen. Das Abwandern vom Geburtsort (natal dispersal) , auch Jugendstreuung genannt)ist der Prozess, während dessen Jungtiere ihren Geburtsort verlassen, um den Platz zu finden, an dem sie zum ersten Mal brüten werden. Sie suchen nach einem „gelobten Land“, das so weit vom Geburtsort entfernt ist, dass es eher unwahrscheinlich ist, auf ein nahe verwandtes Individuum zu treffen und mit ihm zu brüten. Ferner sollte es reichlich Nahrung geben und die Konkurrenz mit Artgenossen gering sein. Es ist zwar immer riskant, unbekannte Gebiete zu durchqueren, doch es hat den Schleiereulen ermöglicht, fast die ganze Welt zu erobern (Abb. 11.1).
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The main factors affecting specific road casualty rates are related to life-history traits, road features, and landscape variables. After road inauguration, roadkill rate and spatial and temporal patterns can change substantially due to changes in traffic intensity, avoidance behaviour or local population decline. Despite the Canary Islands constituting a biodiversity hotspot, Canarian ecosystems are highly threatened because of the high human density, and studies on anthropogenic sources of mortality of wildlife are scarce. Here, we counted roadkills during two annual cycles after the inauguration of an 8.8-km-road section on Tenerife, the largest and most densely populated island of the Canaries. We counted 694 roadkills belonging to a minimum of 19 species of birds and six species of introduced mammals. Seasonal variation was apparent during both annual cycles, particularly for birds, being the majority of victims concentrated in May and June. Although traffic intensity increased since road inauguration, the number of roadkills decreased significantly in the second annual cycle. The reduction in road mortality in the second cycle could be related to some non-mutually exclusive factors such as population decline, road avoidance, or weather conditions. As road networks of the Canary Islands are still increasing, further studies quantifying road mortality impacts on Canarian ecosystems and threatened species are urgently needed to guarantee the management and conservation of its fragile wildlife.
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The Bakonjo have long practiced an agroforestry system of cultivation on the Ugandan slopes of the Rwenzori Mountain range. All terrain above 1600–2200 m has been strictly protected for many years because it is part of a national park. As a trade-off, the landscapes outside the park have been largely deforested. In the meantime, tourist numbers have increased. In Ruboni, a village of 1200 people, the closest to the eastern gate of the park, we interviewed a random sample of 51 residents aged >14 to understand how they perceived the landscape, park and tourism. Cultivated features were not essential to describe the place of residence, in contrast to natural features and human engineered devices. Cultivated and natural elements were judged as beautiful. Even if the inhabitants did not like human engineered facilities, they welcomed their improvement. The origin of native and non-native plants was not consistently recognized. These results show that the inhabitants feel affection for the agroforestry pattern of the Rwenzori landscape. However, ecological, social and economic pressures are challenging land use sustainability. This would be better addressed by an integrated pattern of land governance than the current two models: strict protection inside the park and relaxed land use outside. View Full-Text
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Roads and trafc have various negative ecological and environmental consequences on wildlife. Their impacts on animal populations are not limited to deaths. The main goal of the study is to analyze the spatial patterns of wildlife–vehicle collisions (WVC) at the Ankara–Kırıkkale highway. More specifcally, we identifed the road- and landscape-related features that may promote the WVC likelihood and locate the WVC hotspots. The hotspots of WVC were generated by CrimeStat 3 software. Variables related to the WVC locations were statistically analyzed, and then, they were modelled with logit regression approach. A total of 76 medium and large mammal were recorded from fve species. The number of high-, medium-, and low-density clusters in the hotspots map that contains all the accidents are one, two, and four, respectively. For all species, the model shows that the probability of a fatal accident increases as the speed limit increases and the road slope decreases. To spatially identify where these events are concentrated provides valuable information for reducing the accidents and creating the correct strategies to ensure the safe migratory movements of wild animals
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Promoting biodiversity is a major issue in urban planning. Estimating the biodiversity potential of patches in the landscape matrix often uses the tools of spatial analysis and landscape ecology indices, especially in large study areas. In this paper, we present the construction of a composite biodiversity potential index (CBPI) based on structural and functional approaches of landscape ecology. The CBPI is composed of eight indices (quality: permeability, fragmentation, environmental management; shape: size, shape complexity; configuration: contrast between neighbouring patches, distance to the most favourable habitats, distance from built-up areas). The CBPI appears to be suitable for anthropised and fragmented landscape matrices. It can be used to identify ecological networks in an ‘Avoid, Reduce, Compensate’ approach and can be readily updated with new map databases.
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Human population and economic growth have resulted in roads transecting much of the North American landscape and this has negatively affected wildlife populations by fragmenting habitat, impeding movement between populations and increasing the chance of wildlife‐vehicle collisions. A common conservation tool to counteract these effects is the incorporation of road mitigation structures (RMS, i.e., jumpouts and overpasses/underpasses/fencing) into highway systems. However, gaps remain in our knowledge on RMS efficacy due to a lack of long‐term multispecies studies that can assess temporal and species‐specific variation in use. We investigate the efficacy of the Alberta Environment and Parks and Alberta Transportation RMS on the Trans‐Canada Highway (TCH) in the Bow Valley by analyzing annual reported wildlife‐vehicle collisions over a 23‐year period and wildlife use of the underpasses over a ten‐year period. We found that the incorporation of multiple underpasses and jumpouts, along with fencing, reduced the number of reported wildlife‐vehicle collisions on the TCH. We also found that wildlife use of the RMS exhibited variation with regards to month and location. Overall, our results add to the research supporting RMS effectiveness and suggest that incorporating additional similar infrastructure has the potential to further reduce wildlife‐vehicle collisions on the TCH. A common conservation tool to mitigate for fragmenting habitat, impeding movement between populations, and wildlife‐vehicle collisions is the incorporation of road mitigation structures (i.e., jumpouts and over/underpasses and fencing) into highway systems. In this study, we found in the long‐term that the incorporation of multiple underpasses and jumpouts, along with fencing reduced the number of wildlife‐vehicle collisions on the Trans‐Canada Highway.
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Despite being among the best-studied insect groups in road ecology, assemblage-level effects of major roads on ground beetles have rarely been investigated from the functional perspective. In this study we adopted both species-based and trait-based approaches to investigate spatial dynamics of ground beetle assemblages with respect to motorway proximity and identify main environmental drivers of the observed changes. In 2018, ground beetles were sampled by pitfall traps within homogeneous portions of a grassland habitat in Lika region, Croatia, in eight locations at five distances from a motorway: 10, 25, 50, 100 and 500 m. While no significant spatial patterns were found in taxonomic assemblage metrics, confirming that road-related effects are less prominent in open compared to closed habitat types, functional diversity of ground beetles increased with motorway proximity, possibly owing to an edge effect. Our findings show that, in grassland ecosystems, motorways are likely to affect ground beetle assemblages primarily through changes in vegetation height, with highly vegetated roadsides potentially acting as habitat corridors or supplementary habitats for generalist and mesophilous species.
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Human settlements, including cities, may provide wildlife with new ecological niches, in terms of habitat types and food availability, thus requiring plasticity for adaptation. The crested porcupine Hystrix cristata is a habitat-generalist, large-sized rodent, also recorded in some suburban areas, but no information is available on its habitat use in metropolitan landscapes. Here, we assessed the land-use factors influencing the presence of crested porcupines in a metropolitan area of Central Italy. We collected data on the occurrence of crested porcupines from the metropolitan area of Rome, following an observer-oriented approach to record occurrences and retreive pseudo-absences. We then related the presence/absence of H. cristata to landscape composition. Occupancy models showed that cultivations and scrubland were positively related to porcupine presence, most likely as they provide food resources and shelter sites, respectively. Although the crested porcupine has been confirmed as a “generalist” species in terms of habitat selection, a strong preference for areas limiting the risk of being killed and providing enough food and shelter was observed. We therefore suggest that the crested porcupine may adapt to deeply modified landscapes such as large cities by selecting specific favourable land-use types.
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The features of the urban landscape encouraging large ungulates expansion are not known. However, prevalence and abundance of wild boar Sus scrofa has been steadily increasing over the years, and nowadays the species has become a recognized component of urban wildlife in many parts of its range. The aim of this work was to select habitat and human-related factors that could affect the probability of the species occurrence and constitute the honest indicators of the habitat suitability for this ungulate in the urban landscape. The data on the presence of grubbed patches of ground (an honest indicator of occurrence) were collected on randomly selected sample plots (N = 100) within the city of Kraków (Poland). We found that wild boar used 45% of the sample plots. Whereas the occupied plots were spatially concentrated, the habitat variables increasing the probability of the species occurring in the urban landscape were the presence of large patches of woodland remnants and large areas of semi-natural meadows. However, the study also revealed a negative relationship between the presence of the species and artificial lighting but a positive one with anthropogenic noise pollution. Our results indicate that the urban landscape consists of surrogate habitats for this large mammal but light and noise pollution may have contrasting effects on the species’ occurrence. This indicates that the influence of human-related factors on the attractiveness of natural vegetation remnants for wildlife is more complex than merely a limiting factor. This reveals high potential of light and noise pollution as indicators of the habitat suitability for ungulates in the urban landscape.
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Roads are among the most widespread signs of man’s presence around the globe. From simple low traffic trails to wide and highly used highways, roads have a wide array of effects on wildlife. In the present study, we tested how habitat reduction by roads may affect the space use and movement patterns of the Cabrera vole ( Microtus cabrerae ), a near-threatened Iberian endemism, often living on road verges. A total of 16 voles were successfully radio-tracked in two habitat patches with different size and proximity to roads. Results showed that individuals from the smaller patch (Verge patch) had smaller and less complex home-ranges than those from the larger patch (Meadow patch). Movement patterns were significantly influenced by the day period but only in individuals from the Verge patch. There was evidence of a barrier effect in both habitat patches, being this effect much more noticeable in the verge population. Overall, this study shows that space use and movement patterns of Cabrera voles near roads may be affected by the degree of habitat reduction imposed by these infrastructures. This suggests that species space use and movement patterns at fine-scale should be accounted for in road planning, even for species that may benefit from road verge habitats as refuges.
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Reactions of mountain lions (Felis concolor) to logging and to various human activities were studied in northern Arizona from 1976 to 1980 and in southcentral Utah from 1979 to 1982. Resident mountain lions rarely were found in or near (1 km) sites logged within the past 6 years. Younger (2- or 3-year-old) mountain lions were found in logged areas more often than older mountain lions, but 4 of 5 young mountain lions that visited logged areas did not maintain residence there. In the absence of human disturbance, mountain lions showed peak activity ≤2 hours of sunset and sunrise. Near human presence, lion activity peaks shifted to after sunset. Other activity was concentrated during night hours, and there was no peak of activity at sunrise. Dispersing juvenile mountain lions encountered human disturbances more frequently than resident lions (P < 0.05). Established residents and young mountain lions that ultimately became residents selected home areas with road densities lower than the study area average, no recent timber sales, and few or no sites of human residence. All disturbances examined appeared to have at least potential adverse impacts on mountain lions, especially on dispersing juveniles.
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This study quantified long-term changes in streamflows associated with clear-cutting and road construction and examined alternative hydrologic mechanisms to explain stream hydrograph changes in the Cascades Range, western Oregon. We examined differences in paired peak discharges for 150 to 375 storm events for five basin pairs, using 34-year records from two pairs of 60-to-101-ha experimental basins in the H. J. Andrews Experimental Forest, and 50-to-55-year records from three pairs of adjacent basins ranging from 60 to 600 km2. Forest harvesting has increased peak discharges by as much as 50% in small basins and 100% in large basins over the past 50 years. These increases are attributable to changes both in flow routing due to roads and in water balance due to treatment effects and vegetation succession.
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Biologists studying anuran amphibians usually assume that artificial, visible light does not affect the behaviour of nocturnal frogs. This assumption was tested in a laboratory experiment. The foraging behaviour of grey treefrogs, Hyla chrysoscelis, was compared under four lighting conditions: ambient light (equivalent to bright moonlight, 0·003 lx), red-filtered light (4·1 lx), low-intensity 'white' light (3·8 lx), and high-intensity 'white' light (12·0 lx). The treatments were chosen to correspond to standard methods of field observation of frog behaviour. The foraging behaviour of frogs in the four treatments was observed using infra-red light that was invisible to the frogs. The ability of the frogs to detect, and subsequently consume prey was significantly reduced under all of the enhanced light treatments relative to the ambient light treatment. Thus, the use of artificial light, within the visible spectrum of the frogs' eyes, can influence the outcome of nocturnal behavioural observations. These results lead to the recommendation that anuran biologists use infra-red or light amplification devices when changes in frogs' visual capabilities may influence the conclusions drawn from a study.
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Erosion on roads is an important source of fine-grained sediment in streams draining logged basins of the Pacific Northwest. Runoff rates and sediment concentrations from 10 road segments subject to a variety of traffic levels were monitored to produce sediment rating curves and unit hydrographs for different use levels and types of surfaces. These relationships are combined with a continuous rainfall record to calculate mean annual sediment yields from road segments of each use level. A heavily used road segment in the field area contributes 130 times as much sediment as an abandoned road. A paved road segment, along which cut slopes and ditches are the only sources of sediment, yields less than 1% as much sediment as a heavily used road with a gravel surface.
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Based on field surveys and analysis of road networks using a geographic information system (GIS), we assessed the hydrologic integration of an extensive logging-road network with the stream network in two adjacent 62 and 119 km2 basins in the western Cascades of Oregon. Detailed surveys of road drainage for 20 percent of the 350 km road network revealed two hydrologic flow paths that link roads to stream channels: roadside ditches draining to streams (35 percent of the 436 culverts examined), and roadside ditches draining to culverts with gullies incised below their outlets (23 percent of culverts). Gully incision is significantly more likely below culverts on steep (< 40 percent) slopes with longer than average contributing ditch length. Fifty-seven percent of the surveyed road length is connected to the stream network by these surface flowpaths, increasing drainage density by 21 to 50 percent, depending on which road segments are assumed to be connected to streams. We propose a conceptual model to describe the hydrologic function of roads based on two effects: (1) a volumetric effect, increasing the volume of water available for quickflow and (2) a timing effect, altering flow-routing efficiency through extensions to the drainage network. This study examines the second of these two effects. Future work must quantify discharge along road segments connected to the stream network in order to more fully explain road impacts on basin hydrology.
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The east-west density gradient and the pattern and mode of migration of the wetland exotic, purple loosestrife (Lythrum salicaria L.), were assessed in a survey of populations along the New York State Thruway from Albany to Buffalo to determine if the highway corridor contributed to the spread of this species. During the peak flowering season of late July to early August, individual colonies of purple loosestrife were identified and categorized into three size classes in parallel belt transects consisting of the median strip and highway rights-of-way on the north and south sides of the road. Data were also collected on the presence of colonies adjacent to the corridor and on highway drainage patterns. Although a distinct east-west density gradient existed in the corridor, it corresponded to the gradient on adjacent lands and was greatly influenced by a major infestation at Montezuma National Wildlife Refuge. The disturbed highway corridor served as a migration route for purple loosestrife, but topographic features dictated that this migration was a short-distance rather than long-distance process. Ditch and culvert drainage patterns increased the ability of purple loosestrife to migrate to new wetland sites. Management strategies proposed to reduce the spread of this wetland threat include minimizing disturbance, pulling by hand, spraying with glyphosate, disking, and mowing.
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Roadless areas on public lands may serve as environmental baselines against which human-caused impacts on landscape structure can be measured. We examined landscape structure across a gradient of road densities, from no roads to heavily roaded, and across several spatial scales. Our study area was comprised of 46,000 ha on the Roosevelt National Forest in north-central Colorado. When forest stands were delineated on the basis of seral stage and covertype, no relationship was evident between average stand size and road density. Topography appeared to exert a greater influence on average stand size than did road density. There was a significant positive correlation between the fractal dimension of forest stands and road density across all scales. Early-seral stands existed in greater proportions adjacent to roads, suggesting that the effects of roads on landscape structure are somewhat localized. We also looked at changes in landscape structure when stand boundaries were delineated by roads in addition to covertype and seral stage. Overall, there was a large increase in small stands with simple shapes, concurrent with a decline in the number of stands > 100 ha. We conclude that attempts to quantify the departure from naturalness in roaded areas requires an understanding of the factors controlling the structure of unroaded landscapes, particularly where the influence of topography is great. Because roads in forested landscapes influence a variety of biotic and abiotic processes, we suggest that roads should be considered as an inherent component of landscape structure. Furthermore, plans involving both the routing of new roads and the closure of existing ones should be designed so as to optimize the structure of landscape mosaics, given a set of conservation goals.
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This study examines effects of different forest cutting patterns on habitat fragmentation in managed forest landscapes. We use computer simulation to conduct experiments in which we examine effects of different cutting patterns, cutting-unit size, and special constraints (e.g., a forest reserve, a stream system, or a road system) on landscape patterns. Fragmentation indices are used to quantify structural changes over the cutting cycle and among different treatments of the experiments. Degree of fragmentation varies greatly among the five cutting patterns used; aggregation of cutting units results in low degree and gradual change of fragmentation. Cutting patterns with larger cutting units and additional landscape constraints also lead to lower degree of fragmentation. Moreover, differences in fragmentation among the treatments are not observed until 30% or 50% of the landscape is cut.
Chapter
Fragmentation of habitat can be defined as a process: the destruction of habitat leaving the remaining fragments scattered throughout the newly created landscape. For species restricted to the original type of habitat, fragmentation means a disintegration into small, spatially disjunct patches, separated by land which is unsuitable to reproduce or find food or shelter. Fragmentation may also be perceived as a pattern, the result of this process of disintegration. It may then be described functionally as a spatially distributed set of habitat patches, characterized by patch area and shape, by patch configuration and by the resistance of the intermediate land to movements of individuals of a particular species. Obviously the perception of this pattern, and hence the response to the fragmentation process of a population, will vary widely among species.
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During 14 months 286 white-tailed deer (Odocoileus virginianus) were killed by vehicles on an 8-mile section of Interstate 80 in central Pennsylvania. Mortality among fawns and yearlings was not significantly different between the sexes, but among adults many more females than males were killed. Mortality was highest in the fall, high in spring, and low in summer and winter. The numbers killed per month were strongly correlated with the numbers seen grazing on the planted right-of-way. Mortality was highest in sections of highway that lay in troughs formed by steep median strips and steep rights-of-way, where troughs ended by a lowering of the median strips, and through flat areas where both sides of the highway and the median strip provided good pasture.
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This study was undertaken to review the current status of permit-linked mitigation policies and practices in order to determine implications of the continued use of mitigation as a wetlands management tool within the United States. Based on reviews of both published literature and agency reports, our survey of past mitigation projects nationwide indicates that the success rate of permit-linked mitigation projects remains low overall. In addition, there is continuing difficulty in translating mitigation concepts into legal principles, regulatory standards, and permit conditions that are scientifically defensible and sound. Based on the record of past poor performance, we assert that continued piecemeal revision efforts focused on technical or scientific details are not likely to make compensatory mitigation more effective. There is need to acknowledge the extent to which non-scientific, real-world complications plague current policies and practices. To prevent continued loss of wetlands under compensatory mitigation, decisive action must be taken by placing emphasis on improving compliance, generating desired acreages, and maintaining a true baseline. Without selective changes in the status quo, current policies and poor implementation are likely to lead to further wetland losses.
Article
Human activity is altering the chemistry of the atmosphere, which, in turn, is affecting the physiology and growth of plants. The purpose of this article is to develop four ideas that are currently emerging from the work of a diverse group of plant scientists. (1) Air pollution definitions: The definition of air pollution has been broadened, and research activities are expanding to include analysis of plant responses to a wide range of atmospheric chemicals emitted from anthropogenic sources but not previously considered as air pollutants. Thus experiments with CO2 and other trace gases are being pursued with approaches developed in air pollution research. (2) Air pollution uptake: Efforts are increasing to better quantify air pollution absorption rates through stomata in order to calculate actual dose vs, plant responses. The flux rates of gaseous pollutants into leaves, especially O-3, are largely dependent upon stomatal conductance. Approaches are being developed to calculate stomatal absorption of gaseous pollutants, based on stomatal conductance values for water vapor and ambient air-pollution concentrations. Calculation of air pollution absorption rates will allow responses of plants to pollutants to be assessed in toxicological frameworks and will help characterize the strength of vegetation as sinks for some gaseous pollutants. (3) Compensatory responses: Plant responses to air pollutants can be interpreted as compensatory, i.e., a physiological adjustment to an environmental stress that maximizes productivity above that which would have occurred in the absence of compensation. Examples of compensatory responses to air pollutants are shifts in root-to-shoot ratio and accelerated rates of leaf maturation. Recognition of compensatory responses to air pollutants allows these responses to be placed in a framework that relates to whole-plant processes and ecosystem functions. (4) Air pollution and multiple stresses: Air pollution stress seldom occurs in isolation, and research approaches are being developed around the concept of multiple interacting stresses. Multiple-stress experiments are important because factors such as plant water status, light, and nutrient availability are known to alter plant responses to air pollutants. Multiple-stress studies will involve experiments with model plant species and high degrees of environmental control and monitoring.
Article
Etude de l'effet de routes relativement petites sur les deplacements de ces rongeurs suivant les saisons. La dimension de l'espace inhospitalier que constitue une route ne serait pas le facteur le plus critique determinant la traversee de la route. Le probleme de l'impact d'une route sur la diversite genetique est difficile a cerner
Article
We studied 630 acres of roadside along 23 miles of Interstate 94 in Stutsman County, North Dakota, to assess wildlife values of highway rights-of-way. We found 422 duck nests that had an overall success of 57 percent in 1968, 1969, and 1970. Mammalian predators were responsible for 85 percent of the destroyed nests. To test the effect of mowing on duck nest initiation and success, alternate 1-mile blocks of the study area were not mowed in the fall of 1968. In 1969 and 1970, significantly more ducks chose unmowed vegetation in preference to mowed vegetation for nest sites. Mallards (Anas platyrhynchos), pintails (A. acuta), and gadwalls (A. strepera) were especially responsive to unmowed vegetation. Success of duck nests in unmowed vegetation was 62 percent compared with 51 percent in mowed vegetation. Sixteen percent of the nests were unhatched by July 5, the beginning mowing date previously recommended by the North Dakota Highway Department. Wildlife killed by traffic did not increase when half the mile blocks were unmowed, and no significant difference was observed in buildup of snow between mowed and unmowed blocks in the winter of 1968-69. Of 182 motorists interviewed in the study area, 82 percent had not noticed the unmowed rights-of-way. We strongly recommend no mowing of ditch bottoms or back slopes, minimal mowing of inslopes, and no mowing before July 20 to enhance waterfowl nesting and to reduce maintenance costs of highway rights-of-way in duck-producing regions.
Article
We demonstrate that the social organization and survival rates of the mountain pygmy-possum (Burramys parvus), a rare Australian marsupial, had been disrupted because its habitat had been fragmented by roads and other developments within a ski resort. We restored habitat continuity by constructing a corridor leading to 2 tunnels beneath a road that bisected the breeding area. The corridor and tunnels were filled with rocks that imitated the natural habitat of scree. These constructions allowed males to disperse from the female breeding areas; such dispersal is an essential element in the species social organization. After construction the population structure and survival rates in the disturbed area changed to those observed in the undisturbed area. Our results indicate that wildlife managers should consider that dispersal of individuals plays an important role in the social structure of wildlife populations and corridors and tunnels are strategies available for management of wildlife populations in habitats fragmented by roads and other man-made stuctures.
Article
Responses of deer (Odocoileus hemionus) and elk (Cervus canadensis) to roads were assessed by counting fecal-pellet groups near roads on winter ranges. Data were obtained in Colorado in shrub and pine habitats adjacent to paved, gravel, and dirt roads east of the continental divide; and in shrub and juniper woodland habitats west of the divide. Deer and elk avoid roads, particularly areas within 200 m of a road. Road avoidance was greater (1) east, rather than west, of the continental divide, (2) along more heavily traveled roads, (3) by deer, when compared to elk, and (4) for deer in shrub habitats when compared to pine and juniper habitats. Because of less snow accumulation, winter habitat is more available to cervids east of the continental divide where more pronounced avoidance of roads presumably results from a greater availability of habitat away from roads.
Article
At two time periods, exactly 10 and 20 years after the initial creation and seeding of the verges, vegetation surveys were carried out at seven sites along the highway verges of the A90 dual carriageway in West Lothian, Scotland. Although initially only five species were sown along the entire verges, eighty-four species were present 10 years later and sixty-eight species were identified after 20 years. During the 10-20 year period, the number of grass species increased from nine to thirteen and the number of bryophytes from none to nine. The total number of dicots dropped from seventy-two to forty-four. Hierarchical cluster analysis indicated four clear groups or vegetation associations in both 10 and 20 year data. The spatial locations of these groups were (i) intensively mown flat verges adjacent to the highway, (ii) cliff and rock outcrop, (iii) Fagus/Acer understorey, and (iv) predominantly grassed embankments. The fourth group of embankment types could be further subdivided into two groups in the 10 year vegetation and three groups in the 20 year vegetation, according to the species dominants. In one group, Fagus/Acer understorey, none of the original seeded species were present as either dominants or frequents at either 10 or 20 years. Cynosurus cristatus is not even an associate in any group after 20 years. Trifolium repens is not an embankment associate in any group after 20 year. Lolium perenne, the largest seed type input at 53.6%, is only a dominant in one group (mown verge). Festuca rubra is the main dominant in three out of five of the overall vegetation groups.
Article
The effects of 2-lane and 4-lane highways on forest birds were examined along Interstate 95 (I-95) in northern Maine during 1975-77. Total numbers of breeding birds in forest areas near the highway were not significantly different from those at greater distances. Four species were less abundant near the highway, after accounting for variations in habitat, and 6 other species were more abundant. Addition of species nesting along the forest-right-of-way (ROW) edge caused a slight increase in species richness and diversity. The ROW and median strip along 4-lane highway supported half as many breeding birds as an equal amount of forest habitat. Densities of breeding birds in the ROW along 2-lane highway were 79% of those in forest habitats.
Article
(1) Trapping, observation and road mortality studies indicated that small forest mammals (e.g. Tamias striatus, Sciurus carolinensis, and Peromyscus leucopus-Rodentia) were reluctant to venture on to road surfaces where the distance between forest margins exceeded 20 m. (2) Wider roads were crossed almost exclusively by medium-sized mammals such as Marmota monax, Erethizon dorsatum (Rodentia), Procyon lotor and Mephitis mephitis (Carnivora). (3) Road mortality increased with increasing road improvement for medium-sized mammals and was highest when traffic density was high and young were emerging. (4) A four-lane divided highway may be as effective a barrier to the dispersal of small forest mammals as a body of fresh water twice as wide.
Article
1. Transects made beside 12 main roads in Dorset and Hampshire (UK) showed that verges and central reservations supported a wide variety of butterflies and burnets (Zygaenidae). One site had 23 species of butterfly (=40% of British species), while the average was nine (16%) species per 100-m transect. Most were common species, but some rarities were present. 2. Mark-recapture estimates of adult densities on verges were up to 2774 adults ha-1 for Maniola jurtina. Populations of Melanargia galathea, Pieris rapae and Polyommatus icarus were large or medium-sized for these species. 3. Variation in the number of species, density and diversity of butterflies and burnets depended on the range of breeding habitats on verges. The density of adults and number of species were correlated with verge width, while diversity was correlated with the abundance of nectar. The amount of traffic had no apparent effect on populations on verges. 4. Road verges could be substantially improved for butterflies and burnets by reducing the depth of top soil and amount of fertilizer applied, by planting with native seed mixes and shrubs, by creating an irregular topography and surrounding them with hedges, and by making verges and central reservations as wide as possible. 5. Wide busy roads were no barrier to the movements of species living in open populations, but slightly impeded those with closed populations. Mark-recapture showed that 10-30% of adults of three species with closed populations crossed the road. Roads cannot be considered as a barrier to gene flow in any species in this study. 6. Vehicles killed 0.6-1.9% of adults of species from closed populations, and about 7% of those from open populations. These mortalities were insignificant compared to those caused by natural factors.
Article
Locations of white-tailed deer (Odocoileus virginianus) along a 41.4-km section of Interstate 84 (I-84) right-of-way in Pike County, Pennsylvania, were determined by radio telemetry and spotlight surveys. Bucks crossed roads more often (P 0.05) between road-kills and highway direction, habitat, topography, or fence placement. However, deer were killed more often ≤0.48 km of an interchange. Management efforts to reduce the incidence of road-killed deer should address increasing the effectiveness of deer fence and decreasing the incentive for deer to enter the right-of-way.
Article
Chemical analysis of moss samples collected from a raised Sphagnum bog along a transect at right angles to and away from a gravel road at Pointe Escuminac, New Brunswick, shows that concentrations of Al, Cr, Fe, La, Ni, Sc, Sm and V are strongly correlated with one another, and their concentrations decrease logarithmically away from the road to a distance of 200 m. These elements are deposited primarily in wind-borne soil dust. Concentrations of Na and Cl are correlated; their primary source is precipitaton enriched by sea spray. Amounts of As, Cd, Pb, and Zn are also intercorrelated and vary independently of other elements; their primary source is air pollution. -from Authors
Article
We examined the relationship between the richness of four different wetland taxa (birds, mammals, herptiles, and plants) in 30 southeastern Ontario, Canada wetlands and two anthropogenic factors: road construction and forest removal/conversion on adjacent lands. Data were obtained from two sources: road densities and forest cover from 1:50,000 Government of Canada topographic maps and species lists and wetland areas from Ontario Ministry of Natural Resources wetland evaluation reports. Multiple regression analysis was used to model the relationships between species richness and wetland area, road density, and forest cover. Our results show a strong positive relationship between wetland area and species richness for all taxa. The species richness of all taxa except mammals was negatively correlated with the density of paved roads on lands up to 2 km from the wetland. Furthermore, both herptile and mammal species richness showed a strong positive correlation with the proportion of forest cover on lands within 2 km. These results provide evidence that at the landscape level, road construction and forest removal on adjacent lands pose significant risks to wetland biodiversity. Furthermore, they suggest that most existing wetland policies, which focus almost exclusively on activities within the wetland itself and/or a narrow buffer zone around the wetland perimeter, are unlikely to provide adequate protection for wetland biodiversity.
Article
(1) Small mammal use of median strip habitat along a 27-km section of Interstate Highway 85 on the Piedmont Plateau Physiographic Region of the United States was determined. (2) One hundred and thirty-six small mammals, representing seven species, were snap-trapped during 3096 trap-nights of effort for an average of 4.4 captures per 100 trap-nights. (3) Small mammal density was highest in unmowed right-of-way (ROW) habitat bordered by woods toward the median strip interior. (4) No difference was detected in small mammal density in unmowed ROW habitat along the median strip side of the highway and density in similar habitat along the outside edge of the highway (i.e. the opposite side of the highway from the median strip). (5) Small mammal density within wooded median strip habitat was similar to small mammal density recorded in wooded habitat adjacent to the highway (to a distance of 400 m) in 1978 and the same three species were recorded in both the present and the 1978 study.
Article
A description is given of work developed in the United Kingdom to estimate the conservation importance of roadside verges. Investigations into management requirements that will satisfy the highway engineers, whilst encouraging wildlife habitats, have been made. The importance of liaison between conservation interests and the highway authorities is stressed. Some aspects of the potential for creative conservation of motorway land are discussed, together with the apparent similarity between motorways and railways.
Article
Roads may effect animal communities in various ways. One such way is ‘di sturbance’, i.e. emission of stimuli to which animals may respond by avoiding the vicinity of the road. The extent, intensity and mechanism of this effect is almost entirely unknown. Veen (1973), studying the bird species lapwing Vanellus vanellus, black-tailed godwit Limosa limosa, oystercatcher Haematopus ostralegus, redshank Tringa totanus and ruff Philomachus pugnax in open grassland areas, found disturbance over surprisingly long distances, ranging from 500–600 m for a quiet rural road to 1600–1800m for a busy highway. However, his approach has met with serious methodological criticism.The validity of Veen's conclusions was tested by critically reanalysing bird distribution in one of his study plots. It is inferred that his conclusions do hold for the lapwing, the godwit and possibly the redshank, though not for the oystercatcher. An additional field study in four areas yielded similar results, with comparable disturbance distances. The total population loss over this distance may amount to 60%. Rough indications were obtained that the distance-density graph is a logistic one, while the relation between traffic volume and total population loss is possibly logarithmic. In addition confirmation was obtained of the general impression that, apart from roads, disturbance may also be caused by farms, other buildings and plantations, suggesting that disturbance caused by a road is not easily eliminated by planting trees alongside.It is recommended that extra care be taken in planning new roads, while impact statements concerning roads which disregard disturbance and other long-distance effects on the fauna should be rejected.
Article
Concentrations of Cd, Ni, Pb, and Zn in roadside soil and grass samples from several locations decrease with distance from traffic. These concentrations also decrease with depth in the soil profile. The contamination has been related to the composition of gasoline, motor oil, and car tires, and to roadside deposition of the residues of these materials.
Article
Soils and plants sampled along heavily traveled highways show that lead contents tend to increase with traffic volume and decrease with distance from the highway. Much of the lead was present as a removable surface contamination on the plants. The major effect of traffic was limited to the surface soil and to a narrow zone within 100 feet of the highway. Plants grown in the field contained the most lead in the aerial portion and those grown in the greenhouse had the most lead in the roots. These studies indicate plants may obtain lead through both leaves and roots with little translocation within the plant. The fruiting and flowering parts of plants contained the smallest amounts of lead and showed little effect of changes in amounts of lead supplied. 19 references, 1 figure, 5 tables.
Article
Alien plant species have rapidly invaded and successfully displaced native species in many grasslands of western North America. Thus, the status of alien species in the nature reserve grasslands of this region warrants special attention. This study describes alien flora in nine fescue grassland study sites adjacent to three types of transportation corridors—primary roads, secondary roads, and backcountry trails—in Glacier National Park, Montana (U.S.A.). Parallel transects, placed at varying distances from the adjacent road or trail, were used to determine alien species richness and frequency at individual study sites. Fifteen alien species were recorded, two Eurasian grasses, Phleum pratense and Poa pratensis, being particularly common in most of the study sites. In sites adjacent to primary and secondary roads, alien species richness declined out to the most distant transect, suggesting that alien species are successfully invading grasslands from the roadside area. In study sites adjacent to backcountry trails, absence of a comparable decline and unexpectedly high levels of alien species richness 100 m from the trailside suggest that alien species have been introduced in off-trail areas. The results of this study imply that in spite of low levels of livestock grazing and other anthropogenic disturbances, fescue grasslands in nature reserves of this region are vulnerable to invasion by alien flora. Given the prominent role that roadsides play in the establishment and dispersal of alien flora, road construction should be viewed from a biological, rather than an engineering, perspective. Nature reserve man agers should establish effective roadside vegetation management programs that include monitoring, quickly treating keystone alien species upon their initial occurrence in nature reserves, and creating buffer zones on roadside leading to nature reserves.
Article
Suspended sediment production after road construction, logging, and slash disposal was significantly increased (P = 0.95) on two watersheds in Oregon's Coast Range. A 25% patch-cut watershed showed increases during 3 of 8 posttreatment years. These increases were caused primarily by mass soil erosion from roads. Monthly sediment concentrations before the occurrence of the annual peak flow were increased more than those following the annual peak. Surface erosion from a severe slash burn was the primary cause of increased sediment yields for 5 posttreatment years on a watershed that was 82% clear-cut. Monthly sediment concentrations were generally increased throughout the winter runoff period on this watershed. The flushing of suspended sediment in Oregon Coast Range watersheds is apparent from seasonal changes of suspended sediment rating curves.
Article
Changes in storm hydrographs after road building, clear-cutting, and burning were determined for six small watersheds in the Oregon Coast Range. Peak flows were increased significantly after road building, but only when roads occupied at least 12% of the watershed. Roads had no detectable effect on volumes of storm hydrographs. By reducing transpiration and interception, partial clear-cutting increased peak flow, quick flow, delayed flow, and total storm hydrograph volume of some streams. Most increases were largest in the fall when maximum differences in soil water content existed between cut and uncut watersheds. Maximum increases in storm flow occurred after a 175-acre watershed was 82% clear-cut. Here peak flow increased 16 ft3/s/mi2, quick flow 1.5 in., and total storm hydrograph volume 2.6 in. during the fall. The average increase in winter peak flows was smaller. The effect of roads on peak flows has significance for design of culverts and bridges in headwater areas, but probably does not influence downstream flooding. Increases in streamflow after clear-cutting should have no appreciable effect on either damage to bridges and culverts in headwater areas or downstream flooding. Caution must be used in extending results of this study to storm runoff events of low frequency and large magnitude.
Article
During three storm events, the run-off from a busy road junction in Bayreuth was analysed for dissolved and particle-bound concentrations of heavy metals, polyaromatic hydrocarbons (PAH) and nitrophenols, as well as for general hydrochemical parameters (pH, EC, SS, DOC, POC). Nitrophenols are found to be totally dissolved, whereas heavy metals, especially lead, and PAH are primarily associated with suspended solids. The partitioning of cadmium and copper is significantly governed by organic carbon. Based on the chemographs and the results of the principal component analysis, we suggest the following three wash-off mechanisms for the selected contaminants: solution of easily water-soluble compounds, particle wash-off and mobilisation of oil films.
Article
Lead concentrations were higher in small mammals living 5–10 m from interstate highways than in populations adjacent to less used roads. Absolute concentrations of lead were well below toxic levels. Interstate rights-of-way constitute less than 12·5% of the total habitat available for most species of small mammals in central Illinois. Dispersal from adjacent populations would compensate for any decrease in population density resulting from the deleterious effects of lead in automobile emissions on reproduction or survival of populations of small mammals living adjacent to highways.
Article
Large-scale deforestation is threatening the diversity of tropical forests. Given the paucity of data on life-history characteristics of tropical species, methods are needed to identify those species susceptible to extirpation following forest fragmentation. The approach developed in this paper provides a method to examine potential effects of forest fragmentation on biodiversity considering both land-use changes and traits of susceptible species. Based on certain behavioral characteristics, the effects of forest fragmentation in the Brazilian Amazon were projected for nine groups of animals. The taxonomically diverse species were characterized by gap-crossing ability and area requirements. The probability of local extinction due to destruction of habitat over a 40-year period was estimated for these animal groups under three scenarios of land-use practice, projected with a computer model. These scenarios include the typical land use of central Rondônia, Brazil, and two extremes of land-use practice that bracket the range of possible agricultural land-use changes. Animals with gap-crossing ability proportional to area requirements respond similarly to fragmentation, regardless of their taxonomic affiliation. The available habitat for those species is proportional to the amount of remaining forest under all three agricultural management scenarios. In contrast, species that have large area requirements but that will cross only small gaps are more adversely affected by forest fragmentation. The available habitat for such species is reduced at a rate disproportionately greater than the rate of forest clearing. For a tropical frog, the effects of forest fragmentation were evaluated considering not only gap-crossing ability and area requirement but also specialized habitat requirements and edge effects. For the worst-case scenario of land management, gap-crossing ability and area requirements of the tropical frog imply that only 60% of the forest remaining after seven years of management is suitable habitat. Considering breeding habitat requirements and possible edge effects further reduces the suitable habitat to 39% of the remaining forest. These reductions in the proportion of suitable forest area are likely to change with rate and spatial pattern of forest loss. La deforestación agran escala está poniendo en peligro la diversidad de las selvas tropicales. Dada la insuficiencia de datos sobre las características de la historia natural de las especies tropicales, son necesarios métodos para identificar aquellas especies suceptibles a la extirpación luego de la fragmentación del bosque. La propuesta desarrollada en este trabajo provee un método para examinar los efectos potenciales de la fragmentación del bosque sobre la biodiversidad, considerando los cambios en el uso de la tierra y las características de las especies suceptibles. En el presente estudio se predijeron los efectos de la fragmentación en la Amazónía Brasileña para nueve grupos de animales, en base a ciertas características de comportamiento. Las especies taxonómicamente diversas fueron caracterizadas en base a la habilidad para cruzar claros en el bosque y a los requeimientos de superficie. La probabilidad de la extinción local debido a la destrucción del hábitat en un período de 40 años es estimada para estos grupos de animales bajo tres escenarios de prácticas de uso de la tierra proyectados con un modelo computacional. Estos escenarios incluyen el uso típico de la